This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
Part Number: DRV8323
Moving DRV8323H schematic review email discussion onto e2e for support.
We are evaluating DRV8323H gate driver to be used in our BLDC motor controller module. First, we got and played with a couple of BOOSTXL-DRV8323RH. That went smoothly. Now, we are testing it on our own prototype board with the more powerful MOSFETs. On the multiple boards, the DRV8323H has been blowing out suddenly. Schematic shared offline.
Also I would like to find out if is allowed to swap the SPx and SNx pins in order to have positive amplifying network gain.
Product line response: Yes, you can flip the SPx and SNx.
Questions regarding the design:
How much current load is there and how much current is expected?Customer: 15Amax continues
I see Vds monitoring is off (3v3 to VDS pin).Customer: Yes, this has been done intentionally. Is there any problem with doing that?
Situations, where the DRV can blow up, can be due to voltages being outside of device ratings. The device, per se, does not see currents.Customer: We have measured voltage levels on all PWR and control pins to make sure they are correct.
If possible, please ask for an image of where the blow occurs to know what pins it stems from.Customer: We can send an image, but it won’t be showing anything. There is no visible damage on the IC. After the DRV8323H is damaged the gate driver’s outputs are always 0V while the PWM is present on the inputs.
Is there a fault asserting before the blow?Customer: We are still investigating this matter, but so there is not a fault asserting detected before the blow.
SPx and SNx can be flipped, although it will cause the low side VDS monitoring to include the sense resistor voltage.Customer: If the VDS monitoring is disable, would it be safe to flip the SPx and SNx to have positive amplification gain?
Has the DRV operated successfully lower IDRIVE values?Customer: We tried minimum configuration of IDRIVE (10/20mA). The gate signals were destroyed. This might be because our PWM frequency is 30kHz due to the low inductance (0.3mH) of the motor. 60/120mA IDRIVE and 0.26V VDS are the latest configuration that we are using.
15A max continuous expected? Is that the current seen?Customer: A motor under test is 250W nominal power at 36V. Although it should be 7A we measured up to 16A maximum continues current while the motor was under extreme load.
Product line recommendation:
I wanted to point out that, since the customer is utilizing parallel FETs in their design, we have seen design issues before with improper circuit configuration with parallel FETs. The customer can use the following TIDA-00774 as a reference to parallel FET system design. The Design Guide’s section 6.2.1 goes into detail as to what to consider when designing parallel FET applications.
Of note are the gate resistors added to each parallel FET and the placements of these resistors, the decoupling capacitors, the power layout copper pours, and the FETs.
This post has been shared with the customer to continue the schematic review discussion here.
Hector HernandezMotor Applications Team
We are glad that we were able to resolve this issue, and will now proceed to close this thread.
If you have further questions related to this thread, you may click "Ask a related question" below. The newly created question will be automatically linked to this question.
In reply to Hector Hernandez Luque:
The schematic has been sent to Chuchen offline.
VM voltage is steady.
16A is measured at VBAT input.
There is 1000uF electrolytic and 1uF film capacitors on the VBAT input.
In reply to ashavet:
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.