AP5726_10 Datasheet, PDF (2/17 Pages) Diodes Incorporated – WHITE LED STEP-UP CONVERTER

AP5726
WHITE LED STEP-UP CONVERTER
Pin Descriptions
Pin Name
SW
GND
FB
EN
OVP
V_IN
Description
Switch Pin. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI.
GND pin.
Feedback Pin. Reference voltage is 0.31V. Connect cathode of lowest LED and a sense
resister here. Calculate resistor value according to the formula: R_SET = 0.31V / 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
-+
V_REF
0.31V
Comparator
A2
CONTROL
Rc
LOGIC
OTP
Cc
Σ
1 SW
Driver
Q1
EN 4
Enable
RAMP
Generator
1.2MHz
Oscillator
2 GND
AP5726
Document number: DS31845 Rev. 3 - 2
2 of 17
www.diodes.com
July 2010
© Diodes Incorporated