SP - SN (V)

AVDD

SP

Logic

SNSOUT

VCC

+

-

SO

VREF

I

+

-

R

SN

OFF

V

SENSE

62 ± 9

I

A

R



K

DRV8701

www.ti.com

SLVSCX5B – MARCH 2015 – REVISED JULY 2015

7.3.4 Amplifier Output SO

The SO pin on the DRV8701 outputs an analog voltage equal to the voltage seen across the SP and SN pins

during forward or reverse drive. The H-bridge current is approximately equal to:

(2)

Figure 22. Sense Amplifier Diagram

If the voltage across SP and SN exceeds 1 V, then the DRV8701 flags an overcurrent condition.

The SO pin can source up to 5 mA of current. If the pin is shorted to GND, or if a higher-current load is driven by

this pin, the output acts as a constant-current source. The output voltage is not representative of the H-bridge

current in this state.

This shunt amplifier feature can be disabled by tying the SP and SN pins to GND. When the amplifier is disabled,

current regulation is also disabled.

Figure 23. Sense Amplifier Output

7.3.4.1 SNSOUT

The SNSOUT pin of the DRV8701 indicates when the device is in current chopping mode. When the driver is in

output is pulled low. If the current regulation is disabled, then the SNSOUT pin will be high-Z.

Note that if the H-bridge is put into a slow decay mode using the inputs (PH/EN or IN1/IN2), then SNSOUT is not

pulled low.

During forward or reverse drive mode, SNSOUT is high until the DRV8701 is internally forced into current

SNSOUT pin will be pulled low during this current chopping brake mode. After the driver is re-enabled, the

SNSOUT pin is released high-Z and the drive mode is restarted.

Copyright © 2015, Texas Instruments Incorporated

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Product Folder Links: DRV8701