The world of PC peripherals. World of PC peripherals PWM power supply lpg 899

Powerful pulse laboratory block nutrition.

Main technical characteristics:

Output voltage, at load current 10A....... 0...22V
Stabilization coefficient...... 200...300
Ripple voltage, no more...... 200 mV
Output impedance......0.20m
in current stabilization mode
Output current, ....... 0... 10A
Ripple voltage, no more...... 300mV
The TL494 microcircuit is controlled through the output 4 , and disable the built-in opamps. The entire power supply circuit operates stably, without excitation or overshoot. But be sure to select the correction circuit C4 and C6.

To do this, we connect a regular group stabilization choke directly to the output of the block, +12 volt leads. Let's become an oscilloscope and see what comes out. If instead of constant oscillatory process, then the correction is not configured, you need to continue setting.

On the LM324 op-amp chip (or any other quad low-voltage op-amp that can operate in single-pole switching and with input voltages from 0V), an output voltage and current measuring amplifier is assembled, which will provide measuring signals to the TL494 through pin 4. Resistors R8 and R12 set the reference voltage. Variable resistor R12 regulates the output voltage, R8 regulates the current. Current measuring resistor R7 at 0.05 ohm should have a power of 5 watts (10A^2*0.05 ohm). We take power for the op-amp from the output of the “standby” 20V ATX ​​power supply.
Please make sure that your unit has Y-capacitors. Without them, there is a high level of noise at the output of the unit and the current and voltage regulators do not work well.

The output diode assembly heats up the most, so we leave the fan. We take power for the fan from a 25V source that powers the TL494, lower it with a 7812 stabilizer and supply it to the fan.

It is better to install it so that it blows inside the case. Load resistor 470 ohm 1W.
As a voltmeter and ammeter, you can use either pointer instruments, turned on as usual, or a digital voltammeter, which must be connected to the shunt or LM324 outputs (leg 8 - voltage, leg 14 - current) and calibrated with a tester. Digital voltmeters can be powered from the “standby” 5V - there is a 2A 5V converter.
If current adjustment is not needed, then simply turn R8 to the maximum. The power supply will stabilize like this: if, for example, 15V and 3A are set, then if the load current is less than 3A, the voltage will stabilize, if more, then the current.

The indication is made according to the classical scheme on PV2.

The power supply control boards are the same for all power supplies.

R
regulated up to 150V switching laboratory power supply.
Main technical characteristics:
in voltage stabilization mode
Output voltage, at load current 1A........ 0...150V
Stabilization coefficient.................................... 100...200
Ripple voltage, no more................................... 1000 mV
Output impedance........................................ 0.80m
in current stabilization mode
Output current................................................... ...............0... 1A
Ripple voltage, no more......................... 1000 mV

The circuit is the same as in the previous part, but we modify the transformer, and instead of two diodes we put a bridge on four UF304, output capacitors 200V 220uF. Load resistor 4.7 kom 1W.

We unravel the braid of the transformer and connect all windings in series, maintaining phasing.

Changes on the control board R3 on 100kOhm.

Laboratory power supply.

Everything is clear from the diagram, so let’s talk about the features.

Only parts that were changed or added are shown, the rest was left untouched.

Some parts without positional designations are drawn for a better understanding of the diagram.

Only a few parts are soldered off, blocking the operation of the unit in the absence of negative voltages.

The rectifier in the block was replaced with a bridge made of 2D213A.

The group stabilization choke is rewound with a thicker wire.

Voltage regulation - by changing the reference voltage from zero to +5V. The divider in the voltage stabilization circuit is recalculated so that at a reference voltage of +5v, the output voltage is equal to 42v. Load current adjustment is also done by changing the reference voltage from zero to +5V. The shunt built into the ammeter is used as a current sensor.

The block allows you to adjust: the output voltage within the limits……. 1...41V output current within ……. 0.1...11A. The maximum current value is limited by the capabilities of the ammeter - 10A. With a current (6A), the voltage can be set up to 41V, and with a lower voltage (22V), the current is limited to 11A. The “duty room” is used - a constant voltage of +5V is output outside. Another “standby” voltage (22V) powers the ms PWM controller (TL494) and the fan.

 Charger based on PC power supply

Z charger from a 200 W PC power supply.

Necessary changes in connecting the PHI controller and additional elements are shown in the diagram on which the numbering of the diagram elements is stored. Resistor R1 with a resistance of 4.7 kOhm, connecting pin 1 of the DA1 controller to the +5V circuit, must be unsoldered, pin 16 must be disconnected from the common wire, and the jumper connecting pins 14 and 15 must be removed. In addition, you should unsolder and remove the wires of the -12V, -5V, +5V and +12V output circuits.

Then the connections shown in the diagram. To do this, in the necessary places, the tracks printed circuit board cut and solder the corresponding terminals of the elements to them.

The maximum output current of the charger is approximately 6.5A. The charging current is set by variable resistor R10. As charging proceeds, the voltage on the battery increases and approaches its limit, determined by the resistive divider R1R2, and the current decreases from the set value to zero. When the battery is fully charged, the device goes into output voltage stabilization mode, providing compensation for self-discharge current. Setting up the device consists of selecting resistor R1 so that the open circuit voltage at the middle position of the current setting knob is equal to 13.8... 14.2V.

Power supply on PWM controller SG6105 and DR-B2002

In the last few years, the monopoly of the TL494 controller and its analogues from other companies:
DBL494 - DAEWOO;
KA7500V - FAIRCHILD (http://www.fairchildsemi.com);
KIA494 - KEC (http://www.kec.co.kr)

IR3M02 - SHARP

A494 - FAIRCHILD

KA7500 - SAMSUNG

МВ3759 - FUJITSU, etc.

