Design of low-cost drive circuit for passive liquid crystal optical device

In order to realize the driving of multi-channel passive liquid crystal optical devices,the driving circuit with low cost,low complexity and adjustable amplitude and frequency is designed and developed. Firstly,to facilitate the control of the liquid crystal device,the USB data transmission method is used to transmit the control signal between the PC and the driver board. Secondly,the driver board adopts the combination of the mother board and daughter board,and each daughter board can output 32 driving signals, which can flexibly select the number of daughter board according to actual needs,thereby reducing the cost. The mother board and the daughter board both use STM32 as the main control chip,and the daughter board communicates with the mother board through the SPI interface. Each daughter board distributes data packets to the DAC chip through 2 SPI interfaces,and each DAC chip can control 16 channels of digital-to-analog conversion,realize the output of 192 channels of analog signals eventually. Finally,the board is made and tested. The results show that the output analog voltage is in linear proportional relationship to the gray value,and its absolute error is about 0. 010 V,which is in line with the modulation accuracy of 10 bit,1 024-level voltage gray value. The driver board can realize the output of multi-channel driving signals and meet the requirements of driving control of multi-channel passive liquid crystal optical devices.