Browsing by Author "Sauter, Thilo"

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A new readout/driver circuitry for an optical vibration sensor
(2017-01-01)
Wu, Chun-Hao
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Chao, Paul C. -P.
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Wu, Yi-Cheng
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Sauter, Thilo
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Zan, Hsiao-Wen
This work presents research results on designing the drive and readout circuits for a newly-developed optical vibrations sensor. Tes sensor consists of organic light-emitting diodes (OLEDs) and photodetectors (OPDs) and micro-structure to realize the function of vibration sensing. Proper operations of OLEDs and OPDS needs a driver and a readout circuit, respectively. A driver circuit is designed for driving and controlling OLED light; also, a readout circuit is designed to acquire current signal from OPD and then converts it to digital signals by an analog-to-digital converter (ADC). In addition to readout circuit, a front-end amplifier called transimpedance amplifier (TIA) is designed for converting the output current of the OPDs. The TIA is followed by an IA and LPF for better signal quality before a SAR ADC designed for converting the vibration amplitude to digits. The resolution of 10-bit ADC sub-circuit is 1.95mV/LSB. It is suitable for OPD current output. Moreover, a pulse width modulation (PWM) driver circuit which is designed with frequency output 200 KHz is suitable for driving OLED. The proposed circuit is fabricated by TSMC 0.35-mu m CMOS process where the area is 4.5 mm2 for the whole chip while power consumption is 7.808 mW.
A new single inductor bipolar multi-output (SIBMO) DC-DC converter driven by constant on-time with improved performance
(2016-06-01)
Chao, Paul C. P.
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Chang, Chun-Kai
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Cheng, Chun-Kai
;
Trong-Hieu Tran
;
Sauter, Thilo
This study is dedicated to design and realization of a new single inductor bipolar multi-output (SIBMO) DC-DC converter with performance improvement. A bandgap is first designed to offer a stable input bias with capability to work against inevitable input voltage variations for avoiding possible p-n breakdowns. A new drive technique based on constant on-time (COT) is developed for the designed SIBMO with assistance from level shifters and zero current detection circuits to drive MOS devices. The designed circuit is capable of boosting input voltage 2.8 V to four bipolar outputs of +6, -6, +12 and -12 V. The COT proposed herein adopts a new technique of time multiplexing to offer stable multi-outputs with an off-chip inductor for fast switchings. This new COT is different from the conventional pulse width modulation which usually operates with fixed frequencies. The COT is particularly favorable in regards of crossing regulation and high transfer efficiency in cases of unbalanced loads. The proposed SIBMO and COT are applicable to drive systems of organic light-emitting diodes, optical sensors, and portable electronic devices, displays, etc. The designed on-chip SIBMO and COT are fabricated via the TSMC 0.25 A mu m high-voltage CMOS process. Experimental results clearly show the capability of the designed SIBMO chip to offer four bipolar, stabilized output voltages with a total power consumption minimized to 320 mW and the switching frequency varying from 650 to 500 kHz. Most importantly, the maximum efficiency reaches 83.1 %.
A new single inductor bipolar multi-output (SIBMO) DC-DC converter driven by constant on-time with improved performance
(2016-06)
Chao, Paul C. P.
;
Chang, Chun-Kai
;
Cheng, Chun-Kai
;
Trong-Hieu Tran
;
Sauter, Thilo
This study is dedicated to design and realization of a new single inductor bipolar multi-output (SIBMO) DC-DC converter with performance improvement. A bandgap is first designed to offer a stable input bias with capability to work against inevitable input voltage variations for avoiding possible p-n breakdowns. A new drive technique based on constant on-time (COT) is developed for the designed SIBMO with assistance from level shifters and zero current detection circuits to drive MOS devices. The designed circuit is capable of boosting input voltage 2.8 V to four bipolar outputs of +6, -6, +12 and -12 V. The COT proposed herein adopts a new technique of time multiplexing to offer stable multi-outputs with an off-chip inductor for fast switchings. This new COT is different from the conventional pulse width modulation which usually operates with fixed frequencies. The COT is particularly favorable in regards of crossing regulation and high transfer efficiency in cases of unbalanced loads. The proposed SIBMO and COT are applicable to drive systems of organic light-emitting diodes, optical sensors, and portable electronic devices, displays, etc. The designed on-chip SIBMO and COT are fabricated via the TSMC 0.25 A mu m high-voltage CMOS process. Experimental results clearly show the capability of the designed SIBMO chip to offer four bipolar, stabilized output voltages with a total power consumption minimized to 320 mW and the switching frequency varying from 650 to 500 kHz. Most importantly, the maximum efficiency reaches 83.1 %.
