RT4532WSC Evaluation Board your power partner. RT4532 Evaluation Board Purpose The RT4532 is a high-efficiency LED driver for backlight applications with an internal schottky diode and current source driver. It supports linear mappings with 256 steps to setup the brightness of backlight LEDs. It also supports PWM dimming to adjust the brightness. This document explains the function and use of the RT4532 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 ................................................................................................................................. 3 Schematic, Bill of Materials & Board Layout ........................................................................................................... 5 More Information.................................................................................................................................................... 8 Important Notice for Richtek Evaluation Board ....................................................................................................... 8 EVB_RT4532WSC-00 August 2015 1 http://www.richtek.com RT4532WSC Evaluation Board your power partner. Introduction General Product Information The RT4532 is a high-efficiency LED driver for backlight applications. An asynchronous boost converter with an internal Schottky diode and a current source driver are designed to support 6LED/channel with wide input voltage range from 2.5V to 5.5V. This document explains the function and use of the RT4532 evaluation board (EVB) and provides information to enable operation and modification of the evaluation board and circuit to suit individual requirements. Product Feature Input Voltage Range : 2.5V to 5.5V Internal Schottky Diode Fast-speed mode I2C Compatible Interface Drive Up to 6 WLEDs in 4 String External PWM Brightness Control 550k/1.1MHz Switching Frequency Built-in Internal Soft-Start I2C Programmable 256 Steps Linear Current Regulation Up to 85% Efficiency with Small Magnetics Programmable 16V/24V OVP Current Accuracy 5% and Current Balance 3% UVLO, OVP, OCP, OTP Protection Shutdown Current : < 1µA Temperature Range : 40C to 85C Key Performance Summary Table Key Features Evaluation Board Number: PCB015_V1 Default Input Voltage 2.5V~5.5V Max Output Current 20mA/40mA Default Output Voltage 17V Default Marking & Package Type RT4532 Operation Frequency Steady 1.1MHz at all loads Protection UVLO OVP OCP Thermal Shutdown EVB_RT4532WSC-00 August 2015 2 http://www.richtek.com RT4532WSC 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 [email protected] Test Points The EVB is provided with the test points and pin names listed in the table below. Pin No. Pin Name Comment (expected waveforms or voltage levels on test points) A2 GND Ground. B1 VOUT Power Output of the Asynchronous Boost Converter for Backlight LEDs. Connect a 1μF or larger ceramic capacitor from VOUT to ground. B2 VIN C1 PWM C2 EN D1 SDA I2C Serial Data Input/Output. An external pull-up resistor is required. D2 SCL I2C Serial Data Input/Output. An external pull-up resistor is required. E1 FB2 Single Output 2 for Backlight LED. E2 FB1 Single Output 1 for Backlight LED. Power Input. Connect this pin to the input power supply voltage. Connect a 10μF or larger ceramic capacitor from the VIN to ground. PWM Dimming Input for Backlight LED. Enable Control Input (Active High). The chip is in shutdown mode when the EN pin is low. Power-up & Measurement Procedure 1. 2. 3. 4. 5. Apply 3.6V nominal input power supply (2.5V < VIN < 5.5V) to the VIN and GND terminals. The EN voltage is pulled to logic high by internal circuit to enable operation. Drive EN high (>1.05V) to enable operation or low (<0.4V) to disable operation. Pull EN pin to High pin that make EN voltage equal to VIN. There is a 2-pin header JP2 “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. The JP4 is the I2C control pin that incloud SDA, SCL, GND pin, and it need to connect to Richtek WrenBoard when use the RT4532 I2C dimming. The ILED setting supports I2C dimming and PWM dimming as below. EVB_RT4532WSC-00 August 2015 3 http://www.richtek.com RT4532WSC Evaluation Board your power partner. Output ILED Setting 1. Linear Brightness Dimming The chip is built-in an I2C 8-bit resolution brightness control with maximum 20mA/40mA selection. Reg0x02 <3> corresponds to full-scale LED current control. Reg0x04 <7:0> sets 8bits resolution brightness dimming control. Where ILED, Full : the full-scale LED current set by Reg0x02 <3>. Code : the 8bit brightness code Reg0x04 <7:0> programmed by I2C interface. 2. PWM Brightness Dimming Besides programmable built-in I2C backlight LED current control, the RT4532 features a built-in PWM dimming current control by setting Reg0x02 <6> to 1, offering a linear current dimming by external clock source. In order to guarantee the PWM dimming resolution (7 bit at > 15kHz application), recommending dimming frequency have to be operated at range of 400Hz to 20kHz. 3. LED Short Protection LED short protection prevents abnormal connection to cause IC damage avoiding FB1/FB2 connecting power supply. And, If unbalanced LEDs series (cause FB1 or FB2 > 9.6V) is different between channel1 and channel2, IC will also occur LED short event. As LED short event occur more than deglitch time 2ms, IC will shut-down latch until IC is reset by EN pin. EVB_RT4532WSC-00 August 2015 4 http://www.richtek.com RT4532WSC Evaluation Board your power partner. Schematic, Bill of Materials & Board Layout EVB Schematic Diagram EVB_RT4532WSC-00 August 2015 5 http://www.richtek.com RT4532WSC Evaluation Board your power partner. Bill of Materials Reference Qty Part Number Description Package Manufacture U2 1 RT4532 DC-DC Converter CSP-10B 0.87x2.07 RICHTEK L1 1 NR4018T100M 10µH/1.2A/±20%, 4mm x 4mm x 1.8mm TAIYO YUDEN DCR = 0.18Ω, Inductor C1 1 0603X106M6R3 10µF/±20%/ 6.3V/X5R Ceramic Capacitor 0603 WALSIN C3 1 C2012X7R1H105KT 1µF/±10%/50V/X7R Ceramic Capacitor 0805 TDK R7 1 Short R11 1 Short R13 1 Short D32, D34, D36, D33, D35, D37, D38, D40, D62, D39, D41, D63, D46, D48, D50, D47, D49, D51, D42, D44, D64, D43, D45, D65 24 LED TP 6 GP 4 JP 3 EVB_RT4532WSC-00 3V3, SCL, SDA, 1V8, FB1, FB2 VIN, GND, GND, VOUT Test Pin Golden Pin JP1, JP2, JP4 August 2015 6 http://www.richtek.com RT4532WSC Evaluation Board your power partner. EVB Layout PCB Layout—Top View PCB Layout—Bottom Side EVB_RT4532WSC-00 August 2015 7 http://www.richtek.com RT4532WSC 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_RT4532WSC-00 August 2015 8 http://www.richtek.com