SU750746A1 - Thermocompensated stabilized current generator - Google Patents

Description

The invention relates to a pulse technique, in particular to devices of modulators and demodulators, used in multichannel communication lines with time-pulse and pulse-code modulation. A thermocompensated stabilized current generator containing transistors is known, the first two of which form a composite transistor, a current-setting resistor, a bias source on two series-connected transistors in a diode switch, a resistor, a voltage source, and two power sources 1. The disadvantage of such a device is relatively low stability output current caused by various changes in the voltage drop from a change in ambient temperature on all four base-em transitions tter stabilizing and termokompensiruyuschih transistors. The aim of the invention is to increase the temperature stability of the current rater. This is achieved by the fact that a thermocompensated constant current generator containing α-transistors, the first two of which are connected to the power supply bus, and the emitter of the first transistor is connected to the base of the fourth transistor through the collector-emitter junction of the fourth transistor, the collector of which is connected to the composite emitter transistor, and the emitter of the fourth transistor is connected to the first power source through a current-generating resistor, the bias source on two series-connected transistors in g iodine switching, a resistor, a voltage source, a second power source, two transistors are introduced, the base-emitter junction of the first of which is connected in parallel to the collector-base junction of the second, the emitter of which is connected to the common power supply bus through a voltage source, the third the transistor, the base of which is connected to the base of the first additional transistor, and the collectors of the additional transistors are connected to the emitters of the bias source transistors, the collector the first of which is connected to the database of composite transistor and through rezi Sided - a second power source bus.

The drawing is a schematic diagram of the device.

The device contains transistors 1-8, resistors 9, 10, power sources 11, 12, output terminal of device 13, source 14 of reference voltage.

The device works as follows.

A stable output current is generated by a generator containing transistors 8, 7, 3, 4. Actually the current generator is a transistor 8, a stable current supply resistor 10, a source 14 reference (reference) voltage. Transistors 3, 4, 7 provide thermal compensation.

Transistor 8 is connected according to a common base circuit, its emitter current is determined by the value of the reference voltage of source 14, the value of the current-setting resistor 10 and the voltage drop at the base-emitter junction, which varies with the ambient temperature. For temperature compensation of the base-emitter voltage of transistor 8, a temperature-compensating transistor 3 serves. In this case, the stability is no longer affected by the absolute value of the base-emitter voltage and the base voltage of transistor 2, but the differential bi-edge 2.

The current through the base-emitter junction of transistor 3 using resistor 9 and power sources 12 and 11 is chosen equal to the corresponding current of transistor 8. All transistors in the device are of the same type, and the best results are obtained using assemblies in one chip with identical parameters, which allows to obtain the difference IbeZ-ibe2, very close to zero.

Base currents of transistors 3 and 8. flow through the emitter-collector transitions of transistors 4 and 7., the collector current of transistor 4 is approximately equal to the base current of transistor 3, and the collector current of transistor 7 is current, the base of transistor 8. The collector current of transistor 1 passes through the collector-emitter junction of transistor 5 The sum of these currents is equal to the stable emitter current of the transistor 8. Transistors

6 and 5 provide constant voltage across the collectors of transistors.

7 and 8 from the change in voltage above: to the lock. Transistors 2 and 7 are the bias source for supplying the collector of transistor 4 and the base of transistor 5.

The proposed device has a much better thermal stability, since the circuit, which sets the current, enters n. four- pn junction like a

; prototype, and only two (transistors, 3 and 8). Since the proposed device mainly consists of identical elements, it is convenient to perform it in the form of a hybrid or monolithic microcircuit, where the reference source and the current-setting resistor can be external elements. If several generators are used in the equipment, the reference source may be common. It is convenient to use a thermo-5 compensated zener diode as a reference source. The stability of other food sources may be low.

Formula. the invention

A thermocompensated stabilized current generator containing transistors, the first two of which form a composite transistor, the collector of which is connected to the power supply bus, and the emitter of the first transistor through the collector-emitter junction of the third transistor connected to the emitter

the composite transistor, and the emitter of the fourth transistor through the current-setting resistor is connected to a common bus

power source, a bias source on two series-connected | transistors in a diode switching on, a resistor, a voltage source, a second power source, characterized in that

In order to increase temperature stability, two transistors are introduced into it, the first-baseline-emitter junction of which is connected in parallel to the collector-base junction of the second, the emitter of which is connected to the first power supply through a reference voltage source, the base of the third transistor is connected the base of the first additional transistor, and the collectors of the additional transistors are connected to the emitters of the bias source transistors, the collector of the first of which is connected to the bases second composite transistor and a resistor -

with BUS of the second power source.

Sources of information taken into account in the examination

1. USSR author's certificate No. 451171, cl. H 03 K 1/02, 1971 (prototype).

eight

Claims (1)

Claim A thermally compensated stabilized current generator containing transistors, the first two of which form a composite transistor, the collector of which is connected to the bus of the power source, and the emitter of the first trans. of the resistor 4 through the collector-emitter junction of the third transistor is connected to the base of the fourth transistor, the collector of which is connected to the emitter of the composite transistor, and the emitter of the fourth transistor is connected to the common bus of the power supply via a pickup resistor, a bias source on two series-connected transistors in a diode connection, a resistor, a reference source voltage, the second power source, characterized in that, in order to increase temperature stability, two transistors are introduced into it, the base emitt The black transition of the first of which is connected in parallel ^{: the} collector-base transition of the second, the emitter of which is connected to the first power source through the reference voltage source, the base is connected to the emitter of the third transistor, the base of which is connected to the base of the first additional transistor, and the collectors of additional transistors are connected to the emitters of transistors bias source, the collector of the first of which is connected to the base of the composite transistor and through a resistor - With the bus of the second power source.