Browsing by Author "Chao, Paul C. -P."

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A 1.5 mW front-end readout circuit for a small-sized melanin sensor
(2016-06-01)
Cheng, Shih-Song
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Huang, Sheng-Chieh
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Tran, Trong-Hieu
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Shao, Kai-Yu
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Chao, Paul C. -P.
This study presents a novel readout circuit that serves to evaluate quantity of skin melanin in a noninvasive way via utilizing a photoplethysmography (PPG) optical sensor. PPG sensors are widely used nowadays for noninvasive diagnosis due to their salient features such as low cost and easy-to-useness. PPG signal is known highly correlated with human skin condition and cardiovascular system health. A new readout circuit featuring high-bandwidth, low-noise and low-power is designed in this study to evaluate quantitatively the melanin content of human skin based on PPG signals with high accuracy. This new readout circuit is intended to convert and amplify the electric current of the photo diode in the PPG sensor to voltage signals, and then being further properly amplified to the full dynamic range of the chip circuit fabricated by the TSMC 0.18 mu m process for maximum S/N ratios. The designed circuit has a front-end transimpedance amplifier (TIA), 60 dB in gain, with a degenerate resistor to perform a low noise less than 3 A mu V/aeHz while operating by a 3.3 V supply. In related circuit designs, the mismatch in current sources caused by CMOS process variation is mitigated by a current steering digital-analog-converter (DAC) with least significant bit (LSB) corresponding to 1.25 A mu A. Both TIA and DAC are designed with effort to render high accuracy in the digital outputs for the levels of sensed melanin. The power consumption of chip design is as low as 1.5 mW, while the error rate between measurement and simulation result is less than 3 %.
A 1.5 mW front-end readout circuit for a small-sized melanin sensor
(2016-06)
Cheng, Shih-Song
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Huang, Sheng-Chieh
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Tran, Trong-Hieu
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Shao, Kai-Yu
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Chao, Paul C. -P.
This study presents a novel readout circuit that serves to evaluate quantity of skin melanin in a noninvasive way via utilizing a photoplethysmography (PPG) optical sensor. PPG sensors are widely used nowadays for noninvasive diagnosis due to their salient features such as low cost and easy-to-useness. PPG signal is known highly correlated with human skin condition and cardiovascular system health. A new readout circuit featuring high-bandwidth, low-noise and low-power is designed in this study to evaluate quantitatively the melanin content of human skin based on PPG signals with high accuracy. This new readout circuit is intended to convert and amplify the electric current of the photo diode in the PPG sensor to voltage signals, and then being further properly amplified to the full dynamic range of the chip circuit fabricated by the TSMC 0.18 mu m process for maximum S/N ratios. The designed circuit has a front-end transimpedance amplifier (TIA), 60 dB in gain, with a degenerate resistor to perform a low noise less than 3 A mu V/aeHz while operating by a 3.3 V supply. In related circuit designs, the mismatch in current sources caused by CMOS process variation is mitigated by a current steering digital-analog-converter (DAC) with least significant bit (LSB) corresponding to 1.25 A mu A. Both TIA and DAC are designed with effort to render high accuracy in the digital outputs for the levels of sensed melanin. The power consumption of chip design is as low as 1.5 mW, while the error rate between measurement and simulation result is less than 3 %.
A 3.2 mW MIXED-SIGNAL READOUT CIRCUIT FOR AN ORGANIC VERTICAL NANO-JUNCTIONS SENSOR
(2016)
Chao, Paul C. -P.
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Su, Chin-I
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Tran, Trong-Hieu
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Zan, Hsiao-Wen
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電子工程學系及電子研究所
A new sensitivity organic vertical nano-junctions (VNJ) sensor for ammonia detection and its readout system are presented in this study. The designed ammonia sensor, VNJ-P3HT diode, is a simple structure with real-time response, high reproducibility and low-cost sensor. Along with the designed sensor, a precision and robust readout circuit is designed and successfully implemented as the proposed chip in this study. To utilize for a novel organic bio-chip, a particular readout system is presented that can acquire signal, compute and display concentration values of ammonia without using microcontroller. The chip is fabricated by the TSMC 0.18-mu m 1P6M 3.3V mixed signal CMOS process technique for verification. Experiment results show that the average resolution is 70.48mV/log(ppm) in a short transient time response, 50 seconds, as compared to prior study, 200 seconds. Error rate, average noise and detection rate reliability are 2.86%, 123 mu Vrms, and 99.6%, respectively. This chip could be suitable for application in cars, cell phones, watches, etc.
