Chutham Sawigun

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—Two prior-art transconductance amplifier-based rail-to-rail class-AB analog buffers are examined. Their analysis reveals that the output current drive capability for large input voltages is restricted. To mitigate this drawback, a relatively simple slew-rate enhancement scheme is proposed. The new scheme allows the buffer's speed to be increased by over(More)
— According to recent physiological experiments, the envelope and phase of speech signals are required to enhance the perceptive capability of a cochlear implant processor. In this paper, the design of an analog complex gammatone filter is introduced in order to extract both envelope and phase information of the incoming speech signals as well as to emulate(More)
—In order to realize a nano-power wavelet filter for biomedical applications, this paper applies the Singular Value Decomposition approximation to transform the time domain 1 st-derivative of a Gaussian (gauss1) wavelet base into a 5 th-order z-domain transfer function. Consequently, to realize the approximated transfer function in CMOS technology employing(More)
— A nano-power 4 th-order band-pass filter operating from a 0.5 V supply voltage with an adjustable center frequency, ranging from 250 Hz to 4 kHz (4 octaves), is presented. The filter is constituted from cascadable 2 nd-order circuit cells that are realized by a network of three transistors and two capacitors comprising only one branch of bias current. As(More)
—This paper proposes the design of a current-mode sample and hold circuit using subthreshold MOSFETs. The proposed circuit combines negative feedback and the compressive characteristic of a class-AB weak inversion transconductor to achieve low switching error, high signal-to-noise ratio and high dynamic range from a low supply voltage and very low current(More)
— An ultra low-power, high linearity, wide swing, current sample-and-hold circuit is presented. The proposed circuit employs negative feedback, provides very low switching error and allows for class-AB operation. Sub-threshold CMOS devices are employed to realize all circuit building blocks which leads to ultra low power consumption and large dynamic range.(More)
—Real time action potential (AP) detection is an important requirement for development of fully implantable neuroprosthetic devices. We present an ultra low-power CMOS analog circuit for detection of APs embedded in a noisy signal. The proposed strategy isolates APs by detecting subsequently a positive and a negative spike of each AP. An AP is detected only(More)
— An ultra low-power class-AB four-quadrant current multiplier designed to be used in an energy-based action potential detector is presented. The multiplier is considered the first topology that provides fully class-AB operation. The topology is constituted by a class-AB current amplifier and a current splitter which can handle input signals in excess of(More)