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DRV8711 heating

Aleksey Zelentsov
Prodigy 230 points
Other Parts Discussed in Thread: DRV8711

How can I calculate heating of DRV8711 in Watts?

What is genral reason of IC heating?

If it is internal 5V regulator (I am working at 48VDC voltage) - is it possible to decrease heating by connecting external 5VDC to this IC?

  • 0
    TI__Guru** 114905 points
    Hi Aleksey,

    General reasons for IC heating are:
    1) Switching currents to charge and discharge the FET gate capacitance both inside and outside of the device require current. This current travels through resistive paths creating power loss.
    2) Regulators dropping voltage across transistors to create stable output voltages to drive internal logic, external circuitry, and low side FETs.
    3) Other internal circuitry.

    A quick calculation of power consumption would be (VM - 1.8V )* operating current, or 46.2V * 0.02A = .924W. This is very conservative because it is assuming all current is through the VINT regulator. There is the 5V regulator, a 10V internal supply for the low side gate drive, and the charge pump consuming part of the operating current. The biggest source of heat in DRV8711 systems is generally the FETs and the sense resistors.

    It is not recommended to connect an external 5VDC to V5. This could present issues when powering up or down. An external 5VDC can be used to reduce the load on the V5 regulator.