Resonant gate driver

• US 6,208,535 B1
• Filed: 10/31/1994
• Issued: 03/27/2001
• Est. Priority Date: 10/31/1994
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Parks, David B.
• Primary Examiner(s): NGUYEN, MATTHEW VAN
• Application Number:
  US08/331,435
• Time in Patent Office: 2,339 Days
• Field of Search: 363/22, 363/24, 363/26, 327/407, 327/408, 327/409
• US Class Current: 363/26
• CPC Class Codes: H02M 3/1588 comprising at least one synchronous rectifier element H02M3/1582, H02M3/1584 take precedence
• CPC Class Codes: H02M 3/33592 having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
• CPC Class Codes: H03K 2017/6875 using self-conductive, depletion FETs
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A power supply (500) with vertical field effect transistor synchronous rectifiers (VFET1 and VFET2) having drivers (VFET Driver1 and VFET Driver2) which provide bipolar mode of operation by diode clamping an inductor overshoot which forwards biases the gate-source junction. The rectifiers have low on resistance useful in low output voltage power supplies.

Claims

1. A driver, comprising:

(a) first and second power supply inputs;

(b) an output;

(c) a first switch directly between said first power supply input and said output;

(d) a second switch coupled between said second power supply input and a passive overshoot circuit, said overshoot circuit coupled to said output; and

(e) a switch input coupled to said first and second switches.

2. The driver of claim 1, wherein:

(a) said overshoot circuit includes an inductor.

3. The driver of claim 2, wherein:

(a) said overshoot circuit includes a diode in series with said inductor.

4. The driver of claim 2, wherein:

(a) said first and second switches are field effect transistors on a common substrate.

5. A method of driving the gate of a field effect transistor, comprising the steps of:

(a) providing first and second power supplies;

(b) alternatively (i) coupling said first power supply directly to a gate of a field effect transistor and (ii) coupling said second power supply to said gate through a passive overshoot circuit;

(c) whereby said first power supply may be at a voltage to turn off said field effect transistor.

6. The method of claim 5, wherein:

(a) said overshoot circuit includes an inductor.