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BCD Semiconductor Manufacturing Limited

ADJUSTABLE-SPEED SINGLE-PHASE FULL-WAVE PRE-DRIVER FOR MOTOR

AM4967

Oct. 2008 Rev. 1. 2

Data Sheet

Pin Number

Pin Name

Function

1

OUT2

Second channel P-type driver output. Open-drain output, must be connected

with pull-up resistor to drive external power devices in operation

2

OUT2B

Second channel N-type driver output. Push-pull output to drive external

power devices

3

VCC

Power supply

4CS

Current limiter indicator. Fixed to 0.2V internally. Maximum allowable cur-

rent is decided by external sample resistance. When the voltage of this pin

exceeds 0.2V, the output will be shut down by current limit. If this function is

not used, connect this pin to ground directly

5VMIN

Minimum speed setting terminal. Connect it to VREF when disused. In case it

is tied to other power supply for controlling, an isolated resistor is necessary

6VPWM

Speed control terminal. It is full speed mode when connected to ground. If the

speed is controlled by PWM mode, the frequency of control signal is 20kHz

to 100kHz. Moreover, a low pass network is necessary to transfer PWM to

DC level

7COSC

PWM basic oscillation frequency generator when connected with a capacitor

of 220pF. 30kHz frequency is available.

8FG/RD

"FG" means pin 8 is an output pin of FG signal which is used for detecting

rotation speed. "RD" means pin 8 is an output pin of RD signal, and is used

for detecting fan rotate-stop state. "FG" and "RD" can be selected according

to the requirement. This pin need to be connected with pull-up resistor when

used. A new pulse will be generated once input signal changed. Keep this pin

open when it is not to be used

9HIN-

Hall sensor negative input. To prevent noise, this pin is recommended to be

placed as close as possible to Hall circuit. If necessary, a capacitor may be

added between HIN+ and HIN- to reduce the influence caused by noise

10

HIN+

Hall sensor positive input. To avoid noise, this pin is recommended to be

placed as close as possible to Hall circuit

11

CT

Lock protection and auto start frequency generator. It is connected with an

external 0.47

µF capacitor which decides lock-rotate time and start time. If

lock-rotate protection function is disused, please connect this pin to GND

12

LS

Linear start terminal. This pin is connected to VREF externally via a capacitor

of 0.47

µF to 1µF which enables fan start steadily. Start time is dependent to

the capacitance. If linear start function is not used, connect this pin to ground

13

VREF

5V voltage reference

14

GND

Ground for circuit control

15

OUT1B

First channel N-type driver output. Push-pull output to drive external power

devices

16

OUT1

First channel P-type driver output. Open-drain output, must be connected with

pull-up resistor to drive external power devices in operation

Pin Description