DRV8837_15 Datasheet, PDF (10/24 Pages) Texas Instruments – Low-Voltage H-Bridge Driver

DRV8837, DRV8838
SLVSBA4D – JUNE 2012 – REVISED DECEMBER 2015
www.ti.com
7.3 Feature Description
7.3.1 Bridge Control
The DRV8837 device is controlled using a PWM input interface, also called an IN-IN interface. Each output is
controlled by a corresponding input pin.
Table 1 shows the logic for the DRV8837 device.
nSLEEP
0
1
1
1
1
Table 1. DRV8837 Device Logic
IN1
IN2
OUT1
OUT2
FUNCTION (DC MOTOR)
X
X
Z
Z
Coast
0
0
Z
Z
Coast
0
1
L
H
Reverse
1
0
H
L
Forward
1
1
L
L
Brake
The DRV8838 device is controlled using a PHASE/ENABLE interface. This interface uses one pin to control the
H-bridge current direction, and one pin to enable or disable the H-bridge.
Table 2 shows the logic for the DRV8838.
nSLEEP
0
1
1
1
Table 2. DRV8838 Device Logic
PH
EN
OUT1
OUT2
FUNCTION (DC MOTOR)
X
X
Z
Z
Coast
X
0
L
L
Brake
1
1
L
H
Reverse
0
1
H
L
Forward
7.3.2 Sleep Mode
If the nSLEEP pin is brought to a logic-low state, the DRV883x family of devices enters a low-power sleep mode.
In this state, all unnecessary internal circuitry is powered down.
7.3.3 Power Supplies and Input Pins
The input pins can be driven within the recommended operating conditions with or without the VCC, VM, or both
power supplies present. No leakage current path will exist to the supply. Each input pin has a weak pulldown
resistor (approximately 100 kΩ) to ground.
The VCC and VM supplies can be applied and removed in any order. When the VCC supply is removed, the
device enters a low-power state and draws very little current from the VM supply. The VCC and VM pins can be
connected together if the supply voltage is between 1.8 and 7 V.
The VM voltage supply does not have any undervoltage-lockout protection (UVLO) so as long as VCC > 1.8 V;
the internal device logic remains active, which means that the VM pin voltage can drop to 0 V. However, the load
cannot be sufficiently driven at low VM voltages.
7.3.4 Protection Circuits
The DRV883x family of devices is fully protected against VCC undervoltage, overcurrent, and overtemperature
events.
7.3.4.1 VCC Undervoltage Lockout
If at any time the voltage on the VCC pin falls below the undervoltage lockout threshold voltage, all FETs in the
H-bridge are disabled. Operation resumes when the VCC pin voltage rises above the UVLO threshold.
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