ap1534 Diodes, Inc., ap1534 Datasheet - Page 7

• Manufacturer Part Number: ap1534
• Description: Pwm Control 2a Step-down Converter
• Manufacturer: Diodes, Inc.

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
once V
Current Limit Protection
The current limit threshold is set by external resistor R
connected from V
current I
at OCSET pin. When the PWM voltage is less than the voltage at
OCSET, an over-current condition is triggered.
Marking Information
AP1534 Rev. 2
CC
OCSET
rises above 3.5V.
(90uA typical) across this resistor sets the voltage
Part No.
CC
Logo
supply to OCSET pin. The internal sink
( Top View )
AP1534
YYWW X X
8
1
www.diodes.com
SOP-8L
OCSET
PWM CONTROL 2A STEP-DOWN CONVERTER
7 of 8
5
4
The current limit threshold is given by the following equation:
where,
I
resistance; F
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
recommended.
The recommended minimum R
The maximum R
current output.
PEAK
V
is the output peak current; R
IN
12
18
4
5
(V)
temperature
I
PEAK
S
is the PWM frequency (300KHz typical). Also, the
OCSET
I
Δ
G : Green
Internal code
Xth week: 01~52
Year : "07" = 2007
PEAK
×
I
R
=
V
value should not exceed AP1533 maximum
DS(ON)
OUT
3.3
V
12
1
5
>
IN
(V)
over
I
F
OUT
−
S
"08" = 2008
xL
=
OCSET
V
(MAX)
OUT
I
OCSET
100°C,
value is summarized below:
DS (ON)
x
+
R
V
×
OCSET
V
(
DECEMBER 2007
OUT
6.8K
5.6K
3.9K
4.7K
Δ
R
2
IN
©
is the MOSFET ON
AP1534
I)
R
OCSET
Diodes Incorporated
OCSET
(Ω)
≧6.8KΩ
is