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A fast-transient-response buck converter utilizing analog-voltage-dynamic-estimation (AVDE) techniques is proposed in this paper. The responses of the proposed buck converter are very fast when load changes between heavy load and light load. The switching frequency of the proposed buck converter is 1 MHz for nominal 3.3 V input and 1.0-2.5 V output range application. Experimental results prove that the proposed scheme improves the transient response to within 2 μs and that its maximum power efficiency can be up to 95%. The maximum load current is 300 mA. The proposed AVDE buck converter has been fabricated with a commercial 0.35 μm CMOS 2P4M process, the total chip area is about 1.5 mmX 1.5 mm, including PADs. [ABSTRACT FROM AUTHOR] more...

A low-voltage and low-control-loss RF-dc rectifier with high power conversion efficiency (PCE) at 13.56 MHz band is presented in this paper. This is achieved by utilizing novel reducing reverse loss (RRL) techniques to reduce the reverse leakage current loss. Higher output voltage can also be generated by the multistage stacking method with RRL technology. A boost-type front-end converter composed of an RF-dc rectifier with the RRL technique and a boost converter operating in a discontinuous-conduction mode are also proposed. The single-stage, three-stage pump-type RF-dc rectifier and the boost-type front-end rectifier have been implemented in TSMC 0.18 μm 1P6M technology. Experimental results show that the maximum PCE of the single-stage and three-stage pump-type RF-dc active rectifiers are 68.6% and 67.9% with input powers of 4.9 and 12.8 dB·m, respectively. The maximum PCE of the boost-type front-end converter is 41.3% with 1.2 dB·m input power. [ABSTRACT FROM AUTHOR] more...

This paper exhibits the generation of an operational transconductance amplifier and capacitor (OTA-C) arbitraryphase-shift sinusoidal oscillator (APSO) for an order n ≥ 3 for various advanced applications. A new nth-order quadrature oscillator (QO) is obtained via the algebraic quadrature manipulations of an oscillatory characteristic equation. Based on a phase shift transformation from a quadrature, an APSO is then generated by superposing OTAs with required +/- transconductance(s) in parallel with some grounded capacitor(s) on the QO. For eliminating nonideal and parasitic effects to improve phase accuracy, phase compensation schemes are proposed. A new native amplitude control exploiting the nonlinearity of all employed OTAs of the APSO is presented as well to lead to rather low THD and a lower variation of THD with respect to amplitude enlargement. A fourth-order APSO is demonstrated and simulated using Hspice with a 0.35-μm process for validation. In addition, its real application to a polyphase rectifier is improved. Finally, an experiment using LM13700s shows favorable potential of APSOs. [ABSTRACT FROM AUTHOR] more...

The demand for current-mode fast-transient-response shunt regulator is increasing for the growth of portable electronics, such as cellular phones, PDA, laptops, etc. A new current-mode fast-transient-response shunt regulator is presented in this paper. The proposed shunt regulator used a single Miller compensation capacitor to increase stability. The current-mode shunt regulator helps the transient response to be faster than the voltage-mode low-dropout regulator (LDO) and the power noise (bounce noise) is smaller than one. The proposed current-mode shunt regulator has been fabricated with TSMC 0.35 μm 2P4M CMOS technology . The experimental results show the transient-response time is only 400 ns within 0.5% error and the maximum output voltage dip is only 70 mV for full loading current variation. Moreover, the line and load regulations are 26 μV/mA and 8 ppm/mA, respectively. The dropout current is 1.0741 mA for loading current 150 mA. The active chip area is 226 μm × 310 μm. [ABSTRACT FROM AUTHOR] more...

A high-efficiency multimode Li--Ion battery charger with variable current source and controlling previous-stage supply voltage is presented in this paper. Using variable current source can achieve the goal of constant-current mode to charge the battery and control previous-stage supply voltage which could increase the efficiency of the multimode battery charger. Moreover, the charging mode adopted in this charger is applied by two types of dual-mode strategy decided by the value of the equivalent series resistance of the Li--Ion battery. This technique will reduce the damage of Li--Ion battery. The Li-Ion battery charger is designed with 0.35-μm CMOS double-poly four-metal processes. The experimental results show that the charger works well and the theoretical analysis can be confirmed. The average power efficiency of the multimode Li--Ion battery charger can be up to 91.2% under the average power of 1.24 W, and the accuracy of the adaptive reference voltage is up to 97.3%. The chip area is only 1.32 ×f 0.95 mm². [ABSTRACT FROM AUTHOR] more...

