Browsing by Author "Li, Yilei"

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A 0.56 THz Phase-Locked Frequency Synthesizer in 65 nm CMOS Technology
(2016-12-01)
Zhao, Yan
;
Chen, Zuow-Zun
;
Du, Yuan
;
Li, Yilei
;
Al Hadi, Richard
This paper presents the design and characterization of a 0.56 THz frequency synthesizer implemented in standard 65 nm CMOS technology. Its front end consists of triple-push Colpitts oscillators (TPCOs), followed by the first and second stage injection locking frequency dividers (ILFDs) and a divide-by-16 chain. TPCOs are used to triple their fundamental frequencies to 0.53-0.56 THz, while ILFDs and the subsequent divider chain are used to divide such frequencies to 2.7-2.9 GHz. Its back end consists of separate frequency and phase-locked loops with unique CMOS circuit designs to accomplish the desirable frequency/phase locking, including: 1) band-selection inductor switches; 2) simultaneous bulk voltage tuning over TPCOs and the first ILFD; and 3) a dual port injection architecture for the first ILFD. The resultant prototype realizes a 21 GHz frequency locking range with phase noise lower than -74 dBc/Hz at 1 MHz offset, and consumes 174 mW dc power.
A 0.56 THz Phase-Locked Frequency Synthesizer in 65 nm CMOS Technology
(2016-12)
Zhao, Yan
;
Chen, Zuow-Zun
;
Du, Yuan
;
Li, Yilei
;
Al Hadi, Richard
This paper presents the design and characterization of a 0.56 THz frequency synthesizer implemented in standard 65 nm CMOS technology. Its front end consists of triple-push Colpitts oscillators (TPCOs), followed by the first and second stage injection locking frequency dividers (ILFDs) and a divide-by-16 chain. TPCOs are used to triple their fundamental frequencies to 0.53-0.56 THz, while ILFDs and the subsequent divider chain are used to divide such frequencies to 2.7-2.9 GHz. Its back end consists of separate frequency and phase-locked loops with unique CMOS circuit designs to accomplish the desirable frequency/phase locking, including: 1) band-selection inductor switches; 2) simultaneous bulk voltage tuning over TPCOs and the first ILFD; and 3) a dual port injection architecture for the first ILFD. The resultant prototype realizes a 21 GHz frequency locking range with phase noise lower than -74 dBc/Hz at 1 MHz offset, and consumes 174 mW dc power.
A 16-Gb/s 14.7-mW Tri-Band Cognitive Serial Link Transmitter With Forwarded Clock to Enable PAM-16/256-QAM and Channel Response Detection
(2017-04-01)
Du, Yuan
;
Cho, Wei-Han
;
Huang, Po-Tsang
;
Li, Yilei
;
Wong, Chien-Heng
A cognitive tri-band transmitter (TX) with a forwarded clock using multiband signaling and high-order digital signal modulations is presented for serial link applications. The TX features learning an arbitrary channel response by sending a sweep of continuous wave, detecting power level at the receiver side, and then adapting modulation scheme, data bandwidth, and carrier frequencies accordingly based on detected channel information. The supported modulation scheme ranges from nonreturn to zero/Quadrature phase shift keying (QPSK) to Pulse-amplitude modulation (PAM) 16/256-Quadrature amplitude modulation(QAM). The proposed highly reconfigurable TX is capable of dealing with low-cost serial channels, such as low-cost connectors, cables, or multidrop buses with deep and narrow notches in the frequency domain (e.g., a 40-dB loss at notches). The adaptive multiband scheme mitigates equalization requirements and enhances the energy efficiency by avoiding frequency notches and utilizing the maximum available signal-to-noise ratio and channel bandwidth. The implemented TX prototype consumes a 14.7-mW power and occupies 0.016 mm(2) in a 28-nm CMOS. It achieves a maximum data rate of 16 Gb/s with forwarded clock through one differential pair and the most energy efficient figure of merit of 20.4 mu W/Gb/s/dB, which is calculated based on power consumption of transmitting per gigabits per second data and simultaneously overcoming per decibel worst case channel loss within the Nyquist frequency.
