Switch mode power supply systems

• Main Authors: COULSON, DAVID ROBERT, GARNER, DAVID MICHAEL, PIPER, JOHAN
• Format: Patent
• Language: Chinese; English
• Published: 01.07.2008
• 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

This invention generally relates to methods and apparatus for sensing the output current in a switch mode power supply (SMPS), in particular using primary side sensing. A module for estimating the output current of a switch mode power supply (SMPS), said SMPS including a transformer with at least a primary winding coupled to an input of the SMPS and a secondary winding coupled to an output of the SMPS and having a power switching device to switch power to said primary winding of said transformer responsive to a drive signal, the module comprising: a current sense input to receive a current sense signal sensing a current in said primary winding of said transformer; a voltage sense input to receive a voltage sense signal from said primary or an auxiliary winding of said transformer; a drive signal input to receive said drive signal; a signal averager coupled to said drive signal input and to said current sense input to average said current sense signal over a period when said drive signal is controlling said po