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IGBT Forum Discussions

rohit_ccrete
Level 1
First reply posted First question asked Welcome!
Level 1

I am currently using a setup with a FF1400R12IP4 IGBT with a corresponding 2SP0320TA0 gate driver. I have verified that the diodes are working in the intended direction with the description below.

+(red) to gate 2 and   -(black) to gate 8 reads: 315 (mV?)

- (black) to gate 2 and  +(red) to gate 8 reads: OL (Open loop)

 

+(red) to gate 5 and   -(black) to gate 8 reads: OL (Open loop)

-(black) to gate 5 and  +(red) to gate 8 reads: 315 (mV?)

 

In addition, I have verified that the gate driver is working since it reads ~ -8 V when not commanded, and +15 V when commanded on via a logic signal. To briefly summarize the circuit setup, a + terminal of a capacitor connects to the collector (pin 9 of the IGBT) continuing via the emitter (pin eight) to an electrode. The - terminal of the capacitor is connected to an other electrode. The issue is that the voltage across the electrodes is always high, somehow implying that the IGBT itself is either on or leaking even when there is no logic signal to open the gate. It is worth noting that even outside of this circuit, the IGBT seems to be perpetually on when tested with a 15 V DC power supply. This issue is unlikely to be either the IGBT or the gate driver alone since both components have been replaced but the issue persists. 


Any advice moving forward would be appreciated.

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2 Replies
rohit_ccrete
Level 1
First reply posted First question asked Welcome!
Level 1

Just adding a follow up, the circuit diagram above is irrelevant to the issue.  We tested a single IGBT module by simply connecting it to a DC power supply of 32 V. There was 0.737 V (or ~3%) leakage across the module (see attached image) where technically in a flawless IGBT switch there should not be any voltage leakage. Then, the gate driver was physically was put on the module (without any power or input see attached image 2) and the voltage leakage was 24.59V (or ~75% of the 32V).

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Vinay
Moderator
Moderator 10 solutions authored 10 likes received 25 replies posted
Moderator

Hi @rohit_ccrete,

Good Day!

Thanks for posting your question in Infineon Community.

 

You explained the schematic in words, could you share the schematic or connection diagram for better understanding?

 

DC supply of 32V is connected to Half bridge. Could you mention across which terminals you connected the DC supply, whether it's across Pin 8 and Pin 9 or across Pin 9 and Pin 10?

 

Could you please share the Gate signals for the two IGBTs?

 

Could you please measure the voltage across individual IGBT collector emitter, Pin 8 and Pin 9 (Upper IGBT), Pin 8 and Pin 10 (Lower IGBT) and also measure voltage across Pin 9 and Pin 10(across half bridge)

 

Thank you!

 

Best Regards,
Vinay
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