A theoretical analysis and implementation of a high sensitivity infrared thermometry system for a precise real-time temperature control in domestic induction cooktops is presented. The temperature in the cookware constitutes the control variable of the closed-loop power control system implemented in a commercial induction cooktop. The system includes an InGaAs PIN photodiode and a differential preamplifier which detects the infrared radiation (IR) emitted from the bottom of the cookware and the glass-ceramic top. The analysis includes an algorithm to discount the contribution of the glassceramic material from the total signal. In an infrared thermography application where an IR sensor is used, measuring the object’s surface emissivity is crucial because it significantly impacts the temperature measurement result. For a precise temperature control with a maximum temperature error of 5°C in all range of cooking temperatures (60°C to 250°C) a cookware emissivity measurement system is included. The accuracy and the validity of our model have been tested and confirmed with measurements performed with the proposed system. The experimental arrangement built to test the proposed system has validated the usefulness of the IR thermometry system applied to the cookware within the range of cooking temperatures from 60°C to 250°C, making it suitable for this application. It has been proved that the IR sensor and the associated electronic works properly in a high-temperature environment such as a real induction heating cooktop.
This work overcomes the limitations of a previous work by using three high frequency compensation techniques: polezero
cancellation, shunt-peaking and downscaling. By considering these strategies, a fully integrated limiting amplifier in
a low-cost 0.18 μm CMOS digital process is introduced. This design improves the original design without inductors and
without local multi-feedback loops obtaining a compact, stable and robust design perfectly intended for low-voltage
applications.
This paper presents a study of mismatch effects in a digitally programmable analogue processor designed for small embedded applications. Circuit programmability allows for its adaptation to deviations in circuit operation or environmental effects. Starting from circuit simulation data, the system-level operation is modeled, showing its robustness to circuit mismatch. Simulation results of the proposed processor applied to compensate the response of a sinusoidal sensor and its robustness to mismatch are presented.
In this paper we present a low-voltage preamplifier destined for optical-fiber communication front-ends in the standard Gigabit Ethernet. Designed in a low-cost 0.35 μm CMOS technology, the circuit can work with a single 1.8 V supply voltage, consumes only 6.2 mW and exhibits a tunable transimpedance from 50 to 65 dBΩ with bit rates up to 1.5 Gb/s.
A novel high performance envelope detector structure is proposed in this work. This circuit does not
need the traditional compensation between keeping and tracking required in these circuits due to a system
by what the signal peaks are held in two periods and combined to obtain the envelope of the signal. At the
same time, it solves some drawbacks due to switches used in these kinds of circuits when this technique
has been employed, such as nonlinearities due to charge injection in switches, which reduces the linearity
of these circuits. Thus, it is shown the superior performance of this circuit obtaining for a signal at
10MHz small ripple (<1%), very fast settling (0.4&mgr;s) and using smaller capacitive area (-60%) than
conventional peak detectors. Furthermore, this envelope detector has a dynamic range above 40dB for
nonlinearities below 1dB.
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