SU1206762A2 - D.c.voltage stabilizer - Google Patents

Description

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The invention relates to electrical engineering and is intended to be used in the implementation of secondary power supply of electronic equipment.

The aim of the invention is to increase the reliability of operation by preventing the power current of the stabilizing two-pole power transistor from overload in the mode of exceeding the load current with the maximum value and during a short circuit at the output of the stabilizer.

The drawing shows a functional diagram of the proposed DC voltage regulator.

The device contains a regulating transistor 1, a ballast resistor 2, a voltage divider 3, a reference voltage source 4, a DC amplifier 5, a power current-stabilizing two-terminal 6 with a transistor 7, diodes 8 and 9 and a resistor 10, an auxiliary current-stabilizing two-terminal 11 with a transistor 12, a zener diode 13 and a resistor 14, constituting a parametric voltage regulator, as well as a resistor 15, a coupling diode 16, a two-stage transistor switch 17 with transistors 18 and 19, a capacitor 20 and resistors 21-23 Pos 24, the diagram indicates the load of the device.

The regulating transistor 1 is connected in series with the ballast resistor 2 between the output buses of the device, to which the voltage divider 3 is also connected. The inputs of the DC amplifier 5 are connected to the outputs of the voltage divider 3 and the voltage source 4, and the output is connected to the base circuit of the regulating transistor 1. The power current stabilizing two-pole 6 is connected to the potential stabilizer bus by the corresponding input and output pins, and the auxiliary current-stabilizing two-terminal 11 - to the bias circuit of the power current-stabilizing two-port 6.

A two-stage transistor switch 17 is inserted between the base of the transistor 12 of the auxiliary current-stabilizing two-terminal 11 and the potential-free bus. The collectors of transistors 18 and 19 of the first

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And the second stages, respectively, through resistors 21 and 22 are connected to the output potential output of the parametric stabilizer 13-14 of the auxiliary current-stabilizing two-port 11. The control input of the first stage (emitter-base transition of the transistor 18) is connected to the terminals of the ballast resistor 2 in the circuit control transistor 1. The control input of the second stage (emitter-base transition of transistor 19) is shunted by a capacitor 20.

The device works as follows.

When a supply voltage is applied to the input by means of a parametric stabilizer 13-14 and a resistor 22, the transistor 12 of the auxiliary current-stabilizing two-port 11 is opened. At the same time, the primary power source through the power current-stabilized two-pole 6 flows the equal amount of load current 24 and the current flowing through control transistor 1 and the ballast resistor 2.

Redistributing the current consumed from the primary power source when the load current changes, and the output voltage is stabilized due to the negative feedback of the measuring and amplifying node consisting of the DC amplifier 5, the source 4 of the reference voltage. and divider 3 voltage. Dividing diode 16 provides an increase in the energy performance of the device in the mode of a small load current by closing the transistors 12 and 7 of the auxiliary 11 and power 6 current-stabilizing two-terminal networks.

When the device is switched on in the mode from nominal to maximum load current, the voltage released on the ballast resistor 2 through the resistor 23 opens the transistor 18 of the switch 17 and goes into saturation mode. The presence of a CC link in the base circuit of the transistor 19, consisting of a resistor 21 and a capacitor 20, ensures the closed state of the transistor 19. The time constant in the base circuit of the transistor 19 is chosen longer than the time constant of the voltage regulator as a whole.

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which ensures the correct sequence of installation of the first and second cascades of the key 17 in the initial state, when the device is turned on.

In the steady state, when the load current exceeds 24 the maximum value or a short circuit occurs at the output of the stabilizer, the current through the control transistor 1 decreases. Consequently, the voltage drop across the ballast resistor 2 is reduced, as a result of which the transistor 18 of the first stage closes and the transistor 19 of the second stage opens and enters the end state. In this case, the transistors 12 and 7 of the auxiliary 11 and power 6 current-stabilized bipolar circuits are closed, as a result of which the power of the scattering on the transistor 7 decreases sharply. If the load had a short circuit before the supply voltage was applied, then after switching on the device, the order and sequence of operation of the transistors 18

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and 19 and key 17 are kept the same as in steady state. The resistors 21-23 and the capacitor 20 are selected taking into account the provision of 5 key modes of the transistors 18 and 19. At the same time, the resistor 22 is simultaneously an element of the base bias circuit of the transistor 12 of the auxiliary current-stabilizing bipolar 11 and the load of the transistor 19. Thus, in the proposed device the power dissipated by the transistor 7 of the power current-stabilizing two-terminal 6 automatically decreases in a transient mode with a maximum load current and during a short circuit at the output of the stabilizer. The specified circumstance predetermines the increased reliability of the device operation.

In addition, in this case, a reduction in the power consumed from the primary power source, and a reduction in the size of the heat lead of the transistor 7, is achieved.

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Claims (1)

A DC VOLTAGE STABILIZER according to Autost.No. 1003056, characterized in that, in order to increase reliability in operation by preventing the transistor from overloading a power current-stabilizing bipolar in terms of a torus power of an auxiliary current-stabilizing bipolar, the control input of the first stage through the third additional resistor is connected to the output the resistor of the torus, and the cascade about in the circuit regulating the transis-® control input of the second is shunted by the capacitor • 1 1206762