A Battery Charge Controller for a Flyback Converter with Digital Primary Side Regulation
(2013-01-01)
Chao, Paul C. -P.
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Chen, W. D.
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Wu, R. H.
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影像與生醫光電研究所
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電機工程學系
A battery charge controller realized by a flyback converter with digital primary side regulation for mobile phones
(2014-08-01)
Chao, Paul C. -P.
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Chen, Wei-Dar
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Wu, Ruo-Hua
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電機工程學系
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Department of Electrical and Computer Engineering
A flyback converter with digital control designed and implemented for a lithium battery charging system is proposed in this study. As opposed to the requirement of both voltage and current feedbacks for a conventional flyback converter, this study proposes a converter structure that needs only one voltage feedback to stabilize converter output for implementing the designed battery charging techniques. This single feedback of voltage is made possible by so-called "primary side regulation (PSR)", which in hardware senses the output voltage using an auxiliary winding in the isolating transformer of the flyback converter that is operated in DC-DC discontinuous current mode. The adoption of PSR also enables the elimination of the opto-coupler that is often used in conventional converters for feedback signals. Another essential part of the converter is the proposition of a new a duty control method which regulate successfully the output current by only one feedback voltage signal. The proposed battery charging design consists of three consecutive modes, trickle current (TC), CC and CV. At TC and CC, a duty control method is adopted, which is able to regulate the output current by sensing only the output voltage. Both simulation and experimental results show a 7 % error deviated from targeted output current. As for CV, a proportional-integral controller is designed and implemented to regulate the output voltage. The overall experimental results show a favorable performance of the proposed charging method with proposed PSR-flyback converter.
A CHARGE PUMP WITH MPPT CIRCUIT EMPLOYED IN BATTERYLESS PHOTOVOLTAIC IOT TAGS
(2016)
Men, Guan-Yu
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Cheng, Yuan-Po
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Chao, Paul C. -P.
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Yang, Ching-Cheng
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Pribadi, Eka Fitrah
A dc-dc regulator is proposed to attach to the battery-less solar tag applied in the Internet of Things (IoTs) market. Two main purposes in this design is to maximize the power transfer efficiency and to provide a high voltage supply to the back-end circuit. The overall circuit consists of the cross-coupled charge pump, optimal power point tracking and timing control circuit. It is expected to boost the input voltage from 0.55-0.65V to the output of 1-1.1V at 80-100 mu W condition. Gated PFM circuit is adopted in the optimal power point tracking system to modulate the input frequency of the charge pump to match the inner resistance of the solar cell. This system has been taped-out by TSMC 0.18UM 1P6M process twice and N-fab 0.35UM process once. The experimental results of this chip show that the voltage conversion efficiency (VCE) is 97% and the power conversion efficiency (PCE) is 11.7% at 30 W input power condition. The reason of the low efficiency has been found and improved by enhancing the pumping capacitance. The efficiency of the 3rd tape-out in N-fab has been improved to 81.2% according to the simulation results.
A Continuous Opto-Electronic Sensor for Blood Pressure Monitoring with Real-Time System
(2017-01-01)
Kao, Yung-Hua
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Chao, Paul C. -P.
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Wey, Chin-Long
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
A new continuous wireless opto-electronic blood pressure (BP) sensor is successfully developed by this study. The BP device introduces the principle of photoplethysmograph (PPG) to sense the change of intravascular blood volume and calculate the BP. The real-time system adopts a LEDs of red/infrared light with a wavelengths of 660 and 905 nm. The analog front-end (AFE) circuit contains a pre-amplifier, a band-pass filter, a programmable gain amplifier (PGA), a microprocessor and a wireless module. A mobile phone is also used to display continuous BPs and record statistical analysis/results for users. The passband of filter is from 0.3 to 7.2 Hz. The PGA of adjustable gain are 8 channel. As results, 10 subjects in the experimental validation, in which the obtained BPs are compared with the results from a commercial BP monitor by OMRON. The maximum error of experimental results is 6 mmHg, which is less than 8 mmHg conforming to the requirement by the Advancement of Medical Instrumentation (AAMI).
