Customer found an abnormal waveform when using the INA194A device on H-Bridge MOSFET application.
application: AC inverter.
Issue Description: There are two INA194A to sensing the motor current in bidirectional. When motor loading is increased from 0A to +45A, the CS_OUT1 rise up to 45A, at the same time, the CS_OUT2 is kept the 0A. However, when motor loading is increased from 0A to -45A(Motor in reverse spin), the CS_OUT1 is about 432mV(A little bit higher). We're wondering to know if U9 device is damaged or not? We measured the static impedance, there is no any abnormal impedance on each pin to GND pin shown as below table.
|
Device |
PIN1-GND |
PIN3-GND |
PIN4-GND |
PIN5-GND |
|
U9 |
36K |
305K |
306K |
5.97K |
|
U10 |
35.4K |
307K |
308K |
5.97K |
When we replaced the defective U9 to new INA194A device, the problem is gone. The defective U9 can also duplicate the problem on another new board.
Could you offer your comments? and it's possible to send it to do the FA?
