F1962

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

4 of 8

www.unisonic.com.tw

QW-R109-017. E



TRUTH TABLE

ST

IN

-

IN

+

CT

OUT1

OUT2

FG

HB

Mode

H

off

off

off

off

Standby

L

H

L

L

H

L

H

L

Rotating

L

H

L

H

L

H

off

off

L

Lockup protection

activated



DESIGN REFERENCE

(2) OUT1, OUT2 pins

Single-phase coil output pins.

Bipolar forward or reverse drive output determined by OUT1 or OUT2 high. Built-in regenerative circuit that

regenerates kickback current between lower side NPN outputs if a diode is used for protection against reverse

connection.

(3) IN

Hall signal input pins

The Hall signal is amplified into a square wave by the Hall amplifier with hysteresis characteristics of ±3.5 mV

(typ.). The Hall signal amplitude should be 70 mV or more.

(4) CT pin

This pin serves timing capacitor connecting pin between CT and GND.

The capacitor determines timing of the built-in lockup protection circuit for preventing coil burnout when motor is

locked. Once normal motor rotating condition is restored, the automatic recovery circuit will reset itself.

Adjusting the capacitance alters the lockup detection time.

When a 0.47 mF capacitor is connected between CT and GND

Lockup detection time

:approx. 0.5s

Lockup protection time/automatic recovery time

:approx. 0.16s (output ON)

:approx. 1s (output OFF)

Connecting this pin to ground when lockup function is not used

(6) FG pin

Open-collector output pin for rotation frequency detection.

When IN

When IN

(7) ST pin and HB pin

ST pin: When input to this pin is High, motor drive is stopped (OUT is high impedance).

HB pin: Hall bias switching pin. At ST pin High input, Hall bias is switched to reduce current drain in fan standby

mode.

If not used, both pins should be open.

(8) Thermal protection circuit

damage.