EVB_RT8555WSC

RT8555WSC Evaluation Board your power partner. RT8555WSC Evaluation Board Purpose The RT8555 is a 36V High Efficiency Boost Converter with I2C Controlled 6-CH LED Driver. This document explains the function and use of the RT8555 evaluation board (EVB) and provides information to enable operation and modification of the evaluation board and circuit to suit individual requirements. Table of Contents Purpose ................................................................................................................................................................. 1 Introduction............................................................................................................................................................ 2 Key Performance Summary Table .......................................................................................................................... 2 Bench Test Setup Conditions ................................................................................................................................. 2 Schematic, Bill of Materials & Board Layout ........................................................................................................... 4 More Information.................................................................................................................................................... 8 Important Notice for Richtek Evaluation Board ....................................................................................................... 8 EVB_RT8555WSC-00 September 2015 1 http://www.richtek.com RT8555WSC Evaluation Board your power partner. Introduction General Product Information The RT8555 is a high efficiency driver for white LEDs. It is suitable for single/two cell battery input to drive LED light bars which contains six strings in parallel and up to 10 WLEDs per string. The internal current sinks support a maximum of ±2% current mismatching for excellent brightness uniformity in each string of LEDs. To provide enough headroom for current sink operation, the Boost controller monitors the minimum voltage of the feedback pins and regulates an optimized output voltage for power efficiency. The RT8555 has a wide input voltage operating range from 2.7V to 24V and contains I2C interface for controlling the dimming mode, operating frequency and the LED current. The internal 100mΩ, 36V power switch with current-mode control provides over-current protection. The switching frequency of the RT8555 is adjustable from 300kHz to 2MHz, which allows flexibility between efficiency and component size. The RT8555 is available in the WL-CSP-20B 1.65 x 2.05 (BSC), with pitch 0.4mm package. Product Feature           Wide Operating Input Voltage : 2.7V to 24V High Output Voltage : Up to 36V Programmable Channel Current : 10mA to 35mA Channel Current Regulation with Accuracy ±3% and Matching ±2% Dimming Controls  Direct PWM Dimming up to 20kHz and Minimum On-Time to 400ns  PWM to Analog Dimming up to 20kHz with 8-bit I2C Programs LED Current, Switching Frequency, Dimming Mode Switching Frequency : 300kHz to 2MHz Current Limit, Over-Temperature Protection and Over-Voltage Protection Input Under-Voltage Lockout RoHS Compliant and Halogen Free Key Performance Summary Table Key Features Evaluation Board Number : PCB025_V1 Default Input Voltage 3.8V Default OVP 36V Default Per Channel Output Current 20mA Default Marking & Package Type RT8555WSC, WL-CSP-20B 1.65 x 2.05 (BSC) Operation Frequency 900kHz Other Key Features 2.7V to 24V Input Voltage Range Programmable LED Current, Switching Frequency, Dimming Mode Output Over-Voltage Protection, Current Limit, Thermal Shutdown 20-Ball WL-CSP, with pitch 0.4mm Package EVB_RT8555WSC-00 September 2015 2 http://www.richtek.com RT8555WSC Evaluation Board your power partner. Bench Test Setup Conditions Headers Description and Placement Please carefully inspect the EVB IC and external components, comparing them to the following Bill of Materials, to ensure that all components are installed and undamaged. If any components are missing or damaged during transportation, please contact the distributor or send e-mail to evb_service@richtek.com