LB11961V

No.8794-5/7

Application Circuit Example

*1.Power supply and ground lines

P-GND is connected to the motor power supply system and S-GND is connected to the control circuit power supply system.

These two systems should be formed from separate lines and the control system external components should be connected to

S-GND.

*2. Regeneration power supply stabilization capacitor

The capacitor CM provides power supply stabilization for both PWM drive and kickback absorption. A capacitor with a value of

over 0.1µF is used for CM. A large capacitor must be used when the coil inductance is large or when the coil resistance is low.

Since this IC adopts a technique in which switching is performed by the high side transistor and regeneration is handled by the low

side transistor, the pattern connecting CM to VM and P-GND must be as wide and as short as possible.

*3.Hall sensor input

Lines that are as short as possible must be used to prevent noise from entering the system. The Hall sensor input circuit consists of

a comparator with hysteresis (20mV). We recommend that the Hall sensor input level be at least three times this hysteresis, i.e. at

least 60mVp-p.

*4.PWM oscillator frequency setting capacitor

If a value of 100pF is used for CP, the oscillator frequency will be f = 25kHz, and this will be the basic frequency of the PWM

signal.

*5.RD output

This is an open collector output. It outputs a low level when the motor is turning and a high level when it is stopped. This pin must

be left open if unused.

*6.FG output

This is an open collector output, and a rotation count detection function can be implemented using this FG output, which

corresponds to the phase switching. This pin must be left open if unused.

*7.HB pin

This pin provides a Hall effect sensor bias constant-voltage output of 1.25V.

*8.RMI pin

Connect this pin to VTH if unused. Even if unused, the IC is set internally to operate at a 10% drive duty at the voltage

corresponding to the lowest speed. (The capacitor is used to set up full-speed mode at startup.)

P-GND

VCC

FG

OUT1

OUT2

CT

VTH

IN

+

IN

−

CPWM

*3

CM

H

*2

RMI

RD

HB

S-GND

*7

6VREG

CT = 0.47

μF to 1μF

CP = 100pF