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DRV8412

eli
Guru 13485 points

Using  the  Evaluation board  in the    000  mode.The  inductors  were  removed  and the bootstrap  capacitors  were set to 4.7uF.( c15/18/20/23) 

Chanels A   &  B  were  driven from two 70 Hz   square  wave with variable phase between them.  Our load   was placed between the  A  and B outputs  was a solenoid   15  OHM  /0.3H   coil. 

The system worked  causing the solenoid to vibrate as required. However, under some circumstances  ( when  the input signals had  spikes on them????) we caused damage the IC  that required it to be changed. 

Please tell us  the type of conditions that may cause damage  to the IC.  For example  the order  of Voltage(12V, 50 V) on was NOT important.

  • 0
    TI__Guru** 114905 points

    Hi Eli,

    When using the 4.7uF bootstrap caps, did you also place a 5 Ohm series resistor in line with GVDD?

    From section 7.3.2.1 of the most recent datasheet:

    For applications with lower than 10-kHz switching frequency and not to trigger BST_UVP protection, a larger

    bootstrap capacitor can be used (for example, 1-μF capacitor for 800-Hz operation). When using a bootstrap cap

    larger than 220 nF, it is recommended to add 5-Ω resistors between 12-V GVDD power supply and GVDD_X

    pins to limit the inrush current on the internal bootstrap circuitry.



    Also please note section 8.2.1.2.2

    The DRV83x2 requires a 12-V power supply for GVDD and VDD pins. The total supply current is relatively low at

    room temperature (less than 50 mA), but the current could increase significantly when the device temperature

    goes too high (for example, above 125°C), especially at heavy load conditions due to substrate current collection

    by 12-V guard rings. TI recommends designing the 12-V power supply with a current capability at least 5-10% of

    the load current, and no less than 100 mA to assure the device performance across all temperature ranges.

    Either of these conditions could cause the damage to the IC.

    In addition, the most common damage is electrical overstress. This is when one of the abs max conditions is violated.