Test Points The EVB is provided with the test points and pin names listed in the table below.. Test point/ Pin name Signal Comment (expected waveforms or voltage levels on test points) VIN Input voltage Boost conveter input voltage. VIN_1 Input voltage RT8555 VIN input voltage. Connected to VIN through R1. VOUT Output voltage Output voltage up to 36V. Drive LED light bars by VOUT connect to FB1 ~ FB6. LX Switching node test point LX waveform EN Enable input Enable signal. Connecting this pin to pull high enable operation; floating this EN pin or connecting this pin to GND can disable the device. PWM PWM input PWM Dimming Control Input. FB1 ~ FB6 FB pin Current Sink for LED1 ~ LED6. Drive LED light bars by VOUT connect to FB1 ~ FB6. VCP Internal regulator LDO Output of Internal Regulator. GND Ground Ground. SDA Data signal Data Signal Input of I2C Interface. SCL Clock signal Clock Signal Input of I2C Interface. JP2 Chip enable control Install jumper or drive EN directly to enable or disable operation. JP5 PWM control Install jumper or drive PWM signal directly to operation. EVB_RT8555WSC-00 September 2015 3 http://www.richtek.com RT8555WSC Evaluation Board your power partner. Power-up & Measurement Procedure 1. Connect input power and input ground to VIN and GND test pins respectively. 2. Connect LED ligh bars to VOUT and FB1 ~ FB6 test pins respectively. 3. There is a 3- pin header “EN” for enable control. To use a jumper at “H” option to tie EN test pin to input power VIN for enabling the device. Inversely, to use a jumper at “L” option to tie EN test pin and ground GND for disabling the device. 4. There is a 3- pin header “PWM” for PWM dimming control. To use a jumper at “H” option to tie PWM test pin to input power VIN for PWM = 100% dimming the device. Inversely, to use a jumper at “L” option to tie PWM test pin and ground GND for PWM = 0% dimming the device. 5. Usually use Function Generator to produce PWM signal to PWM dimming RT8555 ILED current. 6. Input PWM frequency about 200Hz ~ 20kHz. 7. For detailed RT8555 function operation, please reference RT8555 datasheet. Schematic, Bill of Materials & Board Layout EVB Schematic Diagram EVB_RT8555WSC-00 September 2015 4 http://www.richtek.com RT8555WSC Evaluation Board your power partner. Bill of Materials Reference Qty Part number Description Package Manufacture U2 1 RT8555 LED Driver WL-CSP-20B 1.65 x 2.05 (BSC) RICHTEK C1, CCP 1 C2012X7R1E105KT 0805 TDK CIN3 1 GRM31CR71H475KA12L 1210 MURATA COUT2, COUT3, COUT4 3 UMK316BJ225KD-T 2.2µF/50V/X5R Ceramic Capacitor 1206 TAIYO D2 1 SR26 Schottky diodes SMB/DO-214 PANJIT L1 1 NR8040T6R8N 6.8μH/3.4A DCR = 25mΩ, Inductor L-NR8040 TAIYO R1 R2, R3, R4, R5, R6, R7, R8, R9, R11, R12 COUT1, CIN1, CIN2, COUT5, C2, C3, C4, C5, C6, L2, R14, R15 J1 1 10Ω/±1%, Resistor 0603 10 0Ω, Resistor 0603 0 Not Installed 1 4 x 2 Pin Header J2, J5 2 3- Pin Header TP1, TP2, TP3, Z3, Z5, Z7, Z8 7 PWM, EN, LX, SDA, SCL, VCP, VIN_1 Test Pin GP1, GP2, GP3, GP4, GP5, GP6, GP7, GP8, GP9, GP10, GP11, GP12 12 VOUT, VIN, GND, LED1, LED2, LED3, LED4, LED5, LED6 Golden Pin EVB_RT8555WSC-00 September 2015 1µF/50V/X7R Ceramic Capacitor 4.7µF/50V/X7R Ceramic Capacitor 5 http://www.richtek.com RT8555WSC Evaluation Board your power partner. EVB Layout Top View (1st layer) PCB Layout—Inner Side (2nd Layer) EVB_RT8555WSC-00 September 2015 6 http://www.richtek.com RT8555WSC Evaluation Board your power partner. PCB Layout—Inner Side (3rd Layer) Bottom View (4th Layer) EVB_RT8555WSC-00 September 2015 7 http://www.richtek.com RT8555WSC Evaluation Board your power partner. More Information For more information, please find the related datasheet or application notes from Richtek website http://www.richtek.com. Important Notice for Richtek Evaluation Board THIS DOCUMENT IS FOR REFERENCE ONLY, NOTHING CONTAINED IN THIS DOCUMENT SHALL BE CONSTRUED AS RICHTEK’S WARRANTY, EXPRESS OR IMPLIED, UNDER CONTRACT, TORT OR STATUTORY, WITH RESPECT TO THE PRESENTATION HEREIN. IN NO EVENT SHALL RICHTEK BE LIABLE T O BUYER OR USER FOR ANY AND ALL DAMAGES INCLUDING WITHOUT LIMITATION TO DIRECT, INDIRECT, SPECIAL, PUNITIVE OR CONSEQUENTIAL DAMAGES. EVB_RT8555WSC-00 September 2015 8 http://www.richtek.com