MOSFET KILLER
New Member
Hello All,
I have designed a circuit that will compare the collector voltage of an IGBT to a fixed variable referance voltage. When the IGBT gate voltage is low, the collector will be at the power supply voltage(in my case 320V), when the IGBT gate voltage is high, the collector voltage will be depednent on the current flowing through the IGBT. This is where the comparator comes in, if the collector voltage goes above a set referance voltage while the gate voltage is high, the comparator will give a pulse that will trigger a latch and shut down the IGBT gate. The purpose of this circuit is to protect an IGBT in the event of an overcurrent.
Question:
1. How will I limit the collector voltage going to the comparator while the gate voltage is low? The voltage will be 320V and that would fry my small LM393.
2.
I have designed a circuit that will compare the collector voltage of an IGBT to a fixed variable referance voltage. When the IGBT gate voltage is low, the collector will be at the power supply voltage(in my case 320V), when the IGBT gate voltage is high, the collector voltage will be depednent on the current flowing through the IGBT. This is where the comparator comes in, if the collector voltage goes above a set referance voltage while the gate voltage is high, the comparator will give a pulse that will trigger a latch and shut down the IGBT gate. The purpose of this circuit is to protect an IGBT in the event of an overcurrent.
Question:
1. How will I limit the collector voltage going to the comparator while the gate voltage is low? The voltage will be 320V and that would fry my small LM393.
2.