Patent ID: 7538587
Filing Date: 2009-05-26
Classification: H02M

Abstract:
1. A power semiconductor device comprising: a first power switching semiconductor element at a high voltage side and a second power switching semiconductor element at a low voltage side connected in series, one end of each of said first and second power switching semiconductor elements being connected to an external direct current power source, and a connection point between another end of each of said first and second power switching semiconductor elements being able to supply an output voltage; flywheel diodes each being respectively connected in antiparallel to one of said first and second power switching semiconductor elements; a first driver circuit connected to a gate of said first power switching semiconductor element; a second driver circuit connected to a gate of said second power switching semiconductor element; a second diode connected to a line to be connected between a controlled power source and a power source terminal of at least one of said first and second driver circuits in a forward direction such that a current does not flow in the line from the power source terminal through said second diode toward said controlled power source; a control signal generating circuit for generating a control signal for at least one of said first and second driver circuits, at least one of said first and second driver circuits comprising an input terminal for receiving the control signal for the at least one of said first and second driver circuits; and a third diode connected to another line to be connected between said control signal generating circuit and the input terminal of at least one of said first and second driver circuits in a forward direction to prevent a current from flowing in the other line from the input terminal through said third diode toward said control signal generating circuit, wherein a breakdown voltage of said second diode is larger than a direct current voltage to be applied to said first and second power switching semiconductor elements by the external direct current power source, and the direct current voltage is larger than a voltage applied at the power source terminal of the at least one of said first and second driver circuits.