Other Parts Discussed in Thread: LAUNCHXL-F28379D, , DRV8305, SYSCONFIG
Following up on the previous thread, I am still seeing an apparent 20V/V gain on the DRV8305EVM rather than 10V/V.
I have routed a DC current through Phase A current sense resistor R4=0.007ohm, using my switchmode power supply at constant current mode.
First image is with zero current with CH1:ISEN_A CH2:N_1
The cursor was used to read the current sense resistor voltage, which was zero. The current sense amplifier output was 1.67V.
Next Image is with 3.998A current with CH1:ISEN_A CH2:N_1
Cursors were used to read the current sense resistor voltage, which was averaging -28.2mV as expected. The current sense amplifier output voltage was 2.24V.
Considering the offset, the gain from the current sense amplifier was (2.24V-1.67V)/(0.0282V-0V) = 20.2V/V
I took the same measurements using a Hioki DT4252 multimeter and obtained the following values:
(2.256V-1.695V)/(0.030V-0.001V) = 19.3V/V
In both cases the default gain on the amplifier appears to be 20V/V, corroborating the results from the last thread. Again I have not made any SPI commands, and I have only turned on the GATE_EN input to turn on the amplifier.I am providing 12V to PVDD and Vreg&Vref is 3.381V according to my multimeter.
I have observed the issue on two boards already. Has anyone else observed this issue or can reproduce it?