Title:
CONSTANT CURRENT CIRCUIT
Document Type and Number:
Japanese Patent JPS58105313
Kind Code:
A
Abstract:
PURPOSE:To increase both speed of response and stability for a constant current circuit which sets the ON time of a transistor and supplies a constant current to a load, by setting the ON time of the transistor by the output of the 2nd comparing/amplifying means. CONSTITUTION:A current flowing to a load RL is detected by a current detecting circuit 9 and then converted into a voltage value. This voltage value is delivered to a differential amplifier 8 and compared with the reference voltage E0, and this differential is amplified and then delivered to a differential amplifier 7. At the same time, a current detecting circuit 5 detects the output current of a transistor Q1 and converts it into a voltage value to deliver it to an amplifier 7. The amplifier 7 compares the voltage value given from the circuit 5 with the voltage value given from the amplifier 8, and this differential is amplified to be delivered to a pulse duration control circuit 6. The circuit 6 sets by the output of the amplifier 7 the time width during which the voltage is applied to the Q1.
Inventors:
SATOU MITSUO
Application Number:
JP20429081A
Publication Date:
June 23, 1983
Filing Date:
December 17, 1981
Export Citation:
Assignee:
FUJITSU LTD
International Classes:
H02M3/28; H02M3/335; (IPC1-7): G05F1/64
Attorney, Agent or Firm:
Koshiro Matsuoka