It began to be disrupted by the use of other types of microcircuits, for example:

KA3511, SG6105, LPG-899, DR-B2002, 2003, AT2005Z, IW1688 and others. The blocks on these MSs contain fewer discrete elements than those built on the TL494.

The manufacturer of the SG6105 chip is the Taiwanese company SYSTEM GENERAL; on its website (http://www.sg.com.tw) you can get a brief technical description for this chip.

With the DR-B2002 microcircuit it is more difficult - searching for information about it on the Internet does not give anything.
MS IW1688 the conclusions are completely identical SG6105, and most likely is its complete analogue.

MS 2003 And DR-B2002 The conclusions are completely identical, they are practically interchangeable.

The table shows the designations, numbers and functional description of the pins of both microcircuits.

Designation	SG6105	DR-B2002	Function performed
PSon	1	2	PS_ON signal input, which controls the operation of the IP: PSon=0, IP is on, all output voltages are present; PSon=1, the power supply is turned off, only the standby voltage +5V_SB is present.
V33	2	3	Voltage input +3.3V.
V5	3	4	Voltage input +5V.
OPp	4	-	Input for organizing protection of the IP converter from excess power consumption (excessive current/short circuit in the converter).
UVac	5	-	Input for organizing control over a decrease in the level (disappearance) of the input AC supply voltage.
NVp	6	-	Input for organizing control of negative output voltages.
V12	7	6	Voltage input +12V.
OP1/OP2	9/8	8/7	Control outputs of a push-pull half-bridge converter IP.
PG	10	9	Open collector output of P.G signal. (Power Good): PG=0, one or more output voltages of the IP do not correspond to the norm; PG=1, the output voltages of the IP are within the specified limits.
Fb2	11	-	Cathode of controlled zener diode 2.
Vref2	12	-	Control electrode of controlled zener diode 2.
Vref1	13	11	Control electrode of controlled zener diode 1.
Fb1	14	10	Cathode of controlled zener diode 1.
GND	15	12	Common wire.
COMP	16	13	The output of the error amplifier and the negative input of the PWM comparator.
IN	17	14	Negative input of error amplifier.
SS	18	15	The positive input of the error amplifier is connected to the internal source Uref=2.5V. Used to organize a “soft start” of the converter.
Ri	19	16	Input for connecting an external 75k? resistor.
Vcc	20	1	Supply voltage is connected to the standby source +5V_SB.
PR	-	5	Login for organizing IP protection.

Differences between DR-B2002 and SG6105:
DR-B2002 has one controlled zener diode (pins 10, 11), similar to TL431,

SG6105 contains two such zener diodes (pins 11, 12 and 13, 14);

DR-B2002 has one pin for organizing IP protection - PR (pin 5),

SG6105 has three such pins - OPp (pin 4); UVac (pin 5); NVp (pin 6).

Figure 1 shows the connection diagram SG6105.

The supply voltage Vcc (pin 20) on the SG6105D MS comes from the standby voltage source +5V_SB. The negative input of the error amplifier IN of the microcircuit (pin 17) receives the sum of the output voltages of the IP +5V And +12V, the adder is made using resistors R101-R103 1% accuracy. Controlled zener diode 1 MS is used in an optocoupler circuit feedback in the standby voltage source +5V_SB, the second zener diode is used in the +3.3V IP output voltage stabilization circuit.

The voltage from the tap of the primary winding of transformer T3 is supplied to a half-wave rectifier D 200C 201, and through the divider R200R201 to the OPp pin (4), and is used as a signal of excess power consumed by the load from a push-pull half-bridge converter of the IP (for example, in the case of a short circuit at the outputs of the IP).

On the elements D105, R122, R123, connected to the NVp pin (6), a circuit for monitoring the negative output voltages of the IP is implemented. Voltage from the cathode of the dual diode output voltage rectifier +5V, through resistor R120 is supplied to the UVac input (5), and is used to control the input AC supply voltage of the IP.

The control circuit for the output push-pull half-bridge converter IP is made according to a standard push-pull circuit using transistors Q5, Q6 and transformer T3.

To power the circuit, a separate winding of the standby transformer T2 is used, the voltage is removed from the output of the half-wave rectifier D21C28, the circuit R27C27 is a damping circuit.

Figure 2 shows the connection diagram DR-B2002 or 2003 .

Since to organize protection for the microcircuit DR-B2002 There is only one pin PR (5), then it is simultaneously used to organize protection against excess power consumed by the load from the push-pull half-bridge converter of the IP, and to control the negative output voltages of the UPS.

A signal, the level of which is proportional to the power consumed from the converter IP, is removed from the middle point of the primary winding of the isolation transformer T3, then through diode D11 and resistor R35 it is supplied to the correction circuit R42; R43; R65; C33, after which it is supplied to the output PR microcircuits. Negative output voltages are controlled using elements R44, R47, R58, R63, D24, D27.

Since the DR-B2002 contains only one controlled zener diode, which is used in the +3.3V voltage stabilizer circuit, in the optocoupler feedback circuit in the standby voltage source +5V_SB A separate controlled zener diode TL431 is used.

The +3.3V output voltage stabilization circuit used in the UPS (Fig. 3) contains an error amplifier on a controlled zener diode, which is part of the SG6105D microcircuit.

