Browsing by Author "Pribadi, Eka Fitrah"

Now showing 1 - 9 of 9

A CHARGE PUMP WITH MPPT CIRCUIT EMPLOYED IN BATTERYLESS PHOTOVOLTAIC IOT TAGS
(2016)
Men, Guan-Yu
;
Cheng, Yuan-Po
;
Chao, Paul C. -P.
;
Yang, Ching-Cheng
;
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 low-power reference-less clock/data recovery for visible light communication devices requiring low data throughput
(2020-01-01)
Liu, Ming-Cheng
;
Pribadi, Eka Fitrah
;
Chao, Paul C-P
;
Pandey, Rajeev Kumar
;
電子工程學系及電子研究所
In this study a reference-less clock and data recovery (CDR) is designed and developed for the low speed visible light communication system based Internet of Things (IoT) tags. Design system incorporates an off-chip photodiode and an integrated-on chip front-end receiver with the reference-less CDR. For an IoT tags low power consumption, low supply voltage, and small area are the major design constraint. Considering these constraints, the circuit of the front-end receiver incorporate the near-threshold cascode current mirror based transimpedance amplifier, low pass filter and a comparator. On the other-hand, low power all-digital phase locked loop-based reference-less CDR is design herein with a modified loop filter, auto tune digital control oscillator and auto duty cycle adjustment circuit. The circuit is implemented in an integrated chip with area of 0.728 mm(2) via TSMC 180 nm process. Experimental measurement results of the tapeout chip shows that the phase noises are - 39.54 dBc/Hz @ 1 kHz, - 80.35 dBc/Hz @ 10 kHz and - 92.26 dBc/Hz @ 100 kHz. The measured jitter in the recovered clock is 3.312 ns (0.0033 UI). At 1 Mbps, the measured total power consumption is 5.58 mu W. The achieve results shows that the implemented circuit in this study highly support the commercial low data rate based optical wireless sensing nodes for IoT tags.
A New Adaptive Readout System For a New OLED OPD Flexible Patch PPG Sensor
(2019-01-01)
Pandey, Rajeev Kumar
;
Pribadi, Eka Fitrah
;
Chao, Paul C. -P
;
電機資訊國際學位學程
;
EECS International Institute
This study proposes a new multiwavelength OLED-OPD flexible PPG sensor with a time-interleaved, optimal high order adaptive analog filter-based readout system for the longtime continuous monitoring of PPG signal. First time, temperature modulation of the light absorption and scattering coefficient of the human skin and its compensation strategy has been explored in this study. This study intended to minimize the issue like motion artifacts and mispositioning. Analog front end of the readout circuit incorporates a transimpedance amplifier, optimal filter, programmable gain amplifier (1x to 7x), PWM-DAC based OLED intensity control, Bluetooth transceiver, MCU with inbuilt ADC and a power management unit. At the backend, digital control and pre-signal processing-algorithm are developed to improve the adaptability of the readout system against non-idealities which enable the readout system for the longtime continuous measurement of the biological sign. Digitally variable resistance is used herein to tune the central frequency of the bandpass filter which helps to minimize low heart rate issue. The sensing range of the readout circuit is 20nA to 10 mu A. With 3.3 V power supply the total power consumption of the readout system is 0.4W. Experimental result shows that the heart rate measurement error is less than 3.4bpm. In the worst case, the measured repulsive pulse transit time (RPTT) variation from PPG cycle to cycle is less than 2%.
Achieving high sensing in 0.5 nA for the driving pixel currents in AMOLEDs with settling time of 7 mu s by a new external current sensing circuit
(1970-01-01)
Pandey, Rajeev Kumar
;
Huang, Tzu Hao
;
Ho, Wei-Hsuan
;
Pribadi, Eka Fitrah
;
Chao, Paul C. -P.