Novel sample-and-hold (S/H) and multiplying digital-to-analogue converter (MDAC) circuits employing fully balanced second-generation current conveyor (FBCCII) are presented. Two main building blocks of the pipelined analogue-to-digital converter, front-end S/H and MDAC are constructed of FBCCII instead of operational amplifier. Besides, the proposed MDAC is designed to eliminate the charge injection. The proposed FBCCII-based S/H and MDAC circuits are realised in TSMC 0.18 μm CMOS technology under a 1.8 V power supply. [ABSTRACT FROM AUTHOR] more...

An integrated class-D amplifier with active current sensing suitable for ac switches is presented in this paper. The proposed current-sensing technique is used to sense and control the inductor current at the output stage and allows the current-sensing element to be integrated into class-D amplifiers. To verify the performance of the proposed circuits, a class-D amplifier was designed and fabricated with 3.3-V 0.35-μm double-polyquadruple-metal CMOS technology on a chip area of 1.79 × 1.45 mm. The maximum power efficiency of the class-D amplifier can be up to 94% for an 8-Ω load. These active current-sensing circuits can be applied to other power converters with ac switches. [ABSTRACT FROM AUTHOR] more...

Abstract  The monolithic hysteresis-current-controlled (HCC) buck and boost converters with simplified convergence analysis methods are presented. The architectures of both converters are very simple and only consist of few components. The convergence condition, which is independent to duty cycle of converters, is derived in this paper. Using this concept to synthesize current-mode converters, the component values of converters will be designed easily. There is no sub-harmonic oscillation in the proposed converters without slope compensation even if the duty cycle greater than 50%. The proposed circuits are implemented into a single chip with TSMC 0.35 μm CMOS DPQM processes and their chip area is only 2.25 mm2, respectively. The maximum power efficiency of proposed converters is measured and described in this paper, too. [ABSTRACT FROM AUTHOR] more...

A hysteresis-current-controlled (HCC) buck converter with active current-sensing and phase-frequency-locked techniques is presented in this paper. The proposed active current-sensing technique can not only consume less power than previous techniques, but also fully sense the inductor current. Although the buck converter is HCC, the switching frequency can be constant due to the devised phase-frequency-locked technique. The proposed converter has been designed and implemented with TSMC 0.35 µm DPQM CMOS processes. It is shown in the experimental results that the HCC buck converter features the following characteristics: 1) up to 800 mA of load current, 2) wide input and output voltage range, 3) high power efficiency, and 4) constant-frequency operation. [ABSTRACT FROM AUTHOR] more...

A new monolithic fast-response buck converter using spike-reduction current-sensing circuits is proposed in this paper. The proposed converters are designed and implemented with TSMC 0.35-µm DPQM CMOS processes. The operation frequency can be up to 1.887 MHz. The response time is only 2 µs and compared with other references. The maximum output current is 750 mA, and the maximum power efficiency can be up to 89.1% at 2.442-W output power. The chip area is only 2.157 mm². [ABSTRACT FROM AUTHOR] more...

A fully differential third-order very high frequency (VHF) Gm–C filter based on linear transformation (LT) techniques is presented in this paper. The systematic design method and the procedure are developed to realize LT Gm–C filters efficiently. A third-order Butterworth lowpass filter embedded bandgap and bias circuits with 200 MHz cutoff frequency is implemented in the TSMC 0.18 μm 1P6M process. The total harmonic distortion (THD) of the proposed filter is - 43 dB with input signal 0.5 Vp-p and output loading capacitance 1 pF at 200 MHz. Power dissipation is 9.77 mW under 1.8 V supply voltage. Its core area occupies 0.188 × 0.1862. Post simulation and experimental results that confirm the theoretical analysis are obtained. Furthermore, the proposed circuits can be extended to high-order Chebychev and elliptic filters. [ABSTRACT FROM AUTHOR] more...

