Continental Device India Pvt. Ltd

An ISO/TS 16949,

ISO 9001 and ISO 14001 Certified Company

TCIL6568

TCIL6568_REV02_22102016

D a t a s h e e t

Page 2 of 10

2. Function Diagram and Pin Description

2. 1、Function Diagram

VCC

Clamp

Power Supply

&VREF

Zero Current

Detection

OVP

Current

Limit

Logic

Control

Drive

CAP

CS

OUT

VCC

ZCD

UVLO

VREF

Vcs

OTA

PWM/

PFC

GND

N1

2. 2、Function Description

The TCIL6568 is a high-PF non-isolated BUCK topology LED controller with Active

Power Factor Correction (APFC) internally. The TCIL6568 works in boundary conduction mode

and employs unique control mode to achieve high precision LED output current. Also it

achieved superior Line Voltage Regulation and Load Regulation

2.2.1、Start up and UVLO

Initially, the capacitor beside VCC pin is charged through the start up resistor from the AC

line. After the VCC voltage climbs up to VCC turn voltage threshold VCC_ON, the control logic

start to work. After the output voltage established, the output voltage supply power for VCC

through diode to reduce system power dissipation.

When VCC falls below VCC turn off voltage threshold VCC_OFF, the system shut down, and

the system enters another start up cycle.

2.2.2、Power-on Soft-start

The TCIL6568 supply soft-start function. The IC works in 10 kHz switch frequency after

power on, and the CAP pin voltage is pulled up to 1.5V. After the output pulse established, CAP

voltage rises from 1.5V, and the inductor peak current rise gradually along with CAP voltage,