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US 11,114,945 B2Granted
Secondary-controlled active clamp implementation for improved efficiency
AssigneeCypress Semiconductor Corporation
InventorsRashed Ahmed, Hariom Rai
Life of this patent
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Abstract
Controlling an active clamp field effect transistor (FET) in a secondary-controlled active clamp converter is described. In one embodiment, an apparatus includes a primary-side FET coupled to a transformer, a secondary-side FET coupled to the transformer, and an active clamp FET disposed on a primary side of the transformer. A secondary-side controller is configured to control the active clamp FET across a galvanic isolation barrier.
Claims17
A secondary-side controlled alternating current to direct current (AC-DC) converter comprising:
- a primary-side field effect transistor (FET);
- a secondary-side FET;
- a transformer of the AC-DC converter, wherein the transformer is coupled to the primary-side FET and the secondary-side FET;
- an active clamp FET coupled to the primary-side FET, wherein the active clamp FET is disposed on a primary side of the transformer;
- and
- a secondary-side controller coupled to the transformer, wherein the secondary-side controller is configured to generate a first control signal and a second control signal, the first control signal to control the primary-side FET via a primary-side controller across a first pulse transformer coupled between the primary-side controller and the secondary-side controller, and the second control signal to control the active clamp FET across a galvanic isolation barrier provided by a second pulse transformer, wherein a gate of the active clamp FET is directly coupled to a primary winding of the second pulse transformer.
3 more elements
A method comprising:
- generating, by a secondary-side controller in a secondary-side controlled alternating current to direct current (AC-DC) flyback converter, a first control signal, a second control signal, and a third control signal;
- controlling, by the secondary-side controller, a secondary-side field effect transistor (FET) coupled to a flyback transformer, using the third control signal, wherein the third control signal is based on the second control signal;
- controlling, by the secondary-side controller, a primary-side FET using the first control signal via a primary-side controller across a first pulse transformer coupled between the primary-side controller and the secondary-side controller;
- and
- controlling, by the secondary-side controller, an active clamp FET that is disposed on a primary side of the flyback transformer using the second control signal, wherein the second control signal is sent across a galvanic isolation barrier provided by a second pulse transformer, wherein a gate of the active clamp FET is directly coupled to a primary winding of the second pulse transformer.
2 more elements
An alternating current to direct current (AC-DC) power adapter device comprising:
- a USB-C connector;
- a power converter comprising a transformer and a rectifier coupled between AC terminals and DC terminals, the rectifier to convert AC power on the AC terminals to DC power on the DC terminals, and the transformer to provide galvanic isolation between the AC terminals and the DC terminals;
- a primary-side field effect transistor (FET);
- a secondary-side FET;
- an active clamp FET coupled to the secondary-side controller, wherein the active clamp FET is disposed on a primary side of the transformer;
- and
- a secondary-side controller coupled to the transformer, wherein the secondary-side controller is configured to generate a first control signal and a second control signal, the first control signal to control the primary-side FET via a primary-side controller across a first pulse transformer coupled between the primary-side controller and the secondary-side controller, and the second control signal to control the active clamp FET across a galvanic isolation barrier provided by a second pulse transformer, wherein a gate of the active clamp FET is directly coupled to a primary winding of the second pulse transformer.
4 more elements
Dependencies are inferred from the claim text.