CL88020 Sequential Linear LED Driver with Four Taps Features Description The CL88020 LED Driver Integrated Circuit (IC) is an Optimized for 120 V Nominal Input Voltage AC off-line sequential linear LED driver designed to pro- -120V 15% input voltage AC vide 8.5W of LED power from a 120 V nominal input AC Targeted for 8.5W Output Power voltage. Programmable Overtemperature Protection CL88020 is designed to drive a long string of inexpen- - Provides Gradual Reduction in Light Output sive, low-current LEDs directly from the AC mains. A with Increasing Temperature basic driver circuit consists of Microchip Technology Active Line Regulation Inc.s CL88020 LED driver IC, six resistors and a bridge - Provides Fairly Constant Output Power over rectifier. Two to four additional components are optional Variations in AC Line Voltage for various levels of transient protection, also with a low-cost NTC to assure remote overtemperature pro- - Typical Line Regulation of 12% to +0% tection (OTP). No capacitors, EMI filters, or power fac- Four Taps with Two Current Set Resistors tor correction circuits are needed unless the optional - Allows Optimization of THD reduced light output ripple feature is desired. Optional Reduced Light Output Ripple A string of series/parallel LEDs is tapped at four loca- - Provides Continuous Power to the LED tions. Four linear current regulators sink current at each - Eliminates Strobing tap through a single control point and are sequentially - Uses an External Ceramic Storage Capacitor turned on and off. High efficiency is achieved by shut- TRIAC Dimmer Compatible ting off upstream regulators when downstream regula- tors achieve regulation. This makes controlling overall Available in a Thermally Enhanced 8-Lead SOIC input current easier than trying to control multiple cur- Package with Heat Slug rent paths, thereby tracking the input sine wave volt- - Larger Creepage Distances between High age. CL88020 uses a self-commutation technique Voltage and Low Voltage Pins using only the tap currents themselves this technique inherently provides smooth transitions from one regula- Applications tor to the next, without relying on tap voltages or the rectified AC to coordinate the transitions. LED Lamps LED Lighting Fixtures PIN DIAGRAM CL88020 8-Pin SOIC TAP1 1 8 ALR GND TAP2 2 7 BIAS 9 TAP3 OTP 3 6 TAP4 4 5 CS * Includes Exposed Thermal Pad (EP) see Table 2-1 2017 Microchip Technology Inc. DS20005753A-page 1CL88020 TYPICAL APPLICATION CIRCUIT R TP1 BR MOV R TP2 R BIAS R ALR1 TAP1 TAP2 TAP3 TAP4 ALR R ALR2 C ALR CL88020 BIAS OTP GND CS C BIAS R OT R CS R OW R NTC INTERNAL BLOCK DIAGRAM BIAS TAP1 TAP2 TAP3 TAP4 V BIAS V AREF K TAP3 ALR R R AS AF (300k ) (120k ) K TAP2 OTP V BIAS K TAP1 R OU V LIM (480k ) R OF R OL (150k ) (90k ) GND CS DS20005753A-page 2 2017 Microchip Technology Inc.