Summary
A very compact ultra‐low power DC‐DC buck converter is presented. The proposed buck converter employs a novel complement value leaping pulse‐width modulation (PWM) technique to realize the desired DC mean‐value for various loads. Incorporating just two counters with a simple digital controller to load the repeatedly complemented value of the 4bit up/down counter as the initial value of the least significant bits of the 5bit up counter, a PWM pulse is created to manage the charge/recharge period. The realized PWM signal maintains the same desired output voltage mean value for any load resistance between 80 and 140 Ω. The switching frequency is 160 kHz, and the overall power consumption is 26.9 nW, while the efficiency is 93.4% for current range of 1.7 to 3 mA. The performance of the proposed converter is validated by Cadence post‐layout simulations utilizing TSMC180nm CMOS technology for 1‐V supply voltage providing the output voltage mean value of 0.24 V.
A 400 MHz high efficiency transmitter for wireless medical application is presented in this paper. Transmitter architecture with high-energy efficiencies is proposed to achieve high data rate with low power consumption. In the on-off keying transmitters, the oscillator and power amplifier are turned off when the transmitter sends 0 data. The proposed class-e power amplifier has high efficiency for low level output power. The proposed on-off keying transmitter consumes 1.52 mw at -5 dBm output by 40 Mbps data rate and energy consumption 38 pJ/bit. The proposed transmitter has been designed in 0.18μm CMOS technology.
The use of infrared radiation as a medium for high speed and short-range application is proposed for communication in the aircraft passenger cabin since it does not cause any interference to aircraft navigation systems. In this paper: first of all, using Lambert's model, the power received at the receiver via single reflection propagation inside the cabin was modeled. Then, the free space loss which depends on distance and height of transmitter and receiver from ceiling was calculated. Thirdly, in order to estimate the multipath power penalty, from the impulse response model, the delays spread dispersions and mean delays, which are related to reflection patterns and the distance between transmitter and receiver were derived and modeled. Finally, ceiling bounce model was developed to obtain the impulse response and 3dB cut off frequency. After modeling in the passenger aircraft cabin, the results are the minimum power received and the maximum bud-rate that is available to be achieved.
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