The regulated power supply 1501 (15 volts, 1 ampere) was no longer enough for my needs, it was decided to buy something like YaXun PS-1502DD + (the price from Ali is around 3500 r) 2 amps, in theory, should be enough.
But then such a power supply turned up in my hands:

Anticipating "why not remake the PSU from the computer to suit your needs, a lot of watts, a lot of amperes and a lot of voltage"? The fact is that I sometimes collect low-power amplifiers (powered by 12 V) and listen to the background impulse block food - well, you don’t want to. And to collect with my own hands - well, this is a long song, and now I don’t have time for it. For these reasons, I undertook to assemble myself an uncomplicated power supply with the following characteristics:
- output voltage up to 12-15 volts (for the most part, this voltage is enough for me);
- the current given to the load - at least 3-5 Amperes (but the transformer of this unit allows you to issue a nominal 10 Amperes);
- a small number of pulsations;
- digital indication of voltage and current;
- adjustment of current and voltage;

Block muzzle:

Below are two holes left from the sockets, the body is aluminum. Instead of one outlet, a button fits well. There are 4 holes around the screws - it was decided to insert LEDs into them to indicate the operation of the unit.
Previously, such a block was ordered from Ali:
Assembled on the stm microcontroller, its price and capabilities bribed.
It fits into the voltage error quite accurately, the ammeter frankly disappointed. The site claims an error of 0.01 A (10 mA), as a result, at zero positions of the knobs, the consumption is 50 mA (this is the current short circuit and the readings of the standard tester), this ammeter does not show anything at all.
When the current reaches 100 mA (standard tester), the readings on this ammeter are ~ 70-80mA, then we give 150 mA, - an error within 10 mA (between the standard tester and this unit) and up to 1 Ampere are more or less accurate (difference 10- 20 mA). Then lies within 50-100 mA. Here, obviously, it does not fit into a 1% error on readings up to 100 mA. Will go for home use.
Further, I decided on the placement on the face of the PSU.
Block connection diagram:
Slightly zakotsal paint - but God bless her, muzzle repainted in black. It was decided to leave the mains fuse, in my opinion it fits well into the interior, and will perform its direct functions of protecting the 220 network from overload.
A little later, I installed terminals of this type, for applications up to 3-4 amperes, these are enough. For operation at currents from 5 to 10 amperes, a thicker wire will be clamped.
In addition to the main function of the laboratory power supply - it can be used to charge the battery. (Two in one)))
I am going to assemble the power part on the LM723, a TIP141 type transistor and 3 KT908A transistors (the inclusion of these transistors as composite ones). I used KT819G transistors. It was decided to put KT908 on a Class A amp.
I'm going to place the current adjustment instead of the second socket (the hole on the right), I will close the 4 holes for the screws with 4 current limiting light guides.
Costs for this block:
1) Voltmeter / ammeter - 160 rubles
2) terminals 30 rubles
3) crocodiles 20 rubles
4) wire 1 meter 30 rubles
Everything else is available, the costs are only temporary, but it's worth it.
I check the current limiting circuit 0.2 amperes
Full load, limited to 10 amps.

At the moment, the power unit is assembled and tested, I am doing the internal layout.

I plan to transfer the power unit to the radiator from the computer and install a fan

After assembly, I decided to try to drive the Sony xm-1 amplifier on the block, the current ate in the region of 5-5.5 amperes, the voltage planted up to 9.5 volts. There are no background noises, which also pleased me unspeakably :)

The power supply is 30 Volts and 5 Amps, widely used by radio amateurs in a variety of schemes. Published in amateur radio literature different types circuits of such devices, it does not require the use of special microcircuits and imported parts. Today, when buying such microcircuits, there are problems, in some areas, finding them is quite problematic. The block uses parts available to most.

The main characteristics of the power supply:

• the output voltage is regulated in the range from 0 to 30 Volts;
• maximum current consumption at the output 5 Amperes;
• the voltage drop at a current from 1 ampere to 6 amperes is very small and does not particularly affect the output parameters.

Power supply circuit.

The scheme of our power supply can be divided into 3 main nodes:

1. internal power supply;
2. node of protection against possible overloads;
3. main node.

Main node- This is a voltage stabilizer that makes it possible to adjust the signal parameters. It consists of a differential stage, two gain stages, and a regulator.

Internal network node- made according to the classical scheme with a transformer, a diode bridge VD1-VD4, capacitors C1 - C7, and stabilizers DA1 and DA2

Node Protection does not have any features. The current sensor is selected for a current of three amperes, but can be increased to five amperes. For a long period of time it was used with a current of five amperes. There were no problems with it.

