• Resolved

UCD9222: Fusion Digital Power Designer fault description

Part Number: UCD9222

I've used this device several times but this current board is being a bit stubborn in bring-up.

When running the Fusion Software I can program the 9222 but when looking at the Monitor or Status windows, I see a fault "Vin OV Fault". This fault cannot be cleared.

VinMon (pin 4) reads 1.5V.

What should I be looking at to resolve this issue?


  • The Graeme,

    UCD9222 measures the voltage on VinMon pin and divide it by Vin Monitor Scale to get actual Vin reading. Then it compares the Vin reading with Vin OV limit. If you see Vin OV fault, you should check: (1) Vin monitor scale is correct (the resistor divider ratio), (2) the voltage on VinMON pin is correct, (3) the Vin OV limit is above nominal Vin.

    For example, if Vin monitor scale = 0.1, VinMON pin has 1.5V, the device will report 15V Vin. To avoid VinOV fault, the Vin OV limit should be greater than 15V.




  • In reply to Zhiyuan Hu:

    Thanks. That makes the process clear.

    It turned out to be the resistor divider. One of the values was wrong on the board, but the circuit was right. The voltage on the VinMon pin is now 0.65, which corresponds to a Vin of 5V.