6/12

Axelite Confidential Materials, do not copy or distribute without written consent.

Rev.1.6 Oct.09, 2019

AX3112/A



FUNCTION DESCRIPTIONS

SENSE1/2

The current limit sense pin, if VSENSE1-VSENSE2≧125mV, the over current is happened

that it can turn-off driver cycle by cycle.

EN/CT

The pin is enable/shutdown and auto restart control functions. When system is

normal operating, this pin is enable/shutdown function. Pulling this pin below a threshold

voltage of under 0.3V shuts the regulator off, and pulling this pin from 0.5V to 1.5V turns

the regulator on. However when VOUT is short (VFB<0.4V), the auto restart function can be

started that restart the regulator cycle by cycle. The cycle time is set by outside capacitor

(C6). Please refer the below waveform and formula, the t2 cycle is regulator off time and t1

cycle is current limit time. The charge-current is 32uA and discharge-current is 1.5uA.

VEN/CT

Time

t1

t2

Time

Iin (A)

0.5V

1.5V

0

Current Limit

.)

Sec

(

u

5

.

1

1

×

6

C

=

2

t

.)

Sec

(

u

32

1

×

6

C

=

1

t

Under Voltage Lockout (UVLO)

To avoid error-operation of the device at low input voltages an under voltage lockout

is included that disables the device, if the input voltage falls below 6.0V.

Current Limit Protection

The Current limit is set by outside resistance (RSENSE), When the SENSE1-SENSE2

voltage larger than 125mV, the current limit is happened that driver can be turned off until

the drop is small than 80mV. The current limit set according to the following equation:

SENSE

xR

2

m

)

45

-

125

(

+

m

125

=

(A)

Limit

Current