Current sensing methods for standby power control of digital-controlled DC/DC converter

The main theme of this paper is to study the current sensing methods for standby power reduction control of digital-controlled DC/DC converter. These methods include using transformer of full-bridge converter, coupling inductor and ORing MOSFET. The most suitable sensing method was verified with a digital-controlled 500 W class DC/DC converter (input/output voltage: 400 V/12 V). Experimental results derived from digital-controlled DC/DC converter using the TI DSP (TMS320F2812) as the control platform show that current sensed by voltage across ORing MOSFET method provides superb solution. This method offers linear relationship between output voltage of sensing circuit and load current while not causing response delay under standby conditions and thereby truly reflecting accurate standby conditions.