A fast battery charging algorithm for an intelligent PV system with capability of on-line temperature compensation
(2013-09-01)
Chao, Paul C. -P.
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Chen, Wei-Dar
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Cheng, Chun-Wei
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影像與生醫光電研究所
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電機工程學系
This study presents a battery fast-charging mechanism for an intelligent generic photovoltaic (PV) system and also a pulse-charging method for the on-line temperature compensation. The fuzzy logic control (FLC) is adopted for fast maximum power point tracking (MPPT) of the PV system. Along with proposed battery charging algorithms, the controller presented in this study is named a fuzzy battery-managing controller (FBMC). The fast battery charging by this controller does not only prolong battery lifetime by restoring the maximum battery state of charge (SOC) in the shortest time but also with the temperature compensation. The designed charging algorithm consists of three different stages, namely constant current (CC), pulse charging and trickle charging. In the CC mode, the current at maximum power of the PV array is used for fast charging. The pulse charging mode is next adopted to contain temperature rise while maintaining relatively fast charging speed. To prevent battery damage by charging as battery capacity is close to its full status, 100 % SOC, the float charging mode is finally activated by further decreasing charging currents. Simulations are conducted via Powersim to validate the FBMC performance and the PV system model. The FBMC is next implemented by a DSP module (TMS320F2812) in order to adjust the switching duty cycle during operations of the buck converter. Finally, experimental results were compared with a general constant current and/or voltage method. The results show favorable performance of the propose charging method.
A fast digital chip implementing a real-time noise-resistant algorithm for estimating blood pressure using a non-invasive, cuffless PPG sensor
(1970-01-01)
Wang, Jeremy H. -S.
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Yeh, Ming-Hua
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Chao, Paul C. -P.
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Tu, Tse-Yi
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Kao, Yung-Hua
A fast digital chip is designed and fabricated successfully to implement the algorithm for estimating blood pressure (BP) in real time by a non-invasive cuffless photoplethysmogram (PPG) Sensor. The fast response accomplished by this digital computation chip is made possible by one-time calibration only and the Taiwan Semiconductor Manufacturing (TSMC) T18 process to realize the chip in an area of 3.97 mm(2). The experimental result shows that the overall power consumption of the chip is 15.62 mW. Finally, the blood pressure measurement platform has been developed with a user interface (UI) for long-term continuous cuffless BP measurement. The non-invasive blood pressure sensor is applied to the wrist arteries of 44 subjects for sensing the PPG pulsation of the blood vessel, and then estimating BPs (blood pressures). Measurement results shows that the maximum error in the BP measurement is +/- 6 mmHg. Which is less than 8 mmHg, defined by the Advancement of Medical Instrumentation (AAMI) and British Hypertension Society (BHS) standard.
A Fast Readout Circuit for an Organic Vertical Nano Junction Sensor
(2016-01-01)
Trong-Hieu Tran
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Chao, Paul C. -P.
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Su, Chin-I
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Zan, Hsiao-Wen
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電機工程學系
A fast mixed-signal readout circuit for high sensitivity organic vertical nano-junctions (VNJ) ammonia sensor detection is proposed in this study. Accompanying with the ammonia sensor, a low power, fast response and high resolution readout circuit is designed and successfully taped-out in this study. The analog front-end circuit includes a pre-amplifier, a sample and hold (S/H) circuit, a differential current, a pulse width modulation (PWM) circuit, an automatically sensing and reset (S/R) circuit. The digital back-end is realized by cell-based technology to compute and display concentration values instantaneously. The chip is fabricated by the TSMC 0.18-um 1P6M 3.3V mixed-signal CMOS process technique for verification. The chip area is 1.5 x 1.6 mm(2). while power consumption is 3.2 mW. Experiment results show a strong linear relationship exists between differential S/R output slope and the gas concentration level in a logarithm scale, which is critically beneficial to sensor design. In results, the readout circuit has fast responses, 50 seconds, based on the auto-sensing circuit catching different slope coefficient of the signal in transient time. The resolution is 70.48mV/log(ppm) while error rate, average noise and detection rate reliability are 2.86%, 123 mu Vrms, and 99.6%, respectively. This chip could be suitable for applications in cars, cell phones, watches, etc.
