DRV8432EVM: Test problem

Hi Adolf,

What is the PWM frequency used? What is the value of the bootstrap capacitors?

PWM frequency less than 10KHz.
Bootstrap capacitors I can't find its value on drv8432 evaluation board.
Is this Bootstrap capacitors value or PWM frequency not enough?

Hi Adolf,

How much less than 10kHz? Please see section 7.3.2.1 Bootstrap Capacitor Undervoltage Protection of the datasheet.

As you lower the PWM frequency and increase the duty cycle, please examine the outputs for recharge cycles.

The cap values can be found in the user's guide: www.ti.com/.../slou291a.pdf The caps are .1uF which should be enough for 10

My output PWM frequency is 100Hz.
So I need to increase Bootstrap capacitors to 10uF when PWM frequency less than 10KHz right?
Or I should increase PWM frequency higher than 10KHz?

HI there.
I have another question.In this case( in Parallel Full Bridge Mode. PWM_A=PWM PWM_B=0), I found that motor works weird when I set PWM duty cycle 100%.but duty cycle under 100% motor works normally.Is this chip should avoid PWM duty cycle in 100% or it will damage the chip?

Hi Adolf,

100% duty cycle can be difficult with this device. It is easier to run at near 100%, where a small recharge cycle for the bootstrap cap is initiated by the PWM inputs.

Please note the first paragraph of section 7.3.2.1 Bootstrap Capacitor Undervoltage Protection of the datasheet.

The time of the recharge cycle depends on the cap value and the time the high side input has been enabled.