A high-resolution,200kHz signal bandwidth,third-order single-loop single-bit ε△ modulator used in low-IF GSM receivers is presented. The modulator is implemented with fully differential switched capacitor circuits i...A high-resolution,200kHz signal bandwidth,third-order single-loop single-bit ε△ modulator used in low-IF GSM receivers is presented. The modulator is implemented with fully differential switched capacitor circuits in standard 0. 6μm 2P2M CMOS technology. The modulator uses two balanced reference voltages of ±1V,and is driven by a single 26MHz clock signal. The measurement results show that,with an oversampling ratio of 64, the modulator achieves an 80.6dB dynamic range,a 71.8dB peak SNDR,and a 73.9dB peak SNR in the signal bandwidth of 200kHz. The modulator dissipates 15mW static power from a single 5V supply.展开更多
When boost power factor correction(PFC) circuit works with large scale load fluctuations, it is easy to cause a higher total harmonic distortion and a lower power factor because of traditional controllers and inductor...When boost power factor correction(PFC) circuit works with large scale load fluctuations, it is easy to cause a higher total harmonic distortion and a lower power factor because of traditional controllers and inductor current mode. To solve this problem, this paper proposes a PFC control system, which can operate with load fluctuations up to 1 000 W by using duty cycle feed-forward control theory to achieve smooth switching mode. The duty cycles in the next period of the control system are pre-estimated in the current cycle, which enhances the speeds of AD samplers and switching frequency, and reduces the cost and volume of the equipment to some extent. Introductions of system decoupling and feed-forward of input-voltage greatly improve the system performance. Both theoretical simulation and experimental results prove the advantage of the proposed scheme.展开更多
A novel optical-spectrum-encoded （OSE） analog-to-digital converter （ADC） is proposed in this letter. To simply exemplify the conversion idea, a 5-bit device structure consisted of Fabry-Perot interferometers （FPI...A novel optical-spectrum-encoded （OSE） analog-to-digital converter （ADC） is proposed in this letter. To simply exemplify the conversion idea, a 5-bit device structure consisted of Fabry-Perot interferometers （FPI） is analyzed and numericaly simulated. The dependence of peak-transmission wavelength on modulation voltage in an electro-optical FPI and the dependence of transmitted power on incident light wavelength in an FPI are discussed and utilized to implement OSEADC. A linearly tunable mode-locked laser, as a voltage-wavelength transformer and a sampler, and chirped grating FPIs, as an encoder array, can be used to obtain much greater sampling rate and bit-resolution.展开更多
In PV （photovoltaic） power systems, a MPPT （maximum power point tracking） algorithm is vital in increasing their efficiency. But it is also vital to take into account the non ideal conditions resulting from comple...In PV （photovoltaic） power systems, a MPPT （maximum power point tracking） algorithm is vital in increasing their efficiency. But it is also vital to take into account the non ideal conditions resulting from complex physical environments in such PV power systems. To minimize the degradation of performances caused by these conditions, and therefore adding reliability and robustness, this paper presents an implementation of a digitally controlled system using a topology based on series connected DC-DC buck converters for a stand-alone PV power system applications, operating with local and autonomous controls, to track the maximum power points of PV modules in non ideal conditions. Simulations are carried out by using C-MEX S-functions under MATLAB-SIMULINK environment. A PV system of 1.44 kWc is described and simulation results are presented.展开更多
This paper introduces a high-revolution,200kHz signal bandwidth EA modulator for low-IF GSM receivers that adopts a 2-1 cascaded single-bit structure to achieve high linearity and stability. Our design is realized in ...This paper introduces a high-revolution,200kHz signal bandwidth EA modulator for low-IF GSM receivers that adopts a 2-1 cascaded single-bit structure to achieve high linearity and stability. Our design is realized in a standard 0.18μm CMOS process with art active area of 0.5mm× 1.1mm.The EA modulator is driven by a single 19.2MHz clock signal and dissipates 5.88mW from 3V power supply. The experimental results show that,with an oversampling ratio of 48, the modulator achieves a 84.4dB dynamic range,73.8dB peak SNDR, and 80dB peak SNR in the signal bandwidth of 200kHz.展开更多
文摘A high-resolution,200kHz signal bandwidth,third-order single-loop single-bit ε△ modulator used in low-IF GSM receivers is presented. The modulator is implemented with fully differential switched capacitor circuits in standard 0. 6μm 2P2M CMOS technology. The modulator uses two balanced reference voltages of ±1V,and is driven by a single 26MHz clock signal. The measurement results show that,with an oversampling ratio of 64, the modulator achieves an 80.6dB dynamic range,a 71.8dB peak SNDR,and a 73.9dB peak SNR in the signal bandwidth of 200kHz. The modulator dissipates 15mW static power from a single 5V supply.
基金Supported by the National Basic Research Program of China("973"Program,No.2009CB219700)
文摘When boost power factor correction(PFC) circuit works with large scale load fluctuations, it is easy to cause a higher total harmonic distortion and a lower power factor because of traditional controllers and inductor current mode. To solve this problem, this paper proposes a PFC control system, which can operate with load fluctuations up to 1 000 W by using duty cycle feed-forward control theory to achieve smooth switching mode. The duty cycles in the next period of the control system are pre-estimated in the current cycle, which enhances the speeds of AD samplers and switching frequency, and reduces the cost and volume of the equipment to some extent. Introductions of system decoupling and feed-forward of input-voltage greatly improve the system performance. Both theoretical simulation and experimental results prove the advantage of the proposed scheme.
文摘A novel optical-spectrum-encoded （OSE） analog-to-digital converter （ADC） is proposed in this letter. To simply exemplify the conversion idea, a 5-bit device structure consisted of Fabry-Perot interferometers （FPI） is analyzed and numericaly simulated. The dependence of peak-transmission wavelength on modulation voltage in an electro-optical FPI and the dependence of transmitted power on incident light wavelength in an FPI are discussed and utilized to implement OSEADC. A linearly tunable mode-locked laser, as a voltage-wavelength transformer and a sampler, and chirped grating FPIs, as an encoder array, can be used to obtain much greater sampling rate and bit-resolution.
文摘In PV （photovoltaic） power systems, a MPPT （maximum power point tracking） algorithm is vital in increasing their efficiency. But it is also vital to take into account the non ideal conditions resulting from complex physical environments in such PV power systems. To minimize the degradation of performances caused by these conditions, and therefore adding reliability and robustness, this paper presents an implementation of a digitally controlled system using a topology based on series connected DC-DC buck converters for a stand-alone PV power system applications, operating with local and autonomous controls, to track the maximum power points of PV modules in non ideal conditions. Simulations are carried out by using C-MEX S-functions under MATLAB-SIMULINK environment. A PV system of 1.44 kWc is described and simulation results are presented.
文摘This paper introduces a high-revolution,200kHz signal bandwidth EA modulator for low-IF GSM receivers that adopts a 2-1 cascaded single-bit structure to achieve high linearity and stability. Our design is realized in a standard 0.18μm CMOS process with art active area of 0.5mm× 1.1mm.The EA modulator is driven by a single 19.2MHz clock signal and dissipates 5.88mW from 3V power supply. The experimental results show that,with an oversampling ratio of 48, the modulator achieves a 84.4dB dynamic range,73.8dB peak SNDR, and 80dB peak SNR in the signal bandwidth of 200kHz.
