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DRV8343-Q1: IVCP

Manabu Ishida
Prodigy 110 points
Part Number: DRV8343-Q1

Hello, Team

1)

Could you check if my IVCP is calculated?
About MOSFETs
　　MOSFET Qg = 30 nC
　　fPWM = 1000Hz
　　Number of items= 5

From the formula "Trapezoidal 120°Commutation":
　　IVCP = 30 nC × 1000Hz × 5 = 0.15mA

Could you tell me if the calculation method is wrong?

2)

If the calculation is correct, the current consumption of IVCP is greater than 0.15 mA (IVCP > 0.15 mA), is it possible that IVCP=10 mA is consumed?
I would like to understand the meaning of the formula IVCP is greater than Qg × PWM.


3)

Also, the datasheet states "IVCP is the charge pump capacity, which depends on the VM pin voltage."

There is no VM terminal voltage parameter in the formula.
How does the VM terminal voltage increase or decrease the IVCP?

best regards
manabu

  • 0
    TI__Prodigy 420 points

    Hi Ishida-san,

    Thank you for you the question. I will aim to provide feedback by the end of this week.

    Best,

    Sarah

  • 0 in reply to Sarah Anthraper
    TI__Prodigy 420 points

    Hi Ishida-san,

    Manabu Ishida said:

    1)

    Could you check if my IVCP is calculated?
    About MOSFETs
    　　MOSFET Qg = 30 nC
    　　fPWM = 1000Hz
    　　Number of items= 5

    From the formula "Trapezoidal 120°Commutation":
    　　IVCP = 30 nC × 1000Hz × 5 = 0.15mA

    Could you tell me if the calculation method is wrong?

    The calculation is correct. One thing to check here, how many high side FETs are you switching? This would be the "multiplier" mentioned in the data sheet. In your calculation the number of high side FETs is 5.

    Manabu Ishida said:

    2)

    If the calculation is correct, the current consumption of IVCP is greater than 0.15 mA (IVCP > 0.15 mA), is it possible that IVCP=10 mA is consumed?
    I would like to understand the meaning of the formula IVCP is greater than Qg × PWM.


    3)

    Also, the datasheet states "IVCP is the charge pump capacity, which depends on the VM pin voltage."

    There is no VM terminal voltage parameter in the formula.
    How does the VM terminal voltage increase or decrease the IVCP?

    As long as your Ivcp is less than the 25mA recommended operating conditions (image above) this will allow you to properly switch your FETs. The relationship between VM and IVCP can be seen below, as VM increase IVCP increases and vice versa.

    Best,

    Sarah