SU675584A1

SU675584A1 - Arrangement for overload protecting of pulsed amplifier output transistor

Info

Publication number: SU675584A1
Application number: SU742077442A
Authority: SU
Inventors: Валентин Макарович Ардашев; Виктор Георгиевич Меэрин
Original assignee: Предприятие П/Я Г-4695
Priority date: 1974-11-22
Filing date: 1974-11-22
Publication date: 1979-07-25

Description

Изобретение относитс к защите элементов усилителей.This invention relates to the protection of amplifier elements.

Известно устройство защиты от перегрузки транзисторов усилител , содержащее вспомогательный транзистор и стабилитрон 1.A device is known to protect an amplifier from overloading a transistor, which contains an auxiliary transistor and a zener diode 1.

Недостатком этого устройства вл етс невысока надежность.A disadvantage of this device is low reliability.

Наиболее близким по технической сущности и достигаемым результатам к предлагаемому вл етс устройство защиты от перегрузки выходного транзистора импульсного усилител , содержащее конденсатор и вспомогательный транзистор с противоположным типом проводимости, база которого соединена с коллектором выходного транзистора, а эмиттер подключен к одной из обкладок конденсатора 2.The closest in technical essence and achievable results to the proposed is an overload protection device of the output transistor of the pulse amplifier, containing a capacitor and auxiliary transistor with opposite type of conductivity, the base of which is connected to the collector of the output transistor, and the emitter is connected to one of the plates of the capacitor 2.

Недостатком этого устройства вл етс его сложность.A disadvantage of this device is its complexity.

Цель изобретени - упрощение.The purpose of the invention is simplification.

Это достигаетс тем, что конденсатор включен последовательно с входным сопротивлением усилител , а коллектор вспомогательного транзистора соединен со второй обкладкой конденсатора.This is achieved by the fact that the capacitor is connected in series with the input resistance of the amplifier, and the auxiliary transistor collector is connected to the second capacitor plate.

На чертеже дана схема предлагаемого устройства.The drawing is a diagram of the proposed device.

Устройство содержит конденсатор 1, включенный последовательно в цепь управлени выходного транзистора 2. Вспомогательный транзистор 3 подключен переходом коллектор-эмиттер к выводам конденсатора через резистор 4, а базой - к коллекторной нагрузке 5 выходного транзистора через резистор 6. Резисторы 7, 8 определ ют ток базы выходного транзистора, а их соотнощение определ ет величину критического значени коллекторного напр жени .The device contains a capacitor 1 connected in series to the control circuit of the output transistor 2. The auxiliary transistor 3 is connected by a collector-emitter junction to the capacitor leads through a resistor 4, and the base to the collector load 5 of the output transistor through a resistor 6. Resistors 7, 8 determine the base current output transistor, and their ratio determines the critical value of the collector voltage.

При отсутствии входного сигнала транзисторы 2, 3 закрыты, а конденсатор 1 разр жен .In the absence of an input signal, transistors 2, 3 are closed, and capacitor 1 is discharged.

Claims

When a control signal is applied, transistor 2 is opened by the capacitor current. The voltage on the collector of transistor 2 drops, which leads to the opening of transistor 3. Open transistor 3 transmits the base current of transistor 2 and provides a discharge of capacitor 1. If the collector voltage exceeds a critical value when the control signal is applied, the transistor 3 does not open and after charging Yes, to the capacitor 1, the supply of the base current of the transistor 2 is stopped, it goes into the closed state. In the event of an overload or short circuit at the time of the open state of the transistors 2, 3, the circuit goes into the closed state in a similar way. The values of the capacitor capacitance I and the resistances of the resistors 7, 8 determine the possible value of the output transistor overload duration. Claims A device for protecting an output transistor of a switching amplifier against overload, containing an input resistance, a capacitor and an auxiliary transistor with an opposite type of conduction, the base of which is connected to the collector of the output transistor, and the emitter connected to one of the capacitor plates, the capacitor is connected in series with the input resistance of the amplifier, and the collector of the auxiliary transistor is connected to the second capacitor plate. Sources of information taken into account in the examination 1.Patent of Germany No. 1283907, cl. 2 a 18/08 1968.

2. The patent of Germany No. 1438675, cl. 02 H 7/10. 1970.