Really surprised to see a Microchip part in a Tesla -- I've always thought of Microchip as a bit niche. A 12A IGBT driver. That's insane. I didn't know they made them that high current. I suppose, with huge gate charge comes huge driver requirements
These devices? IXGX120N60B
http://datasheet.octopart.com/IXGX120N60B-IXYS-datasheet-11760468.pdf About $10 a piece 10kunits, so probably costing Tesla around $840 in IGBT per car, which is dirt cheap for what they are.
Each driver controls 7 IGBTs, 350nC/FET, Q=CV, C=23nF/FET (@18V drive), so it's driving 160nF @ 32kHz... that's a pretty heavy load there, explains why there's four of the ICs!
Marco, did you replace the driver when replacing the IGBTs? It's highly recommended to, because IGBT failure can damage the driver.