The voltage at its input comes from the UPS output +3.3V through a divider R31R32R33, the error amplifier controls a bipolar transistor Q7 type KN2907A, which in turn provides the formation of the so-called “reset current” through a special saturable inductor L1, connected between the secondary 5-volt winding of the output pulse transformer T1 and a voltage rectifier +3.3V - dual Schottky diode D9 type MBR2045CT.

Under the influence of the reset current, inductor L1 enters a saturation state, while its inductance decreases, and accordingly the inductor's resistance to alternating current decreases.

In the case when the reset current is minimal or absent, inductor L1 has maximum inductance and, accordingly, maximum resistance to alternating current, while the voltage supplied to the input of the +3.3V rectifier decreases, and accordingly, the voltage at the output of the +3.3V IP decreases. Such a circuit allows, with a small number of elements used, to carry out adjustment (stabilization) in a circuit with a very significant output current (for example, for the LPK2-4 300W power supply in the +3.3V circuit, 18 Amperes are stated).

A simplified test of the described microcircuits can be carried out as follows: an external supply voltage (5V) is applied to the Vcc pin relative to the GND pin; when the SS and Vcc pins of the microcircuit are short-circuited, rectangular pulses can be seen at its outputs OP1 and OP2 with an oscilloscope. It should only be noted that this method does not allow checking the switching circuit (PSon), PG signal generation, etc.

The built-in controlled zener diodes of the microcircuits are tested as usual, discrete TL431.

How to convert to a different shunt resistance?

In=(Uop/(R2/R1+1))/Rsh

For example, it looks like this:

If:
Uop = 5V (reference voltage);
R2 = 10KOhm;
R1 = 0.27KOhm;
Rsh = 0.01 Ohm

That:
In=(5V/(10KOhm/0.27KOhm+1))/0.01Ohm=13A

Substitute your data and get the resistor values.

The size of one, of which ask yourself right away...

MS PWM controller LPG899 PSU ATX

The LPG 899 chip provides the following functions:

Generating signals to control power transistors of a push-pull converter;

Monitoring the output voltages of the power supply (+3.3v, +5v, +12v) for their increase, as well as for the presence of a short circuit in the channels;

Protection against significant overvoltage;

-control of negative voltages of the power supply (-12v and -5v);

Power Good signal generation;

Monitoring the remote turn-on signal (PS _ ON) and starting the power supply at the moment this signal is activated;

Ensuring a “soft” start of the power supply.

The microcircuit is made in a 16-pin package (Fig. 1). The supply voltage is +5V, generated by the standby power supply (+5v _ SB). The use of LPG 899 allows you to significantly simplify the circuit design of the power supply, because The microcircuit is an integrated design of four main modules of the control part of the power supply, namely:

PWM controller;

Output voltage control circuits:

Power Good signal conditioning circuits;

Circuits for monitoring the PS_ON signal and remotely starting the power supply.

Functional diagram The LPG 899 PWM controller is shown in Fig. 2.

Description of the PWM controller contacts and its main operating features

are given in Table 1.

№	Naimenov.	Enter exit	Description
1	V33	entrance	Channel voltage control input +Z.V. Through the contact, both overvoltage in the channel and undervoltage (which corresponds to a short circuit in the channel load) are monitored. The contact is directly connected to the +Z.ZV channel. Both overvoltage and short circuit lead to blocking of the output pulses of the microcircuit. The input pin impedance is 47 kOhm.
2	V5	entrance	+5V channel voltage control input. Through the contact, both overvoltage in the channel and undervoltage (which corresponds to a short circuit in the channel load) are monitored. The contact is directly connected to the +5V channel. Both overvoltage and short circuit lead to blocking of the output pulses of the microcircuit. The input pin impedance is 73 kOhm.
3	V12	entrance	+12V channel voltage control input. Through the contact, both overvoltage in the channel and undervoltage (which corresponds to a short circuit in the channel load) are monitored. The +12V channel voltage is supplied to this contact through a limiting resistor. Both excess voltage and a short circuit in the +12V channel lead to blocking of the output pulses of the microcircuit. The input pin impedance is 47 kOhm.
4	RT	entrance	Protection input. The contact can be used in different ways, depending on the practical connection circuit. This input signal allows you to provide extreme overvoltage protection (if the contact potential becomes higher than 1.25V) or allows you to inhibit the operation of short circuit protection (if the contact potential becomes lower than 0.625V). The input pin impedance is 28.6 kOhm.
5	GND	nutrition	Common for the power circuit and the logical part of the microcircuit
6	ST	-	Contact for connecting a frequency-setting capacitor. At the moment the microcircuit is powered, a sawtooth voltage begins to be generated at this contact, the frequency of which is determined by the capacitance of the connected capacitor.
7	C1	exit	Output of the microcircuit. Pulses with varying duration are generated at the contact. The pulses of this contact are in antiphase to the pulses on pin 8.
8	C2	exit	Output of the microcircuit. Pulses with varying duration are generated at the contact. The pulses of this contact are in antiphase to the pulses on pin 7.
9	R.E.M.	entrance	Signal input remote control PS_ON. Setting a low level on this contact leads to the startup of the microcircuit and the start of generating pulses on pin 7 and pin 8.
10	TPG	...	Contact for connecting a capacitor, which sets a time delay when generating the Power Good signal.
11	PG	exit	Output signal Power Good - PG (power is normal). Setting this pin high means that all power supply output voltages are within the acceptable range. .
12	DET	entrance	Detector input that controls the Power Good signal. This contact can, for example, be used to proactively reset the PG signal to a low level when the primary network fails.
13	VCC	nutrition	Supply voltage input +5V
14	OPOUT	exit	Output of internal error amplifier.
15	OPNEGIN	entrance	Inverting input of error amplifier. This internal error amplifier compares the OPNEGIN signal with the VADJ signal on pin 16. Internally, this pin is biased by 2.45V by the reference voltage. This pin is also used to connect an external compensating circuit to control the frequency response of the amplifier's closed loop feedback.
16	VADJ	entrance	Non-inverting input of the internal error amplifier. The most typical use of the contact is to control the combined feedback signal of the +5V and +12V channels. Changing the potential of this contact leads to a proportional change in the duration of the output pulses of the microcircuit, i.e. Through this contact the output voltages of the power supply are stabilized.

