SU873229A2 - Electric power supply source with central tap - Google Patents

Description

(54) MEDIUM POWER SUPPLY SOURCE

one

The invention relates to a secondary source of electrical power and can be used to power electronic radio equipment.

According to the main auth. N 631906 is known as a stabilizer, which is powered from one source and has an output to two different types of voltage. Having only one inlet fighter simplifies and improves the reliability of the power supply system, in general 1.

The disadvantage of the circuit is its sensitivity to the sign of the asymmetry of the load currents. The circuit is operable only if the load current, y, of which one of the poles is common with the input voltage source, is greater than or equal to the current of the other load. This restriction on mutual values of load currents narrows the scope of application of the stabilizer.

The purpose of the invention is the expansion of the possible field of application of the stabilizer, namely, its application with different polarity asymmetries of the values of consumed currents.

This is achieved by introducing an additional transistor, a collector and an emitter into the circuit.

which is respectively connected to the midpoint of the source and to the common terminal of the circuit, and the base is connected via a Zener diode to the collector of a transistor connected through a resistor to the output of the regulating element. By common clamp is meant the point of connection between the poles of the input voltage source and one of the load resistances.

In the drawing there is a diagram of the proposed power supply with a midpoint.

The circuit includes a current-supplying resistor 1, which can be taken as a resistor or transistor, turned on in current generator mode Zener diode 2, which determines

Claims (2)

15 is the magnitude of the first output voltage (Ugjj,) zener diode 3, which determines the magnitude of the second output voltage (IJWtj.vj); the main regulating transistor 4, transistor 5, which provides protection for the circuit at short circuiting UQ, y; BbtXZ circuit protection for short circuit of this output, resistor 7 to limit the current in the collector circuit of transistor 6, transistor 8, additionally introduced into the prototype circuits, Zener diode 9 for connection of the collector of transistor 6 to the base of transistor 8, resistor 10 for shun ation Bazo-emitter transition of the transistor circuit 8. The principle of action comprises of the following. The main control transistor 4, included by the emitter follower, outputs to the voltage defined by the expression ШХ ШХ2-2 Э-Э4 where and and the voltage on the zener diodes 2 and 3; y is the voltage of the base-emitter junction of transistor 4. If the current consumed from the first output is less than the current consumed from the second output, then the difference current flows through the resistor 7 and the transistor b. When the difference in consumed currents decreases, the voltage on the collector of transistor 6 increases and at some value of the difference current becomes equal to 1M the stabilization voltage of Zener diode 9 in total with the voltage of the base-emitter junction of the transistor 8. The latter opens. A further change in the difference of consumed currents to zero and towards the opposite sign is compensated by the collector current of transistor 8. Thus, the circuit retains its characteristics when the load currents are asymmetrical with any sign. It can be shown that for the proposed scheme, as well as for the known one, the output values of the stresses are defined by (2). 6e6 Short-circuit protection is performed in the same way as in the prototype circuit. When the first output is closed, the current from the zmitter of transistor 4 enters the base of transistor 5. The latter short-circuits the zener diode 2. The voltage at the second output in this case is equal to eyhgz eb (4) where and is the voltage of the base-emitter junction of the transistor 5. In the case of the second output closing, the zener diode 3 is shunted by the base-emitter junction of transistor 6, xrV j96-Ucr.4 Comparing (2) with (4) and (3) with (5), it follows that the closure of the first output leads to an increase in the search for base, zmitter, and double the value of 1-1.5 V, depending on the type of transistor. When the second output U-g is closed,) does not change. In order for the newly introduced transistor 8 to not degrade the protection properties, the stabilization voltage of the Zener diode 9 in the sum of the base-zmitter transition must be greater than each output voltage. In this case, when the closure of any of the outputs of the transistor 8 is closed. On the other hand, the indicated sum of voltages must be less than the sum of the output voltages. Otherwise, the transistor 8 is locked in any mode and the circuit but its electrical characteristics do not differ from the prototype. The device is tested experimentally. In this case, KT807B transistors are used as elements 4, 5, 6, and 8. The source of the reference voltage (elements 1-3) is assembled on a resistor ZZO and two Zener diodes of the type D814. Resistors 7 and 10 have a value of 27 and 200 cm, respectively. As element 9, two D814D-type zener diodes in series are used. The resistances of both loads are taken with variables with the possibility of adjustment from 20 to 30 ohms. With any load variations within the specified limits and a 34 V input voltage, the stabilizer has the following characteristics GG - -. EX ± B ± 0.2B Instability with ± 10% change in input voltage no more than 1% for Uebix-l ® more than 0.5% for GENERAL 2- It is assumed that this stabilizer will be the main for +12 V voltages power supply units of the newly developed equipment of the C (modlometer) and G (measuring generators) groups. The invention The source of power with a midpoint on the author.St. No. 631906, characterized in that, in order to extend the functionality by applying it with a different polarity. the asymmetry of the values of consumed currents; an additional transistor transistor is introduced in the circuit, the collector and emitter of which are respectively connected to the midpoint of the source and to the common terminal for input and output voltages, and the base is connected to the collector of a transistor through a resistor to the output of the regulator. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 631906, cl. G 05 F 1/58, 1977. .f