© 2012 Fairchild Semiconductor Corporation
3
FEBFL7701_L31H008A • Rev.1.0.2
This user guide supports the evaluation kit for the FL7701. It should be used in
conjunction with the FL7701 datasheet as well as Fairchild’s application notes and
technical support team. Please visit Fairchild’s website at
www.fairchildsemi.com
.
1.
Introduction
This document describes the proposed solution for an universal input, 2.4W LED ballast
using the FL7701. The input voltage range is 187 V
RMS
– 264 V
RMS
and there is one DC
output with a constant current of 250 mA at 31 V
MAX
. This document contains general
description of FL7701, the power supply specification, schematic, bill of materials, and
the typical operating characteristics.
1.1.
General Description
The FL7701 LED lamp driver is a simple IC with PFC function and integrated switching
MOSFET. The special “adopted digital” technique automatically detects input voltage
condition and sends an internal reference signal, resulting in high Power Factor (PF).
When AC input voltage is applied to the IC, PFC function is automatically enabled.
When DC input voltage is applied to the IC, PFC function is automatically disabled. The
FL7701 does not require a bulk capacitor (electrolytic capacitor) for supply rail stability,
which can significantly improve LED reliability.
1.2.
Features
Digitally Implemented Active PFC Function
(No Additional Circuit Necessary for High PF)
Built-in HV Supplying Circuit: Self Biasing
Application Input Range: 80 V
AC
~ 308 V
AC
AOCP Function with Auto-Restart Mode
Built-in Over-Temperature Protection (OTP)
Cycle-by-Cycle Current Limit
Current-Sense Pin-Open Protection
Low Operating Current: 0.85 mA (Typical)
Under-Voltage Lockout with 5 V Hysteresis
Programmable Oscillation Frequency
Programmable LED Current
Analog Dimming Function
Soft-Start Function
Precise Internal Reference: ±3%