A new external current sensing circuit with baseline compensation for the active matrix organic light emitting diode (AMOLED) display is developed herein to achieve the sensing precision of 0.5 nA in pixel with 7 mu s of settling time. Current sensing circuit incorporates a new push-pull transient current feedforward whereas the current analog to digital converter (CADC) based digital baseline current compensation incorporates an 11-bit current digital-to-analog converter, a current comparator and a digital control circuit with an 11-bit successive approximation register. The proposed integrated mixed signal IC drives a 6T1C pixel-based AMOLED panel with one horizontal time of 7.7 mu s at a scan frequency of 60 Hz. The design readout chip can simultaneously sense and compensate TFT baseline current variation. The readout circuit and the baseline compensation circuit are implemented in the integrated chip with chip area of 125 mu m x 46 mu m and fabricated via TSMC T18 process. With the standard 3.3 V supply, experimental result shows that the overall power consumption of the chip is 988 mu W watt. The minimum LSB current for the CADC is 10 nA and the maximum achievable sampling rate is 500 KS/s. The measured INL and DNL of CADC is 0.84 and 0.98 respectively. Despite of heavy data line parasitic capacitances (2.6 K ohm/20 pF) of the AMOLED display, experimental results show that the proposed circuit can sense 0.5 nA current within 7 mu s of settling time. The sensing precision of 0.5 nA within 7 mu s are the best among all reported literature to date whereas the current sense range (0.5-500 nA), system sampling rate (142 KS/s), INL (0.84) and DNL (0.98) of the CADC is approximately comparable among all reported.
ACHIEVING SENSING PRECISION OF 0.5nA IN PIXEL WITH 7 mu s SETTLING TIME BY A NEW EXTERNAL CURRENT SENSING CIRCUIT FOR AMOLED DISPLAYS
(2019-01-01)
Pandey, Rajeev
;
Huang, Tzu Hao
;
Ho, Wei-Hsuan
;
Chao, Paul C. -P.
;
Pribadi, Eka Fitrah
This study proposes a new push-pull transient current feedforward (PPTCF) based pixel current sensing circuit for active matrix organic light emitting diode (AMOLED) displays with precision within 0.5nA. A finite state machine (FSM) based digital control circuit is designed and developed for the baseline compensation. In order to achieve high accuracy, the digital baseline compensation circuit also incorporates the current digital -to -analog converter (CDAC) and successive approximation current analog-to-digital converter (CADC). The minimum LSB current for the CADC is 10nA. The readout circuit is implemented in the integrated chip with chip area of 1251.1m x 46 m and fabricated via TSMC T18 process. With standard 3.3V supply, the experimental result shows that the overall power consumption of the chip is 990 W watt. Despite of all parasitic capacitances of the panel display, experimental results show that the proposed circuit can sense 0.5nA current within 7 s of settling time. The sensing precision of 0.5nA within 71 mu s are the best among all reported literature to date.
APPLICATION OF CODE DIVISION MULTIPLE ACCESS TECHNOLOGY IN READOUT CIRCUIT AND SYSTEM DESIGN FOR AN ULTRA-THIN ON-CELL FLEXIBLE CAPACITIVE TOUCH PANEL
(2019-01-01)
Lin, Ying-Jia
;
Su, Ying-Cheng
;
Chao, Paul C. -P.
;
Zhang, Jia-Yu
;
Pribadi, Eka Fitrah
A capacitive sensing circuit including electrodes for a 7-inch ultra-thin flexible on-cell touch panel has been designed. Implementing code-division multiple sensing (CDMS) with Walsh transform to scan Tx electrodes is chosen to improve the signal-to-noise ratio (SNR). The algorithm applies to field programmable logic array (FPGA). The sensing readout algorithm is applied to work on 4 Tx transmitter electrodes and 4 Rx sensing electrodes. The switched-capacitor (SC) circuit is applied to avoid disturbing sample signal from parasitic capacitance and enlarge the voltage difference from capacitance changes of the touch panel. 12-bit ADC to transfer the front-end analog signal to digital code. The digital part adopts a correction algorithm to eliminate the background value of the panel, the moving average algorithm has an adjustable signal-to-noise ratio function, and the Walsh conversion demodulation algorithm improves the touch report rate to achieve high SNR with up-to 34 dB.
