Miyuki Takeshita

Low-loss rectification circuit with no external drive input

We have developed the new low-loss rectification circuit that needed neither external signals nor power supplies for driving. This circuit creates the control power supply for the circuit operation from reverse voltage. The direction of the current that flows in this circuit is detected from the voltage between the MOSFET drain and source. The current is rectified by driving MOSFETs according to this detection result. Also, the circuit has several types of MOSFET connected in parallel. Types and numbers of MOSFETs are automatically selected to minimize the loss according to the magnitude of the current detected from the voltage between the MOSFET drain and the source. To create the power supply and the signal for the rectification circuit, the circuit needs no inputs from outside like a diode. Therefore, this circuit can be easily substituted for a conventional diode. In operation tests, the minimum forward voltage drop was 0.04 [V] when the current was rectified. As a result, the forward voltage drop was less than 1/10 compared to conventional diodes, and the loss could be decreased extremely. Therefore, the miniaturization of the electric equipment that radiation fin and fan becomes possible, too. The low-loss rectification circuit can save energies by substituting diodes for prevention of global warming.