Adaptive synchronous rectifier sensing deglitch

Patent metadata

Field	Value
Publication number	US-10797610-B2
Application number	US-201916559471-A
Country	US
Kind code	B2
Filing date	Sep 3, 2019
Priority date	Jun 30, 2017
Publication date	Oct 6, 2020
Grant date	Oct 6, 2020

Abstract

A synchronous rectifier controller method is provided for controlling the on and off periods of a synchronous rectifier (SR) switch transistor in a switching power converter. The method includes a first step of monitoring an unfiltered to control whether the SR switch transistor is turned on during a first part of a power switch cycle. The method also includes a second step of monitoring a filtered SR switch signal to control whether the SR switch is turned on during a remaining second part of the power switch cycle.

First claim

We claim:

1. A method for controlling a synchronous rectification (SR) switch on a secondary side of a flyback converter, comprising:
during a first part of a power switch cycle, monitoring an unfiltered SR switch signal to control whether the SR switch is turned on; and
during a remaining second part of the power switch cycle, monitoring a filtered SR switch signal to control whether the SR switch is turned on.

2. The method of claim 1 , wherein the first part of the power switch cycle ends at a transformer reset time, and wherein the second part of the power switch cycle begins at the transformer reset time.

3. The method of claim 1 , further comprising:
integrating a difference between a voltage across the SR switch and an output voltage for the flyback converter to provide an integrated signal; and
comparing the integrated signal to a threshold to identify the first part of the power switch cycle and to identify the second part of the power switch cycle.

4. The method of claim 1 , further comprising:
comparing a voltage across the SR switch to a threshold to identify the first part of the power switch cycle and to identify the second part of the power switch cycle.

5. The method of claim 1 , wherein the unfiltered SR switch signal is a voltage across the SR switch signal.

6. The method of claim 1 , wherein the filtered SR switch signal is a filtered version of a voltage across the SR switch.

7. The method of claim 1 , further comprising:
comparing a voltage across the SR switch to provide a comparator output signal, wherein the unfiltered SR switch signal is the comparator output signal.

Assignees

• Dialog Semiconductor Inc

Inventors

• Kong Pengju
• Li Tao
• Bui Hien
• Liang Wenbo
• Zhang Hanguang

Classifications

• H02M3/33592 Primary

  having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer · CPC title

• H03K5/1252

  Suppression or limitation of noise or interference (specially adapted for transmission systems H04B15/00, H04L25/08) · CPC title

• Y02B70/10

  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 · CPC title

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• Y02B70/1475

  Cross-Sectional Technologies · mapped topic