Diodes AP5726 - Manual (Page 2)

AP5726
WHITE LED STEP-UP CONVERTER
AP5726
Document number: DS31845 Rev. 3 - 2
2 of 17
www.diodes.com
July 2010
© Diodes Incorporated
Pin Descriptions
Pin Name Description
SW Switch Pin. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI.
GND GND pin.
FB
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
EN
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.
OVP Output Voltage detect pin for over voltage protection.
V
IN
Input Supply Pin. Must be locally bypassed with 1 μF or 2.2μF to reduce input noise.
Functional Block Diagram
1.2MHz
Oscillator
RAMP
Generator
Σ
-
+
-
+
- +
V
REF
0.31V
VIN
3 FB
Rc
Cc
Comparator
A2
CONTROL
LOGIC
A1
1
Driver
SW
Q1
2 GND
4 EN Enable
6
OTP
5
OVP