PWM 3X Mode with only three PWM Inputs

Nikos Tosis

Part Number: DRV8304

Hi,

I have a question, in datasheet from DRV8343 there is the following text,

In 3x PWM mode, the INHx pin controls each half-bridge and supports two output states: low or high. The INLx
pin is used to put the half bridge in the Hi-Z state. If the Hi-Z state is not required, tie all INLx pins to logic high.

In DRV8304 does not exist the same information but the PWM 3X mode is supported too. So I made a test with drv8304 and it seems to working.

Is it correct? Can I use this also with DRV8304 so I need only 3 PWM Channels?

King Regards,

Nikos

over 3 years ago

0 Michael Arrant over 3 years ago

TI__Expert 3535 points

Hi Nikolaoas,

Both DRV8343 and DRV8304 both support 3x PWM mode, and the truth tables are the same for each device.

In both cases INHx pin controls each half-bridge and supports two output states: low or high and The INLx pin is used to put the half bridge in the Hi-Z state (High impedance).

So yes you can use either device for a 3x PWM application.

Thanks,

Michael

0 Nikos Tosis over 2 years ago in reply to Michael Arrant

Intellectual 390 points

So it is correct with a FOC Software to use PWM 3X mode and tie the INLx Pins High. In my test is working but I am not sure if I missing something or make a mistake?

Is it ok too? Because in an older Question, Texas had writte, only with 6 PWM Channels it is possible to implement a FOC Algorithm.

+1 Michael Arrant over 2 years ago in reply to Nikos Tosis

TI__Expert 3535 points

Hi Nikolaoas,

https://e2e.ti.com/support/motor-drivers/f/motor-drivers-forum/849310/drv8323-downside-to-using-3x-pwm-mode-for-foc-motor-control

This post from Adam should directly answer your question regarding using FOC for 3x PWM.

Thanks,

Michael

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PWM 3X Mode with only three PWM Inputs