Patent ID: 7864550
Filing Date: 2011-01-04
Classification: H02M

Abstract:
1. A power adapter with voltage-stabilized compensation including a transformer which has a primary coil to receive input power and transmit energy to a secondary coil to deliver output power and a pulse frequency modulation circuit to generate a driving pulse which has a constant ON time interval and a variable OFF time interval to control power transformed and output by the transformer, the power adapter further comprising: an ancillary coil which is magnetically coupled with the secondary coil and induced to generate a feedback signal; wherein the pulse frequency modulation circuit has a feedback contact, a time interval modulation unit to receive the feedback signal through the feedback contact and a feedback compensation unit; the time interval modulation unit setting a level voltage compared with the feedback signal to generate a sample signal to modulate the OFF time interval, the feedback compensation unit providing a compensation signal to the time interval modulation unit to alter the size of the feedback signal or the sample signal.