DRV8844_15 Datasheet, PDF (9/25 Pages) Texas Instruments – DRV8844 Quad ½-H-Bridge Driver IC

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8.3 Feature Description
DRV8844
SLVSBA2C – JULY 2012 – REVISED MAY 2015
8.3.1 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 5.
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 5. Motor Control Circuitry
The output pins are driven between VM and VNEG. VNEG is normally 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.
8.3.2 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 (for example, microcontroller). This allows LGND to be at a different
voltage than VNEG; for example, the designer can drive a load with bipolar power supplies by driving VM with
+24 V and VNEG with -24 V, and connect LGND to 0 V (ground).
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