The LPG 899 chip provides the following functions:

Generating signals to control power transistors of a push-pull converter;

Monitoring the output voltages of the power supply (+3.3v, +5v, +12v) for their increase, as well as for the presence of a short circuit in the channels;

Protection against significant overvoltage;

Control of negative voltages of the power supply (-12v and -5v);

Power Good signal generation;

Monitoring the remote turn-on signal (PS _ ON) and starting the power supply at the moment this signal is activated;

Ensuring a “soft” start of the power supply.

The microcircuit is made in a 16-pin package (Fig. 1). The supply voltage is +5V, generated by the standby power supply (+5v _ SB). The use of LPG 899 allows you to significantly simplify the circuit design of the power supply, because The microcircuit is an integrated design of four main modules of the control part of the power supply, namely:

PWM controller;

Output voltage control circuits:

Power Good signal conditioning circuits;

Circuits for monitoring the PS_ON signal and remotely starting the power supply.

The functional diagram of the LPG 899 PWM controller is shown in Fig. 2.

Description of the PWM controller contacts and its main operating features

are given in Table 1.

№	Naimenov.	Enter exit	Description
	V33	entrance	Channel voltage control input +Z.V. Through the contact, both overvoltage in the channel and undervoltage (which corresponds to a short circuit in the channel load) are monitored. The contact is directly connected to the +Z.ZV channel. Both overvoltage and short circuit lead to blocking of the output pulses of the microcircuit. The input pin impedance is 47 kOhm.
	V5	entrance	+5V channel voltage control input. Through the contact, both overvoltage in the channel and undervoltage (which corresponds to a short circuit in the channel load) are monitored. The contact is directly connected to the +5V channel. Both overvoltage and short circuit lead to blocking of the output pulses of the microcircuit. The input pin impedance is 73 kOhm.
	V12	entrance	+12V channel voltage control input. Through the contact, both overvoltage in the channel and undervoltage (which corresponds to a short circuit in the channel load) are monitored. The +12V channel voltage is supplied to this contact through a limiting resistor. Both excess voltage and a short circuit in the +12V channel lead to blocking of the output pulses of the microcircuit. The input pin impedance is 47 kOhm.
	RT	entrance	Protection input. The contact can be used in different ways, depending on the practical connection circuit. This input signal allows you to provide extreme overvoltage protection (if the contact potential becomes higher than 1.25V) or allows you to inhibit the operation of short circuit protection (if the contact potential becomes lower than 0.625V). The input pin impedance is 28.6 kOhm.
	GND	nutrition	Common for the power circuit and the logical part of the microcircuit
	ST	-	Contact for connecting a frequency-setting capacitor. At the moment the microcircuit is powered, a sawtooth voltage begins to be generated at this contact, the frequency of which is determined by the capacitance of the connected capacitor.
	C1	exit	Output of the microcircuit. Pulses with varying duration are generated at the contact. The pulses of this contact are in antiphase to the pulses on pin 8.
	C2	exit	Output of the microcircuit. Pulses with varying duration are generated at the contact. The pulses of this contact are in antiphase to the pulses on pin 7.
	R.E.M.	entrance	PS_ON remote control signal input. Setting a low level on this contact leads to the startup of the microcircuit and the start of generating pulses on pin 7 and pin 8.
	TPG	...	Contact for connecting a capacitor, which sets a time delay when generating the Power Good signal.
	PG	exit	Output signal Power Good - PG (power is normal). Setting this pin high means that all power supply output voltages are within the acceptable range. .
	DET	entrance	Detector input that controls the Power Good signal. This contact can, for example, be used to proactively reset the PG signal to a low level when the primary network fails.
	VCC	nutrition	Supply voltage input +5V
	OPOUT	exit	Output of internal error amplifier.
	OPNEGIN	entrance	Inverting input of error amplifier. This internal error amplifier compares the OPNEGIN signal with the VADJ signal on pin 16. Internally, this pin is biased by 2.45V by the reference voltage. This pin is also used to connect an external compensating circuit to control the frequency response of the amplifier's closed loop feedback.
	VADJ	entrance	Non-inverting input of the internal error amplifier. The most typical use of the contact is to control the combined feedback signal of the +5V and +12V channels. Changing the potential of this contact leads to a proportional change in the duration of the output pulses of the microcircuit, i.e. Through this contact the output voltages of the power supply are stabilized.

The pulses that control the power transistors of the push-pull converter are generated at contacts C 1 and C 2, which are open-drain outputs.

The internal transistors that generate the signals C 1 and C 2 are switched in antiphase, which is provided by a Flip - Flop trigger, which can be considered a divider of the input frequency (FF - CLK) in half.

The duration of the pulses FF - CLK is determined by two comparators:

PWM comparator;

Comparator of "dead" time.

The PWM comparator provides comparison of the sawtooth voltage generated at the CT pin with the signal direct current, generated by the error amplifier (OPOUT signal).

