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Method and apparatus for fault detection in a switching power supply

  • US 20070002510A1
  • Filed: 07/01/2005
  • Published: 01/04/2007
  • Est. Priority Date: 07/01/2005
  • Status: Active Grant
First Claim
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1. A switching regulator circuit, comprising:

  • a switch to be coupled to an energy transfer element of a power supply;

    a feedback circuit coupled to the controller and coupled to receive a feedback signal from an output of the power supply;

    a controller coupled to the switch and to the feedback circuit to control a switching of the switch to regulate a combination of an output voltage and an output current at the output of the power supply, wherein combinations of the output voltage and the output current correspond to output regions such that there is at least one regulated output region and one unregulated output region, the controller including an oscillator having first and second switching frequencies, wherein the second switching frequency is greater than the first switching frequency, the controller further including a fault detection circuit having a fault timer to measure a duration of an absence of an adequate feedback signal, the fault detection circuit having a fault mode of operation and a feedback check mode of operation, the fault mode of operation to substantially reduce an average power at the output of the power supply when the feedback signal is absent longer than a fault time, the feedback check mode of operation to raise the switching frequency from the first switching frequency to the second frequency when the feedback signal is absent for a duration less than the fault time.

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