METHOD AND APPARATUS FOR IMPLEMENTING AN UNREGULATED DORMANT MODE WITH OUTPUT RESET IN A POWER CONVERTER

摘要

A control circuit includes a feedback circuit, a drive signal generator, an unregulated dormant mode and output reset control circuit, and a counter. The feedback circuit generates an enable signal and in response, the drive signal generator regulates the output of the power converter. The unregulated dormant mode and output reset control circuit powers down the drive signal generator such that the regulation is ceased when the energy requirement at the output has fallen below a threshold. The drive signal generator is then powered up after a first period of time such that the regulation resumes. The counter then counts cycles of a clock signal for which the enable signal indicates an increase in the energy requirement at the output. The counter disables the drive signal generator when a count of the counter reaches a threshold number to discharge the output to less than a regulation output voltage value.