Please tell me how to calculate the current consumption and power consumption of the meter driver.

The calculation of power consumption includes, in general, power consumption due to IC bias current and power consumption due to current flowing in the output section, which are affected by the drive voltage and drive duty cycle.

〈Example calculation for a brushed motor TB67H450AFTG (from the application note)〉
The power consumed by the IC can be roughly divided into two parts: the power consumed by the transistors in the output block and the power consumed by the logic block. (Calculated with 100% drive duty below.)

P(total)=P(out)+P(bias)

  • Power consumption of motor output block

Power of the output block (P(out)) is consumed by the high-side and low-side MOSFETs of the H-Bridge.

P(out)=Iout(A)×VDS(V)=Iout(A)×Iout(A)×Ron(Ω) ……………………… (1)

When the current waveform of the motor output corresponds to the ideal waveform, the average power of the output block can be provided as follows.
Assuming Ron=0.60 Ω, Iout(peak:max)=1.5 A, VM=24 V, it can be calculated as follows

P(out)    =1.5(A)×1.5(A)×0.60(Ω) …………………………………………………(2)
             =1.35(W)

  • Power consumption of logic and IM system

The power consumption of the logic and IM system is calculated separately by the state of operating and stopping.

I(IM3) = 3.5 mA(typical): during operation (fPWM=30kHz)
I(IM2) = 3.0 mA(typical): when stopped (brake mode)

The output system is connected to VM (24V).
(Output system: Sum of the current consumed by the circuit connected to VM and the current consumed by the output stage switching)

Power consumption during operation can be calculated as follows.

P(bias)=24(V)×0.0035(A) ………………………………………………………(3)
          =0.084(W)

  • Power consumption

From the values of formulas (2) and (3), the total power consumption P(total) during operation can be calculated as follows.

P(total)=P(out)+P(bias)=1.35+0.084=1.434(W)

The power consumption n in non-operation mode (stopping) can be calculated as follows.

P=24(V)×0.003(A)=0.072(W)

Additionally, th power consumption can also be reduced by stopping operation with standby mode (IM1=1 μA(max))

In actual motor operation, the average current will be lower than the calculated value due to the transition time of current steps and ripple caused by constant current PWM. Please refer to the above calculated values and set them with a margin after sufficient evaluation of the thermal design of the board and other components.
For individual power consumption calculations, please refer to the individual specifications or contact.

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