大尺寸红外触摸技术的驱动电路设计与分析

Design and analysis of infrared drive circuit for large-size infrared touch technology

为了设计大尺寸的红外触摸屏,解决大尺寸情况下触摸信号弱的问题,本文提出了一种适用于该触摸屏的驱动电路设计方案,并对方案进行了系统的测试与分析。在电路设计中,采用普通的中小功率管:三极管、达林顿管、MOSFET管等,调整电路参数充分发挥管子的性能,使电路的瞬态发射功率从传统的几百毫瓦提升到几千毫瓦。最后,基于PIC32MX440F256H对实验方案进行了测试,并与传统的驱动方法进行对比分析。实验结果表明,红外发射传感器驱动电路的最高瞬态电流达到500mA,功率达到2 500mW,远远大于普通驱动电路125mA的电流;接收传感器驱动电路能够准确无误的接收每个发射传感器的光信号并完整输出相应的电信号。该方案能够有效的驱动大尺寸红外触摸屏,提高了瞬态发射功率,降低了整体功耗,提升了系统信噪比。

In order to solve the weak signal on the large size touch screen and design a large size infrared touch screen,a driving circuit design proposal is proposed which is suitable for this kind of touch screen,and it is well tested and analyzed systematically.In the circuit design,common small and medium size power tubes,such as transistors,Darlington transistors,MOSFET transistors are used to adjust circuit parameters to maximize the performance of the tube,then the transmit power of the circuit transient increases from the traditional hundreds of milliwatts to several thousands of milliwatts.Finally,based on the PIC32MX440F256H,the experimental design proposal was fully tested and the output results were compared with traditional driving circuit methods.The experimental results show that the maximum instantaneous current of infrared emission sensor driving circuit reaches up to 500 mA,and the instantaneous power is up to 2 500 mW,which is much larger than 125 mA of ordinary driving circuit.And the driving circuit of reception sensor can receive signal accurately from each emission sensor and output the corresponding electrical signal completely.The proposal can drive large-size infrared touch screen effectively,improve transient emission power,and reduce the overall power consumption,and also can improve the Signal to Noise Ratio （SNR）.