EV24895-J-00A Step-Down White LED Driver Evaluation Board The Future of Analog IC Technology DESCRIPTION FEATURES The EV24895-J-00A is an evaluation board for the MP24895GJ, a step-down converter designed in hysteretic current control mode for driving the high brightness LEDs from wide input voltage of 9V to 30V. • • • • • • • • • The MP24895 employs hysteretic control architecture to regulate LED current. Moreover, this control scheme provides optimal circuit stabilization and a very quick response time without loop compensation. The highly accurate LED current is measured through an external high-side current-sense resistor. Its low 100mV average feedback voltage reduces power loss and improves the efficiency. The MP24895 implements PWM and analog dimming together on the EN/DIM pin. The MP24895 includes under-voltage lockout, and thermal overload protection to prevent damage in the event of an output overload. Internal 36V MOSFET Wide 9V to 30V Input Range 750mA Output LED Current High Efficiency Hysteretic Control PWM and Analog Dimming 1000:1 PWM Dimming Resolution UVLO Thermal Shutdown APPLICATIONS • • • • • Low-Voltage Halogen Replacement Low-Voltage General Illumination Automotive/Decorative LED Lighting Signs/Emergency Lighting LED Backlighting All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Quality Assurance. “MPS” and “The Future of Analog IC Technology” are Registered Trademarks of Monolithic Power Systems, Inc. ELECTRICAL SPECIFICATIONS Parameter Symbol Value Units VIN 9 to 30 V Output Voltage VOUT <VIN-3 V LED Current ILED 750 mA Input Voltage EV24895-J-00A EVALUATION BOARD (L x W x H) 20mm x 14mm x 11mm Board Number MPS IC Number EV24895-J-00A MP24895GJ EV24895-J-00A Rev.1.0 www.MonolithicPower.com 8/7/2014 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 1 EV24895-J-00A---STEP-DOWN WHITE LED DRIVER EVALUATION BOARD EVALUATION BOARD SCHEMATIC D1 1 B260A R1 1 2 2 1 LED+ 1 LED- 0.4 2 2 2 C1 2.2uF/50V 2 D4 0.2 2 2 D5 2 C4 NC 1 1 1 R2 1 2 2 C2 220uF/35V 1 1 AC1 1 D3 D2 1 1 1 PGND C5 NC AGND PGND 2 L1 47uH/1.45A 4 5 AC2 1 RS IN 1 R5 0 EN/DIM 1 1 1 2 Q1 NC MP24895 SW 1 C3 1nF 1 GND R6 NC 1 2 2 R3 NC 2 2 NC EN/DIM 2 R4 3 1 U1 3 2 1 AGND PGND EV24895-J-00A BILL OF MATERIALS Qty Ref Value 1 C1 2.2µF/50V 1 C2 220µF/35V 1 C3 1nF/25V 2 5 1 1 1 C4, C5 D1 to D5 L1 R1 R2 R3, R4, R6 R5 Q1 U1 NC B260A 47µH 0.4Ω 0.2Ω 3 1 1 1 Description Ceramic Capacitor, 50V, X7R Electrolytic Capacitor, 35V Ceramic Capacitor, 25V, C0G Package Manufacturer Part Number 1206 muRata GRM31CR71H225KA88L DIP Sanyo 0603 muRata GRM1885C1E102JA01D Schottky Diode Inductor, 1.2A Film Resistor, 1% Film Resistor, 1% SMA SMD 0805 0805 Diodes TDK Royalohm Yageo B260A SLF7055T-470M1R2-3PF 0805F400LT5E RL0805FR-070R2L Film Resistor, 5% 0603 Yageo MPS WLED Driver TSOT23-5 MPS 220µF/35V NC 0Ω NC MP24895 RC0603JR-070RL MP24895GJ-Z EV24895-J-00A Rev.1.0 www.MonolithicPower.com 8/7/2014 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 2 EV24895-J-00A---STEP-DOWN WHITE LED DRIVER EVALUATION BOARD PRINTED CIRCUIT BOARD LAYOUT Figure 1—Top Layer Figure 2—Bottom Layer EV24895-J-00A Rev.1.0 www.MonolithicPower.com 8/7/2014 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 3 EV24895-J-00A---STEP-DOWN WHITE LED DRIVER EVALUATION BOARD QUICK START GUIDE 1. Connect the positive and negative terminals of the load to the LED+ and LED- pins on the EV board, respectively. 2. Connect the positive and negative terminals of the 24V AC power supply to the AC1 and AC2. If apply a DC power supply, please connect + and – to AC1 and AC2. Turn the power supply on. 3. If PWM dimming is required, provide a 200Hz to 2kHz PWM signal to EN/DIM pin. Remove R5 and put a 1kΩ resistor on R4. 4. If analog dimming is required, please open R4 and short R5, then provide a 0.3V to 2.5V DC voltage to the EN/DIM pin. 5. The LED current is adjustable by set current sense resistor R1//R2 as below formula, R1//R2=100mV/ILED NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. EV24895-J-00A Rev.1.0 www.MonolithicPower.com 8/7/2014 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2014 MPS. All Rights Reserved. 4