DRV593

DRV594

SLOS401A - SEPTEMBER 2002 REVISED - OCTOBER 2002

www.ti.com

12

HEATING MODE

Figure 19 shows the DRV593 and DRV594 in heating mode. The H/C output is at VDD and the PWM output is

proportional to the voltage across the load.

The differential voltage across the load is determined using equation (3). The variables are the same as used

previously for equations (1) and (2).

V

–(1–D)

V

DD

For example, a 50% duty cycle, shown in Figure 19, results in - 2.5 V across the load for VDD = 5 V. The differential

voltage across the load is defined as the voltage measured after the filter on the PWM output relative to the H/C output.

H/C

PWM

Load

Voltage

-VDD

VDD

VDD

-VDD/2

0

0

0

Figure 19. Heating Mode

(3)