Primary side sense output current regulation
AssigneeiWatt Inc.
InventorsLiang Yan, John William Kesterson, Xiaoyan Wang, Guang Feng, Clarita Poon
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Abstract
The embodiments disclosed herein describe a method of a controller to maintain a substantially constant average output current at the output of a switching power converter. In one embodiment, the controller uses a regulation voltage that corresponds to the primary peak current regulation level to regulate the average output current.
Claims14
A switching power converter comprising:
- a transformer including a primary winding coupled to an input voltage and a secondary winding coupled to an output of the switching power converter;
- a switch coupled to the primary winding of the transformer, current through the primary winding being generated while the switch is turned on and not being generated while the switch is turned off;
- and
- a controller configured to generate a control signal to turn on or turn off the switch at each switching cycle of the switch to maintain a substantially constant average output current at the output of the switching power converter;
- wherein the controller is configured to generate the control signal by estimating an average output current for each switching cycle of the switch based on a reset time of the transformer calculated from a sensed output voltage from a previous switching cycle and a regulation voltage corresponding to a peak of the current through the primary winding in the previous switching cycle.
In a controller, a method of controlling a switching power converter, the switching power converter including a transformer coupled between an input voltage and an output of the switching power converter, the transformer including a primary winding coupled to the input voltage and a secondary winding coupled to the output of the switching power converter, and a switch coupled to the primary winding of the transformer, current through the primary winding being generated while the switch is turned on and not being generated while the switch is turned off, the method comprising:
- estimating an average output current for each switching cycle of the switch based on a reset time of the transformer from a previous switching cycle calculated from a sensed output voltage and a regulation voltage corresponding to a peak of the current through the primary winding in the previous switching cycle;
- and
- generating a control signal to turn on or turn off the switch at each switching cycle of the switch to maintain a substantially constant average output current at the output of the switching power converter based on the estimated average output current.
Dependencies are inferred from the claim text.