We use DRV8301 as motor Gate Driver, the motor control method is FOC, now the motor can run in open loop. But the current is very larger when motor run in low speed, the current will down until the motor speed is very high(36000rpm).
We measured the output signal of DRV8301 amplifier (SO1/ SO2), found the signal is abnormal during motor starting, it will become 1.65V and not tracking the input signal, please see Figure 1&2 for reference.
When the motor speed is very high, the output signal of DRV8301 amplifier seems normal, please see figure 3
Figure 4&5 are the schematic.
Seems the abnormal signal of SO1 result the MCU get the wrong feedback current signal, then result the MCU output larger current signal,
Due to the very large current in motor low speed, we can’t debug the motor drive for long time.
Could anyone help about this? Many thansks!
The DC_CAL pin of DRV8301 already directly connect to GND in PCB, and no operation for DC_CAL by SPI.
SP1,SN1&SP2,SN2 are Differential pair in PCB.
The Gain of Amplifier is 10.
OC protection is disabled by SPI. (Enable or disables is the same)
Yellow ：phase current， 1mv = 100mA
Blue ：output of DRV8301 amplifier (SO1), SO2 is similar.
Figure 1 ，
Figure2 ，
Figure3 ，
Figure4 ，
Figure5 ，
