Calculating Motor Driver Power Dissipation

http://www.ti.com/lit/an/slva504/slva504.pdf

Abstract

When selecting a motor driver IC

for a particular application,

consider the maximum amount of current

that must be driven.

The thermal characteristics of the IC and PCB

are often the limiting factor

in how much current

a given motor provides.

To calculate the maximum allowable current

in a given application,

an estimation of the total motor driver power dissipation

is needed.

This application report shows how to estimate this power dissipation

in DC brush motor

& stepper motor applications.

---

1 Sources of Power Dissipation in a Motor Driver

1.1 R Dissipation

1.2 Switching Losses

1.3 Operating Supply Current Dissipation

1.4 Other Power Dissipation

2 Example Calculation

2.1 Conditions and Assumptions

2.2 Power Calculation

2.3. Die Temperature Estimation