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STEP-UP CONVERTER. AP5725 Datasheet

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STEP-UP CONVERTER. AP5725 Datasheet






AP5725 CONVERTER. Datasheet pdf. Equivalent




AP5725 CONVERTER. Datasheet pdf. Equivalent





Part

AP5725

Description

WHITE LED STEP-UP CONVERTER



Feature


AP5725 WHITE LED STEP-UP CONVERTER Desc ription Pin Assignments The AP5725 is a step-up DC/DC converter specifically designed to drive white LEDs with a co nstant current. The device can drive 2 ~ 6 LEDs in series from a Li-Ion cell. Series connection of the LEDs provides identical LED currents resulting in uni form brightness and eliminates the need for ballast resis.
Manufacture

Diodes

Datasheet
Download AP5725 Datasheet


Diodes AP5725

AP5725; tors. For driving higher number of LEDs, AP5725 also supports a single feedback of parallel connected multiple strings of equal number of LEDs. The AP5725 sw itches at 1.2MHz that allows the use of tiny external components. A low 0.25V feedback voltage minimizes power loss i n the current setting resistor for bett er efficiency. (Top View) SW 1 6 VIN (Top View) GND .


Diodes AP5725

2 FB 3 SW 1 5 OVP VIN 2 74 EN OVP 3 6 GND 5 FB 4 EN SOT26 / TSOT23-6 DFN202 0C-6 Features Applications • High efficiency: 84% typical • Fast 1.2MHz switching frequency • Current limit and UVLO protections • Internal therm al shutdown • Internal .


Diodes AP5725

.

Part

AP5725

Description

WHITE LED STEP-UP CONVERTER



Feature


AP5725 WHITE LED STEP-UP CONVERTER Desc ription Pin Assignments The AP5725 is a step-up DC/DC converter specifically designed to drive white LEDs with a co nstant current. The device can drive 2 ~ 6 LEDs in series from a Li-Ion cell. Series connection of the LEDs provides identical LED currents resulting in uni form brightness and eliminates the need for ballast resis.
Manufacture

Diodes

Datasheet
Download AP5725 Datasheet




 AP5725
AP5725
WHITE LED STEP-UP CONVERTER
Description
Pin Assignments
The AP5725 is a step-up DC/DC converter specifically
designed to drive white LEDs with a constant current. The
device can drive 2 ~ 6 LEDs in series from a Li-Ion cell.
Series connection of the LEDs provides identical LED
currents resulting in uniform brightness and eliminates the
need for ballast resistors. For driving higher number of LEDs,
AP5725 also supports a single feedback of parallel
connected multiple strings of equal number of LEDs.
The AP5725 switches at 1.2MHz that allows the use of tiny
external components. A low 0.25V feedback voltage
minimizes power loss in the current setting resistor for better
efficiency.
(Top View)
SW 1
6 VIN
(Top View)
GND 2
FB 3
SW 1
5 OVP
VIN 2
74 EN OVP 3
6 GND
5 FB
4 EN
SOT26 / TSOT23-6
DFN2020C-6
Features
Applications
• High efficiency: 84% typical
• Fast 1.2MHz switching frequency
• Current limit and UVLO protections
• Internal thermal shutdown
• Internal Over Voltage Protection
• Integrated soft-start function
• SOT26, TSOT23-6 and DFN2020C-6: Available in
“Green” Molding Compound (No Br, Sb)
• Lead Free Finish/ RoHS Compliant (Note 1)
• Cellular Phones
• PDAs, Hand held Computers
• Digital Cameras
• MP3 Players
• GPS Receivers
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
Typical Application Circuit
VIN
ON OFF
PWM Dimming
L1
22uH
D1
C IN
1uF
VIN SW
AP5725 OVP
EN FB
GND
COUT
1uF
2~6 LEDs
RSET
12
AP5725
Document number: DS31844 Rev. 3 - 2
Figure 1. Typical Application Circuit
1 of 17
www.diodes.com
July 2010
© Diodes Incorporated




 AP5725
AP5725
WHITE LED STEP-UP CONVERTER
Pin Descriptions
Pin Name
SW
GND
FB
EN
OVP
VIN
Description
Switch Pin. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI.
GND pin.
Feedback Pin. Reference voltage is 0.25V. Connect cathode of lowest LED and a sense
resister here. Calculate resistor value according to the formula: RSET = 0.25V / ILED
Converter On/Off Control Input. A high input at EN turns the converter On, and a low input
turns it off. If On/Off control is not needed, connect EN to the input source for automatic
startup. The EN pin cannot be left floating.
Output Voltage detect pin for over voltage protection.
Input Supply Pin. Must be locally bypassed with 1μF or 2.2μF to reduce input noise.
Functional Block Diagram
OVP
5
FB 3
VIN 6
A1
-+
VREF
0.25V
Comparator
A2
CONTROL
Rc LOGIC
OTP
Cc
Σ
1 SW
Driver
Q1
EN 4
Enable
RAMP
Generator
1.2MHz
Oscillator
2 GND
AP5725
Document number: DS31844 Rev. 3 - 2
2 of 17
www.diodes.com
July 2010
© Diodes Incorporated




 AP5725
AP5725
WHITE LED STEP-UP CONVERTER
Absolute Maximum Ratings
Symbol
Parameter
Rating
Unit
VIN
VSW
VIN Pin Voltage
SW Voltage
-0.3~7
-0.3~34
V
V
VOVP
VFB
OVP Pin Voltage
Feedback Pin Voltage
-0.3~35
-0.3~7
V
V
EN EN
-0.3~7
V
TJ(MAX)
TLEAD
TST
Maximum Junction Temperature
Lead Temperature
Storage Temperature Range
150
300
-65 to +150
oC
oC
oC
Caution: Operation above the absolute maximum ratings can cause device failure. These values, therefore, must not be exceeded under
any condition. Operation at the absolute maximum rating for extended periods, may reduce device reliability.
Recommended Operating Conditions
Symbol
VIN
TJ
TA
Parameter
Input Voltage
Operating Junction Temperature
Operating Ambient Temperature
Min Max Unit
2.7 5.5
-40 125
-40 85
V
oC
oC
AP5725
Document number: DS31844 Rev. 3 - 2
3 of 17
www.diodes.com
July 2010
© Diodes Incorporated



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