DRV8833_15 Datasheet, PDF (9/28 Pages) Texas Instruments – DRV8833 Dual H-Bridge Motor Driver

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DRV8833
SLVSAR1E – JANUARY 2011 – REVISED JULY 2015
7.3 Feature Description
7.3.1 Fixed-Frequency PWM Motor Drivers
DRV8833 contains two identical H-bridge motor drivers with current-control PWM circuitry. Figure 5 shows a
block diagram of the circuitry.
xIN1
xIN2
VCP, VINT
OCP
Pre-
drive
PWM
OCP
-
+
REF (200mV)
VM
VM
xOUT1
xOUT 2
DCM
xISEN
Optional
Figure 5. Motor Control Circuitry
7.3.2 Bridge Control and Decay Modes
The AIN1 and AIN2 input pins control the state of the AOUT1 and AOUT2 outputs; similarly, the BIN1 and BIN2
input pins control the state of the BOUT1 and BOUT2 outputs. Table 1 shows the logic.
xIN1
0
0
1
1
Table 1. H-Bridge Logic
xIN2
xOUT1
xOUT2
0
Z
Z
1
L
H
0
H
L
1
L
L
FUNCTION
Coast/fast
decay
Reverse
Forward
Brake/slow
decay
The inputs can also be used for PWM control of the motor speed. When controlling a winding with PWM, when
the drive current is interrupted, the inductive nature of the motor requires that the current must continue to flow.
This is called recirculation current. To handle this recirculation current, the H-bridge can operate in two different
states: fast decay or slow decay. In fast decay mode, the H-bridge is disabled and recirculation current flows
through the body diodes; in slow decay, the motor winding is shorted.
To PWM using fast decay, the PWM signal is applied to one xIN pin while the other is held low; to use slow
decay, one xIN pin is held high.
Table 2. PWM Control of Motor Speed
xIN1
PWM
1
0
PWM
xIN2
0
PWM
PWM
1
FUNCTION
Forward PWM, fast decay
Forward PWM, slow decay
Reverse PWM, fast decay
Reverse PWM, slow decay
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