L6208Q datasheet(26/34 Pages) STMICROELECTRONICS

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Output current capability and IC power dissipation

L6208Q

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DocID018710 Rev 3

Output current capability and IC power dissipation

Figure 26, 27, 28 and 29 show the approximate relation between the output current and the

IC power dissipation using PWM current control driving a two-phase stepper motor, for

different driving sequences:



HALF STEP mode (Figure 26) in which, alternately, one phase / two phases are

energized.



NORMAL DRIVE (FULL STEP TWO-PHASE-ON) mode (Figure 27) in which two

phases are energized during each step.



WAVE DRIVE (FULL STEP ONE-PHASE-ON) mode (Figure 28) in which only one

phase is energized at each step.



MICROSTEPPING mode (Figure 29), in which the current follows a sinewave profile,

provided through the Vref pins.

For a given output current and driving sequence the power dissipated by the IC can be

easily evaluated, in order to establish which package should be used and how large the

onboard copper dissipating area must be to guarantee a safe operating junction

temperature (125 °C maximum).

Figure 26. IC power dissipation vs. output current in half step mode

L6208Q Datasheet(PDF) 26 Page - STMicroelectronics