NCP9003

NCP9003 Compact Backlight LED Boost Driver The NCP9003 is a high efficiency boost converter operating in current loop, based on a PFM mode, to drive White LED. The current mode regulation allows a uniform brightness of the LEDs. The chip has been optimized for small ceramic capacitors, capable to supply up to 1.0 W output power. Features http://onsemi.com MARKING DIAGRAM 5 5 1 TSOP−5 SN SUFFIX CASE 483 DBNAYWG G 1 • 2.7 to 5.5 V Input Voltage Range • Vout to 24 V Output Compliance Allows up to 5 LEDs Drive in • • • • • • • • • • • • Series Built−in Overvoltage Protection Full EMI Immunity Inductor Based Converter brings up to 90% Efficiency Constant Output Current Regulation 0.3 mA Standby Quiescent Current Includes Dimming Function (PWM) Enable Function Driven Directly from Low Battery Voltage Source Automatic LEDs Current Matching Thermal Shutdown Protection All Pins are Fully ESD Protected Low EMI Radiation Pb−Free Package is Available DBN = Specific Device Code A = Assembly Location Y = Year W = Work Week G = Pb−Free Package (Note: Microdot may be in either location) PIN CONNECTIONS Vout GND FB 1 2 3 (Top View) 4 EN 5 Vbat Typical Applications • LED Display Back Light Control • Keyboard Back Light • High Efficiency Step Up Converter ORDERING INFORMATION Device NCP9003SNT1G Package TSOP−5 (Pb−Free) Shipping† 3000 Tape & Reel †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. © Semiconductor Components Industries, LLC, 2006 August, 2006 − Rev. 1 1 Publication Order Number: NCP9003/D NCP9003 Vbat U1 4 EN Vbat 5 Vbat C1 4.7 mF L1 22 mH GND 2 3 GND FB NCP9003 Vout 1 D1 MBR0530 C2 1.0 mF D4 D3 D2 GND GND GND R1 15 W D6 D5 LWT67C LWT67C LWT67C LWT67C LWT67C Figure 1. Typical Application Thermal Shutdown Current Sense Vbat 5 Vbat Vsense CONTROLLER EN 4 100 k 1 Vout Q1 GND FB 3 300 k +200 mV Band Gap − + 2 GND GND Figure 2. Block Diagram http://onsemi.com 2 NCP9003 PIN FUNCTION DESCRIPTION Pin 1 Pin Name Vout Type POWER Description This pin is the power side of the external inductor and must be connected to the external Schottky diode. It provides the output current to the load. Since the boost converter operates in a current loop mode, the output voltage can range up to +24 V but shall not extend this limit. However, if the voltage on this pin is higher than the Over Voltage Protection threshold (OVP) the device comes back to shutdown mode. To restart the chip, one must either send a Low to High sequence on Pin EN, or switch off the Vbat supply. A capacitor must be used on the output voltage to avoid false triggering of the OVP circuit. This capacitor should be 1.0 mF minimum. Ceramic type, (ESR