A new pipelined analog-to-digital converter (ADC) using second-generation current conveyor (CCII) is presented. Two main building blocks of the pipelined ADC, sample-and-hold (S/H) circuit and multiplying digital-to-analog converter (MDAC) are constructed of CCII instead of operational amplifier (OA). Experimental results show that the proposed CCII-based pipelined ADC can work at 12. 5?MHz with a 7. 3-bit resolution. The DNL is within ?0. 4?LSB and 0. 4?LSB and INL is within ?0. 8?LSB and 0. 8?LSB, respectively. The pipelined ADC is realized in TSMC 0. 35??m CMOS technology and consumes 29?mW under a 3. 3?V power supply. The core size is 0. 85?0. 85?mm2. [ABSTRACT FROM AUTHOR] more...

1 The present study was to investigate the direct effect and action mechanism of propylthiouracil (PTU), an antithyroid drug, on the production of progesterone in rat granulosa cells. 2 PTU (3-12 mM) decreased the basal and human chorionic gonadotropin (hCG)-stimulated release of progesterone from rat granulosa cells. 3 PTU (3-12 mM) attenuated the stimulatory effects of forskolin and 8-bromo-cyclic 3':5'-adenosine monophosphate on progesterone release from rat granulosa cells. 4 PTU (12 mM) inhibited the activities of both the cytochrome P450 side-chain cleavage enzyme (P450scc, conversion of 25-hydroxyl cholesterol to pregnenolone) and the 3β-hydroxysteroid dehydrogenase (conversion of pregnenolone to progesterone) in rat granulosa cells. PTU decreased the V[SUBmax] but increased the K[SUBm] of P450scc. 5 PTU (12 mM) decreased the hCG-increased amount of steroidogenic acute regulatory (StAR) protein in rat granulosa cells. 6 The present result suggest that PTU decreases the progesterone release by granulosa cells via a thyroid-independent mechanism involving the inhibition of post-cAMP pathway, and the activities of intracellular calcium, steroidogenic enzyme, and StAR protein functions. [ABSTRACT FROM AUTHOR] more...

The application of MATLAB/SIMULINK is developed for simulation and learning feedback controller design of dc-dc switching converters. With the help of its intuitive graphical user interface and some basic circuit theories, the corresponding SIMULINK models of the switching converter circuits can be easily constructed. Students can then use these models to learn and evaluate the closed-loop behavior of the entire system in the MATLAB/SIMULINK environment, after feedback controllers are devised by any classical or modern control theory. The accuracy of this approach is also verified by comparing the simulation results with the responses obtained from a buck-type dc-dc switching converter circuit and existing experimental results. [ABSTRACT FROM AUTHOR] more...

Examines the acute effects of thyroid hormones on the production of adrenal cyclic adenylic acid (cAMP) and corticosterone in male rats. Effects of thyroid hormones on the activities of steroidogenic enzymes of zona fasciculata-reticularis (ZFR) cells; Suggestion that thyroid hormones counteract adrenocorticotropic hormone (ACTH) in adrenal steroidogenesis. more...

Abstract  New current-mode high-order all-pole and elliptic filters employing second-generation and third-generation current conveyors are presented in this paper. The synthesis method is based on signal flow graph design of simulating LC passive ladder filters. Simple architectures are obtained along with only grounded resistors and capacitors in our all-pole filter design. Moreover, the numbers of resistors, capacitors and current conveyors in our proposed all-pole filters are equal to the numbers of filter order. The proposed elliptic filter can be designed by only adding floating capacitor to the corresponding nodes as the all-pole filter counterpart. Third-order current-mode Chebychev and elliptic lowpass filters are demonstrated to verify the proposed method. [ABSTRACT FROM AUTHOR] more...

A high-efficiency fast-transient-response V2-controlled boost converter with a small equivalent series resistance (ESR) capacitor is presented. The proposed boost converter can achieve a fast and stable load transient response without relying on the ESR of the output capacitor. The switching frequency of the proposed boost converter is 500 kHz for a nominal 2.5-4.2 V input and a 3.3-5 V output application. Experimental results show that the transient recovery time inheriting the advantage of V2 control is shorter than 6.4 μs with the load step from 250 to 20 mA and the highest efficiency can be up to 95.4%. The proposed boost converter has been fabricated with a 0.35 μm 2P4M CMOS process, the total chip area is about 1.5 × 1.5 mm2, including the PADs. [ABSTRACT FROM AUTHOR] more...