Datasheet

V
Load
+ D V
DD
D +
A
v
ǒ
V
IN)
–V
IN–
Ǔ
V
DD
H/C
PWM
Load
Voltage
VDD
VDD
VDD
VDD/2
0
0
0
DRV593
DRV594
www.ti.com SLOS401C –OCTOBER 2002–REVISED JULY 2010
APPLICATION INFORMATION
PULSE-WIDTH MODULATION SCHEME FOR DRV593 AND DRV594
The pulse-width modulation scheme implemented in the DRV593 and DRV594 eliminates one-half of the full
output filter previously required for PWM drivers. The DRV593 and DRV594 require only one inductor and
capacitor for the output filter. The H/C outputs determine the direction of the current and do not switch back and
forth. The PWM outputs switch to produce a voltage across the load that is proportional to the input control
voltage.
COOLING MODE
Figure 18 shows the DRV593 and DRV594 in cooling mode. The H/C outputs (pins 14-17) are at ground and the
PWM outputs (pins 24-27) create a voltage across the load that is proportional to the input voltage.
The differential voltage across the load is determined using Equation 1 and the duty cycle using Equation 2. The
differential voltage is defined as the voltage measured after the filter on the PWM output relative to the H/C
output.
(1)
(2)
where D duty cycle of the PWM signal A
v
Gain of DRV593/594 (DRV593: 2.3 V/V, DRV594: 14.5 V/V) V
IN+
Positive input terminal of the DRV593/594 V
IN–
Negative input terminal of the DRV593/594 V
DD
Power supply
voltage
For example, a 50% duty cycle, shown in Figure 18, results in 2.5 V across the load for V
DD
= 5 V.
Figure 18. Cooling Mode
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Product Folder Link(s): DRV593 DRV594