SU1244650A1 - Voltage stabilizer - Google Patents

Abstract

The invention relates to stabilized power sources. The aim of the invention is to increase the reliability of the stabilizer in a wide range of input voltages, by reducing the output current in the short circuit mode. The goal is achieved with a current mirror .14, transistor 12 and resistor 13 introduced into the stabilizer. When a short circuit occurs, transistor 12 opens and its collector current is reflected by the current mirror 14. The collector current of transistor 7 increases, which leads to a decrease in output current stabilizer in a wide range of input voltages. 1 il. (L s: K) 4 th F

Description

one

The invention relates to electrical engineering and can be used in electronic devices of photographic photographic equipment, communication devices, automation and computer technology.

The purpose of the invention is to increase the reliability of the stabilizer in a wide range of input voltages by reducing the output current in the short circuit mode.

The drawing shows a voltage regulator including an operational amplifier 1 with power buses, the output of which is connected to the output transistor 2, the collector of which is connected to the input of the stabilizer 3, the emitter through the current limiting resistor 4 to the output of the stabilizer 5 and through the base resistor 6 - The base of the current-limiting transistor 7, the collector of which is connected to the output of the operational amplifier, and the emitter - to the output of the stabilizer 5. The divider on the resistors 8 and 9 is connected between the output of the stabilizer 5 and the surrounding bus 10 power. The output of the divider is connected to the inverting input of the operational amplifier, the non-inverting input of which is connected to the source I 1 of the reference voltage and the base of the additional transistor, 12, the emitter

which through a resistor 13 is connected to the inverting input of the operational amplifier, and the collector - to the input of the current mirror 14, the output of which is connected to the base of the current-carrying transistor 7,

The stabilizer works as follows. in a way. In the operating mode, through feedback of the operational amplifier, the potential of the inverting input (I) is maintained equal to the potential of the non-inverting (ES,)

Uc,

(one)

The output voltage of the stabilizer in this case is determined by the ratio

and ,,, and „p (1- |),

(2)

where UQ J is the magnitude of the output voltage of the source of the reference voltage;

Rg is the value of resistor 8; . Rg - the value of the resistor 9.

When the condition (1) is fulfilled, the transistor 12 is closed and the output current of the current mirror 14 is absent. By increasing the output current for example 2446502

resistor 4 increases, transistor 7 opens and limits the output current to

YYH.MMKS

 s, 7 R.

(3)

 - hl

where I / mskke maximum output current in operating mode; ,

V

R

bet the voltage of the junction transistor emitter junction 7;

- the value of the resistor 4. RAB; Equity 3 is true, i.e. the voltage drop across resistor 6 is easy to make significantly less

". --7r -; f-- 6 and ,,, (4)

where - the value of the resistor 6; 7) P gain factors for

current in the circuit with a common emitter of transistor 2 and 7, respectively.

In the event of a short circuit, the output voltage becomes zero. The potential at point B is practically zero, the transistor 12 opens and its collector current 1c., 2 is reflected by the current mirror 14

 ., .tfi.,. .5) to 12. R -

where 1.3 is the output current of the current mirror 14;

Ug5i2 is the voltage of a forward-displaced emitter junction of transistor 12:

R is the magnitude of the resistor 13. The current current of the current mirror flows into the base of the transistor 7 and the base resistor 6, while the ratio

,

(6) de. ,, - the current flowing through

resistor 6; 1, - - base current of the transistor 7.

The collar current of transistor 7 increases, which leads to a decrease in the output current of the stabilizer in the short-circuit mode. If the base current of the transistor 7 is determined by the ratio

t / Isiilfja ltc UjJi

ev &. B, R. e

7-

4 -h

(7)

satisfies the Is-j.4 relation. „, (8) then the maximum output current in short circuit mode (I gt ,,, (., VLc)

can be found from the relation

and

b9

 In b - In M. Lyi.S a

(9)

 I

3

Comparing (3) and (9), it can be seen that the maximum output current in the short-circuit mode is decreased by

  -, / MOifrfС Ы..ллоии -

Technical and economic advantages of the proposed device as compared to the known ones are caused by a decrease in the output current of the stabilizer in the short-circuit mode in a wide range of output voltages of the stabilizer, which leads to a significant decrease in power dissipation, in the short-circuit mode by the output transistor and thereby bilizer in a wide range of input voltages.

Claims (1)

Invention Formula Voltage stabilizer containing an operational amplifier, the output of which is connected to the base of the output transistor, the collector of which is connected to the power input terminal, the emitter through the current limiting resistor - to the output output - and through the base resistor - to the base of the current collector. L. Povhan Order 3915/51 Circulation 836  VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, from. Uzhgorod, st. Project, 4 2446504, A limiting transistor, the latter’s collector is connected to the output of the operational amplifier, and the emitter is connected to the output output, a resistive divider is connected between the 5 output output and the common bus, the output of which is connected to the inverting input of the operating amplifier, the non-inverting input of which is connected to the reference source voltage, characterized by the fact that, in order to increase the reliability of the stabilizer in a wide range of input voltages, by reducing the output current J5 in the short circuit mode, current mirror on transistors of opposite conductivity type of output and limiting transistors, resistor and 20 transistor of the same type of conductivity with output and limiting transistors, the base of the limiting transistor connected to the non-inverting input of the operational amplifier, 25 emitter through a resistor with an inverting input, and the collector - to the current input mirrors, the output of which is connected to the base of the current-limiting transistor, and the emitters of the transistors of the current mirror are connected to the power input the conclusion. Compiled by V. Baranov Tehred N. Bonkalo Proofreader C, Cherni Subscription