Cheng-Ta Chiang

A low-photocurrent CMOS retinal focal-plane sensor with a pseudo-BJT smoothing network and an adaptive current Schmitt trigger for scanner applications

In this work, a new structure of low-photocurrent CMOS retinal focal-plane sensor with pseudo-BJT smoothing network and adaptive current Schmitt trigger is proposed. The proposed structure is very simple and compact. This new circuit can easily be implemented in CMOS technology with a small chip area. Another innovation of this circuit is that the proposed circuit could be operated for low-induced current levels (pA), and the current hysteresis of the proposed current Schmitt trigger could be adjusted adaptively according to the value of induced photocurrents. In this work, the detection of static and moving objects, such as a moving white bar, are proven by projecting a pattern through HSPICE simulation. The proposed retinal focal-plane sensor includes a 32 /spl times/ 32 pixel array with a pixel size of 70 /spl times/ 70 /spl mu/m/sup 2/. The fill factor is 75% and the total chip area is 3000 /spl times/ 3030 /spl mu/m/sup 2/. It is with fully functional 32 /spl times/ 32 implementations consuming less than 8.8 /spl mu/W per pixel at 3.3 V. Measurement results show that the proposed new retinal focal-plane sensor has successfully been used in character recognition of scanner systems, such as pen scanners, etc.

A Semicylindrical Capacitive Sensor With Interface Circuit Used for Flow Rate Measurement

In this paper, a semicylindrical capacitive sensor with an interface circuit used for flow rate measurement is proposed. The numerical analysis method to calculate the capacitance of the semicylindrical capacitive sensor is analyzed and discussed. The picofarad-range capacitive variation of the semicylindrical capacitive sensor can be detected and converted into voltage variation by the interface circuit. Besides, the interface circuit is compact enough to simplify the circuit complexity and could be easily implemented for flow rate measurement. All the functions of the capacitive sensing method of the semicylindrical capacitive sensor used for flow rate measurement are proved successfully through HSPICE simulation. Measurement results have successfully confirmed the correct functions and performance of the semicylindrical capacitive sensor with an interface circuit used for flow rate measurement, which ranges from 0.136 to 4.746 L/min, on the liquid crystal display panel coating machine

A low-photocurrent CMOS retinal focal-plane sensor with pseudo-BJT smoothing network and adaptive current Schmitt trigger for scanner applications

In this paper, a new structure of low-photocurrent CMOS retinal focal-plane sensor with pseudo-BJT smoothing network and adaptive current Schmitt trigger is proposed. The proposed structure is very simple and compact. This new circuit can be easily implemented in CMOS technology with a small chip area. Besides, another innovation of this circuit is that the proposed circuit could be operated for low-induced current level (pA), and the current hysteresis of proposed current Schmitt trigger could be adjusted adaptively according to the value of induced photocurrent. In this paper, the detection of static and moving objects, such as a moving white bar, are proven by projecting a pattern through HSPICE simulation. The proposed retinal focal-plane sensor includes 32 /spl times/ 32 pixel array with a pixel size of 70 /spl times/ 70 /spl mu/m/sup 2/. The fill factor is 75% and the total chip area is 3000 /spl times/ 3030 /spl mu/m/sup 2/. It is with fully functional 32 /spl times/ 32 implementations consuming less than 8.8 /spl mu/W per pixel at 3.3 V. Measurement results present the proposed retinal focal-plane sensor could be successfully used in character recognition, such as pen-scanner or etc.

A CMOS Integrated Capacitance-to-Frequency Converter with Digital Compensation Circuit Designed for Sensor Interface Applications

In this work, a capacitive signal conditioner of a CMOS integrated capacitance-to-frequency converter with digital compensation circuit designed for sensor interface applications is newly proposed. The proposed converter has the low cost feature. That is due to that the output signal of the proposed converter is a digitized signal produced without realizing the analog to digital converter. Hence, the hardware cost could be reduced. Besides, the output of the proposed converter is a pulse stream, it could be easily sent over a wide range of transmission media, such as PSN, radio, optical, IR, ultrasonic, and etc. Based upon 0.35 um 2P4M CMOS technology, measurement results have successfully verified the correct functions and performance of the integrated capacitance-to-frequency converter with digital compensation circuit designed for sensor interface applications. The area of this fabricated chip is 940 times 1080 um2 and the power consumption is 6.4 mW. The proposed converter is not only suitable for capacitive measurement systems, but also applications of demanding wide dynamic output frequency range.