A fast-sensing readout circuit in 240 Hz enabled by code division multiple access (CDMA) implemented for an ultra-thin on-cell flexible capacitive touch panel
(1970-01-01)
Chang, Chia Yu
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Chao, Paul C. -P.
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Wang, Jeremy H. -S.
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Su, Ying Cheng
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Thakur, Smriti
A new fast readout circuit employing the known coding scheme of code division multiple access (CDMA) is successfully designed and applied to a 7-inch ultra-thin, flexible on-cell touch screen panel (TSP). The adopted CDMA is known originally as a coding scheme for data communication, which is applied in this study to address the sensing electrodes of the ultra-thin flexible touch panel. Due to the orthogonality between the driving signals to the touch panel coded by Walsh transform, one type of CDMA, the interference noises between sensing electrodes can be reduced effectively to render accurate touch sensing results. The electromagnetic interference from the flexible display can also be filtered out as baseline component in the output signal. And the frame time of touch reporting can be substantially shortened. Following the sensing electrode is a new readout designed of the switched-capacitor (SC) circuit, to avoid distributing sample signals from parasitic capacitance and also to enlarge the voltage changes due to the capacitance changes caused by touches. A 12-bit analog-to-digital converter (ADC) is orchestrated after the SC circuit to transform the front-end analog signal to digital codes. The digital part of the designed readout adopts a correction algorithm to eliminate the background signals from the display, and also a moving average algorithm to minimize the higher-frequency noises from the display and other electrodes. Experiments are conducted to validate the expected performance. It is evidenced that the Walsh code driving algorithm improves the quality of the readout output signal to be in 42 dB SNR, the report rate to a fast 240 Hz, and a power consumption of 0.39 mW by each sensing channel.
A HIGHLY EFFICIENT AND ADAPTIVE SOLAR-ENERGY HARVESTING CIRCUIT FOR BATTERYLESS IOT DEVICES
(2018-01-01)
Yang, Ching-Cheng
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Chao, Paul C. -P.
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Pandey, Rajeev Kumar
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
In this paper a new on-chip 2nd generation solar energy harvesting DC-DC converter has been proposed for a battery less Internet of Things (IoTs) Devices. The propose circuit is design to maximize the transfer efficiency and stability as well as enough high power supply to the back-end loads. Altogether the proposed circuit consists of a cross-coupled charge pump, a maximum power point tracking (MPPT) circuit, a timing control circuit and regulator. The range of input voltage is from 0.5V to 3V. Required boosted output voltage is in the range of 1V to 3.3V. The maximum transfer efficiency is more than 60% and the maximum throughout power is 20011W. A gated clock frequency modulation circuit has been designed and employed in the maximum power point tracking (MPPT) unit to lock the input resistance of the charge pump. In addition, to provide a stable voltage to the load a low dropout (LDO) regulator circuit is used. The experimental results show that the maximum power conversion efficiency (PCE) is 78% at 52 W input power condition.
A low-power self-biased rail-to-rail preamplifier as a readout circuit for a capacitor-type microphone
(2013-09-01)
Tu, Tse-Yi
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Chao, Paul C. -P.
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Mai, Yueh-Teng
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影像與生醫光電研究所
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電機工程學系
This study is dedicated to design a readout circuit to extract the output signal of a capacitive-type MEMS microphone. A low-power preamplifier is forged for a capacitive-type microphone to meet the demands on cell phone applications. The design starts with modeling the electro-mechanical behavior of a biased capacitive-type microphone using combination of AV and DC voltages sources. This aims to enable co-simulation of the microphone and the readout circuit design. The output signal of a capacitance-to-voltage converter is normally small and may cause substantial noise in the output signals. Therefore, a preamplifier is designed and applied to amplify the signal to an acceptable level for the convenience of ensuing signal processing. The designed readout circuit consists of two main sub-circuits, responsible for functions in two different stages. One is a newly-designed self-bias circuit in the structure of a capacitance-to-voltage converter at the first stage, while another is a low-voltage low-power two-stage or rail-to-rail MOS operational amplifier at the second stage. The proposed circuit is implemented by using the technology of TSMC 0.35 A mu m Mixed-Signal MODE (2P4M, 3.3 V/5 V) POLYCIDE. The supply voltage is fixed at low voltage (3 V), the total power dissipation is merely 200 mu W. Experiments are finally conducted to validate the performance of the designed readout circuit from 20 to 20k Hz with appropriate add-on high- and low-pass filters.
