Copyright

© ANPEC Electronics Corp.

Rev. A.6 - Mar., 2008

APX9267

www.anpec.com.tw

6

Typical Application Circuit

Note 2: In hot plug application, it’s necessary to protect against a hot plug input voltage overshoot. Add an input zener diode, between

the VCC and GND, to clamp the overshoot. In normal operation diode, the zener diode isn’t stressed because output current

doesn’t reverse to VCC.

Function Description

Lockup Protection and Automatic Restart

This IC detects the rotation of the motor by hall signal,

and adjusts lock detection ON time (T

tion OFF time (T

(T

Lock

OUT1

FG

Release

T

OFF

T

ON

OUT2

IN+

IN-

Lock

Detection

Reset

T

OFF

Figure 1. Lock Protection and Automatic Protection Wave-

form

Quick Start and Standby mode

This IC would enter standby mode when the PWM input

keeps low level for more than 66.5ms (typ.). In standby

mode, it will shutdown amplifier and FG. Thus, the supply

current is around 150

µA. In standby mode, the lock pro-

tection function doesn’t work, therefore, starting fan is

unobstructed when releasing standby mode.

66.5ms

(typ.)

disable

enable

enable

PWM

Lock

protect

enable (internal)

Figure 2. Quick Start Waveform

Frequency Generator Function

The FG pin is an open collector output, connecting a pull

up resistor to a high level voltage for the frequency gen-

OUT2

GND

1

2

3

4

5

6

7

8

VCC

IN+

IN-

FG

PWM

OUT1

Hall

PWM

control signal

10k

Ω

R

FG

6V

C1

D1

Zener

D2

Pull High

Voltage

V

IN

FG Output