Using the ISL97631 White LED Driver Demo Board ® Technical Brief Introduction The complete schematic of ISL97631 white LED driver Demo Board is shown in Figure 1. It shows ISL97631 boost performance in simple and complicated control schemes. In order to test the demo board properly, it is necessary to understand the purpose and function of the onboard jumpers (JP1, JP2, JP3, JP4, JP5, JP6, and JUMP SHDNB). The first four jumpers (JP1 to JP4) are used to disable four of the six LEDs. Without any of the jumpers placed, all six LEDs are driven by the ISL97631 boost converter. Placing jumper JP1 shorts out LED D2, JP2 shorts out D3, and so on for the four LED jumpers. If all four LED jumpers are placed, LEDs D6 and D7 will remain active. JP5 is for PWM dimming control function. One pin of JP5 is connected with Vin and the other pin of JP5 is connected with EN pin of ISL97631 through JUMP SHDNB. For PWM dimming control, the PWM signal can be applied to the pin of JP5 to implement PWM dimming function. February 3, 2006 TB454.0 JP6 is used to step decrease the RSET resistance. This resistance, in turn, adjusts the LED supply current. If JP6 is not placed, RSET is 10kΩ and the LED current is set to 10mA. If JP6 is placed, RESET is 5kΩ and the LED current is set to 20mA. To test the demo board, the following procedure must be followed: Shunt JP1~JP4. Based on the required test LED number, suitable JP1~JP4 are placed to bypass the required LED number. Set up the required output current. Based on the required LED current, either place or remove JP6 to make the LED current equal to the required LED current. Apply a DC power voltage source on Vin and GND pins. For ISL97631, the allowed input voltage range is from 2.7 to 5V. Due to the boost function, the input DC voltage must be lower than the output voltage in order to regulate the output LED current. JUMP SHDNB is used to enable or disable the ISL97631 chip. If JUMP SHDNB is shorted to GND, the chip is disabled. 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2006. All Rights Reserved All other trademarks mentioned are the property of their respective owners. Technical Brief 454 VIN VIN VIN VOUT 1 C1 0.22µF D2 LED JP1 2 L1 22µH D3 LED JP2 VIN VOUT 6 U1 GND FB 5 ISL97631 3 LX ENAB VIN C2 1.0µF 4 JP5 SHDNB 2 1 3 LX JP3 D4 LED JP4 D5 LED D6 LED D7 LED FB JP6 R1 10 R2 10 GND FIGURE 1. COMPLETED SCHEMATIC OF ISL97631 BOOST DEMO BOARD 2 TB454.0 February 3, 2006 Technical Brief 454 ISL97631 Bill of Materials DESIGNATOR PART TYPE FOOTPRINT DESCRIPTION C1 0.22µF/25V 1206 Capacitor C2 1.0µF/10V 1206 Capacitor R1 10 1206 Resistor R2 10 1206 Resistor L1 22µH DT1608 U1 ISL97631 SOT23-6 JP2 JUMPER JUMPER-2PIN Jumper JP1 JUMPER JUMPER-2PIN Jumper JP3 JUMPER JUMPER-2PIN Jumper JP5 JUMPER JUMPER-2PIN Jumper JP4 JUMPER JUMPER-2PIN Jumper JP6 JUMPER JUMPER-2PIN Jumper D7 LED LED-2832 D2 LED LED-2832 D6 LED LED-2832 D3 LED LED-2832 D4 LED LED-2832 D5 LED LED-2832 VIN POWER POST POWERPOST GND POWER POST POWERPOST LX TEST POINT TESTPOINT FB TEST POINT TESTPOINT VOUT TEST POINT TESTPOINT 3 MANUFACTURE Sumida Vishay TB454.0 February 3, 2006 Technical Brief 454 Demo Board Layout FIGURE 2. TOP SILKSCREEN OF ISL97631 BOOST DEMO BOARD 4 TB454.0 February 3, 2006 Technical Brief 454 FIGURE 3. TOP LAYER OF ISL97631 BOOST DEMO BOARD 5 TB454.0 February 3, 2006 Technical Brief 454 FIGURE 5. BOTTOM LAYER OF ISL97631 BOOST DEMO BOARD Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that the Application Note or Technical Brief is current before proceeding. For information regarding Intersil Corporation and its products, see www.intersil.com 6 TB454.0 February 3, 2006