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

Rev.2.0 Oct.08, 2019

AX3101



FUNCTION DESCRIPTIONS

WM Control

The AX3101 consists of DC/DC converters that employ a pulse-width modulation (PWM)

system. In converters of the AX3101, the pulse width varies in a range from 0 to 100%,

according to the load current. The ripple voltage produced by the switching can easily be

removed through a filter because the switching frequency remains constant. Therefore, these

converters provide a low-ripple power over broad ranges of input voltage and load current.

RDS (ON) Current Limiting

The current limit threshold is setting by the external resistor (R3) connecting from VCC

supply to OCSET pin. The internal 130uA sink current crossing the resistor sets the voltage

at pin of OCSET. When the PWM voltage is less than the voltage at OCSET, an over-current

condition is triggered. Please refer to the formula for setting the minimum current limit value:

R

I

I

DS(ON)

OCSET

.

R3

SW(MIN)

08

0







(Normally, The ISW(MIN) setting more than IOUT 1.0A ).

Example:

ISW = (0.13mA x 1.3k + 0.08)/ 0.070Ω= 3.56A - (VIN=12V)

ISW = (0.13mA x 2.5K + 0.08)/ 0.10Ω= 4.05A - (VIN=5V)

Setting the Output Voltage

Application circuit item shows the basic application circuit with adjustable output version.

The external resistor sets the output voltage according to the following equation:











 





2

1

1

8

.

0

R

R

V

V

OUT

Table 1 Resistor select for output voltage setting

VOUT

R2

R1

5V

1.3K

6.8K

5.6K

30K

3.3V

1.5K

4.7K

5.6K

18K

2.5V

2.2K

4.7K

1.8V

2K

2.5K

1.5V

2.2K

2.0K

1.2V

3K

1.5K

1.0V

3K

0.75K

The R2 setting 5.6k that No load current can be reduce to under 4mA for EL CAP.