DRV8353: 1x PWM mode (DRV8353 with Hardware Interface)

Ahmed Iftikhar

Part Number: DRV8353

Hello.

I am using DRV8353H to drive a BLDC motor.

IC settings:

I have grounded mode pin though 510K resistor (for 1xPWM mode).

VDS mode is disbaled.

IDRIVE is set 700/1400mA current.

Vm = 15V

Vdrain = 24V

PWM = 20KHz at INHA.

INLC tied to DVDD to disable brakes.

INHC tied to ground for unidirectional mode.

Hall sensor connected to INLA, INHB & INLB.

Fault pin tied to DVDD through 10K resistor.

After the circuit is powered-up, 5V at DVDD pin and 14.8V at VGLS pin are present. But no gate drive PWMs are present at GLx and GHx pins. All the GLx pins are at 6V. And Fault pin is low.

I have also confiured the IC in independent PWM mode, but the FAULT pin stays low.

What am I doing wrong?

Thanks in advance.

Regards.

over 2 years ago

0 Eli Sorenti-Burns over 2 years ago

TI__Intellectual 1350 points

Hi Ahmed,

Thank you for posting to the E2E forum. What's the status of your Enable pin? Please see Section 8.4 of DRV835x 100-V Three-Phase Smart Gate Driver datasheet (Rev. A) (ti.com) to observe the device's functional modes.

Best,

Eli

0 Ahmed Iftikhar over 2 years ago in reply to Eli Sorenti-Burns

Prodigy 20 points

Thanks for the reply.

The ENABLE pin is connected to DVDD.

0 Ahmed Iftikhar over 2 years ago in reply to Eli Sorenti-Burns

Prodigy 20 points

One more thing. Upon circuit power-up, the FAULT pin goes high for about 10ms and then goes low and stays low. I have not connected motor windings yet.

0 Eli Sorenti-Burns over 2 years ago in reply to Ahmed Iftikhar

TI__Intellectual 1350 points

Hi Ahmed,

Thank you for the extra information! What is the voltage of VCP and what is the voltage between SNx and SPx? I'm guessing this could be a VDS_OCP, VSEN_OCP or GDF fault given that nFAULT stays low.

The following FAQ ((+) [FAQ] Debugging faults with Hardware variant devices - Motor drivers forum - Motor drivers - TI E2E support forums) should be helpful when looking at how to debug hardware devices. This FAQ gives tips on how to identify which fault you are facing and how to solve the issue. Additionally, we can look at 'Table 6. Fault Action and Response' in DRV835x 100-V Three-Phase Smart Gate Driver datasheet (Rev. A) (ti.com) to determine which fault it is and then continue debugging from there.

Best,

Eli

0 Ahmed Iftikhar over 2 years ago in reply to Eli Sorenti-Burns

Prodigy 20 points

Hello Eli.

Should SNx and SPx pins be left open if current sense is not being used ?

I will follow these links and also update you about the voltages.

Regards.

0 Ahmed Iftikhar over 2 years ago in reply to Eli Sorenti-Burns

Prodigy 20 points

Please tell me VGLS should be 11V or 14.8V? Because I have 14.8V whereas datasheet says 11V in Pin Functions table of the datasheet.

+1 Eli Sorenti-Burns over 2 years ago in reply to Ahmed Iftikhar

TI__Intellectual 1350 points

Hi Ahmed,

Thank you for the reply.

Ahmed Iftikhar said:
Should SNx and SPx pins be left open if current sense is not being used ?

If CSAs are not going to be used, then leave SOx open and ground SNx and SPx near each other so there is no voltage difference between the two.

Ahmed Iftikhar said:
Please tell me VGLS should be 11V or 14.8V? Because I have 14.8V whereas datasheet says 11V in Pin Functions table of the datasheet.

This may be the issue; however, it is not violating any ABS_MAX conditions listed in Section 7 of the datasheet. I'll align with my team on this and get back to you after I hear about your VCP voltage.

Best,

Eli

0 Ahmed Iftikhar over 2 years ago in reply to Eli Sorenti-Burns

Prodigy 20 points

Hi Eli.

I found out that one my SPx pins was not properly grounded, causing the FAULT condition. After grounding the pin, the IC got out of the FAULT condition and PWMs were available as per datasheet.

Thanks for your time.

Reards.