Indicates VCP charge pump and/or VGLS undervoltage fault condition with modified configurations of DRV8353RS-EVM
Hi,
I wanted to test the DRV8353Rs-EVM-Board for our future application. To adapt the Gate Driver for the application we need to use the Gate Driver in “Single Rail” configuration
First I used the DRV8353Rs-EVM-Board in default configuration. No changes of the hardware. The DC Link was connected to a 48V voltage supply. The motor phases were connected to a BLDC drive. I used the “DRV8353RS 1.0.0” software to get the application running. The drive identification and the speed control mode were run without any problems.
Then I wanted to change the operating mode of the Gate Driver from “Split rail” to “Single rail”. Therefore I by replaced of resistor R19 and R18. (see picture)
I checked the change by measuring the adapted voltage at measure point of Vm (TP16).
Again the drive identification and the speed control mode worked fine.
The next step was to adapt the buck regulator from 12V output to 5V output. I changed the Resistor R29 ( from 2,61k to 10k). (see the above picture)
I checked the hardware changed by measure the voltage directly at the Vbuck.
I run the application with open motor connection (no BLDC drive connected). No Error accure.
After connecting the BLDC drive to the board and starting the drive identification, after a time less than one second the procedure stopped. The error “GDUV” occurs. I was not able to acknowledge the error. After a reboot the board trips again.
I after supplying the board (without activating the demo application) I measured the high and low side outputs of the gate driver. The high side Mosfet of phase A and B are switched on (VDC = 48V). The high side Mosfet of phase C is low (3.3V).
The nFAULT-LED is lighting up. Based on the register report on program DRV8353Rx 1.0.0, I suspect the error is due to VCP- Charge pump under voltage, and over-temperature warning. You can see these pictures of register report above.
I have also measured the voltages VM, Vcp, Vgls, Vcc and Dvdd. Only the charge pump voltage Vcp is not good. This is 42,2V (VM+2V), although it’s supposed to be VM+10,5V as a recommendation. And Vcc = about 7V (not 3,3V).
That is not my first time, when I have this problem. It was the second EVM Board and I have the same fault of the board. I don’t have any others ideas, how to test this gate driver DRV8353RS with my configurations.
Any helps will be appreciate!
Thanks for your attention,