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US 2017/0317600 A1Published application
Auxiliary winding ground fault detection for isolated dc/dc converter
AssigneeDialog Semiconductor GmbH
InventorsPengju Kong, Duc Doan, Fuqiang Shi
Life of this patent
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Abstract
A flyback converter is provided with a controller that is configured to analyze the reflected feedback voltage waveforms to determine the presence of a ground connection fault for the auxiliary winding.
Claims8
A switching power converter, comprising:
- a transformer including a primary winding, a secondary winding, and an auxiliary winding;
- a power switch coupled to the primary winding;
- and
- a controller configured to cycle the power switch on and off to produce an output voltage at a load coupled to the secondary winding, wherein the controller is configured to time a delay from when a reflected feedback voltage on the auxiliary winding crosses a first threshold voltage to when the reflected voltage on the auxiliary winding subsequently crosses a second threshold voltage following an off time for the power switch in each cycle of the power switch, and wherein the controller is further configured to cease cycling the power switch responsive to the delay exceeding a threshold value.
1 more element
A method, comprising:
- cycling a power switch coupled to a primary winding to generate an output voltage at a load coupled to a second winding and to generate a reflected feedback voltage on an auxiliary winding;
- after an off time for the power switch in each cycle of the power switch, timing a delay from when the reflected feedback voltage crosses a first threshold voltage to when the reflected voltage crosses a second threshold voltage;
- and
- ceasing the cycling of the power switch responsive to the delay exceeding a threshold value.
1 more element
A method, comprising:
- cycling a power switch coupled to a primary winding to generate an output voltage at a load coupled to a second winding and to generate a reflected feedback voltage on a primary winding;
- after an off time of the power switch in each cycle of the power switch, comparing the reflected feedback voltage to a threshold voltage;
- determining times between crossings of the reflected voltage with the threshold voltage to determine whether the times are spaced apart by a constant separation or by a changing separation;
- and
- ceasing the cycling of the power switch responsive to the determination indicating that the times are separated by the changing separation.
2 more elements
Dependencies are inferred from the claim text.