Title:
CIRCUIT FOR INCREASE OF BREAKDOWN VOLTAGE OF BIPOLAR TRANSISTOR
Document Type and Number:
Japanese Patent JPH077398
Kind Code:
A
Abstract:
PURPOSE: To increase the reverse breakdown voltage of a bipolar transistor which supplies a driving current to an inductor by providing a voltage controlling transistor between the collector and base of the bipolar transistor. CONSTITUTION: A circuit 30 supplies a driving current to an inductor 31. When a switching transistor(STR) 35 is turned on by an input to a terminal 44, an electric current flows from a power source VS through a coil 31 and the drain- source route of the STR 35. When a driver transistor(TR) 34 is turned on, the voltage at a node N1 increases due to the current-voltage relation imposed by the inductor 31. When the voltage at the node N1 exceeds VCC, an N-channel MOSFET 40 is turned on and the base and collector of the TR 34 are substantially short-circuited to each other. Therefore, the voltage at the node N1 can stably rise to a high voltage higher than the power supply voltage before a breakdown occurs and the breakdown voltage increasing ability of the circuit 30 is substantially increased.
Inventors:
FURANSESUKO KAROBORANTE
Application Number:
JP31756893A
Publication Date:
January 10, 1995
Filing Date:
December 17, 1993
Export Citation:
Assignee:
SGS THOMSON MICROELECTRONICS
International Classes:
H03K17/08; H03K17/082; H03K17/567; H03K17/64; (IPC1-7): H03K17/08; H03K17/567; H03K17/64
Attorney, Agent or Firm:
Kazuo Kobashi (1 person outside)
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