The dead time comparator compares the sawtooth voltage generated at the CT pin with the PROTOUT signal, which is generated by the protection trigger. When one of the protections is triggered, the PROTOUT signal is set to high level, blocks the operation of the “dead” time comparator, which leads to the cessation of generation of the signal FF - CLK, and as a result, to the absence of pulses at outputs C 1 and C 2. A constant bias (indicated DTC in the diagram) is supplied to the input of the dead time comparator, specified internal voltage source. This offset sets the minimum value of the “dead” time, which ensures that in any case there is a small “gap” between the pulses on contacts C 1 and C2 (see Fig. 3). “Dead time” (the moment when both transistors are closed) protects power transistors from “breakdown along the rack”.

The operating principle of the pulse width modulation unit of the LPG-899 microcircuit is presented in Fig. 4.

The pulse width modulation block is triggered by the REMON signal, which is generated with a time delay of 40.5 ms (the sum of two time delays: 36 ms and 4.5 ms) after setting the REM input signal to a low level.

At the moment the microcircuit is started, its internal short circuit protection may operate, because The output voltages of the power supply (+3.3V, +5V and +12V) when starting the microcircuit, of course, are still zero. To avoid turning off the chip in this case, the short circuit protection is blocked for a certain period of time by the protection blocking comparator.

Short circuit protection becomes operational only after a potential greater than 0.62V is established at the PT contact, i.e. when the corresponding voltages appear at the output of the power supply.

The main electrical characteristics and values ​​of the limiting parameters of the microcircuit are presented in table. 2 and table 3.

Table 2

Characteristic	Meaning	Unit.
min	type	Max
Trigger level of protection against overvoltage in channel +3.3V (pin 1)	3.8	4.1	4.3	IN
Trigger level protected from overvoltage in channel +5V (pin 2)	5.8	6.2	6.6	IN
Trigger level is protected against excess voltage in the +12 V channel (cont. 3)	4.42	4.64	4.90	IN
Trigger level protected against overvoltage at RT input (pin 4)	1.2	1.25	1.3	IN
Short circuit protection level in channel +3.3V (pin 1)	1.78	1.98	2.18	IN
Trigger level protected from short circuit in channel +5V (pin 2)	2.7	3.0	3.3	IN
Trigger level of short circuit protection in the +12V channel (cont. 3)	2.11	2.37	2.63	IN
Level of blocking protection against short circuit at the RT input (pin 4)	0.55	0.62	0.68	IN
Generation frequency (with frequency-setting capacitor C = 2200 pF)		...		kHz
Time delay in generating the Power Good signal (with capacitor C = 2.2 µF)				ms

Table.3

The basic option for switching on the LPG-899 microcircuit, which you need to focus on when designing power supplies, is shown in Fig. 4.

However, in real circuits You can find other examples of connecting LPG -899.

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Introduction.

I have accumulated a lot of computer power supplies, repaired as a training for this process, but for modern computers they are already rather weak. What to do with them?

I decided to convert it somewhat into a charger for charging 12V car batteries.

Option 1.

So: let's start.

The first one I came across was the Linkworld LPT2-20. This animal turned out to have PWM on the Linkworld LPG-899 m/s. I looked at the datasheet and the power supply diagram and understood - it’s elementary!

What turned out to be simply amazing is that it is powered by 5VSB, that is, our modifications will not affect its operating mode in any way. Legs 1,2,3 are used to control the output voltages of 3.3V, 5V and 12V respectively within the permissible deviations. The 4th leg is also a protection input and is used to protect against deviations of -5V, -12V. We not only don’t need all these protections, but even get in the way. Therefore they need to be disabled.

The points:

The stage of destruction is over, it’s time to move on to creation.

By and large, we already have the charger ready, but it does not have a charging current limitation (although short-circuit protection works). In order for the charger to not give as much to the battery as it fits, we add a circuit to VT1, R5, C1, R8, R9, R10. How does it work? Very simple. As long as the voltage drop across R8 supplied to the base VT1 through the divider R9, R10 does not exceed the opening threshold of the transistor, it is closed and does not affect the operation of the device. But when it starts to open, a branch from R5 and transistor VT1 is added to the divider at R4, R6, R12, thereby changing its parameters. This leads to a voltage drop at the output of the device and, as a consequence, to a drop in the charging current. At the indicated ratings, the limitation begins to work at approximately 5A, smoothly lowering the output voltage with increasing load current. I strongly recommend not to remove this circuit from the circuit, otherwise, with a severely discharged battery, the current may be so large that the standard protection will work, or the power transistors or Schottks will fly out. And you won’t be able to charge your battery, although savvy car enthusiasts will figure out at the first stage to turn on a car lamp between the charger and the battery to limit the charging current.

VT2, R11, R7 and HL1 are engaged in “intuitive” indication of the charge current. The brighter HL1 lights up, the greater the current. You don't have to collect it if you don't want to. Transistor VT2 must be germanium, because the voltage drop is transition B-E it has significantly less than silicon. This means that it will open earlier than VT1.

A circuit of F1 and VD1, VD2 provides simple protection against polarity reversal. I highly recommend making it or assembling another one using a relay or something else. You can find many options online.

And now about why you need to leave the 5V channel. 14.4V is too much for a fan, especially considering that under such a load the power supply does not heat up at all, well, except for the rectifier assembly, it heats up a little. Therefore, we connect it to the former 5V channel (now there is about 6V), and it does its job quietly and quietly. Naturally, there are options for powering the fan: stabilizer, resistor, etc. We will see some of them later.

