DRV8844 Datasheet, PDF (7/17 Pages) Texas Instruments – QUAD 1/2-H-BRIDGE DRIVER IC

DRV8844
www.ti.com
FUNCTIONAL DESCRIPTION
SLVSBA2 – JULY 2012
Output Stage
The DRV8844 contains four 1/2-H-bridge drivers using N-channel MOSFETs. A block diagram of the output
circuitry is shown in Figure 2.
VM
VM
VM
IN1
EN1
IN2
EN2
IN3
EN3
IN4
EN4
Logic
Pre-
drive
OCP
Pre-
drive
OCP
Pre-
drive
OCP
OUT 1
OUT2
OUT 3
Pre-
drive
OCP
OUT4
Figure 2. Motor Control Circuitry
The output pins are driven between VM and VNEG. VNEG is normaly ground for single supply applications, and
a negative voltage for dual supply applications.
Note that there are multiple VM motor power supply pins. All VM pins must be connected together to the motor
supply voltage.
Logic Inputs
The logic inputs and nFAULT output are referenced to the LGND pin. This pin would be connected to the logic
ground of the source of the logic signals (e.g., microcontroller). This allows LGND to be at a different voltage
than VNEG; for example, you could drive a load by with bipolar power supplies by driving VM with +24 V and
VNEG with -24 V, and connect LGND to 0 V (ground).
Bridge Control
The INx input pins directly control the state (high or low) of the OUTx outputs; the ENx input pins enable or
disable the OUTx driver. Table 2 shows the logic.
Copyright © 2012, Texas Instruments Incorporated
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