AP1534

PWM CONTROL 2A STEP-DOWN CONVERTER

AP1534 Rev. 2

7 of 8

DECEMBER 2007

www.diodes.com

Function Description

PWM Control

The AP1534 is a DC/DC converter that employs pulse width

modulation (PWM) scheme. Its pulse width varies in the range of

0% to 99%, based on the output current loading. The output

ripple voltage caused by the PWM high frequency switching can

easily be reduced through an output filter. Therefore, this

converter provides a low ripple output supply over a broad range

of input voltage & output current loading

Under Voltage Lockout

The under voltage lockout circuit of the AP1534 assures that the

high-side MOSFET driver remains in the off state whenever the

supply voltage drops below 3.3V. Normal operation resumes

Current Limit Protection

at OCSET pin. When the PWM voltage is less than the voltage at

OCSET, an over-current condition is triggered.

The current limit threshold is given by the following equation:

R

I

R

I

OCSET

OCSET

DS(ON)

PEAK

×

=

×

2

I)

(

I

I

(MAX)

OUT

PEAK

Δ

+

>

where,

IN

OUT

S

OUT

IN

V

V

x

xL

F

V

V

I

−

=

Δ

inductor value will affect the ripple current

ΔI.

The above equation is recommended for input voltage range of

5V to 18V. For input voltage lower than 5V, higher than 18V or

ambient

temperature

over

100°C,

is

recommended.

4

1

6.8K

5

3.3

5.6K

12

5

3.9K

18

12

4.7K

current output.

( Top View )

SOP-8L

AP1534

YYWW X X

Logo

Part No.

Internal code

Year : "07" = 2007

"08" = 2008

Xth week : 01~52

5

8

4

1

G : Green

Marking Information