ACE714C

Max. 3MHz, Variable Frequency Step-up DC/DC Converter

VER 1.2

1

Description

The ACE714C 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 250mA output current at

4-LEDs application with 3V input voltage is as low as 120uA. All of these features make ACE714C be

suitable for the portable devices, which are supplied by a single battery.

Features

Application

Typical Application

L1

D1

Vin

10uH

SS14

LED 1

LED 17

LED2

LED 18

+

Cin

+

Cout

4.7uF

4.7uF

LED 3

LED 19

ON

Vin

LX

OFF

ACE714C OVP

LED 4

LED 20

CE

FB

GND

R1

R5

Figure 1. ACE714C Typical Application Circuit