【作者】 王熙；

【导师】 梁煜；

【作者基本信息】 天津大学 ， 电子科学与技术， 2023， 硕士

【摘要】 光电编码器作为一种测量角位移、角速度和角加速度等物理量的精密仪器,被广泛应用于智能机器人、航空航天系统、伺服系统、数控机床等众多领域,并且正在向着高光电集成度、高分辨率和低安装误差要求的趋势发展。传统的透射式光电编码器由于其结构特点,很难实现小型化设计,并且容易受到安装误差的影响,装配难度和环境要求都较高。而新兴的反射式光电编码器可以实现更高的光电集成度,允许更大的安装误差,在提高精度和分辨率上具有更大的潜力。本文以反射式光电编码器为基础,针对混合编码型光电编码器中绝对码输出信号容易因光源光强变化而产生误码的问题,提出了一种差分式绝对码结构,并基于该结构设计了一款应用于反射式混合编码型光电编码器的光电集成芯片。该芯片由LED光源、两条绝对码信号链路、两条增量码信号链路和供电模块组成。其中,绝对码信号链路包括绝对码光电二极管阵列、跨阻放大器、减法器和迟滞比较器,增量码信号链路包括增量码光电二极管阵列、跨阻放大器和全差分放大器。在绝对码信号链路设计中,为实现不同位置绝对码输出信号的一致性,提出了一种基于光强分布特性的面积补偿设计,同时结合差分式信号处理结构,实现了绝对码信号的高准确性和强抗干扰性。在增量码信号链路设计中,为提高增量码信号的质量,采用了一种能够滤除奇次谐波的异形光电二极管阵列,同时采用全差分放大器进行差分输入输出,有效滤除了增量码信号中的高次谐波。本文光电集成芯片基于0.35μm CMOS工艺进行设计和流片,并在传统方形扁平无引脚封装基础上,将LED芯片叠装,实现了光电一体化封装。测试结果表明:所研发的光电集成芯片性能优良,增量码输出信号的正弦性和正交性良好;不同工作条件下绝对码输出信号的占空比误差均较小,当LED光源的工作电流发生50%变化时,绝对码输出信号的占空比误差低于5.5%。芯片裸片尺寸为5.87mm×5.97mm,可在4.5～5.5V的宽电源电压范围内正常工作,在典型5V电源电压下,芯片的功耗电流为53.153mA。更多还原

【Abstract】 Photoelectric encoder is a precision instrument for measuring physical quantities such as angular displacement,angular velocity and angular acceleration.It is widely used in many fields such as intelligent robots,aerospace systems,servo systems,CNC machine tools and so on.And it is developing toward the trend of high photoelectric integration,high resolution and low installation error requirements.The traditional transmissive photoelectric encoder is difficult to achieve miniaturization because of its structural characteristics.Moreover,it is easily affected by installation errors,and the assembly difficulty and environmental requirements are high.The emerging reflective photoelectric encoder can achieve higher photoelectric integration,allowing greater installation error,and has greater potential in improving accuracy and resolution.Based on reflective photoelectric encoder,this thesis proposes a differential absolute code structure to solve the problem that the output signal of absolute code in hybrid encoding photoelectric encoder is prone to error due to the change of light intensity.And based on this structure,a photoelectric integrated chip is designed for reflective hybrid encoding photoelectric encoder.The chip consists of an LED light source,two absolute code signal links,two incremental code signal links and a power supply module.The absolute code signal links include absolute code photodiode arrays,trans-impedance amplifiers,subtractors and hysteresis comparators.The incremental code signal links include incremental code photodiode arrays,trans-impedance amplifiers and fully differential amplifiers.In the design of absolute code signal links,in order to achieve the consistency of absolute code output signals at different positions,an area compensation design based on light intensity distribution characteristics is proposed.At the same time,combined with the differential signal processing structure,the high accuracy and strong anti-interference of the absolute code signals are realized.In the design of the incremental code signal links,in order to improve the quality of incremental code signals,the special-shaped photodiode arrays that can filter out odd harmonics are used,and fully differential amplifiers are used for differential input and output,which effectively filters out the higher harmonics in the incremental code signals.The photoelectric integrated chip in this thesis is designed and taped out based on the 0.35μm CMOS process.And on the basis of the traditional quad flat no-leads package,the LED chip is stacked to realize the photoelectric integrated package.The test results show that the developed photoelectric integrated chip has excellent performance.The output signals of incremental code have good sinusoidal and orthogonality.The duty cycle error of the absolute code output signals is small under different working conditions.When the working current of the LED light source changes by 50%,the duty cycle error of the absolute code output signals is less than5.5%.The die size of the chip is 5.87mm×5.97mm.The chip can operate normally in the supply voltage range of 4.5～5.5V,and the power consumption current of the chip is 53.153mA at typical 5V supply voltage.更多还原