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DRV8832驱动阀门时堵转时无Fault信号

QingFeng Yuan
Prodigy 10 points
Other Parts Discussed in Thread: DRV8832

Hi Ti Engineer,

  您好，最近采用DRV8832的电机驱动芯片，驱动阀门开关阀。阀门在静态时电阻为23到25欧姆左右，标称工作电流<85ma, 工作电压范围: 2.5 - 6v之间。目前，采用以下电路设计，发现Risens太大，导致Vout带载输出电压0.9v左右，而在低电压Vcc为4.0V时，关阀时无Fault信号。

经过，咨询Risense的阻值太大，导致限制了Vout带载输出电压。而调整到Risense为2.2， Vout能够输出2.6左右，但是关阀时无Fault信号。Risense两端的电压波形图如下:

请帮忙分析下，是什么原因，如何改进电路??? Rinsens两端电压达到什么程序才会触发Fault信号??

Best regards,

Vine

  • 0
    TI__Genius 13080 points
    The motor current is sensed by monitoring the voltage across an external sense resistor. When the voltage
    exceeds a reference voltage of 200 mV (160mV min. / 240mV max.) for more than approximately 3 µs, the PWM duty cycle is reduced to limit
    the current through the motor to this value.
    An overcurrent event must persist for approximately
    275 ms before the fault is registered. After approximately 275 ms, a fault signaled to the host by driving the
    FAULTn signal low.