DRV8704 Datasheet, PDF (12/38 Pages) Texas Instruments – Dual H-Bridge PWM Gate Driver

DRV8704
SLVSD29 – OCTOBER 2015
www.ti.com
7.3 Feature Description
7.3.1 PWM Motor Drivers
The DRV8704 contains two H-bridge motor gate drivers with current-control PWM circuitry.
7.3.2 Direct PWM Input Mode (Dual Brushed DC Gate Driver)
In direct PWM input mode, the AIN1, AIN2, BIN1, and BIN2 directly control the state of the output drivers. This
allows for driving up to two brushed DC motors. Table 1 shows the logic.
SLEEPn
0
1
1
1
1
xIN1
X
0
0
1
1
xIN2
X
0
1
0
1
Table 1. Output Control Logic Table
xOUT1
Hi-Z
Hi-Z
L
H
L
xOUT2
Hi-Z
Hi-Z
H
L
L
DESCRIPTION
Sleep mode; H-bridge disabled Hi-Z
Coast; H-bridge disabled Hi-Z
Reverse (current xOUT2 → xOUT1)
Forward (current xOUT1 → xOUT2)
Brake; low-side slow decay
In direct PWM mode, the current control circuitry is still active. The full-scale VREF is set to 2.75 V. The
TORQUE register may be used to scale this value, and the ISEN sense amplifier gain may still be set using the
ISGAIN bits of the CTRL register.
xIN1
xIN2
PWM
logic
Gate
Drive
and
OCP
Gate
Drive
and
OCP
x1HS
VM
xOUT1
x1LS
x2HS
VM
xOUT2
x2LS
VREF
TORQUE
Torque
DAC
Comp
Comp
ISEN
amp
ISGAIN
xISENP
xISENN
R_ISENSE
Figure 8. Motor Driver Block Diagram
12
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