A 16Gb/s 14.7mW Tri-Band Cognitive Serial Link Transmitter with Forwarded Clock to Enable PAM-16 / 256-QAM and Channel Response Detection in 28 nm CMOS
(2016)
Du, Yuan
;
Cho, Wei-Han
;
Li, Yilei
;
Wong, Chien-Heng
;
Du, Jieqiong
A cognitive tri-band transmitter with forwarded clock using multi-band signaling and high-level digital signal modulations is presented for serial link application. The transmitter features learning an arbitrary channel response by sending a sweep of continuous wave, detecting power level, and accordingly adapts modulation scheme, data bandwidth and carrier frequency. The modulation scheme ranges from NRZ/QPSK to PAM-16/256-QAM. The highly re-configurable transmitter is capable of dealing with low-cost serial link cables/connectors or multi-drop buses with deep and narrow notches in frequency domain (e.g. 40dB loss at notches). The adaptive multi-band scheme mitigates equalization requirement and enhances the energy efficiency by avoiding frequency notches and utilizing the maximum available signal-to-noise ratio and channel bandwidth. The implemented transmitter consumes 14.7mW power and occupies 0.016mm(2) in 28nm CMOS. It achieves a maximum data rate of 16Gb/s per differential pair and the most energy-efficient FoM (defined in Fig. 8) of 20.4 mu W/Gb/s/dB considering channel condition.
A 2-GS/s 8-Bit ADC Featuring Virtual-Ground Sampling Interleaved Architecture in 28-nm CMOS
(2018-11-01)
Wang, X. Shawn
;
Jin, Xin
;
Du, Jieqiong
;
Li, Yilei
;
Du, Yuan
This brief presents a two-way time-interleaved twostep pipelined analog-to-digital converter (ADC) architecture built upon a new concept of virtual-ground sampling, featuring merged front-end track-and-hold, residue generation, input termination, and buffering. This architecture is investigated to alleviate the front-end performance tradeoff among the total-harmonic- distortion, bandwidth, and sampling rate (interleaving factor). A 2-GS/s 8b ADC using the new architecture was designed and fabricated in 28-nm CMOS, achieving 43-dB SNDR and 55-dB SFDR up to Nyquist frequency.
A 38mW 40Gb/s 4-Lane Tri-Band PAM-4 / 16-QAM Transceiver in 28nm CMOS for High-Speed Memory Interface
(2016)
Cho, Wei-Han
;
Li, Yilei
;
Du, Yuan
;
Wong, Chien-Heng
;
Du, Jieqiong
A 7.5-mW 10-Gb/s 16-QAM Wireline Transceiver with Carrier Synchronization and Threshold Calibration for Mobile Inter-chip Communications in 16-nm FinFET
(2019-01-01)
Du, Jieqiong
;
Wong, Chien-Heng
;
Tu, Yo-Hao
;
Cho, Wei-Han
;
Li, Yilei
A compact energy-efficient 16-QAM wireline transceiver with carrier synchronization and threshold calibration is proposed to leverage high-density fine-pitch interconnects. Utilizing frequency-division multiplexing, the transceiver transfers four-bit data through one RF band to reduce inter-symbol interferences. A forwarded clock is also transmitted through the same interconnect with the data simultaneously to enable low-power PVT-insensitive symbol clock recovery. A carrier synchronization algorithm is proposed to overcome nontrivial current and phase mismatches by including DC offset calibration and dedicated I/Q phase adjustments. Along with this carrier synchronization, a threshold calibration process is used for the transceiver to tolerate channel and circuit variations. The transceiver implemented in 16-nm FinFET occupies only 0.006-mm(2) and achieves 10 Gb/s with 0.75-pJ/bit efficiency and <2.5-ns latency.
A Novel Fully Synthesizable All-Digital RF Transmitter for IoT Applications
(2018-01-01)
Li, Yilei
;
Dhwaj, Kirti
;
Wong, Chien-Heng
;
Du, Yuan
;
Du, Li
In this paper, a fully synthesizable all-digital transmitter (ADTX) is first proposed. This transmitter (TX) uses Cartesian architecture and supports wide-band quadratic-amplitude modulation with wide carrier frequency range. Furthermore, the design methodology for ADTX and corresponding bandpass filter is discussed. This TX is synthesized with digital register transfer level-graphic database system flow, and can be easily implemented in any standard CMOS technology. An exemplary TX is synthesized by TSMC 28-nm standard cell library with extremely small area (0.0009 mm(2)) and supports carrier frequency as high as 6 GHz with excellent error vector magnitude (<-30 dB). To the best of the authors' knowledge, this is the first work on a fully synthesizable design of RF transistors, allowing easy technology migration and portability.
