Low supply voltage and multiphase all‐digital crystal‐less clock generator

Tu, Yo Hao; Liu, Jen Chieh; Cheng, Kuo Hsing; Chang, Chi Yang

doi:10.1049/iet-cds.2018.5149

Cited by 3 publications

(2 citation statements)

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“…The relationship between the phase (θ) and the phase position (P<9:0>) is defined by Eq. (2) [34]. Fig.…”

Section: B Proposed Dco With the Bootstrapped And Forward Interpolatmentioning

confidence: 97%

A Low Supply Voltage All-Digital Phase-Locked Loop With a Bootstrapped and Forward Interpolation Digitally Controlled Oscillator

Liu

2021

IEEE Access

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An all-digital phase-locked loop (ADPLL) with a multiphase digitally controlled oscillator (DCO) incorporating the bootstrapped and interpolated schemes is proposed in this paper. The bootstrapped ring oscillator can boost the output voltage to a higher level than the supply voltage. Thus, the oscillator can be operated in low-supply-voltage applications. MOS varactor is used in the bootstrapped capacitor to reduce the area cost. Circuit analysis and simulated verification were performed for an optimized design. The interpolated DCO has multiphase outputs and a high operating frequency. The test chip was implemented in a 90-nm CMOS process, and the core area was 60 × 117 μm 2. The power consumptions at 1160 MHz and 20 MHz were 912.6 μW (at 0.6 V) and 2.94 μW (at 0.2 V), respectively. In the worst-case jitter performance, the root mean square (RMS) jitters were less than 0.42%. INDEX TERMS Bootstrapped, digitally controlled oscillator (DCO), interpolation, multiphase, phaselocked loop (PLL).

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“…The relationship between the phase (θ) and the phase position (P<9:0>) is defined by Eq. (2) [34]. Fig.…”

Section: B Proposed Dco With the Bootstrapped And Forward Interpolatmentioning

confidence: 97%

A Low Supply Voltage All-Digital Phase-Locked Loop With a Bootstrapped and Forward Interpolation Digitally Controlled Oscillator

Liu

2021

IEEE Access

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“…Tu et al [35] propose a frequency compensation technique to tackle the temperature drifts experienced by a DCO. At startup, the DCO frequency is defined as a target frequency at the startup room temperature, and its value is digitized and stored in a register.…”

Section: Related Workmentioning

confidence: 99%

Dynamic Channel Calibration on a Crystal-Free Mote-on-a-Chip

et al. 2019

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The single chip integration of a wireless sensor node would allow for cheap, low-power, dust-size devices. The key to realizing this vision is to eliminate bulky off-chip frequency references such as crystal oscillators or resonators, and their associated power-hungry circuitry. The immediate challenge of removing off-chip references is that there is no accurate on-chip frequency references, which makes it hard to tune the radio to the right frequency, and to keep an accurate sense of time. This article offers a full solution for crystal-free devices, which includes (1) initiating communication in an IEEE802.15.4 network, (2) synthesizing the 16 communication channels at startup temperature, and (3) continuously applying corrections to the inaccurate timing source to allow keeping frequency synchronization on all communication channels over a 5-55 • C temperature range. The proposed methods are accompanied by simulations and an experimental validation on the first fully-functional Single Chip Micro Mote hardware implementation. Our simulations and experimental results validate that the proposed approach achieves radio clock synchronization accuracy close to the 40 ppm limit imposed by the IEEE802.15.4 standard.

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