DRV8302 wiring (PullUps, ..)

A R

Other Parts Discussed in Thread: DRV8302, DRV8301

Hello guys,

I have some questions about wiring the DRV8302.

PWRGD: the datasheet says 'open drain output with external pullup resistor required'. Do I need a pullup resistor, if I don't read the output of this pin? I would like to let it floating with no connection. Is it allowed?

/OCTW: is there a pullup resistor required, if I don't need the output, also no connection?

DTC: I use 6 independent PWM inputs. Is it allowed to let the DTC with no connection and no resistors?

M_PWM: for 6 independent PWM inputs put M_PWM = LOW. There is an internal pulldown R_m_pwm = 100k. Is it enough or do I have to put M_PWM low-impedance to GND?

M_OC: here the same, is the internal 100k pulldown enough or do I need an additional connection to GND?
M_OC: if I want to put it to high is it allowed to connect it to DVDD? Just asking because datasheet says about DVDD 'This is an output, but not specified to drive external circuitry'.

I would like to make my PCB as small as possible and to reduce the number of parts

best regards

over 7 years ago

0 Nicholas Oborny over 7 years ago

TI__Mastermind 21305 points

If PWRGD and nOCTW feedback are not used then can leave floating and remove pull up resistor.

Short DTC to GND for minimum dead time setting.

Internal pull down of M_PWM should be sufficient. Same comment for M_OC.

It would be preferred to short it to the logic system supply rail if this is available instead of DVDD.

0 A R over 7 years ago in reply to Nicholas Oborny

Prodigy 120 points

thank you very much for your response.

Short DTC to GND for minimum dead time setting
So it's not allowed to leave DTC floating if I'm generating the deadtime inside my uC using the 6 PWM inputs?

0 Nicholas Oborny over 7 years ago in reply to A R

TI__Mastermind 21305 points

The DRV8301 has an internal handshake mechanism that cannot be bypassed.

This minimum dead time will apply even if the MCU is generating external dead time.

0 A R over 7 years ago in reply to Nicholas Oborny

Prodigy 120 points

1) If I short the DTC to GND but use 6 PWM inputs and generate 100ns in my MCU, the DRV will output 100ns deadtime right?
2) leaving the DTC floating and using 6 PWM inputs generating 100ns in my MCU, the DRV will output 100ns deadtime?
I dont want to generate <50ns deadtime but simplify the PCB design leaving the DTC floating if possible.

0 Nicholas Oborny over 7 years ago in reply to A R

TI__Mastermind 21305 points

1) Correct. See note 1 on page 8.

2) Incorrect. If there is no resistor and the pin is floating it will see a high resistance which correlates to a larger dead time.

What is gained by leaving DTC floating vs. tied to GND?

0 A R over 7 years ago in reply to Nicholas Oborny

Prodigy 120 points

thank you very much.
I haven't started routing the PCB yet, but maybe it could save some place.

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DRV8302 wiring (PullUps, ..)