적분형 A/D 컨버터를 이용한 누설전류 감지회로 설계에 관한 연구 = A study on the design of leakage current sensing circuit by using integrating A/D converter

다국어 초록 (Multilingual Abstract)

The variation of parameters in the chips due to the microscopic semiconductor fabrication process, have been a critical problem on the industry as the chip size is scaling down. Particularly, the variation on Delay Time() and Leakage Current() properties are arising as the main factor of yield reduction. It is available to control and by tunning the threshold voltage(). However, the characteristic between and shows trade-off relationship in terms of improvement of the performances. Therefore, it is required to apply different on each chip respectively, in order to control variations of the two characteristics. This process is called ABB(Adaptive Body Bias), which applies the voltage on the substrate to control the .
In this paper, the novel sub-threshold leakage current sensing circuit with Integrating Analog-to-Digital(ADC) Converter based on ABB. It was designed in terms of two important points. First, the switch which floating the target MOSFET was designed Staked MOSFET, to avoid the by-pass current. Second, Integrating ADC was inserted at the sensing circuit to get more stable converting performance.
In order to prove the effect of this circuit, the simulation was implemented and the real chip was fabricated. in the result of simulation, we could sense the variation of accurately. The simulation output result showed same tendency with real leakage current, and ADC output, measuring value of the chip showed 2% of error rate.

목차 (Table of Contents)

• 1. 서 론 ………………………………………………………………………1
• 1.1 CMOS 공정의 Scaledown에 따른 전력소모 현황 ……………1
• 1.2 공정변수 조절을 통한 누설전류 제어 시 고려사항 ………………3
• 2. ABB(Adaptive Body Bias) 및 누설전류 검출회로의 이론적 해석6
• 2.1 지연시간에 따른 전류 수식 해석 ……………………………………6
• 2.2 대기상태 누설전류 수식 해석 ………………………………………11
• 2.3 ABB를 통한 문턱전압의 조절 ………………………………………13
• 2.3.1 FBB를 통한 전파지연 특성 향상 ……………………………13
• 2.3.2 RBB를 통한 누설전류 특성 향상 ……………………………15
• 3. 적분형 A/D 컨버터를 이용한 누설전류 센서의 제안 및 이론적 고찰19
• 3.1 전류감지용 가변 드레인 전압의 측정 회로 고찰 ………………… 19
• 3.2 적분형 A/D 컨버터를 통한 전압감소 시간의 디지털화 방안고찰23
• 3.3 새로운 구조의 누설전류 감지회로 제안 …………………………26
• 3.4 채널길이 가변 A/D 컨버터 회로의 제안 ………………………28
• 3.5 지연 시간 측정 회로 분석 …………………………………………… 31
• 4. 시뮬레이션과 실제 제작회로의 특성 측정 결과 및 고찰 ……………36
• 4.1 제안한 감지회로의 시뮬레이션 결과 및 고찰 ……………………36
• 4.1.1 누설전류 감지용 적분형 A/D 컨버터 특성 고찰 ………… 36
• 4.1.2 지연시간 감지용 TDC 특성 확인 및 고찰 …………………39
• 4.2 제작한 감지회로의 특성 측정 결과 및 고찰………………………43
• 5. 결 론 …………………………………………………………………51