Research on DLP Driver Circuit Based on STM32 Microcontroller

DLP projection technology is a technology that uses digital micromirror components developed by Texas Instruments, DMD (Digital Micromirror Device) as the main key processing components to realize digital optical processing [1]. DLP displays high-definition color, brilliance, exquisiteness, and true-to-life, and is extremely reliable for all-digital display, and can be used in a variety of products (such as large-screen digital TV, corporate/home/professional conference projectors and digital cameras (DLP) Cinema)) provides the best image effects [2]. At present, most home or commercial DLP projectors use a monolithic structure, making them easy to carry and thus more and more widely used. On the basis of the current application development, it puts forward higher requirements for the simplicity and carrying convenience of its structure. The traditional DLP projector receives an external signal through the DVI interface, and transmits the signal to the DLP controller to control the display of the DLP. The occupied space is large, and the mode of receiving the signal is limited, and it is difficult to integrate into the existing equipment. If digital signals from existing instruments can be sent directly to DLP without multiple data conversions, volume and cost can be reduced, and DLP can be easily integrated into instrumentation.

DLP projectors use three-color LEDs as the light source, which is also critical to the choice of LEDs. In recent years, RGB tri-color LEDs have surpassed other light-emitting devices in terms of heat dissipation, reliability, color saturation and energy efficiency. The use is also becoming more common [3]. Many LED device manufacturers currently use separate combinations of red, green, and blue LEDs to provide the desired color. There are some disadvantages to using discrete LED packages in applications, such as space waste caused by the package structure, and Separating farther sources to achieve the extra effort required for effective color mixing requires an integrally packaged LED chip to replace the traditional stand-alone source, a product that integrates red, green and blue LED chips in a single package, each of which An LED chip can be independently controlled to provide a variety of different color outputs [4].

Taking the DLP1700 as an example, the traditional DLP projection system is improved from the two aspects of signal input control and display light source. The display light source uses high-power RGB tri-color LED instead of traditional multi-color LED, signal input control. Eliminate the traditional DVI connector, MSP430, use the Stim32 microcontroller with I2C function to generate control signals and image signals to directly control the DLP1700 controller DLPC100, and then control the display of the DLP1700. This design can make the DLP display hardware circuit structure more streamlined, circuit control easier to implement, and can be easily integrated into various instruments.

1 signal input control

The signal input terminal of the traditional digital micromirror display technology is to provide image signal and line sync signal by DVI interface, which is paired by MSP430

The DLPC100 performs basic control and transmits control signals through the I2C bus. The whole process involves more chips and more complicated lines. In this design, we use the STM32 series single-chip microcomputer based on Cortex M3 core to improve the signal input part. The image signal and the line sync signal sent by Stm32 are transmitted to the DLPC100 to control the display of the DLP1700 and the driving of the LED. Because the STM32 itself carries the I2C bus interface, it can replace the traditional MSP430 and I2C bus with a series of controls inside the DLPC100. The specific circuit connection block diagram is shown in Figure 1.