Drive device for voltage-controlled semiconductor element
A drive device for driving a voltage-controlled semiconductor element. The drive device includes: a drive circuit connected to the gate of the semiconductor element via a gate resistor; a delay circuit connected to the drive circuit, for delaying a drive signal output from the drive circuit until a gate voltage of the semiconductor element enters a Miller effect period, which is a period during which the gate voltage transitionally changes, the gate voltage having temperature dependency on a chip temperature of the semiconductor element; a one-shot circuit connected to the delay circuit, for outputting a pulse signal with a pulse width shorter than the Miller effect period; a comparator that compares the gate voltage with a reference voltage; and an AND circuit that outputs an overheat detection signal in response to the gate voltage exceeding the reference voltage.
1. A drive device for driving a voltage-controlled semiconductor element having a gate, the drive device comprising:
a drive circuit that is connected to the gate of the voltage-controlled semiconductor element via a gate resistor provided therebetween;
a delay circuit connected to the drive circuit, the delay circuit being configured to delay a drive signal output from the drive circuit by a predetermined period of time until a gate voltage of the voltage-controlled semiconductor element enters a Miller effect period, the Miller effect period being a period during which the gate voltage transitionally changes, the gate voltage having temperature dependency on a chip temperature of the voltage-controlled semiconductor element;
a one-shot circuit connected to the delay circuit, the one-shot circuit being configured to output a pulse signal with a pulse width shorter than the Miller effect period;
a comparator that compares the gate voltage with a reference voltage; and
an AND circuit that receives the pulse signal output from the one-shot circuit and an output signal of the comparator, and outputs an overheat detection signal in response to the output signal indicating that the gate voltage exceeds the reference voltage.
2. The drive device for driving the voltage-controlled semiconductor element according to claim 1 , further comprising an alarm output terminal that outputs the overheat detection signal generated by the AND circuit.
3. A drive device for driving a voltage-controlled semiconductor element having a gate, the drive device comprising:
a drive circuit that is connected to the gate of the voltage-controlled semiconductor element via a gate resistor provided therebetween;
a delay circuit connected to the drive circuit, the delay circuit being configured to delay a drive signal output from the drive circuit by a predetermined period of time until a gate voltage of the voltage-controlled semiconductor element enters a Miller effect period, the Miller effect period being a period during which the gate voltage transitionally changes, the gate voltage having temperature dependency on a chip temperature of the voltage-controlled semiconductor element;
a one-shot circuit connected to the delay circuit, the one-shot circuit being configured to output a pulse signal with a pulse width shorter than the Miller effect period; and
a sample-hold circuit that receives the gate voltage while receiving the pulse signal, and holds to output the received gate voltage until the receiving of the pulse signal ends.
4. The drive device for driving the voltage-controlled semiconductor element according to claim 3 , further comprising a chip temperature output terminal that outputs a chip temperature detection signal, which is an output of the sample-hold circuit.
5. A drive device for driving a voltage-controlled semiconductor element having a gate, the drive device comprising:
a drive circuit that is connected to the gate of the voltage-controlled semiconductor element via a gate resistor provided therebetween;
a delay circuit connected to the drive circuit, the delay circuit being configured to delay a drive signal output from the drive circuit by a predetermined period of time until a gate voltage of the voltage-controlled semiconductor element enters a Miller effect period, the Miller effect period being a period during which the gate voltage transitionally changes, the gate voltage having temperature dependency on a chip temperature of the voltage-controlled semiconductor element;
a one-shot circuit connected to the delay circuit, the one-shot circuit being configured to output a pulse signal with a pulse width shorter than the Miller effect period;
a comparator that compares the gate voltage with a reference voltage;
an AND circuit that receives the pulse signal output from the one-shot circuit and an output signal of the comparator, and outputs an overheat detection signal in response to the output signal indicating that the gate voltage exceeds the reference voltage; and
a sample-hold circuit that receives the gate voltage while receiving the pulse signal, and holds to output the received gate voltage until the receiving of the pulse signal ends.
6. The drive device for driving the voltage-controlled semiconductor element according to claim 5 , further comprising:
an alarm output terminal that outputs the overheat detection signal generated by the AND circuit; and
a chip temperature output terminal that outputs a chip temperature detection signal, which is an output of the sample-hold circuit.