MOSFET fullbridge switching regulator having transformer coupled MOSFET drive circuit

• US 4,758,941 A
• Filed: 10/30/1987
• Issued: 07/19/1988
• Est. Priority Date: 10/30/1987
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Felton, Bruce C., McCoy, William B.
• Primary Examiner(s): BEHA JR, WILLIAM
• Application Number:
  US07/115,141
• Time in Patent Office: 263 Days
• Field of Search: 363/17, 363/98, 363/132, 307/571, 307/577, 307/579, 307/582, 307/583, 307/584
• US Class Current: 363/132
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: H03K 17/6871 the output circuit comprising more than one controlled field-effect transistor
• CPC Class Codes: H03K 17/6872 using complementary field-effect transistors
• CPC Class Codes: H03K 17/691 using transformer coupling

Abstract

An FET full bridge regulator has a driving transformer for the gates of the power FETs of the regulator, and a driving circuit for the primary of the driving transformer, the driving circuit including a full bridge formed by first and second sets of driving FETs, each set formed by a complementary pair of FETs and being connected across the transformer, primary, one FET of each set being driven ON to together form a series of conducting paths across the primary of the transformer in the absense of driving signals.

The voltage supply for the driving FETS in the driving circuits of the primary of the driving transformer includes a resistance across which there is developed a voltage proportional to the current drawn by the driving transformer primary in each half cycle of its operation for reducing imbalance between the half cycles.

Claims

1. A power supply including a main switch section comprising a bridge arrangement of field effect transistors, a transformer connected to drive the gates of said transistors and drive means connected to a primary winding of said transformer comprising a three-state control to drive the primary of said transformer alternatively opposite directions with deadtimes therebetween and to short circuit said primary during said deadtimes.

2. FET Full bridge regulator comprising a driving transformer for the gates of the power FETs of the regulator, and a driving circuit for the primary of the driving transformer, said driving circuit comprising:

a voltage source,

a full bridge formed by first and second sets of driving FETs, each said set comprising a complementary pair of FETs having reverse current carrying capability and being connected across the transformer primary, one FET of each set being driven ON to together form a conducting path connecting said voltage source across the primary of the transformer and in the absence of driving signals one transistor of each pair conducting forwardly and one conducting reversely to establish a short circuit across said primary.

3. A regulator in accordance with claim 2, further comprising a voltage supply for the driving FETs in the driving circuits of said primary of said driving transformer, said supply including a resistance across which there is developed a voltage proportional to the current drawn by the driving transformer primary in each half cycle of its operation, whereby the voltage applied to that primary is reduced asymmetrically in a corrective direction when the currents drawn during the respective half cycles are not equal.