• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 30 subscribers
  • Views 546 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

DRV8320: Leakage current on the DRV8320S device

RJ
Intellectual 2550 points
Part Number: DRV8320

I’m trying to design based on the leakage current of the DRV8320 but the leakage seems to change based on the resistors I use. So I’m thinking it’s some kind of resistance between the charge pump voltage and the SHX pins.

So… I basically need to better understand what is causing the leakage current for me to try to come up with a model.

1)      What is causing the leakage current exactly at SHX in the DRV8320S when in independent mode and all FETS off?

2)      Can I model this leakage as a resistor between SHX and VCP or VM?

  • 0
    TI__Genius 14487 points
    Ramon,

    1) The bias current for the VDS detection and gate drive circuitry is ~300 uA.

    2) The leakage due to bias current would be modeled as a 300-uA current source between VCP and the SHx pin. You may see the current changing for a few reasons. One, other small leakage paths inside the high-side gate drive may impact the total current. These other leakage paths would be modeled as a resistor in parallel with the current source. Two, after the current leaves the SHx pin, some of it will flow through the body diode of the high-side FET into VM. The remaining current will flow into the supply and ground of your resistor network on the SHx pin. With currents this small, you may also see the leakage of the comparator or MCU impact the performance also. Three, if a motor is connected, the leakage currents can flow through the other phases, body diodes, and SHx pins into VM as well.

    Using smaller resistors for your resistor network to draw larger currents will help to minimize the offset of these leakage currents from the SHx pin of the IC for your resistor network measurement scheme.