Abstract:
본 발명은 SHA, MDAC 및 flash ADC를 포함하는 ADC에 관한 것으로서, SHA 또는 MDAC의 입력단을 두 개의 채널인 X 채널과 Y 채널로 구성하고, 두 개의 채널은 증폭기를 공유하도록 하며, SHA에 X 채널의 샘플링 클록과 Y 채널의 샘플링 클록을 생성하는 SHA 샘플링 클록 발생기를 더 포함하고, SHA의 X 채널의 샘플링 클록과 Y 채널의 샘플링 클록을 SHA 샘플링 클록 발생기의 기준 클록의 폴링 에지(falling edge)에 동기시키는 것을 특징으로 하며, 외부에서 인가되는 아날로그 입력 신호를 샘플링할 때 균등한 간격으로 샘플링하지 못하는 샘플링 시간 부정합 문제를 해결하여 각 채널의 샘플링 클록이 동일한 간격으로 입력신호를 샘플링할 수 있다.
Abstract:
PURPOSE: An ADC(Analog to Digital Converter) sharing amplifiers between two channels is provided to additionally reduce the number of pre-amplifiers by 50% by applying an interpolation method to flash ADCs. CONSTITUTION: An ADC(Analog to Digital Converter) includes a SHA(Sample-and-Hold Amplifier)(110), a MDAC1(Multiplying Digital to Analog Converter)(120), a MDAC2(130), a FLASH1(140), a FLASH2(150), and a FLASH3(160). The ADC includes an on-chip reference current and voltage generator(170), a digital correction circuit(180) including a divider, and a clock generator(190). Input terminals of the SHA, the MDAC1, and the MDAC2 are composed of two channels. Two channels share only one amplifier. The FLASH1, the FLASH2, and the FLASH3 are composed of a pre-amplifier and a latch. The FLASH1, the FLASH2, and the FLASH3 reduce the number of pre-amplifiers by 50% to consecutively process signals outputted from the SHA, the MDAC1, and the MDAC2 by sharing one pre-amplifier having a DDA(Differential Difference Amplifier) structure.
Abstract:
PURPOSE: A dual channel analog to digital converter (ADC) is provided to sample an input signal by using a sampling clock of each channel by solving a mismatching problem. CONSTITUTION: An ADC comprises an SHA (110), an MDAC (120-130), an SHA sampling clock generator, and a flash ADC (140-160). An input end of the SHA or the MDAC constructs an X channel and a Y channel. The X channel shares an amplifier with the Y channel. The SHA sampling clock generator generates the sampling clock of the X channel and the sampling clock of the Y channel. The sampling clock of the X channel and the sampling clock of the Y channel are synchronized with a falling edge of a reference clock. A delay control circuit controls the delay time of a reference clock synchronizing with the SHA sampling clock generating the SHA sampling clock generator used in a digital correction circuit.