I am building a step up transformer for an output of 100 kV, 50 mA, at 50 kHz.
simulate this circuit – Schematic created using CircuitLab
For that I have planned to use a half bridge circuit with a ferrite transformer. However to test the circuit I am putting 30 V DC across a half bridge input. I am using a TLP350 as a Gate driver. I am using 10 Ω resistor as a gate turn on resistance, and a 1N5822 as a turn off diode for gate driver.
This is my lower side IGBT gate voltage, the probe directly connected at IGBT legs. 15 V. The probe is in 10X mode…
This is my half bridge output, load is a 60 Watt 12 Volt car headlight.
This is my issue, a voltage spike/overshoot at the leg of lower side IGBT. Probe is connected in emitter and collector pin. Collector pin referenced to emitter. This waveform taken without the snubber circuits.
My question is how I can reduce the spike at the IGBT's collector emitter pin?
This is my test setup for now. I have a 2 µf, 2 kV snubber cap close to half bridge IGBTs. 10 kΩ resistor connected in gate and emitter at both IGBT to reduce accidental turn on. I am using IHW40N65R5 IGBT with DSEI60-12A diode with each IGBT.
After I put the snubber circuit my lower side IGBT collector emitter voltage look like this, spike reduced but little ringing happening now… Is that ok? Can I power up my circuit up to high voltage DC? Like 300 Volt DC?
Best Answer
Limiting the inductance solved the issue.