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US 9,520,797 B2Granted
Adaptive reference voltage for switching power converters
AssigneeDialog Semicoductor Inc.
InventorsPengju Kong, Hien Bui, Duc Doan, Fuqiang Shi, Judy Sha
Life of this patent
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Abstract
A switching power converter is provided that detects an activity signal generated in response to load activity using an adaptively-declining threshold.
Claims17
A switching power converter, comprising:
- a power switch coupled to a primary winding of a transformer;
- a controller configured to cease a cycling of the power switch responsive to processing a first reflected voltage produced at a transformer reset time after each cycling of the power switch, the controller being further configured to time a detection period beginning after a termination of a blankout period following a last cycle of the power switch;
- and
- a comparator configured to determine whether a second reflected voltage triggered by an activity detector coupled to a secondary winding of the transformer exceeds an adaptive threshold that declines during the detection period, wherein the controller is further configured to initiate an additional cycle of the power switch responsive to a determination by the comparator that the second reflected voltage exceeds the adaptive threshold, wherein the controller is configured to control the adaptive threshold such that it has a maximum value at an initiation of the detection period and such that it declines from this maximum value over the detection period until it is clamped at a minimum value.
1 more element
A method, comprising:
- responsive to the removal of a load coupled to a secondary winding of a transformer, stopping the cycling of a power switch after a last power switch cycle, wherein the power switch is coupled to a primary winding of the transformer;
- after a blanking period has expired from a transformer reset time following the last power switch cycle, generating an adaptive threshold that declines as a function of a delay from a termination of the blanking period, wherein generating the adaptive threshold comprises generating an adaptive threshold that linearly declines until it is clamped at a minimum value;
- and
- detecting whether a reflected voltage on an auxiliary winding of the transformer exceeds the adaptive threshold, wherein the reflected voltage is generated by an activity detector coupled to the secondary winding.
1 more element
A switching power converter, comprising:
- an activity detector coupled to an output diode on a secondary side of a transformer, the activity detector being configured to activate a low impedance path bypassing the output diode in response to a detection of activity by a load, wherein the activation of the low impedance path triggers a current pulse in a secondary winding in the transformer;
- a power switch coupled to a primary winding of the transformer;
- and
- a controller configured to cycle the power switch responsive to a detection that a reflected voltage produced on an auxiliary winding of the transformer in response to the current pulse exceeded an adaptively declining threshold following a blankout period subsequent to a previous cycle of the power switch, wherein the adaptively declining threshold is a linearly-declining threshold.
1 more element
Dependencies are inferred from the claim text.