Hongchin Lin

A Simple Subthreshold CMOS Voltage Reference Circuit With Channel- Length Modulation Compensation

This brief presents a simple reference circuit with channel-length modulation compensation to generate a reference voltage of 221 mV using subthreshold of MOSFETs at supply voltage of 0.85 V with power consumption of 3.3 muW at room temperature using TSMC 0.18-mum technology. The proposed circuit occupied in less than 0.0238 mm 2 achieves the reference voltage variation of 2 mV/V for supply voltage from 0.9 to 2.5V and about 6 mV of temperature variation in the range from -20degC to 120 degC. The agreement of simulation and measurement data is demonstrated

A comparison of numerical solutions of the Boltzmann transport equation for high-energy electron transport silicon

In this work we have undertaken a comparison of several previously reported computer codes which solve the semiclassical Boltzmann equation for electron transport in silicon. Most of the codes are based on the Monte Carlo particle technique, and have been used here to calculate a relatively simple set of transport characteristics, such as the average electron energy. The results have been contributed by researchers from Japan, Europe, and the United States, and the results were subsequently collected by an independent observer. Although the computed data vary widely, depending on the models and input parameters which are used, they provide for the first time a quantitative (though not comprehensive) comparison of Boltzmann Equation solutions. >

Switching power dependence on detuning and current in bistable diode laser amplifiers

Measurements of the optical power required to switch on‐and‐off an optical bistable diode laser amplifier as a function of detuning and current from threshold are presented. Good quantitative agreement between the theory for a nonlinear Fabry–Perot and the experimental results are obtained. A linewidth enhancement factor of 3.1 and a value for the change of the refractive index versus carrier density of −1.8×10−20 cm3 are extracted from the measurements.

Novel high positive and negative pumping circuits for low supply voltage

Novel charge pumping circuits for low supply voltages utilizing N-MOSFETs or P-MOSFETs with capacitors to generate positive and negative boosted voltages are presented. The two major factors limiting the pumping gain and efficiency are the body effect and the threshold voltage. Two techniques are proposed to minimize the influence of them. One is the new substrate connected technique to eliminate the body effect. The other one is the small pumping circuit providing higher gate voltages for the major pumping circuit to enhance pumping gain. With these two new techniques, the new pumping circuits have high positive and negative boosted voltages at low supply voltages.

A simple high-speed low current comparator

A high-speed low current comparator with low input impedance using a simple biasing method is proposed. Simulation results demonstrate the propagation delay is about 2.8 nsec and the average power consumption is 0.58 mW for 0.1 /spl mu/A input current at supply voltage of 3 V using 0.35 /spl mu/m CMOS technology.

An efficient deterministic solution of the space-dependent Boltzmann transport equation for silicon

Abstract The space-dependent nonequilibrium distribution function is obtained by directly solving the Boltzmann transport equation for Si. Legendre polynomials are used to express the Boltzmann equation in an analytical form which incorporates the effects of a nonparabolic band structure, inelastic phonon scattering, as well as spatial variation. The resulting linear difference/differential equation is discretized and solved using sparse-matrix methods in the energy domain, and iterative methods in the real-space domain. Values for average electron energy and electron drift velocity calculated from the resulting distribution function are in good agreement with those obtained from Monte-Carlo calculations. This method should prove to be useful in CAD tools for semiconductor devices.

Device modeling by deterministic self-consistent solution of Poisson and Boltzmann transport equations

Abstract A new deterministic approach to device modeling has been developed in which the Boltzmann transport equation and the Poisson equation are solved self-consistently. With this approach, the non-equilibrium space-dependent momentum distribution function along with the electric potential are obtained throughout the entire device. The distribution function provides essentially all the information required for all aspects of device analysis. The new method has been applied to an n + - n - n + diode. The simulations have provided good results, and are obtained in approx. 1/100 the CPU time required by similar Monte-Carlo calculations. This method is valuable for use in CAD tools for semiconductor devices.

New four-phase generation circuits for low-voltage charge pumps

A new four-phase clock generator for the four-phase charge pumping circuits for very low supply voltages using 0.5 /spl mu/m double poly CMOS technology to generate high boosted voltages is presented. With the new clock generator, the ten-stage charge pump can efficiently pump to 9 V at supply voltage of 1 V.

A Multilevel Read and Verifying Scheme for Bi-NAND Flash Memories

A multilevel sensing and read verifying circuit is proposed for Bi-NAND (Buried bit-line NAND) type flash memories. The Bi-NAND technology employs the negative programmed threshold voltage to facilitate the multilevel storage with lower program/erase bias and programming disturbance. The sensing circuit utilizes an advanced cross-coupled sense amplifier to achieve excellent immunity against mismatch effect and reduction of power consumption. As well, it acts as data latch during multilevel sensing and verifying operations. By comparing to the conventional and simultaneous verifying circuits, the proposed scheme with dichotomous architecture simplifies the verifying circuit and speeds up verification process for multilevel operation. By adding only one latch and a pair of switches, the circuit can be easily expanded for one more bit per cell

A Low-Voltage Process Corner Insensitive Subthreshold CMOS Voltage Reference Circuit

A reference voltage circuit is presented for generating a constant reference voltage of 278mV using subthreshold characteristics of 0.18mum CMOS technology at supply voltages from 0.8V to 2.6V with total current of 3.6muA. The threshold voltage variation due to process corner variation is minimized by a threshold voltage tracking technique between the normal and high threshold NMOS transistors. In the mean time, channel-length modulation effect is also compensated. The proposed circuit on chip area of 0.04mm2 achieves the total reference voltage variation of 2.5mV for various process corners and temperature variation from -20degC to 120degC