VOLTAGE CONTROLLED CURRENT SOURCE

PURPOSE:To attain the control of a voltage control current with high accuracy independent of the temperatures by applying feedback so as to secure the coincidence between the emitter voltage of a transistor TR which supplies a current to the load and the voltage of a control voltage source and then attaining the proportional control of the load current based on the control voltage. CONSTITUTION:The current mirror circuits of the TR 9 and 10 supply the collector current of the same level to the TR 6 and 7. As a result, the coincidence is obtained between the base voltage of the TR 6 and that of a TR 7. Therefore the voltage (control voltage) of a control voltage source 5 is set equal to the emitter voltage of a TR 2 which supplies a current to a load 1. Under such conditions, the load current is proportional to the emitter current of the TR 2. This emitter current, however, is proportional to the emitter voltage. This emitter voltage is equal to the control voltage. As a result, the load current can be proportionally controlled by the control voltage. Thus the voltage control current is controlled with high accuracy independent of the temperatures.