PWM Controller of a Transmitter and High-Precision Phase Adjustment of a Receiver for a Portable Ultrasound System

• Main Authors: CHIANG, CHENG-LIN, 江政霖
• Other Authors: CHEN, TZU-CHIANG
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/d4g47g

碩士 === 國立中正大學 === 電機工程研究所 === 105 === Nowadays, the development of the ultrasound field has become more and more flourishing, and the demand increased for scanner-related products, There are more and more products has been transferred to portable systems. Therefore, in the ultrasonic system, there has several improved points, reducing the chip layout area, power consumption, increasing stability and accuracy for the goal of the transmitter and receiver, the transmitter side of the power supply is provided by the DC-DC converter to convert, the stability of the voltage conversion process is a major consideration to ensure that signal accuracy; On the receiver side, the low-voltage differential signal (LVDS) transmission widely used for transmission interface, It has several advantages, like high-speed, low power consumption, and the best anti-noise capability. In this paper, We purpose a voltage mode control of PWM Controller for voltage regulating , the principle is coming from DC to DC conversion output voltage through the feedback voltage, Then using the error amplifier to detect the feedback voltage and bandgap reference voltage difference between the voltage and output a reference level voltage, finally we use the other comparator, using reference level voltage as input to positive side and a fixed cycle oscillation sawtooth wave as input to negative side, by comparing both inputs to control the Duty Cycle width for adjust the stability of voltage conversion, In addition, the positive and negative voltage source feedback into the same chip to facilitate the integration with the pulser system of ultrasound, The purposed PWM controller has been fabricated by VIS 0.5μm high-voltage process for circuit design and simulation, Open-Loop Gain is 83dB, FBN(0~-5V) to transform FBP(0~5V) function is correct; On the other hand , We purpose a modified delay phase adjuster of low-voltage differential signal (LVDS) receiver, the single delay cell expansion into 32 step, we use 32 groups 2 to 1-multiplexer to select high or low frequency operation switch for increasing the accuracy of unit delay on each cell, and the overall maximum delay time, by "isolation", "gate control" and "reducing switch activities" concept to reduce the power consumption, the overall layout area is 280x76.2〖μm〗^2, delay cell precision is 0.268ns, and power consumption is 1.18mW, as the structure into the low-voltage differential system, and achieve the low-voltage differential signal 16 channel receiver circuit; The proposed has been fabricated by TSMC 0.18μm 1P6M CMOS standard process provided by (CIC) for circuit design and simulation. The simulation verify its function work, and eight-channel part has been successfully tape out.