Browsing by Author "Chang, C. -W."

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Near-threshold all-digital PLL with dynamic voltage scaling power management
(2016-01-21)
Chang, C. -W.
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Chang, K. -Y.
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Chu, Y. -H.
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Jou, S. -J.
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電子工程學系及電子研究所
A near-threshold all-digital phase-locked loop (ADPLL) with a power management unit (PMU) is presented to make the proposed ADPLL work reliably across variations and power consumption as well is reduced. When operated under near-threshold condition from 0.52 to 0.58 V V-DD, the gated digitally controlled oscillator frequency range is from 90.8 to 245.7 MHz. When the ADPLL is operated at 0.52 V V-DD, a lock-in time of 9.5 mu s at 100 MHz output clock frequency is measured with an rms period jitter of 0.17% UI. With the PMU, the ADPLL power reduction at 130 MHz output frequency is 39% and the buck converter power consumption is nearly 30 mu W. Consequently, the proposed ADPLL with PMU is suitable to event-driven or low-voltage applications.
Wireless and batteryless biomedical microsystem for neural recording and epilepsy suppression based on brain focal cooling
(2011-12-01)
Hou, K. -C.
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Chang, C. -W.
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Chiou, J. -C.
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Huang, Y. -H.
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Shaw, F. -Z.
This work presents a biomedical microsystem with a wireless radiofrequency (RF)-powered electronics and versatile sensors/actuators for use in nanomedicinal diagnosis and therapy. The cooling of brain tissue has the potential to reduce the frequency and severity of epilepsy. Miniaturised spiral coils as a wireless power module with low-dropout linear regulator circuit convert RF signals into a DC voltage, can be implanted without a battery in monitoring free behaviour. A thermoelectric (TE) cooler is an actuator that is employed to cool down brain tissue to suppress epilepsy. Electroencephalogram (EEG) electrodes and TE coolers are integrated to form module that is placed inside the head of a rat and fastened with a biocompatible material. EEG signals are used to identify waveforms associated with epilepsy and are measured using readout circuits. The wireless part of the presented design achieves a low quiescent current and line/load regulation and high antenna/current efficiency with thermal protection to avoid damage to the implanted tissue. Epilepsy is suppressed by reducing the temperature to reduce the duration of this epileptic episode. Related characterisations demonstrate that the proposed design can be adopted in an effective nanomedicine microsystem.