Title:
CONSTANT VOLTAGE CIRCUIT
Document Type and Number:
Japanese Patent JPS59117616
Kind Code:
A
Abstract:
PURPOSE:To reduce the current flowed to a light emitting diode in case of a low temperature to prevent the rise of the output voltage and to increase this curent in case of a high temperature to prevent the fall of the output voltage. CONSTITUTION:A resistance R3 is connectd in series to a thermistor 4, and a resistance R4 is connected in parallel to them, and the anode of a light emitting diode 3 is connected in series to them. One end of the thermistor 4 and one end of the resistance R4 are connected to the positive pole of a battery 1, and the cathode of the light emitting diode 3 is connected to the negative pole of the battery 1. The anode of the light emitting diode 3 is connected to the non-inverted input terminal of an operational amplifier 2. The inverted input terminal of the operational amplifier 2 is connected to the positive pole of the battery through a resistance R1, and the inverted input terminal and the output terminal are connected by a resistance R2. The resistance value of said resistance R2 is set to a value lower than that of the resistance R1.
Inventors:
YAMAMIYA OSAMU
Application Number:
JP23093882A
Publication Date:
July 07, 1984
Filing Date:
December 25, 1982
Export Citation:
Assignee:
NIPPON DENSO CO
International Classes:
G05F1/613; H05B44/00; (IPC1-7): G05F1/56; G05F1/58
Attorney, Agent or Firm:
Motomu Itou