DRV8844_15 Datasheet, PDF (13/25 Pages) Texas Instruments – DRV8844 Quad ½-H-Bridge Driver IC

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DRV8844
SLVSBA2C – JULY 2012 – REVISED MAY 2015
Typical Application (continued)
9.2.1 Design Requirements
The following truth tables describe how to control the arrangement in Figure 8.
FUNCTION
EN1
Forward
1
Reverse
1
Brake
1
Brake
1
Coast
0
Coast
X
Table 3. Brushed DC Motor
EN2
IN1
IN2
1
PWM
0
1
0
PWM
1
0
0
1
1
1
X
X
X
0
X
X
OUT1
H
L
L
H
Z
X
OUT2
L
H
L
H
X
Z
FUNCTION
On
Brake
Coast
Table 4. Single-Direction Brushed DC Motor
EN3
IN3
1
PWM
1
1
0
X
OUT3
L
H
Z
FUNCTION
On
Off or slow decay
Off or coast
9.2.2 Detailed Design Procedure
Table 5. Inductive Loads
EN4
IN4
1
PWM
1
0
0
X
OUT4
H
L
Z
9.2.2.1 Motor Voltage
The ratings of the motor selected and the desired RPM determine the motor voltage the designer should use. A
higher voltage spins a brushed DC motor faster with the same PWM duty cycle applied to the power FETs. A
higher voltage also increases the rate of current change through the inductive motor windings.
9.2.3 Application Curves
Figure 10. DC Motor With 80 PWM
Figure 11. IN1 to OUT1 Propagation Delay
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