US 4,837,457 AGranted

High voltage power transistor circuits

AssigneeU.S. Philips Corporation

InventorsMichael J. Bergstrom, Derek J. Gent

Life of this patent

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Abstract

A high voltage power transistor circuit composed of a pair of transistors (TR1, TR2) serially connected through an inductor (L) to a supply voltage. Associated components are connected to the transistors which determine various periods of operation. In order to ensure that the transistors (TR1, TR2) are rendered non-conducting simultaneously, sensors (S1, S2) sense their change in base current to produce pulses in monostable multivibrators (M1, M2) whose relative phases are compared in a digital phase comparator (PC). The drive for each transistor (TR1, TR2) is provided by an associated driver stage (DR1, DR2) via an associated device (DC1, DC2) having a characteristic used to control the cut-off of its associated transistor. One of the devices (DC2) has a variable characteristic which is controlled by the output of the phase comparator (PC) to ensure the required simultaneous non-conduction of the transistors.

Claims19

Dependent claims

A circuit arrangement comprising:

a first high voltage bipolar power transistor, first control means for repeatedly cutting-off said first transistor, means connecting said first control means to a signal source which produces a drive signal for said first transistor, said first control means comprising a first device having an electric characteristic which is used to control said drive signal, a comparison stage having an output coupled to said first device for controlling the electric characteristic of said first device, first sensor means coupled to said first transistor for sensing the rate of change of base current of said first transistor each time said first transistor is cut off, first means for applying the sensing signa so produced to a first input of said comparison stage, second means for applying a time-related signal to a second input of the comparison stage, said first device controlling the instant of cut-off of said first transistor in response to a resulting comparison between said sensing signal and said time-related signal.

Dependencies are inferred from the claim text.

Facts

Application: 07/132,536Filed 14 Dec 1987
Priority: GB 863040619 Dec 1986
Granted: 6 Jun 1989
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H03K 4/64
Using a semiconductor device operating as a switching device: combined with means for generating the driving pulses
H03K 17/04126
By measures taken in the control circuit: in bipolar transistor switches
H03K 17/10
Electronic switching or gating, i.e. not by contact-making and –breaking: modifications for increasing the maximum permissible switched voltage
H03K 17/14
Electronic switching or gating, i.e. not by contact-making and –breaking: modifications for compensating variations of physical values, e.g. of…