I freely mounted the entire circuit in a place freed from unnecessary parts, without making any boards, with a minimum of additional connections. It all looked like this after assembly:

In the end, what do we have?

The result is a charger with a limitation of the maximum charging current (achieved by reducing the voltage supplied to the battery when the threshold of 5A is exceeded) and a stabilized maximum voltage at the level of 14.4V, which corresponds to the voltage in the vehicle’s on-board network. Therefore, it can be safely used without turning off battery from on-board electronics. This Charger You can safely leave it unattended overnight, the battery will never overheat. In addition, it is almost silent and very light.

If the maximum current of 5-7A is not enough for you (your battery is often very discharged), you can easily increase it to 7-10A by replacing resistor R8 with a 0.1 Ohm 5W. In the second power supply with a more powerful 12V assembly, this is exactly what I did:

Option 2.

Our next test subject will be the Sparkman SM-250W power supply implemented on the widely known and beloved PWM TL494 (KA7500).

Remaking such a power supply is even simpler than on the LPG-899, since the TL494 PWM does not have any built-in protection for channel voltages, but there is a second error comparator, which is often free (as in this case). The circuit turned out to be almost identical to the PowerMaster circuit. I took this as a basis:

Action plan:

This was perhaps the most economical option. You will have much more soldered parts than the spent J. Especially when you consider that the SBL1040CT assembly was removed from the 5V channel, and diodes were soldered there, which in turn were extracted from the -5V channel. All costs consisted of crocodiles, LED and fuse. Well, you can also add legs for beauty and convenience.

Here is the complete board:

If you are afraid of manipulating the 15th and 16th PWM legs, selecting a shunt with a resistance of 0.005 Ohm, eliminating possible crickets, you can convert the power supply to TL494 in a slightly different way.

Option 3.

So: our next “victim” is the Sparkman SM-300W power supply. The circuit is absolutely similar to option 2, but has on board a more powerful rectifier assembly for the 12V channel and more solid radiators. This means we will take more from him, for example 10A.

This option is clear for those circuits where legs 15 and 16 of the PWM are already involved and you don’t want to figure out why and how this can be changed. And it is quite suitable for other cases.

Let's repeat exactly points 1 and 2 from the second option.

Channel 5B, in this case, I completely dismantled.

In order not to frighten the fan with a voltage of 14.4V, a unit was assembled on VT2, R9, VD3, HL1. It does not allow the fan voltage to exceed 12-13V. The current through VT2 is small, the transistor also heats up, you can do without a radiator.

You are already familiar with the principle of operation of reverse polarity protection and the charging current limiter circuit, but here its connection location here it’s different.

The control signal from VT1 through R4 is connected to the 4th leg of the KA7500B (analogous to TL494). It’s not shown in the diagram, but there should have been a 10 kOhm resistor left from the original circuit from the 4th leg to ground, it no need to touch.

This restriction works like this. At low load currents, transistor VT1 is closed and does not affect the operation of the circuit in any way. There is no voltage on the 4th leg, since it is connected to the ground through a resistor. But when the load current increases, the voltage drop across R6 and R7 also increases, respectively, transistor VT1 begins to open and, together with R4 and the resistor to ground, they form a voltage divider. The voltage on the 4th leg increases, and since the potential on this leg, according to the TL494 description, directly affects the maximum opening time of the power transistors, the current in the load no longer increases. At the indicated ratings, the limiting threshold was 9.5-10A. The main difference from the restriction in option 1, despite the external similarity, is the sharp characteristic of the restriction, i.e. When the triggering threshold is reached, the output voltage drops quickly.

Here is the finished version:

By the way, these chargers can also be used as a power source for a car radio, 12V portable and other automotive devices. The voltage is stabilized, the maximum current is limited, it won’t be so easy to burn anything.

Here is the finished product:

Converting a power supply to a charger using this method is a matter of one evening, but don’t you feel sorry for your favorite time?

Then let me introduce:

Option 4.

The basis is taken from the Linkworld LW2-300W power supply with PWM WT7514L (analogue of the LPG-899 already familiar to us from the first version).

Well: we dismantle the elements we don’t need according to option 1, with the only difference being that we also dismantle channel 5B - we won’t need it.

Here the circuit will be more complex; the option of mounting without making a printed circuit board is not an option in this case. Although we will not completely abandon it. Here is the partially prepared control board and the experiment victim itself, not yet repaired:

But here it is after repairs and dismantling of unnecessary elements, and in the second photo with new elements and in the third its reverse side with already taped gaskets for insulating the board from the case.

What is circled in the diagram in Fig. 6 with a green line is assembled on a separate board, the rest was assembled in a place freed from unnecessary parts.

First, I’ll try to tell you how this charger differs from previous devices, and only then I’ll tell you what details are responsible for what.

• The charger is turned on only when an EMF source (in this case, a battery) is connected to it; the plug must be plugged into the network in advance J.
• If for some reason the output voltage exceeds 17V or is less than 9V, the charger is turned off.
• The maximum charging current is regulated by a variable resistor from 4 to 12A, which corresponds to the recommended battery charging currents from 35A/h to 110A/h.
• The charge voltage is automatically adjusted to 14.6/13.9V or 15.2/13.9V depending on the mode selected by the user.
• The fan supply voltage is adjusted automatically depending on the charging current in the range of 6-12V.
• In the event of a short circuit or polarity reversal, an electronic self-resetting 24A fuse is triggered, the circuit of which, with minor changes, was borrowed from the design of the honorary cat of the 2010 competition winner Simurga. I didn’t measure the speed in microseconds (nothing), but the standard power supply protection doesn’t have time to twitch - it’s much faster, i.e. The power supply continues to work as if nothing had happened, only the red LED for the fuse is flashing. Sparks are practically invisible when the probes are shorted, even when the polarity is reversed. So I highly recommend it, in my opinion, this protection is the best, at least of those that I have seen (although it is a little capricious in terms of false alarms in particular, you may have to sit with the selection of resistor values).

