Control method and apparatus for a flyback converter
AssigneeKoninklijke Philips Electronics N.V.
InventorsDemetri Giannopoulos, Nai-Chi Lee, Qiong Li
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Abstract
A power supply comprising a flyback converter and a controller is disclosed. The flyback converter drives a load when electrically coupled to an alternating current power source. The controller controls a soft switching during each switching time period of the flyback converter. Upon an initial switching time period, the controller determines each acceptable switching frequency for the subsequent switching time periods and selects one of the acceptable switching frequencies for soft switching the flyback converter over one or more switching time periods during a constant load.
Claims20
A power supply comprising:
- a flyback converter including a switch operable to be switched between an on state and an off state;
- and
- a controller operable during a first switching time period to determine at least two soft switching frequencies, each being acceptable by a switching frequency range specification, for transitioning said switch from said off state to said on state during a second switching time period subsequent to said first switching time period, and to select one soft switching frequency from said at least two soft switching frequencies by applying at least one performance parameter.
A power supply, comprising:
- a flyback converter operative within a selected range of frequencies and including a switch having a gate terminal, a drain terminal, and a source terminal;
- and
- a controller electrically coupled to said gate terminal and said drain terminal, said controller operable to provide a gate voltage to said gate terminal in response to a drain voltage at said drain terminal;
- wherein said controller is operable during a first switching time period to determine at least two soft switching frequencies, each corresponding to a valley of a drain voltage and acceptable by a switching frequency range specification, for transitioning said switch from an off state to an on state during a second switching time period, and to select one soft switching frequency from said at least two soft switching frequencies by applying at least one performance parameter.
A method for soft switching a switch of a flyback converter, comprising:
- a first switching time period;
- determining at least two soft switching frequencies, each being acceptable by a switching frequency range specification, for transitioning said switch from an off state to an on state during a second switching time period subsequent to said first switching time period, and
- selecting one soft switching frequency from said at least two soft switching frequencies by applying at least one performance parameter.
Dependencies are inferred from the claim text.