All nodes connected according to the Darlington scheme.

The resistor for tripping the protection is selected according to need. Power supply 30v 5a, with high-quality assembly and serviceable parts, can be used immediately after connecting to the network. Its adjustment consists in setting the required limits for changing the output voltage and current for the protection to operate.

The digital panel includes an input voltage and current divider based on the KR572PV2A microcircuit and four seven-segment LED indicators. The microcircuit is a highly sensitive converter up to three and a half decimal places, it works by serial counting with double integration, zero correction is carried out automatically, with input signal polarity check.

For a clearer indication of the signal parameters, a circuit is used on the KR572PV6 board. The dimensions of such a board are eighty by fifty millimeters. The pads of the voltage and current contacts of the digital panel board are connected using flexible conductors to the contacts of the corresponding indicators. The KR572PV2A circuit is often changed to the imported ICL7107CPL circuit, since its parameters and quality are superior to the standard one.

stabilized adjustable block power supply 220/0-30 volts 7.5 amps with overload protection

A lot of amateur radio power supplies (PSUs) are made on KR142EN12, KR142EN22A, KR142EN24 chips, etc. The lower adjustment limit of these microcircuits is 1.2 ... 1.3 V, but sometimes a voltage of 0.5 ... 1 V is necessary. The author offers several technical solutions for a power supply unit based on these microcircuits.

The integrated circuit (IC) KR142EN12A (Fig. 1) is an adjustable voltage regulator of the compensation type in the KT-28-2 package, which allows you to power devices with a current of up to 1.5 A in the voltage range of 1.2 ... 37 V. This integrated The stabilizer has thermally stable current protection and output short circuit protection.

Rice. 1. IC KR142EN12A

Based on the IC KR142EN12A, it is possible to build an adjustable power supply, the circuit of which (without a transformer and diode bridge) is shown in Fig. 2. The rectified input voltage is supplied from the diode bridge to the capacitor C1. Transistor VT2 and chip DA1 must be located on the radiator. The heat sink flange DA1 is electrically connected to pin 2, so if DA1 and the transistor VD2 are located on the same heatsink, they must be isolated from each other. In the author's version, DA1 is installed on a separate small heatsink, which is not galvanically connected to the heatsink and transistor VT2.

Rice. 2. Adjustable PSU on IC KR142EN12A

The power dissipated by a chip with a heat sink must not exceed 10 watts. Resistors R3 and R5 form a voltage divider included in the measuring element of the stabilizer, and are selected according to the formula:

U out = U out min (1 + R3/R5).

A stabilized negative voltage of -5 V is supplied to the capacitor C2 and resistor R2 (used to select the thermally stable point VD1).

To protect against a short circuit of the output circuit of the stabilizer, it is enough to connect an electrolytic capacitor with a capacity of at least 10 μF in parallel with the resistor R3, and shunt the resistor R5 with a KD521A diode. The location of the parts is not critical, but for good temperature stability it is necessary to use the appropriate types of resistors. They should be located as far as possible from heat sources. The overall stability of the output voltage is made up of many factors and usually does not exceed 0.25% after warming up.

After turning on and warming up the device, the minimum output voltage of 0 V is set by the resistor Radd. Resistors R2 (Fig. 2) and resistor Radd (Fig. 3) must be multi-turn trimmers from the SP5 series.

Rice. 3. Switching scheme Radd

The current capabilities of the KR142EN12A microcircuit are limited to 1.5 A. Currently, microcircuits with similar parameters are on sale, but designed for a higher current in the load, for example, LM350 - for a current of 3 A, LM338 - for a current of 5 A. Data on these microcircuits can be found on the National Semiconductor website.

Recently, imported microcircuits from the LOW DROP series (SD, DV, LT1083/1084/1085) have appeared on sale. These chips can work with undervoltage between the input and output (up to 1 ... 1.3 V) and provide a stabilized voltage at the output in the range of 1.25 ... 30 V at a load current of 7.5/5/3 A, respectively. The closest domestic analogue of the KR142EN22 type in terms of parameters has a maximum stabilization current of 7.5 A.

At the maximum output current, the stabilization mode is guaranteed by the manufacturer at an input-output voltage of at least 1.5 V. The microcircuits also have built-in protection against exceeding the current in the load of an acceptable value and thermal protection against overheating of the case.

These stabilizers provide output voltage instability of 0.05%/V, output voltage instability when the output current changes from 10 mA to the maximum value no worse than 0.1%/V.