A Monolithic CMOS Autocompensated Sensor Transducer for Capacitive Measuring Systems

In this paper, a monolithic complimentary metal-oxide-semiconductor (CMOS) autocompensated sensor transducer for capacitive measuring systems is newly presented. The proposed converter is compact and robust to integrate in capacitive measuring systems. The proposed autocompensated sensor transducer is attractive due to the fact that a digitized signal is produced without realizing the analog-to-digital converter. Hence, the hardware cost could be reduced. Furthermore, the output signal of the proposed transducer is a pulse stream; it could be easily sent over a wide range of transmission media, such as package switch networks (PSNs), radios, and optical, infrared (IR), and ultrasonic media. Another innovation is that the proposed automatic compensation circuits enhance and compensate the linear relation between the variable capacitance of the detected sensor and the output digital frequency over a wide dynamic frequency range. Measurement results have successfully verified the functions and the performance of the proposed autocompensated sensor transducer and confirmed that it is possible to apply it to the air pressure sensor. The area of this chip is 940 times 1080 mum2, and the power consumption is 6.4 mW. The proposed transducer is not only suitable for capacitive measuring systems but also practical for application in the front-end systems of the wireless sensor network.

A CMOS Digitized Silicon Condenser Microphone for Acoustic Applications

In this paper, a CMOS digitized silicon condenser microphone for acoustic applications is newly proposed. The proposed CMOS digitized silicon condenser microphone is attractive due to the fact that the sensor and all the circuits are robustly and compactly integrated. Another innovation of this proposed CMOS digitized silicon condenser microphone is that it could be operated without charge pump circuits. Thus, the sensor and circuits can be performed at the same power supply. Based upon 0.35 μ m 2P4M CMOS technology with 3 V power supply, measurement results have successfully verified the correct function and performance of the proposed CMOS digitized silicon condenser microphone. The area of the proposed CMOS digitized silicon condenser microphone is 1444 × 1383 μm2 and the FOM of the sigma-delta modulator is 163.85 dB. The proposed CMOS digitized silicon condenser microphone is suitable for mobile phones, laptops, PDAs, and hearing aids, etc.

A CMOS digitized silicon condenser microphone for acoustic applications

In this paper, a CMOS digitized silicon condenser microphone for acoustic applications is newly proposed. The proposed digitized silicon condenser microphone is attractive due to that the sensing sensor and all the circuits are robust and compact to be integrated. Besides, another innovation of this proposed digitized silicon condenser microphone is that it could be operated without charge pump circuits. Thus, the sensing sensor and circuits can be performed at the same power supply. Based upon the device parameters of 0.35 μm 2P4M CMOS technology with 3 V power supply, measurement results have successfully verified the correct functions and performance of the proposed digitized silicon condenser microphone. The area of the proposed digitized silicon condenser microphone is 1444 × 1383 µm2 and the power consumption is 6.1 mW. The proposed digitized silicon condenser microphone is suitable to be applied on mobile phones, laptops, PDAs, and hearing aids, etc.

A CMOS readout circuit with frequency optimization for microphone sensor arrays

In this paper, a CMOS readout circuit with frequency optimization for microphone sensor arrays is newly proposed. The proposed readout circuit is attractive due to that all the analog block circuits are robust and compact to be integrated. Based upon the device parameters of 0.35 μm 2P4M CMOS technology with 3 V power supply, all the functions and performance of the proposed analog front-end circuits for silicon condenser microphones are successfully proven through measurements. The area of the analog front-end circuits is 1142 × 1305 µm2.

A Low-Cost CMOS Integrated Sensor Transducer Implemented as a Capacitance-to-Frequency Converter for Capacitive Measuring

In this paper, a low-cost CMOS integrated sensor transducer implemented as a capacitance-to-frequency converter for capacitive measuring is newly proposed. The proposed converter is attractive due to that a digitized signal is produced without realizing the analog to digital converter. Hence, the hardware cost could be reduced. Based upon the device parameters of 0.35 mum 2P4M CMOS technology with 3.2 V power supply, all the functions and performance of the proposed converter for capacitive measuring are tested and proven through SPICE simulations. The output frequency range is from 0.5 to 500 kHz under the variable capacitance of the detected sensor ranges from 4 to 24 pF. The area of this fabricated chip is 940 x 1080 mum2 and the simulated power consumption is 5.917 mW. The proposed converter is suitable for capacitive measurement systems, for example, applied in the interfaces of pressure measurement, flow meter, humidity sensing, displacement sensors, etc.

A 14-bit oversampled delta-sigma modulator for silicon condenser microphones

In this paper, a 14-bit oversampled delta-sigma modulator for silicon condenser microphones is newly proposed. The proposed oversampled delta-sigma modulator is attractive due to that the requirements of silicon condenser microphones are successfully matched. Based upon the device parameters of 0.35 μm 2P4M CMOS technology with 3.0 V power supply, all the functions and performance of the proposed delta-sigma modulator for silicon condenser microphones are successfully tested and proven through MATLAB in the behavior simulations and SPICE in the circuit simulations. The area of this fabricated chip is 1327 × 944 μm2 and the simulated power consumption is 5.25 mW. The proposed delta-sigma modulator is suitable for silicon condenser microphones applied on mobile phones, laptops, PDAs, and hearing aids, etc.