Now who is responsible for what:

• R1, C1, VD1 – reference voltage source for comparators 1, 2 and 3.
• R3, VT1 – power supply autostart circuit when the battery is connected.
• R2, R4, R5, R6, R7 – reference level divider for comparators.
• R10, R9, R15 – the output surge protection divider circuit that I mentioned.
• VT2 and VT4 with surrounding elements - electronic fuse and current sensor.
• Comparator OP4 and VT3 with piping resistors - fan speed controller; information about the current in the load, as you can see, comes from the current sensor R25, R26.
• And finally, the most important thing is that comparators 1 to 3 provide automatic control of the charging process. If the battery is sufficiently discharged and “eats” current well, the charger charges in the mode of limiting the maximum current set by resistor R2 and equal to 0.1 C (comparator OP1 is responsible for this). In this case, as the battery charges, the voltage at the charger output will increase and when the threshold of 14.6 (15.2) is reached, the current will begin to decrease. Comparator OP2 comes into operation. When the charge current drops to 0.02-0.03C (where C is the battery capacity and A/h), the charger will switch to recharging mode with a voltage of 13.9V. Comparator OP3 is used solely for indication and has no effect on the operation of the control circuit. Resistor R2 not only changes the maximum charge current threshold, but also changes all levels of charge mode control. In fact, with its help, the capacity of the charged battery is selected from 35A/h to 110A/h, and current limitation is a “side” effect. The minimum charging time will be in the correct position, for 55A/h approximately in the middle. You may ask: “why?”, because if, for example, when charging a 55A/h battery, you set the regulator to the 110A/h position, this will cause a too early transition to the stage of recharging with a reduced voltage. At a current of 2-3A, instead of 1-1.5A, as intended by the developer, i.e. me. And when set to 35A/h, the initial charge current will be small, only 3.5A instead of the required 5.5-6A. So if you don’t plan to constantly go and look and turn the adjustment knob, then set it as expected, it will not only be more correct, but also faster.
• Switch SA1, when closed, switches the charger to the “Turbo/Winter” mode. The voltage of the second stage of charge increases to 15.2V, the third remains without significant changes. It is recommended for charging at sub-zero battery temperatures, in poor condition, or when there is insufficient time for the standard charging procedure; frequent use in the summer with a working battery is not recommended, because it may negatively affect its service life.
• LEDs help you understand what stage the charging process is at. HL1 – lights up when the maximum permissible charge current is reached. HL2 – main charging mode. HL3 – transition to recharging mode. HL4 - shows that the charge is actually complete and the battery consumes less than 0.01C (on old or not very high-quality batteries it may not reach this point, so you shouldn’t wait very long). In fact, the battery is already well charged after igniting the HL3. HL5 – lights up when the electronic fuse trips. To return the fuse to its original state, it is enough to briefly disconnect the load on the probes.

As for setup. Without connecting the control board or soldering resistor R16 into it, select R17 to achieve a voltage of 14.55-14.65V at the output. Then select R16 so that in recharging mode (without load) the voltage drops to 13.8-13.9V.

Here is a photo of the device assembled without the case and in the case:

That's all. The charging was tested on different batteries; it adequately charges both a car battery and a UPS one (although all my chargers charge any 12V batteries normally, because the voltage is stabilized J). But this is faster and is not afraid of anything, neither short circuit nor polarity reversal. True, unlike the previous ones, it cannot be used as a power supply (it really wants to control the process and does not want to turn on if there is no voltage at the input). But, it can be used as a charger for backup batteries without ever turning it off. Depending on the degree of discharge, it will charge automatically, and due to the low voltage in the recharging mode, it will not cause significant harm to the battery even if it is constantly turned on. During operation, when the battery is almost charged, the charger can switch to pulse charging mode. Those. The charging current ranges from 0 to 2A with an interval of 1 to 6 seconds. At first, I wanted to eliminate this phenomenon, but after reading the literature, I realized that this was even good. The electrolyte mixes better, and sometimes even helps restore lost capacity. So I decided to leave it as it is.

Option 5.

Well, I came across something new. This time LPK2-30 with PWM on SG6105. I have never come across such a “beast” for modification before. But I remembered numerous questions on the forum and user complaints about problems with altering blocks on this m/s. And I made a decision, even though I don’t need exercise anymore, I need to defeat this m/s out of sporting interest and for the joy of people. And at the same time, try out in practice the idea that arose in my head for an original way to indicate the charge mode.

Here he is, in person:

I started, as usual, by studying the description. I found that it is similar to LPG-899, but there are some differences. The presence of 2 built-in TL431s on board is certainly an interesting thing, but... for us it is insignificant. But the differences in the 12V voltage control circuit, and the appearance of an input for monitoring negative voltages, somewhat complicate our task, but within reasonable limits.

As a result of thoughts and short dancing with a tambourine (where would we be without them), the following project arose:

Here is a photo of this block already converted to one 14.4V channel, without the display and control board yet. On the second is its reverse side:

And these are the insides of the block assembly and appearance:

Please note that the main board has been rotated 180 degrees from its original location so that the heatsinks do not interfere with the installation of the front panel elements.

