Once relegated to the hinterlands of low cost indicatorlights, the LED is again in the spotlight of the lightingworld. LED lighting is now ubiquitous, from car headlightsto USB-powered lava lamps. Car headlights exemplifyapplications that capitalize on the LED’s clear advantages—unwavering high quality light output, tough-assteelrobustness, inherent high effi ciency—while a USBlava lamp exemplifi es applications where only LEDs work.Despite these clear advantages, their requirement forregulated voltage and current make LED driver circuitsmore complex than the venerable light bulb, but some newdevices are closing the gap. For instance, the LTM®8040μModule™ LED driver integrates all the driver circuitryinto a single package, allowing designers to refocus theirtime and effort on the details of lighting design criticalto a product’s success.
現有基于MAX7219芯片的數碼管驅動電路只適用于小尺寸LED，為擴展其使用范圍，在介紹動態顯示芯片MAX7219功能的基礎上，提出了一個基于該芯片的8位高亮度8英寸數碼管驅動電路。電路保留了MAX7219芯片的功能強大、編程簡單等優點，通過74LS273鎖存器和ULN2803達林頓驅動器，實現了對任意大尺寸數碼管提供較高電壓和電流驅動的靜態顯示，并亮度可調。
Abstract:
The existing display-driving circuit based on MAX7219 was only applicable to small-size LED. To expand its use, based on the function introduction of dynamic display chip MAX7219, a display-driving circuit for high-brightness 8-bit LED with the size of 8-inch was proposed. The advantages of MAX7219 were retained, such as powerful function and simple programming. Static display with adjustable brightness for large-size LED with higher voltage and current was achieved with the help of 74LS273 and ULN2803.
The XL6003 regulator is fixed frequency PWM Boost (step-up) DC/DC converter, capable ofdriving 1050mA load current with excellent line and load regulation. The regulator is simple to use because it includes internal frequency compensation and a fixed-frequency oscillator so that it requires a minimum number of external components to work. The XL6003 could directly drive 5~10 3W LED units at VIN=12V.
The PAM2862 is a continuous mode inductivestep-down converter, designed for driving singleor multiple series connected LEDs efficientlyfrom a voltage source higher than the LEDvoltage. The device operates from an inputupply between 6V and 30V and provides anexternally adjustable output current of up to 1A.Depending upon supply voltage and externalcomponents, this can provide up to 24 watts ofoutput power.