A New Single Inductor Bipolar Multiple Output (SIBMO) Boost Converter using Pulse Frequency Modulation (PFM) Control for OLED Drivers and Optical Transducers
(2015)
Chang, Chun-Kai
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Su, Chung-Hsin
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Kao, Yung-Hua
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Yu, Ming-Hung
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Sauter, Thilo
This study proposes a single-inductor bipolar multiple-output (SIBMO) boost converter utilizing pulse frequency (PFM) control for organic light-emitting diode (OLED) drivers and optical transducers. The purpose of the converter designed herein is to provide multiple voltage sources with opposite polarities to meet the requirements of various applications such as OLEDs or optical transducers. The bipolar voltage sources are essential for offering alternating driving voltages to extend the lifetime of OLEDs. The converter boosts the input of 2.8 V to two positive and two negative outputs, i.e., +12 V, +6 V, -12 V, and -6 V. Different from the commonly-used pulse width modulation (PWM), the constant on-time (COT) approach is adopted herein with a dynamic charging algorithm to automatically adjust the operating frequency, thus profiting from less circuit complexity, improvement of cross regulation, and high transfer efficiency in unbalanced load cases. The total maximum output power is 320 mW, as the switching frequency varies from 650 kHz to 0 Hz, and the maximum efficiency reaches 83.1% by simulation. The converter was fabricated by TSMC 0.25 mu m 1P3M high voltage CMOS technology for verification.
Design and Implementation of OLED Driving and OPD Readout Circuitry for an Optical Vibration Sensor
(2018-01-01)
Wu, Yi-Cheng
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Kao, Yung-Hua
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Chao, Paul C. -P.
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Wey, Chin-Long
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Sauter, Thilo
This study presents an organic light-emitting diode (OLED) drive circuit and an organic photo detector (OPD) readout circuits for a vibration sensor. Vibration sensor consist of micro-electro-mechanical systems (MEMS), which are OLED and OPD needs to be integrated for many applications in automation or consumer electronics. The light flux is generated by an OLED located on top of the structure and the modulated light flux is measured by an OPD. The OLED drive circuit contains pulse width modulation (PWM) driver to control PWM output for optimization of voltage operation is designed in order to minimize power consumption efficiency of device. The readout circuit includes a trans-impedance amplifier (TIA) to convert incident light of OPD to voltage output, a 14-bit analog-to-digital converter (ADC) to extract amplitude of vibration level, circuit to generate clock for time-to-digital converter (TDC) which detect frequency of vibration sensor. The designed circuit has been successfully fabricated by using TSMC 0.18 mu m CMOS process, the chip area is 1.012 mm(2). The power consumption of chip is about 6.2 mW. The measured frequency of PWM is about 200 kHz with 50% duty cycle. The frequency range of the vibration can be sensed well as about 10 Hz-1.5 kHz, and resulting in high SNR at frequencies under 60 Hz.
High-resolution proximity sensor using flexible semi-transparent organic photo detector
(2017-10-01)
Chen, Chao-Hsuan
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Lin, Ching-Fu
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Wang, Kuan-Hsun
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Liu, Hung-Chuan
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Zan, Hsiao-Wen
We propose a flexible proximity sensor to detect sub-centimeter distance with an ultra-high displacement resolution. The proximity sensor is realized by integrating a semi-transparent organic photo detector with a transparent top electrode and a finger-type bottom electrode. By placing the semitransparent finger-type photodetector on a light source, such as a light-emitting diode (LED), the photodetector can detect the light reflected from an object on top of the sensor. With the highly compact structure, the detecting range is from 1 mm to 30 mm. From 1 mm to 10 mm, the sensor is particularly sensitive and delivers a resolution of 1 mm. The air-stable photodetector can also be fabricated on a flexible substrate without encapsulation, enabling the integration with arbitrary light sources. After 1000 times bending, the flexible photodetector shows no obvious degradation. (C) 2017 Elsevier B.V. All rights reserved.
Making Optical MEMS Sensors more compact using Organic Light Sources and Detectors
(2014-01-01)
Sauter, Thilo
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Hortschitz, Wilfried
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Steiner, Harald
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Stifter, Michael
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Chiao, Hsin
Vibration and displacement sensors need to be compact for many applications in automation or consumer electronics, and microelectromechanical structures are a convenient way to implement such sensors. For these MEMS devices, optical readout methods have proven to be superior to capacitive or piezoresistive strategies in terms of sensitivity as well as noise and interference immunity, however the integration of light sources and detectors is not easily possible. This paper presents an approach to use organic optoelectronic devices for the readout. OLED and OPD (organic photo detector) are structured on the glass substrate and cover encapsulating the MEMS devices, allowing for a tightly integrated sensor based on vertical light flux modulation by a horizontally moving proof mass. The paper describes the principle sensor structure as well as the fabrication of suitable organic devices. First test results show that the approach is feasible.
Solution-processed finger-type organic proximity sensor with high displacement resolution
(2016)
Liao, Jung-Sung
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Wang, Kuan-Hsun
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
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Yeh, Ping-Hung
Proximity sensors are interesting devices for applications like smart homes or human-machine interfaces. This work investigates a cheap and compact short-range proximity sensor based on an organic photo detector combined with a commercial LED. Low-cost solution-processed organic materials are used, and low process temperatures at 140 degrees C also facilitate future integration on, e.g., plastic substrates. In particular, to avoid damage of the organic layer during the patterning process, a new organic photo detector with a semi-transparent organic active layer and a transparent silver nanowire top electrode was designed. The proposed sensor can be realized by using only one shadow mask to pattern the opaque bottom electrode layer. The opaque finger-type bottom electrode not only partly shields the light emitted from below the device, but also defines the active regions with vertical electric field to generate and collect photo current. In the experiments conducted in this paper, the maximum detection distance was found to be 2 cm, whereas the lower end of the measurement range was 0.2 cm.