DRV8305-Q1: DRV8305-Q1

(copying/pasting from yesterday)

Hi Adam,

We removed the blown DRV chip, cleaned up the pads, and soldered a replacement part. (thank you TI for samples!), however the replacement part failed after some use, too (AVDD reads 0V).  I have attached the schematic for the PCB as well as some selections from the PCB layout. 

Notes:

0. PVDD for testing has been set at 13.7V.

1. The PCB is designed to mate with a Launchpad TMS320F28069M for development.  I have a 3.3V buck converter to power the launchpad board as well as the pullup resistors for PWRGD and nFAULT.

2. At the moment half of the power MOSFETs (Q2, Q4, Q6, & Q8) are not present on the board.

3. I failed to include the pullup resistors for PWRGD and nFAULT as well as the VSEN_PVDD voltage divider on the PCB.  I built these parts of the system (matching the DRV8305EVM design for PWRGD and nFAULT) on a prototyping board and am confident that they are wired up correctly.

4. Because of the design error for VSEN_PVDD, I broke off the pins connecting VREG from the driver board to the Launchpad board.

5. There is a strong chance that all 16V-rated capacitors were replaced with 25V capacitors with the same capacitance values.

Bob,

I need to review this with the team, I will get back to you this week.

Regards,

-Adam

Bob,

Sorry for the delay here, did you find any additional info?

Regards,

-Adam

Hi Adam,

I am redesigning the driver board to add some of the boosterpack features such as 3.3V regulated power supply and transient voltage suppression as well as include the omitted VSENSE_PVDD voltage divider and the PWRGD and nFAULT pullups.

One of the applications for this driver board includes a motor which requires 5V (~2.5mA) for its hall effect sensors (required for some non-TI microcontroller which is working at the moment with an 8305N boosterpack).  For this reason we are going to use the 83055 variant.  However I am concerned that using the 83055 driver may change the arithmetic for the current sense amplifiers and maybe something else on the board.  I'll likely have more to say tomorrow.

Best,

Bob