Datasheet

OUT 1
OUT2
VM
EN2
Pre-
drive
VM
Logic
IN2
Pre-
drive
OCP
OCP
EN1
IN1
OUT 3
OUT4
VM
EN4
Pre-
drive
IN4
Pre-
drive
OCP
OCP
EN3
IN3
DRV8844
www.ti.com SLVSBA2A –JULY 2012–REVISED OCTOBER 2012
FUNCTIONAL DESCRIPTION
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.
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 Submit Documentation Feedback 7
Product Folder Links: DRV8844