DRV593
DRV594
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SLOS401A - SEPTEMBER 2002 REVISED - OCTOBER 2002
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
Load
DD
(3)
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.
VDD
PWM
0
VDD
H/C
0
Load
0
Voltage
-VDD/2
-VDD
Figure 19. Heating Mode
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