On fig. 4 shows a power supply circuit for a home laboratory, which allows you to do without transistors VT1 and VT2, shown in fig. 2. Instead of the DA1 KR142EN12A chip, the KR142EN22A chip was used. This is an adjustable regulator with a low voltage drop, allowing you to get a current of up to 7.5 A in the load.

Rice. 4. Adjustable PSU on IC KR142EN22A

The maximum power dissipation at the output of the stabilizer Pmax can be calculated by the formula:

P max \u003d (U in - U out) I out,
where U in is the input voltage supplied to the DA3 chip, U out is the output voltage at the load, I out is the output current of the microcircuit.

For example, the input voltage supplied to the microcircuit is U in \u003d 39 V, the output voltage at the load U out \u003d 30 V, the current at the load I out \u003d 5 A, then the maximum power dissipated by the microcircuit at the load is 45 W.

Electrolytic capacitor C7 is used to reduce the output impedance by high frequencies, and also lowers the noise voltage level and improves ripple smoothing. If this capacitor is tantalum, then its rated capacity must be at least 22 uF, if aluminum - at least 150 uF. If necessary, the capacitance of the capacitor C7 can be increased.

If the electrolytic capacitor C7 is located at a distance of more than 155 mm and is connected to the PSU with a wire with a cross section of less than 1 mm, then an additional electrolytic capacitor with a capacity of at least 10 microfarads is installed on the board parallel to the capacitor C7, closer to the microcircuit itself.

The capacitance of the filter capacitor C1 can be determined approximately, based on 2000 microfarads per 1 A of output current (at a voltage of at least 50 V). To reduce the temperature drift of the output voltage, the resistor R8 must be either wire or metal-foil with an error of no worse than 1%. Resistor R7 is the same type as R8. If the KS113A zener diode is not available, you can use the assembly shown in fig. 3. The protection circuit solution given in, the author is quite satisfied, as it works flawlessly and has been tested in practice. You can use any power supply protection circuitry, for example, those proposed in. In the author's version, when relay K1 is activated, contacts K1.1 close, shorting resistor R7, and the voltage at the PSU output becomes 0 V.

The printed circuit board of the PSU and the location of the elements are shown in fig. 5, the appearance of the PSU - in fig. 6. PCB dimensions 112x75mm. Radiator selected needle. The DA3 chip is isolated from the heatsink by a gasket and attached to it with a steel spring plate that presses the chip to the heatsink.

Rice. 5. Printed circuit board of the PSU and the location of the elements

Capacitor C1 of type K50-24 is composed of two parallel-connected capacitors with a capacity of 4700 μFx50 V. An imported analog of a capacitor of type K50-6 with a capacity of 10,000 μFx50 V can be used. The capacitor should be located as close as possible to the board, and the conductors connecting it to the board should be as short as possible. Capacitor C7 manufactured by Weston with a capacity of 1000 uFx50 V. Capacitor C8 is not shown in the diagram, but there are holes on the printed circuit board for it. You can use a capacitor with a rating of 0.01 ... 0.1 μF for a voltage of at least 10 ... 15 V.

Rice. 6. Appearance BP

Diodes VD1-VD4 are an imported diode microassembly RS602, designed for a maximum current of 6 A (Fig. 4). The RES10 relay (passport RS4524302) is used in the power supply protection circuit. In the author's version, a resistor R7 of the SPP-ZA type was used with a parameter spread of no more than 5%. Resistor R8 (Fig. 4) should have a spread of no more than 1% from the given value.

The power supply usually does not require configuration and starts working immediately after assembly. After heating the unit with resistor R6 (Fig. 4) or resistor Rdop (Fig. 3), 0 V is set at the nominal value of R7.

In this design, applied power transformer brand OSM-0.1UZ with a power of 100 watts. Magnetic core ShL25/40-25. Primary winding contains 734 turns of PEV wire 0.6 mm, winding II - 90 turns of PEV wire 1.6 mm, winding III - 46 turns of PEV wire 0.4 mm with a tap from the middle.

The RS602 diode assembly can be replaced with diodes rated for a current of at least 10 A, for example, KD203A, V, D or KD210 A-G (if you do not place the diodes separately, you will have to redo printed circuit board). As a transistor VT1, you can use the transistor KT361G.

Literature

1. http://www.national.com/catalog/AnalogRegulators_LinearRegulators-Standardn-p-n_PositiveVoltageAdjutable.html
2. Morokhin L. Laboratory power supply//Radio. - 1999 - No. 2
3. Nechaev I. Protection of small network power supplies from overloads//Radio. - 1996.-№12

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