In this paper, an all-digital, 10-bit, low-power Time-to-Digital Converter (TDC) is proposed for use in biomedical applications. To reduce the area and power consumption, as well as provide noise ...shaping capability, the Gated Ring Oscillator (GRO) architecture is chosen as the core for the proposed TDC. Regarding the problems created by the leakage current in GROs, especially in low-frequency applications, a new approach for data capturing is used. The proposed modified data capturing method tackles the leakage current effect and allows the TDC to operate at ultralow frequencies. The proposed TDC achieves a dynamic range of 1.76 µs, and the resolution of 1.76 ns at 1KS/s sampling frequency. Simulations were performed using the 0.13 µm CMOS process. The TDC power consumption was 45.85 nW at a 0.4 V supply and the Signal to Noise and Distortion Ratio (SNDR) was 54.55 dB.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this paper the issue of obtaining an accurate equation for the delay of a CMOS inverter is explored. In the conventional equations provided for the propagation delay, many simplifying assumptions ...are made. Also some important events that occur during the charging/discharging of the capacitances are neglected. This reduces the accuracy of the conventional delay equations. Since the propagation delay time is used in many applications, such as obtaining the ring oscillator frequency, its accuracy is very important. Hence, we calculate an accurate equation for the propagation delay time. The intricacies and challenges in deriving an improved accuracy equation will be addressed. The approach of deriving an improved equation is explained in detail. The accuracy of the derived equation is verified through simulation. We will look into the obtained equation to evaluate the effect of different parameters on the delay and compare the improved and conventional equations.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
As neuron is the fundamental unit of the nervous system, it is one of the main building blocks in the spiking neural networks hardware implementation. To implement hardware that consists of many ...thousands of neurons and accurately mimics the brain functions, an energy and area-efficient design for the neuron is essential. In this paper, we propose a VLSI circuit for the leaky integrate and fire (LIF) neuron model, in 130 nm CMOS technology. The proposed neuron has some important features: first, it consumes very low energy; second, it is simple and area-efficient. Third, it has the spike frequency adaptation capability that makes it more biologically plausible. The spike frequency adaptation mechanism is added to the model only by one additional transistor, and it is done just by one parameter. The energy per spike of the neuron circuit in the worst case is only 0.67 fJ/spike. The spike frequency is in the MHz range, which enables attractive hardware acceleration.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study the authors propose a novel and straightforward design procedure for the single-ended ring oscillator (SERO). This procedure determines the values of the circuit parameters to reach the ...desired oscillation frequency while the power consumption and the area are minimised and the noise is kept below the desired value. Furthermore, the authors analyse the SERO and suggest a practical formula for the oscillation frequency. In comparison to the conventional equations, the derived formula is accurate as well as explicit. The accuracy of the proposed frequency equation is verified using simulation. The average of the absolute errors over a wide range of parameters is 2.52%, and the worst case error is 9.64%. In addition, the power consumption of the SERO is analysed and a formula is presented for estimating the power consumption.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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