A Low-ppm Digitally Controlled Crystal Oscillator Compensated by a New 0.19-mm(2) Time-Domain Temperature Sensor
(2017-01-01)
Tran, Trong-Hieu
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Peng, Hsuan-Wen
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Chao, Paul C. -P.
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Hsieh, Jing-Wen
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電子工程學系及電子研究所
A low-ppm digitally controlled crystal oscillator (DCXO) in a Pierce readout topology with a new 0.19-mm(2) CMOS time-domain temperature sensor (TDTS) circuit for temperature compensation is designed and fabricated in this paper. The Pierce readout circuit is designed to output a 16-MHz oscillating signal as an important base clock for mobile devices. To cope with inevitable imprecision caused by environmental temperature variation, the readout should be compensated based on crystal\'s frequency-temperature curve via a temperature sensor. To this end, a new low-power, small-sized, CMOS on-chip temperature sensor circuit is successfully synthesized by 20-stages of newly designed delay cells. Each delay cell is compensated by a CMOS-process-compatible varactor, enabling a TDTS consisting of only a low number of delay cells to generate long enough delay that is proportional to temperature and in required precisions. In addition to Pierce and TDTS circuits, the DCXO consists of the logics to compute capacitance correction, a switched-capacitor array to adjust Pierce capacitances, and regulators for DCXO and TDTS. The proposed circuits are fabricated by TSMC 0.18-mu m CMOS process, where the active area is 0.516 mm(2) for the whole chip, while 0.19 mm(2) for the TDTS. With temperature compensation enabled, the best measured frequency deviations of a calibrated TCXO is within +/- 0.2 ppm from -40 degrees C to 85 degrees C. The temperature resolution of the developed TDTS is successfully designed to reach 0.18 degrees C/LSB with an accuracy of +/- 1 degrees C validated by one of the tape-out chips.
A Miniaturized Electromagnetic Generator With Planar Coils and Its Energy Harvest Circuit
(2009-10-01)
Liao, Lun-De
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Chao, Paul C. -P.
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Chen, Jian-Ting
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Chen, Wei-Dar
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Hsu, Wei-Hsuan
This study presents design, analysis and experiment of a miniaturized rotary generator in size of 10 10 2 mm and its compact energy harvest circuit chip. The designed generator consists of patterned planar copper coils and a multipolar hard magnet ring made of NdFeB. To perform modeling, a harmonic-like magnetic field model along the circumferential path of each magnetic pole is assumed with the assistance from measured peak magnetic flux densities. This is followed by the application of Faraday's law to predict generated electromotive forces (EMFs) in terms of the relative rotational speed between the magnet ring and coils. The genetic algorithm (GA) is next applied to optimize the critical dimensions of the miniaturized generator. The theoretical model of this power microgenerator is evaluated and compared with experimental results, and it is found that the analytical simulation shows a good agreement with the experimental results. The optimized generator offers 4.5 V and 7.23m W in root mean square (rms) at 10 000 r/min. With microgenerator successfully fabricated, a novel energy harvest circuit employing Dickson charge pump is designed and fabricated via the 0.35-um process offered by National Chip Implementation Center (CIC) of Taiwan. This charge pump circuit owns the merit of almost-zero thresholds of employed metal-oxide-semiconductor (MOS) transistors, enabling the conversion of low-power alternating current (ac) signals by the microgenerator to direct current (dc) ones.
A Multi-Touch Interface Circuit for a Large-Sized Capacitive Touch Panel
(2010)
Ruan, Juan-Yao
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Chao, Paul C. -P.
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Chen, Wei-Dar
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
This study presents a multi-touch sensing circuit for large-sized (more than 12 inches) capacitive touch panel. A new AC sensing technique is developed to enable the touch sensing in a large-sized capacitive touch panel. This novel designs of multi-touch sensing circuit lies in the operation principles through a 4X4 ITO film sensor array, a low-disturbance array circuit, a capacitance to voltage converter circuit and the proposed design procedure of chip parameters by circuit simulation. Furthermore, the sequence control for the array is generated by an FPGA module to accomplish the operation of the whole circuit. Some of objectives are to reduce environmental disturbance of the panel and to distinguish multi-touching locations from the panel. The corresponding output voltages of multi-touch sensing circuit are output in proportional to location touched by a human finger. Finally, the whole circuit is implemented by using TSMC 0.35 mu m 2P4M process. The circuit output voltages are used to distinguish touch locations by a proposed algorithm.
