Time Domain Processing Techniques Using Ring Oscillator-Based Filter Structures
Time Domain Processing Techniques Using Ring Oscillator-Based Filter Structures
复制标题
使用基于环形振荡器的滤波器结构的时域处理技术
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
T. Constandinou
中科院分区：
文献类型：
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作者：
Lieuwe B. Leene;T. Constandinou
对于先进纳米技术节点使用的时域 (TD) 电路技术来说，高保真度处理时间编码信号的能力变得越来越重要。本文提出了一种基于振荡器的紧凑子系统，该子系统对异步脉宽调制编码信号进行精确滤波，并广泛使用数字逻辑，从而实现低电压操作。引入了一阶和二阶原语，可用作 TD 存储器或启用 TD 信号的模拟滤波。可以对这些结构进行精确建模，以使用单元集合来实现更高级的线性或非线性功能。本文介绍了使用 65 nm CMOS 技术制造的原型的测量结果，以实现四阶低通巴特沃斯滤波器。该系统利用 0.5V 电源电压和异步数字控制进行闭环操作，以实现 73nW 的功率预算。所实施的滤波器可实现 53 dB 的最大信噪比和失真比，并具有 5kHz 窄带宽，从而产生 8.2 fJ/极的品质因数。由于该电路占用了紧凑的 0.004mm2 硅足迹，因此该技术有望比传统的 Gm-C 滤波器大幅减小尺寸，同时还提供与数字系统的直接集成。
The ability to process time-encoded signals with high fidelity is becoming increasingly important for the time domain (TD) circuit techniques that are used at the advanced nanometer technology nodes. This paper proposes a compact oscillator-based subsystem that performs precise filtering of asynchronous pulse-width modulation encoded signals and makes extensive use of digital logic, enabling low-voltage operation. First- and second-order primitives are introduced that can be used as TD memory or to enable analogue filtering of TD signals. These structures can be modeled precisely to realize more advanced linear or nonlinear functionality using an ensemble of units. This paper presents the measured results of a prototype fabricated using a 65-nm CMOS technology to realize a fourth-order low-pass Butterworth filter. The system utilizes a 0.5-V supply voltage with asynchronous digital control for closed-loop operation to achieve a 73-nW power budget. The implemented filter achieves a maximum signal to noise and distortion ratio of 53 dB with a narrow 5-kHz bandwidth resulting in an figure-of-merit of 8.2 fJ/pole. With this circuit occupying a compact 0.004-mm2 silicon footprint, this technique promises a substantial reduction in size over conventional Gm-C filters, whilst additionally offering direct integration with digital systems.