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HT7L4091

Universal Step-Down PWM Control

For High Brightness LED Lighting Control

Table of Contents

Features ......................................................................................................................... 4

Applications................................................................................................................... 4

General Description ...................................................................................................... 4

Pin Assignment ............................................................................................................. 5

Pin Description .............................................................................................................. 5

Absolute Maximum Ratings ......................................................................................... 5

Recommended Operating Ranges............................................................................... 6

Block Diagram ............................................................................................................... 6

Electrical Characteristics ............................................................................................. 7

Functional Description ................................................................................................. 8

LED Cu��ent Cont�o�................................................................................................................. �

P�og�ammab�e Off Time ........................................................................................................... �

Cu��ent Sense.......................................................................................................................... 9

Leading-Edge B�anking............................................................................................................ 9

F�equency Jitte� Function......................................................................................................... 9

In�ut Su���y Cu��ent ................................................................................................................ 9

Sta�t-u� Cu��ent and �uxi�ia�y Powe� Sou�ce ........................................................................ 10

Linea� Dimming...................................................................................................................... 10

PWM Dimming ....................................................................................................................... 10

LED O�en and Sho�t Ci�cuit P�otection ................................................................................. 10

Enhanced Sho�t Ci�cuit P�otection......................................................................................... 11

Application Description .............................................................................................. 12

In�ut Bu�k Ca�acito� – C1 ...................................................................................................... 1�

Switching F�equency and Duty Cyc�e .................................................................................... 13

Tu�n-off Time.......................................................................................................................... 13

Off-time Resisto� – RT ........................................................................................................... 14

Inducto� Design...................................................................................................................... 14

Cu��ent Sense Resisto� – RCS ............................................................................................... 14

In�ut Su���y Cu��ent ............................................................................................................. 15

In�ut Limit Resisto� (RIN) ........................................................................................................ 15

Out�ut Ca�acito� – CO ........................................................................................................... 15

Typical Performance Characteristics ........................................................................ 16

Efficiency vs. Power Supply Circuit – Working Frequency.................................................... 16

Efficiency for Resistor Only Power and Single Input Voltage................................................. 17

Efficiency Using Resistor Only Power and 85~265 V�C In�ut................................................. 1�

Typical Application Circuit ......................................................................................... 19

Other Application Circuit............................................................................................ 20

No In�ut Bu�k Ca�acito� Ci�cuit ............................................................................................. �0

High Efficiency Circuit ............................................................................................................ �0

BJT Powe� Su���y ����ication Ci�cuit .................................................................................... �1