DESIGN AND IMPLEMENTATION OF A HIGH ACCURACY INTERPOLATION ENCODER IC FOR MAGNETIC SENSOR
(2019-01-01)
Chen, Wen-Yu
;
Zhang, Yi-Feng
;
Chao, Paul C. -P.
;
Pribadi, Eka Fitrah
;
電機資訊學士班
The magnetic encoder (ME) always employs sensor passing through periodic and equal distance grating and then generates periodic quadrature scaling signals for displacement measurement. The phase is relative to the movement. To improve encoder accuracy or resolution, electronic interpolation technique had been developed to subdivide the phase of quadrature scaling signals. According to the trends, this paper proposed a specific method with excellent noise immunity characteristic and a complete calibration process to improve the accuracy of the system. The designed circuit is taped-out using TSMC 0.18-mu m CMOS process, where the active area is 1643 mu m x 1676 mu m. The chip has the specification of3.3 V supply voltage, 20 MHz clock frequency, and 0.0859 mW power consumption. The accuracy of the measurement system is 1.065um.
OPTICAL SIMULATION FOR DESIGNING A PPG SIGNAL PATCH
(2019-01-01)
Pribadi, Eka Fitrah
;
Chao, Paul C. -R
;
電機資訊國際學位學程
;
EECS International Institute
Designing an optical patch for photoplethysmogram (PPG) signal considers the optical simulation of the patch on the skin. The skin model for the optical simulation consists of epidermis, a dermis, a subcutaneous fat, and a blood vessel, while the model ofthe patch includes an organic light emitting diode (OLED) and an organic photodiode (OPD). Each model of skin layers is implemented using bulk and scattering of the optical parameter. In order to model the AC/DC ofPPG signal, the blood vessel of the optical model uses the diameter of 2 mm and 2.2 mm. The simulation conducted by sweeping the distance of OPD model apart of OLED in knowing the optimal distance between OLED and OPD. The simulation of the different shape of patches is conducted to know the optimum shape ofthe patch. The 8 -shaped patch has the optimum value of the AC/DC signal which is 0.0045.
Optimizing a novel PPG sensor patch via optical simulations towards accurate heart rates
(1970-01-01)
Pribadi, Eka Fitrah
;
Pandey, Rajeev Kumar
;
Chao, Paul C. -P.
;
電子工程學系及電子研究所
;
電機資訊國際碩士學位學程
This study proposes the design and optimization of the flexible OLED-OPD photoplethysmography (PPG) sensor patch to estimate the long time continuous heart rate. Using optical simulation, the distance between OLED-OPD and the aperture area of the OLED-OPD has been optimized to enhance the AC/DC ratio of the receive PPG signal. The optical simulation incorporates an empirical optical skin model. All the patches incorporate green OLED@525 nm wavelength and red OLED@630 nm wavelength. Simulation results show that the optimized AC/DC ratio of the cross-type patch for the green and the red OLED is 2.16% and 6.25%, respectively. Similarly, the optimized AC/DC ratio of the square-type patch for the green, and the red OLED is 9.6% and 5.8%, respectively. Experiment results show that the received PPG signal AC/DC ratio for the square type and cross-type are 2%@green OLED and 4.5% @green OLED, respectively. Also, the AC/DC ratio of the received PPG signal from the square type and cross-type are 1.4%@red OLED and 1.1%@red OLED, respectively. The AC/DC ratio is reduced because the skin and blood itself act as a lossy medium so that the DC signal increased more; as a result, the overall AC/DC ratio decrease. The best design of the optical patch is the square-type OPD patch due to the wide area of the OPD. The OLED drive current ranges between 0.1 and 0.4 mA. The average OPD current is 800 nA. The flexibility of the design PPG sensor patch is 130 degrees. The non-invasive square-type PPG sensor patch is applied to the wrist artery of 40 subjects for sensing the PPG pulsation of the blood vessel. The heart rate measurement accuracy is 95%, whereas the standard error rate is 0.37 +/- 1.96 bpm, respectively.