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Patent Searching and Data


Title:
POWER DRIVE CIRCUIT
Document Type and Number:
Japanese Patent JP3431545
Kind Code:
B2
Abstract:

PROBLEM TO BE SOLVED: To save power consumption by detecting the current value of an output transistor, through which an idling current corresponding to an idling current set value flows, to increase or reduce the idling current so as to suppress oscillation phenomena, even when an output current is large.
SOLUTION: Between the base and emitter of an NPN-type bipolar transistor Q10, the base/emitter of an NPN-type bipolar transistor Q13 for detecting current and a resistor R5 are connected. Between the base and emitter of an NPN-type bipolar transistor Q12, the base/emitter of an NPN-type bipolar transistor Q14 for detecting current and a resistor R6 are connected. A current proportional to a current flowing through the transistor Q10 flows through the transistor Q13 to increase the voltage drop (Vr2) of a second adjusting resistor R2. An idling current is increased in response to the increase of voltage drop Vr2 to prevent the occurrence of unnecessary oscillation.


Inventors:
Nakagawa, Eiji
Application Number:
JP1999000230313
Publication Date:
July 28, 2003
Filing Date:
August 17, 1999
Export Citation:
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Assignee:
ROHM CO LTD
International Classes:
G11B7/09; G05F1/565; H03F3/30; H03K17/042; H03K17/615; H03K17/66; (IPC1-7): H03F3/30
Attorney, Agent or Firm:
紋田 誠 (外1名)