UCC27517: UCC27517DBVR schematics review

Hi Kevin, 

1. Is SRNBAT- connected to SGND? If it is not, this will be problematic because the gate driver signal output is relative to ground. If the source is not grounded, you cannot accurately supply the correct voltage from the gate driver across the gate and source of the FET. Also, there would not be a proper return loop. In this case, the connection from gate-source, where source is grounded, provides the return loop connected to ground. 
2. Typically the diode (D9) would be connected between OUT and GND (SGND in your design) -- the diode will be more effective in clamping undershoot on OUT. If the source is connected to SGND, this configuration should be ok. Also, the pulldown resistor (R17) is quite large. A typical value for this is around 10kΩ up to 100kΩ. 
3. The output resistor, (R20) also appears to be high. A typical value is around 0Ω-5Ω as to limit switching speed, but not completely limit current flow from out of the gate driver. 
4. We recommend two capacitors between VDD and GND. In addition to the 0.1µF capacitor (C20) in your design, a large bypass capacitor, around 1µF or more is recommended. 

We recommend looking at the schematic review template for guidance. 

Thanks,

Amy

Hi Kevin, 

Thanks for your reply, it appears the gate driver will function correctly.

Best,

Amy