New Family of Highly Efficient Low Noise Electroluminescent Lamp Drivers Designed for Backlighting Applications

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Micrel’s new MIC4830 and MIC4832 are a series of 180Vpp and 220Vpp low noise electroluminescent lamp (EL) drivers designed to drive panels of up to 4 in.2 or greater, suitable for applications in mobile phones, multimedia players or portable navigation products. The MIC4830 offers design flexibility with adjustable lamp and boost converter frequencies, simply by applying external resistors. The two drivers also feature a novel H-Bridge design, which reduces audible noise by creating smoother AC voltage across the EL panel.

The MIC4830 and MIC4832 both raise the efficiency standard for EL drivers so that designers can achieve the longer battery life so crucial for today’s most demanding and feature rich consumer applications. As shown in Figure 1, when compared with a leading competitor, the MIC4832 offers a 10 percent improvement in brightness with up to a 20 percent decrease in power consumption. Although not shown, the MIC4830 offers similar brightness to the same leading competitor with a further decrease in power consumption.

The high efficiency for the MIC4830 and MIC4832 is achieved, in part, by consuming a typical supply current of just 45µA. Utilizing Micrel’s advanced Bipolar, CMOS, DMOS (BCD) technology, the ICs integrate a high voltage boost converter and a new H-bridge driver for driving a large EL lamp. In contrast to previous designs that often produced an annoying audible buzz, the new H-Bridge is designed specifically for quiet operation with customer comfort in mind. Operating from an input voltage range of 1.8V to 5.5V, the MIC4830 and MIC4832 offer the flexibility to adjust the switch and drive frequencies according to the specification of the EL panel load via REL and RSW for optimum efficiency and brightness as shown in Figure 2. The MIC4830 and MIC4832 are both available in RoHS-compliant MLF® 3mm x 3mm and MSOP-8 Pb-free package options designed for operation in –40ºC to +85ºC ambient temperature range.

 

FEATURES 1.8V to 5.5V input voltage 180Vpp or 220Vpp output voltage Low audible noise EL drive waveform Supports EL panel sizes up to 4 in.2 (25cm2) Low 45µA operating supply current Small inductor size with low profile (220µH) Tiny 3mm × 3mm MLF®-8L or MSOP-8 package options Adjustable boost converter frequency Adjustable EL lamp frequency Low 10nA shutdown current

APPLICATIONS LCD panel backlights Mobile phones PDAs Pagers Calculators Multimedia players Remote controls GPS receivers

 

 

 

 

Note: MLF is a registered trademark of Amkor Technology

 

 

 Featured Products

Part Number		Description	Data Sheet	App. Notes
MIC4830YMM		Low Input Voltage, Low Noise, 180m Vpp Output Voltage EL Driver
MIC4832YMM		Low Input Voltage, Low Noise, 220m Vpp Output Voltage EL Driver

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