A New 4T0.5C AMOLED Pixel Circuit With Reverse Bias to Alleviate OLED Degradation
(2012-07-01)
Lee, Kuei-Yu
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Hsu, Yen-Ping
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Chao, Paul C. -P.
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交大名義發表
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National Chiao Tung University
A new 4T0.5C circuit is proposed to achieve a high-resolution active-matrix organic light-emitting diode (OLED) display with the capability of alleviating OLED degradation, while the panel nonuniformity is compensated by an already-proposed system. The designed circuit is built on two adjacent pixels with eight transistors and one capacitor, thus equivalently as a 4T0.5C pixel circuit in occupied layout area. In this circuit, a single storage capacitor is shared by the two adjacent pixels to minimize the entire layout area. The minimized pixel size is compatible to a conventional 2T1C pixel circuit. Along with this 4T0.5C circuit, a new alternative drive scheme is developed to address the panel. The scheme offers the function of automatic reverse biasing on OLEDs to alleviate degradation. The designed circuit is fabricated, and the performance of OLED degradation is successfully validated.
A New Active 3D Optical Proximity Sensor Array and Its Readout Circuit
(2014-07-01)
Huang, Sheng-Chieh
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Hsu, Wei-Hsuan
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Chao, Paul C. -P.
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Tsai, Che Hung
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電機工程學系
A new 3-D proximity sensor panel (3-D touch panel) for a single object is proposed in this paper. The sensor panel consists of a photo detector (PD) array as active pixels, along with its optics design, a computation algorithm, and sensing circuitry to eliminate background lighting. This sensing panel system acts as a noncontact 3-D positioning sensor, which is able to sense spatial positions of the object without realistic touching to the panel. New active readout pixel circuits for the PDs are designed to efficiently convert PD-received light intensities to voltage signals. It offers high readout resolutions, larger output ranges, and lower noises, as compared with the conventional active pixel sensor (APS) with a 3T-structure (called 3T-APS). Toward success of the sensor, background light is eliminated by a specially designed sample and hold circuitry, whereas a computation algorithm for 3-D object detection is developed based on photometry. The circuit is fabricated by Taiwan Semiconductor Manufacturing Company 0.35-mu m 2P4M 3.3 V mixed signal CMOS process. Sensing trials for a moving object are finally conducted. The sensor performance is validated and further illustrated by a Labview program. The sensing errors of a sphere object are successfully limited to 5% in percentages.
A New Active 3D Optical Proximity Sensor Array and Its Readout Circuit
(2013-01-01)
Chao, Paul C. -P.
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Hsu, Wei-Hsuan
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Tsai, Che-Hung
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電機工程學系
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Department of Electrical and Computer Engineering
A new adaptive front-end circuit for high-resolution magnetic scales
(2015)
Chien, Ping-Chieh
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Kao, Yung-Hua
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Chen, Hong-Yang
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Huang, Jing-Hao
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Chao, Paul C. -P.
A new front-end readout circuit design using an adaptive amplifier is proposed by this study for magnetic and optical scales. The purpose of the integrated chip (IC) designed herein is to provide the magnetic/optical scales the capability of sensing translational or angular positions of an object in largely-arying amplitudes with high resolutions. Toward this end, a new front-end readout circuit is designed with two adaptive programmable gain amplifiers (PGAs) and two analog-to-digital converters (ADCs). The PGA is particularly designed to accept signals up to 1 MHz from MR sensor signals, which could be one of three voltage levels: 120 mVp-p, 250 mVp-p, 330 mVp-p. The resulted power consumption is 56 mW. The chip also includes a successive approximation register (SAR) ADC having two 12-bit channels for sine-to-digital conversions. The linearity of ADC achieve satisfactory performance (+/- 1LSB) in the input range of 0.5 similar to 2.5V in Vp-p. The chip was fabricated by the TSMC 0.35-icron 2P4M CMOS technology for verification.