BA6872AFM datasheet(8/11 Pages) ROHM

8 / 11 page

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Motor driver ICs

BA6872AFM

Reversible motor driver for loading

(6)

Input block (FIN and RIN) and mode explanation

These are the control signal input pins. The operations

of the various modes are explained below. When FIN is

high level, and RIN is low level, the mode is forward mode,

and current flows from OUT1 to OUT2.

When FIN is low level, and RIN is high level, the mode is

reverse mode, and current flows from OUT2 to OUT1.

When FIN and RIN are both high level, the mode is brake

mode. In brake mode, the upper-side output transistor is

off, and stops supply of current to the motor. The lower-

side output transistor is on, and absorbs the back-rush of

the motor and applies braking. When FIN and RIN are both

low level, OUT1 and OUT2 are open-circuit potential,

and the motor stops.

FTruth table

(7)

Vref pin (output high voltage setting pin)

The output voltage can be varied by controlling Vref.

VOH = Vref

) VBE (PNP) * VBE (NPN) ) (VOUT * Vref off-

set)

) IREF

However, Vref

x VM2 * [Vsat (PNP) ) VBE (NPN)]

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Connection pins for output ground and output cur-

rent sense resistor (RNF)

By connecting a resistor to this pin, it is possible to sense

the amount of current flowing in the motor. By adding an

electronic governor, and controlling Vref, it is possible to

construct a reversible motor driver.

BA6872AFM Datasheet(PDF) 8 Page - Rohm