ACE714_12 Datasheet, PDF (1/9 Pages) ACE Technology Co., LTD. – High Efficiency Low Noise PFM Step-up DC/DC Converter

ACE714
High Efficiency Low Noise PFM Step-up DC/DC Converter
Description
The ACE714 veriable frequency step-up Converter drives white LEDs with a constant current to provide
backlight in cell phones, PDAs, and other handheld devices. It features allowing series connection of the
white LEDs so that the LED currents are identical for uniform brightness. An enable input can be pulsed
repeatedly to adjust LEDs brightness. The fast 3MHz operation frequency allows for smaller capacitor
and inductor. Fault condition protection uses cycle-by cycle current limiting to sense maximum inductor
current and over-voltage protection. The 0.2V low reference voltage minimized the power loss across the
current sense resistor.
The converter can operate from 2V to 6V, and capable of delivering maximum 200mA output current at
4-LEDs application with 3V input voltage is as low as 120uA. All of these features make ACE714 be
suitable for the portable devices, which are supplied by a single battery.
Features
 Up to 24V Output Voltage
 Wide Operation Range: 2V to 6V
 Maximum 3MHz Operating Frequency
 PWM Dimming Control
 Shutdown Current <1uA
 Current Limit Cycle-by-Cycle
 Low Current Sense Threshold: 200mV
 24V Over Output Voltage Protection
Application
 Compact Back Light Module
 Power Source for LED
 Constant Current Source
Typical Application
L1
Vin
10uH
D1
SS14
LED 1
LED 17
+ Cin
4.7uF
LED2
+ Cout
4.7uF
LED 3
ON
OFF
Vin
LX
ACE714 OVP
CE
FB
GND
LED 4
R1
Figure 1. ACE714 Typical Application Circuit
LED 18
LED 19
LED 20
R5
VER 1.3 1