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DRV8818 question about external capacitor

NAOKI AOYAMA
Guru 11215 points
Other Parts Discussed in Thread: DRV8818, DRV8811

Hello,

Our customer use the DRV8818.

The customer place the capacitor at VGD-GND and have question.

a) How much the voltage ratings?

In the EVM, the capacitor rated for 50V. 

b) How much the current through the capacitor?

The customer want to know the wattage.

Best Regards,

Naoki Aoyama

  • 0
    TI__Guru** 114905 points
    Hi Aoyama-san,

    The customer place the capacitor at VGD-GND and have question.

    a) How much the voltage ratings?

    A 16V capacitor is recommended. This will be added to the next datasheet update for the DRV8818 and DRV8811.

    In the EVM, the capacitor rated for 50V.

    b) How much the current through the capacitor?

    Can you clarify? What wattage does the customer want to know?
  • 0 in reply to Rick Duncan
    Guru 11215 points
    Hi Rick-san,

    Thank you for your reply.

    //A 16V capacitor is recommended. This will be added to the next datasheet update for the DRV8818 and DRV8811.
    Thank you for your information.

    //Can you clarify? What wattage does the customer want to know?
    I'm sorry for my poor information.
    The customer check the rush current of capacitor.
    Could you tell me the impedance of the VGD, VCP, CP1,CP2 pin?
    I think the current through the capacitor is small value.

    Thanks,
    Naoki Aoyama
  • 0 in reply to NAOKI AOYAMA
    TI__Guru** 114905 points
    Hi Aoyama-san,

    This information is not readily available. The IVM spec provides an average current of VGD, VCP, and internal circuitry.

    IVM -- VM operating supply current VM = 35 V, fPWM < 50 KHz -- max is 10 mA

    Figure 2 shows typical values for 8V, 24,V, and 35V across temp.
  • 0 in reply to Rick Duncan
    Guru 11215 points

    Hi Rick-san,

    Thank you for your reply.

    I understood your view of wattage.

    I will explain the customer  the wattage due to the average current.

    Thanks,

    Naoki Aoyama