Overall this is a slightly simplified version 4. The difference is as follows:

• As a source for generating “fake” voltages at the control inputs, 15V was taken from the power supply of the boost transistors. It, complete with R2-R4, does everything you need. And R26 for the negative voltage control input.
• The reference voltage source for the comparator levels was the standby voltage, which is also the power supply of the SG6105. Because, in this case, we do not need greater accuracy.
• Fan speed adjustment has also been simplified.

But the display has been slightly modernized (for variety and originality). I decided to do it according to the principle mobile phone: a jar filling with contents. To do this, I took a two-segment LED indicator with a common anode (you don’t need to trust the diagram - I didn’t find a suitable element in the library, and I was too lazy to draw L), and connected it as shown in the diagram. It turned out a little differently than I intended; instead of the middle “g” stripes going out in the charge current limiting mode, it turned out that they were flickering. Otherwise, everything is fine.

The indication looks like this:

The first photo shows the charging mode with a stable voltage of 14.7V, the second photo shows the unit in current limiting mode. When the current becomes low enough, the upper segments of the indicator will light up, and the voltage at the charger output will drop to 13.9V. This can be seen in the photo above.

Since the voltage at the last stage is only 13.9V, you can safely recharge the battery for as long as you like, this will not harm it, because the car’s generator usually provides a higher voltage.

Naturally, in this option you can also use the control board from option 4. You just need to wire the GS6105 as it is here.

Yes, I almost forgot. It is not at all necessary to install resistor R30 this way. It’s just that I couldn’t find a value in parallel with R5 or R22 to get the output required voltage. So I turned out in this... unconventional way. You can simply select the denominations R5 or R22, as I did in other options.

We make a charger for 12V lead-acid batteries from an ATX computer power supply. part 4

Option 5.

Well, I came across something new. This time LPK2-30 with PWM on SG6105. I have never come across such a “beast” for modification before. But I remembered numerous questions on the forum and user complaints about problems with altering blocks on this m/s. And I made a decision, even though I don’t need exercise anymore, I need to defeat this m/s out of sporting interest and for the joy of people. And at the same time, try out in practice the idea that arose in my head for an original way to indicate the charge mode.
Here he is, in person:

Photo 18

I started, as usual, by studying the description. I found that it is similar to LPG-899, but there are some differences. The presence of 2 built-in TL431s on board is certainly an interesting thing, but... for us it is insignificant. But the differences in the 12V voltage control circuit, and the appearance of an input for monitoring negative voltages, somewhat complicate our task, but within reasonable limits. The main difficulty, unlike the LPG-899, was that the 12V voltage control input had to be supplied with a voltage greater than the PWM supply. It was possible, of course, to take the voltage from the output, a resistor + a zener diode, but somehow I didn’t want to. The voltage I needed was on the second output of the control room: 15V. It was used to power a cascade of drive transistors. I decided to use it to deceive the PWM positive voltage control inputs. With the negative voltage control input, oddly enough, everything turned out to be simpler. According to the documentation, there was an internal current source, and the voltage at this input was controlled. That is, the banal law of old man Ohm gave us a comprehensive answer.
As a result of thoughts and short dancing with a tambourine (where would we be without them), the following project arose:

Fig 7.

Here is a photo of this block already converted to one 14.4V channel, without the display and control board yet. On the second is its reverse side:

Photos 19 and 20.

And these are the insides of the assembled block and its appearance:

Photos 21 and 22.

Please note that the main board has been rotated 180 degrees from its original location so that the heatsinks do not interfere with the installation of the front panel elements.
Overall this is a slightly simplified version 4. The difference is as follows:
As a source for generating “fake” voltages at the control inputs, 15V was taken from the power supply of the boost transistors (I already wrote about this at the beginning). It, complete with R2-R4, does everything you need. And R26 for the negative voltage control input.
The reference voltage source for the comparator levels was the standby voltage, which is also the power supply of the SG6105. Because, in this case, we do not need greater accuracy.
Fan speed adjustment has also been simplified.
But the display has been slightly modernized (for variety and originality). I decided to make it based on the principle of a mobile phone: a jar filled with contents. To do this, I took a two-digit LED indicator with a common anode (you don’t need to trust the diagram - I didn’t find a suitable element in the library, and I was too lazy to draw), and connected it as shown in the diagram. It turned out a little differently than I intended; instead of the middle “g” stripes going out in the charge current limiting mode, it turned out that they were flickering. Otherwise, everything is fine.
The indication looks like this:

Photos 23 and 24.

Apparently it doesn’t matter, but I didn’t edit it with Photoshop. If you look closely you can still see the differences.
The first photo shows the charging mode with a stable voltage of 14.7V, the second photo shows the unit in current limiting mode. When the current becomes low enough, the upper segments of the indicator will light up, and the voltage at the charger output will drop to 13.9V. This can be seen in the photo above.
Since the voltage at the last stage is only 13.9V, you can safely recharge the battery for as long as you like, this will not harm it, because the car’s generator usually provides a higher voltage.
Naturally, in this option you can also use the control board from option 4. You just need to wire the GS6105 as it is here.
Yes, I almost forgot. It is not at all necessary to install resistor R30 this way. It’s just that I couldn’t find a value in parallel with R5 or R22 to get the required voltage at the output. So I turned out in this... unconventional way. You can simply select the denominations R5 or R22, as I did in other options.

There are no developments for other PWM yet; such power supplies have not come across.
So far, work is progressing towards reducing body movements during remodeling in simple versions and developing new gadgets.