A 1.8-V 6.9-mW 120-fps 50-Channel Capacitive Touch Readout With Current Conveyor AFE and Current-Driven $\Delta \Sigma $ ADC

Hwang, Ho Jung; Lee, Hyeyeon; Han, Myungjin; Kim, Hongchae; Chae, Youngcheol

doi:10.1109/jssc.2017.2750326

Cited by 44 publications

(17 citation statements)

References 18 publications

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“…Among them, we changed only the thickness of hard coating film and the performance of fingerprint recognition depending on the thickness of hard coating films was investigated. The fingerprint sensors were measured with a current conveyor analog front end (AFE) and a current-driven ΔΣ analog-to-digital converter (ADC) [6]. The current conveyor AFE is able to reduce the baseline signal due to the detection of differential currents from adjacent pixels, and isolate parasitic capacitance from the charge amplifier.…”

Section: -3 / S H Leementioning

confidence: 99%

9‐3: Flexible Mutual‐capacitive Fingerprint Sensor with Hard and Flexible Overlaid Dielectric Layer for Biometrics Application

Lee

Jeon

Kim

et al. 2018

Symp Digest of Tech Papers

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We present cost-effective flexible fingerprint sensor for biometrics application beyond Si-based material. Our Cu electrode based fingerprint sensors were fabricated on PI substrate with flexible and durable overlaid dielectric material. Overlaid layer has roles of both the dielectric layer of capacitance and protective layer from the environment in place of reinforced glass. The planarization of Cu electrode suppresses generation of noise signal between the electrodes, resulting in realistic fingerprints.

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Section: -3 / S H Leementioning

confidence: 99%

9‐3: Flexible Mutual‐capacitive Fingerprint Sensor with Hard and Flexible Overlaid Dielectric Layer for Biometrics Application

Lee

Jeon

Kim

et al. 2018

Symp Digest of Tech Papers

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“…Since the introduction of current conveyors in 1968 [1], the well-known operational amplifiers (Op-Amps) have started to be replaced in several applications [2][3][4]. Generally, current conveyors take inherent advantages of current mode signal processing and, in comparison to conventional Op-Amp based circuits, those employing current conveyors exhibit better frequency performance and simpler circuitry [5,6]. A literature survey shows that, in current conveyor families, second generation current conveyors (CCIIs) [7][8][9][10][11][12] are the most widely used.…”

Section: Introductionmentioning

confidence: 99%

A New Rail-to-Rail Second Generation Voltage Conveyor

et al. 2019

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In this paper, a novel low voltage low power CMOS second generation voltage conveyor (VCII) with an improved voltage range at both the X and Z terminals is presented. The proposed VCII is formed by a current buffer based on a class AB regulated common-gate stage and a modified rail-to-rail voltage buffer. Spice simulation results using LFoundry 0.15 μm low-Vth CMOS technology with a ±0.9 V supply voltage are provided to demonstrate the validity of the designed circuit. Thanks to the class AB behavior, from a bias current of 10 µA, the proposed VCII is capable of driving 0.5 mA on the X terminal, with a total power consumption of 120 µW. The allowed voltage swing on the Z terminal is at least equal to ±0.83 V, while on the X terminals it is ±0.72 V. Both DC and AC voltage and current gains are provided, and time domain simulations, where the voltage conveyor is used as a transimpedance amplifier (TIA), are also presented. A final table that summarizes the main features of the circuit, comparing them with the literature, is also given.

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Section: Introductionmentioning

confidence: 99%

“…The third prototype is the capacitive method [ 27 , 28 , 29 ] which uses on-display mutual capacitance to provide a fingerprint sensing functionality. This prototype [ 28 , 29 ] verified a 500-dpi transparent on-glass fingerprint sensor using 15-V TX driver. The capacitive sensing method uses the projective capacitance technique used for the touchscreen to implement the fingerprint sensing for the in-cell phone display [ 28 , 29 ].…”

Section: Introductionmentioning

confidence: 99%

“…This prototype [ 28 , 29 ] verified a 500-dpi transparent on-glass fingerprint sensor using 15-V TX driver. The capacitive sensing method uses the projective capacitance technique used for the touchscreen to implement the fingerprint sensing for the in-cell phone display [ 28 , 29 ]. The drawbacks of this approach like that of the touchscreen such as the need for a high TX voltage around 15–20 V to compete with the panel noise and surrounding noise [ 28 , 29 , 30 , 31 ].…”

Section: Introductionmentioning

confidence: 99%

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CMOS Capacitive Fingerprint Sensor Based on Differential Sensing Circuit with Noise Cancellation

Hassan

Kim

2018

Sensors

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In this paper, we introduce a differential sensing technique for CMOS capacitive fingerprint detection. It employs a new capacitive-sensing cell structure with charge sharing detection and readout circuit. The proposed technique also can eliminate the effect of parasitic capacitances by employing parasitic insensitive switched-capacitor structure and so increases the sensitivity even under severe noisy conditions. It can also overcome the performance degradation caused by various conditions of finger surface by using a differential integrator and adjusting its number of integrations. In addition, the proposed architecture allows parallel detection of all sensing channels. It can, therefore, substantially speed up the detection process compared with conventional architectures. We implemented a prototype fingerprint sensor chip with an array of 20 × 16 sensor cells using a 130 nm CMOS process. Simulation experiments demonstrated that the proposed architecture provided an SNR gain of 54 dB, whereas a conventional single line sensing gives an SNR gain of only 13 dB.

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A 1.8-V 6.9-mW 120-fps 50-Channel Capacitive Touch Readout With Current Conveyor AFE and Current-Driven $\Delta \Sigma $ ADC

Cited by 44 publications

References 18 publications

9‐3: Flexible Mutual‐capacitive Fingerprint Sensor with Hard and Flexible Overlaid Dielectric Layer for Biometrics Application

9‐3: Flexible Mutual‐capacitive Fingerprint Sensor with Hard and Flexible Overlaid Dielectric Layer for Biometrics Application

A New Rail-to-Rail Second Generation Voltage Conveyor

CMOS Capacitive Fingerprint Sensor Based on Differential Sensing Circuit with Noise Cancellation

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