CS272561B1 - Connection for amplifier's output voltage limitation - Google Patents

Abstract

The solution falls within the field of electronic circuits. It is based on the final stage formed the first serial transistor (9) resistance (3) between the input terminal (2) and the base and the emitter resistor (10) f with the limiter a current formed by the second transistor (4), connected collector to the base of the first transistor (9)> emitter to ground and base through a resistor (8) to the first emitter transistor (9). The second transistor (4) has between collector and base stabilizing RC member (5 and 6). Between the first transistor collector (9) and the positive pole of the power supply (1) voltage is variable load impedance (13) and a resistor divider in parallel (II and 12). The third transistor (7) is the base is connected to the resistor, divider output (11 and 12) and emitter to positive source (1) supply voltage. According to the invention is the collector of the third transistor (7) connected to the base of the second transistor (4) thereby closing the negative feedback limiting stress on the load (13).

Description

The invention relates to an amplifier whose output voltage is to be limited to a certain maximum value which is lower than the supply voltage. The connection is particularly suitable for the minute pulse end amplifier in the main clock.

In some cases, ae does not limit the maximum output voltage. As a result, the watches suffer in minor hours, exhibit mechanical mechanical vibrations, are noisy and shorten their life. Alternatively, the terminal amplifier is powered from a voltage stabilizer, which requires two power components unnecessarily: a stabilizer and a terminal transistor.

and

The actual output stage is in a known circuit, equipped with a HEN transistor or two transistors in a Darlington circuit. There is a series resistance between its base and the input terminal, and an emitter resistance between the emitter and ground. The second transistor, for limiting the output stage current, is connected by an output stage collector, an emitter to ground and a base via a limiting resistor to the output stage emitter. The limiting transistor has a stabilizing RC element between the collector and the base. The variable load impedance is between the output stage collector and the positive pole of the DC voltage source. It also includes a resistor divider connected in parallel to the load impedance and a third transistor, ENP, soldered by the base to the resistor divider output and the emitter to the positive pole of the power supply. The principle of the invention then consists in that the third transistor is connected by a collector to the base of the second transistor to limit the output stage current.

The advantage of this circuit is that it limits the output voltage of the minute pulses from the main clock, so that the mechanical clocking of the clockwork in the slave clock is reduced, the clockwork is not excessively noisy and its service life is not shortened. In contrast to the possible stabilization of the DC supply voltage, the circuit according to the invention is considerably simpler and cheaper.

In the attached drawing, a circuit for limiting the output voltage of an amplifier according to the invention is shown. Output stage 9 consists of a first, HEH, transistor with a series resistor 3 connected between its base and input terminal 2, with an emitter resistor 1.0 connected between the emitter and ground. The second transistor 4 for limiting the current of the output stage 9 is connected by a collector to the output stage base 9, the emitter to ground and a base through a limiting resistor 8 to the output stage emitter 9. A stabilizing serial RC member 5, 6 is connected. The load impedance 1.3 is between the output stage collector 9 and the positive pole of the power supply source. The resistive divider 1.1, 12 is connected in parallel to the load impedance 1.3 and its base is connected to a base, a EKP, a transistor 7 whose emitter is connected to the positive pole of the power supply 6 and the collector to the base of transistor 4 to limit the output stage 9.

The function of the connection is as follows: If the voltage on the load 1.3 exceeds the permissible value, a third transistor 7 opens via the resistive divider 1.2. This results in a positive voltage based on the second current limiting transistor 4 and a negative voltage on its collector, 9. The output stage 9 is closed and the voltage on its load 13 is stabilized by negative feedback at the maximum permissible value.

Claims (1)

OBJECT OF THE BACKGROUND Circuit for limiting the output voltage of an amplifier whose output stage consists of a first HEH transistor with a series resistor connected between its base and input terminal, an emitter resistor connected between the emitter and ground, and a second HEH transistor to limit the output stage current connected to the collector to the output stage base, ground emitter and base via a limiting resistor to the output stage emitter, a stabilizing series RC member is connected between the collector and the base of the limiting transistor and a load impedance is connected between the output stage collector and the positive pole of the power supply; CS 272 561 B1 further comprises a resistive voltage divider and a third PHP transistor connected by a base to the output of a resistive divider connected in parallel to the load impedance and an emitter to the positive pole of the power supply, characterized in that the third transistor (7) is connected to the collector a base of a second transistor (4) for limiting the current of the output stage (9).