A Reconfigurable Streaming Deep Convolutional Neural Network Accelerator for Internet of Things
(2018-01-01)
Du, Li
;
Du, Yuan
;
Li, Yilei
;
Su, Junjie
;
Kuan, Yen-Cheng
Convolutional neural network (CNN) offers significant accuracy in image detection. To implement image detection using CNN in the Internet of Things (IoT) devices, a streaming hardware accelerator is proposed. The proposed accelerator optimizes the energy efficiency by avoiding unnecessary data movement. With unique filter decomposition technique, the accelerator can support arbitrary convolution window size. In addition, max-pooling function can be computed in parallel with convolution by using separate pooling unit, thus achieving throughput improvement. A prototype accelerator was implemented in TSMC 65-nm technology with a core size of 5 mm(2). The accelerator can support major CNNs and achieve 152GOPS peak throughput and 434GOPS/W energy efficiency at 350 mW, making it a promising hardware accelerator for intelligent IoT devices.
A Single Layer 3-D Touch Sensing System for Mobile Devices Application
(2018-02-01)
Du, Li
;
Liu, Chun-Chen
;
Zhang, Yan
;
Li, Yilei
;
Du, Yuan
Touch sensing has been widely implemented as a main methodology to bridge human and machine interactions. The traditional touch sensing range is 2-D and therefore limits the user experience. To overcome these limitations, we propose a novel 3-D contactless touch sensing called Airtouch system, which improves user experience by remotely detecting single/multi-finger position. A single layer touch panel with triangle-shaped electrodes is proposed to achieve multitouch detection capability as well as manufacturing cost reduction. Moreover, an oscillator-based-capacitive touch sensing circuit is implemented as the sensing hardware with the bootstrapping technique to eliminate the interchannel coupling effects. To further improve the system accuracy, a grouping algorithm is proposed to group the useful channels' data and filter out hardware noise impact. Finally, improved algorithms are proposed to eliminate the fringing capacitance effect and achieve accurate finger position estimation. EM simulation proved that the proposed algorithm reduced the maximum systematic error by 11 dB in the horizontal position detection. The proposed system consumes 2.3 mW and is fully compatible with existing mobile device environments. A prototype is built to demonstrate that the system can successfully detect finger movement in a vertical direction up to 6 cm and achieve a horizontal resolution up to 0.6 cm at 1 cm finger-height. As a new interface for human and machine interactions, this system offers great potential in finger movement detection and gesture recognition for small-sized electronics and advanced human interactive games for mobile device.
An 8.8-GS/s 8b Time-Interleaved SAR ADC with 50-dB SFDR Using Complementary Dual-Loop-Assisted Buffers in 28nm CMOS
(2018-01-01)
Wang, X. Shawn
;
Chan, Chi-Hang
;
Du, Jieqiong
;
Wong, Chien-Heng
;
Li, Yilei
This paper presents an 8.8 GS/s 16-way time-interleaved asynchronous SAR ADC fabricated in 28-nm CMOS technology. A two-level 2x8 master-slave hierarchical interleaved architecture is employed. A complementary dual-loop-assisted buffer is proposed to achieve both high linearity and bandwidth with low power. This time-interleaved ADC achieves 38.4-dB SNDR and 50-dB SFDR with a Nyquist input at 8.8 GS/s sampling rate and consumes 83.4 mW, resulting in a 140 fJ/conv.-step Walden FOM with buffers.
Digital PLL for Phase Noise Cancellation in Ring Oscillator-Based I/Q Receivers
(2016)
Chen, Zuow-Zun
;
Li, Yilei
;
Kuan, Yen-Cheng
;
Hu, Boyu
;
Wong, Chien-Heng
A digital phase noise cancellation technique for ring oscillator-based I/Q receivers is presented. Ring oscillator phase noise, including supply-induced phase noise, is extracted from digital phase-locked loop (DPLL) and used to restore the randomly rotated baseband signal in digital domain. The receiver prototype fabricated in 65nm CMOS technology achieves phase noise reduction from - 88 to - 109dBc/Hz at 1MHz offset, and an integrated phase noise (IPN) reduction from - 16.8 to - 34.6dBc, when operating at 2.4GHz.
DPLL for Phase Noise Cancellation in Ring Oscillator-Based Quadrature Receivers
(2017-04-01)
Chen, Zuow-Zun
;
Kuan, Yen-Cheng
;
Li, Yilei
;
Hu, Boyu
;
Wong, Chien-Heng
In this paper, a low overhead phase noise cancellation technique for ring oscillator (RO)-based quadrature receivers is presented. The proposed technique operates in background and extracts RO phase noise as well as supply-induced phase noise from the digital phase-locked loop. The obtained phase noise information is then used to restore the randomly rotated baseband signal in digital domain. A receiver prototype is fabricated in standard 65-nm CMOS technology. It demonstrates a phase noise reduction from -88 to -109 dBc/Hz at 1-MHz offset and an integrated phase noise reduction from -16.8 to -34.6 dBc when operating at 2.4 GHz.