LB11660FV

No.8318-4/8

Application Circuit Example 1

*1.Power supply and ground lines

The IC ground is the control current power supply system ground, and the external n-channel transistor ground is the motor power

supply system ground.

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

IC ground.

*2. Regeneration power supply stabilization capacitor

Use a 4.7µF/25V capacitor at least for CM, which is the power supply stabilization capacitor for both PWM drive and kickback

absorption.

The capacitor CM must be connected to prevent destruction of the IC when power is applied or removed.

*3.Speed Control

(1) Control voltage

The PWM duty is determined by comparing the VTH pin voltage with the PWM oscillator waveform.

When the VTH voltage falls, the on duty increases and when the VTH voltage falls below the PWM output low level, the duty will

go to 100%.

(2) Thermistor

For thermistor applications, normally the 6VREG level will be resistor divided and the divided level input to the VTH pin.

The PWM duty is changed by changes in the VTH pin voltage due to changes in temperature.

*4. Current limiter setting

The current limiter circuit operates if the voltage across the resistor between VCC and the VM pin exceeds 0.5V.

Since the current limiter circuit applies limitation at a current determined by IO = VRf/Rf (where VRf = 0.5V (typical), Rf:

resistance of the current detection resistor), the current limiter will operate at IO = 1A when Rf = 0.5Ω.

The resistor RF must be connected in the circuit and it must have a value such that the circuit operates within the recommended

current limiter operating range.

VCC

FG

OUT1

OUT2

CT = 0.47 to 1

μF

CT

VTH

IN+

IN-

CPWM

*5

CP = 200pF *f = 23kHz

CP = 100pF *f = 46kHz

*1

*7

H

*2

HB

GND

6VREG

VM

Rf

*4

Control valtage

RMI

R3

PRE1

PRE2

*3

*9

CM = 4.7

μFor

more

R4