Short-circuit protection circuit, semiconductor device, and short-circuit protection method

A semiconductor device comprising:

• a semiconductor switch element;
• a voltage dividing circuit that divides a power supply voltage supplied from a power supply connected to one end thereof;
• a semiconductor rectifying element, one end of which is connected between resistance elements of the voltage dividing circuit and the other end of which is connected onto a path of a conductive wire connected to a current-inflow-side terminal of the semiconductor switch element, the connection being made such that a direction from the one end to the other end becomes a rectifying direction;
• an RC parallel circuit connected to the other end of the voltage dividing circuit;
• and
• a drive unit that turns off the semiconductor switch element when it is detected that a short-circuit current flows through the conductive wire, on the basis of a voltage of a capacitor element included in the RC parallel circuit, in a case in which the semiconductor switch element is turned on,
• wherein a stray capacitance of the semiconductor rectifying element is a stray capacitance that satisfies a condition that a voltage at one end of the capacitor element of the RC parallel circuit, which is connected to the voltage dividing circuit, is higher than a voltage at the other end of the capacitor element, when the short-circuit current flows through the conductive wire.

A short-circuit protection method,

• wherein a voltage dividing circuit divides a power supply voltage supplied from a power supply connected to one end thereof,
• wherein a capacitor element included in an RC parallel circuit connected to the other end of the voltage dividing circuit is charged on the basis of a current supplied,
• wherein, a semiconductor rectifying element in which a direction from one end to the other end becomes a rectifying direction, and in which the one end is connected between resistance elements of the voltage dividing circuit and the other end is connected onto a path of a conductive wire connected to a current-inflow-side terminal of a semiconductor switch element to be protected and which has a stray capacitance that satisfies a condition that a voltage at one end of the capacitor element of the RC parallel circuit, which is connected to the voltage dividing circuit, is higher than a voltage at the other end of the capacitor element, when a short-circuit current flows through the conductive wire, conducts a current in the rectifying direction in a case in which a voltage at the one end thereof is higher than a voltage at the other end thereof, and
• wherein a drive unit turns off the semiconductor switch element when it is detected that the short-circuit current flows through the conductive wire, on the basis of a voltage of the capacitor element included in the RC parallel circuit, in a case in which the semiconductor switch element is turned on.