METHOD AND APPARATUS FOR REDUCING STANDBY POWER IN POWER SUPPLIES

Power consumption of a low-power flyback power converter under standby-load or no-load conditions is reduced by modulating the OFF time of the flyback transformer's main switch as a function of the feedback control current when the load drops below a predetermined level. This modulation overcom...

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Bibliographic Details
Main Author TANG ALLEN
Format Patent
LanguageEnglish
Published 19.09.2002
Edition7
Subjects
APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC,OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWERSUPPLY SYSTEMS
CONTROL OR REGULATION THEREOF
CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUTPOWER
CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
ELECTRICITY
GENERATION
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Summary:Power consumption of a low-power flyback power converter under standby-load or no-load conditions is reduced by modulating the OFF time of the flyback transformer's main switch as a function of the feedback control current when the load drops below a predetermined level. This modulation overcomes the conventional frequency-increasing modulation of the ON time at low output power levels so as to reduce the switching frequency, and hence the switching losses, to minimal levels as the load is reduced. Excessive frequency reduction can optionally be avoided by a clamping feature that limits the expansion of the OFF time.
Bibliography:Application Number: US20010805625