MIC4826 Low Input Voltage, 160VPP Output Voltage, EL Driver - Micrel - #1

Text version of the page

March 2009 1 MIC4826 MIC4826 Micrel MIC4826 Low Input Voltage, 160VPP Output Voltage, EL Driver General Description Micrel’s MIC4826 is a high output voltage, DC to AC converter, designed for driving EL (Electroluminescent) lamps. The device operates from an input voltage range of 1.8V to 5.5V, making it suitable for 1-cell Li Ion and 2- or 3-cell alkaline/NiCad/NiMH battery applications. The MIC4826 converts a low voltage DC input to a 160VPP AC output signal that drives the EL lamp. The MIC4826 is comprised of two stages: a boost stage, and an H-bridge, lamp driver, stage. The boost stage steps the input voltage up to +80V. The H-bridge stage then alternately switches the +80V output to each terminal of the EL lamp, thus creating a 160VPP AC signal to drive the EL lamp and generate light. The MIC4826 features separate oscillators for the boost- and H-bridge stages. External resistors independently set the operating frequency of each stage. This flexibility allows the EL lamp circuit to be optimized for maximum efficiency and brightness. The MIC4826 uses a single inductor and a minimum number of external components, making it ideal for portable, space-sensitive applications. The MIC4826 is available in an 8-pin MSOP package with an ambient temperature range of –40°C to +85°C. Typical Application Features • 1.8V to 5.5V DC input voltage • 160VPP regulated AC output waveform • Independently adjustable EL lamp frequency • Independently adjustable boost converter frequency • 0.1ìA shutdown current Applications • LCD panel backlight • Cellular phones • PDAs • Pagers • Calculators • Remote controls • Portable phones Ordering Information Part Number Standard Pb-Free Temp. Range Package MIC4826BMM MIC4826YMM –40°C to +85°C MSOP-8 Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com High Voltage EL Driver 442k 2MVINCOUT0.01ìF/100VD1BAV19WSL1220ìH2in2 EL LAMP15687234SWCSVAVBVDDRSWRELGNDMIC4826CIN10ìF TIME (2ms/div)VB(50V/div)VA(50V/div)VA Ð VB(50V/div)VIN = 3.0VL = 220ìH..COUT = 0.01ìFLamp = 2in2..RSW = 332k..REL = 3.32M