DRV10983 Power Dissipation Equation

To whom it may concern,

Since I got the equation of power dissipation of DRV10983, I post that as follows, 

• Power dissipated in IC = Pcircuits + Pswitching + Pfets
  • Pcircuits – power consumed by internal circuit
    • Measure Vreg first and externally force Vreg pin to +0.5V to what you have measured
    • Pcircuits = forced voltage  * current from external supply.
  • Pswitching – Switching loss
    • Measure VCP pin voltage first and externally force VCP pin to +0.7V to what you have measured
    • Pswitching = forced voltage * current from external supply
  • Pfets – loss through Fets
    • 3 x  (Amplitude of phase current / sqrt(2) )^2 * Rdson (H+L)/2
    • 3 is for three bridges
    • I^2*R = Power loss on FET
    • Rdson(H+L)/2 – Since phase current will be always going through either high side or low side not both at the same time.
  • There are other loss but there are very small.

By using this Pd and Tt which is package case top temperature measured by a thermocouple , we can estimate the junction temperature (Tj) of DRV10983.

Tj[℃] = Pd[W] * ΨJT[℃/W] + Tt[℃]
Where,
  Tj: Device Junction Temperature
  Tt: Package Case Top Temperature
  ΨJT: Junction-to-Top Thermal Impedance
  Pd: Device Power Dissipation

Thank you.

Best Regards,

Koshi Ninomiya