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To preferably regulate the charging current and decrease circuit complexity for parallel charging, a battery charger with variable charging current (VCC) and automatic voltage compensation (AVC) controls is presented. Based on the battery voltages, the VCC control not only dynamically maximizes the charging currents in both the trickle current (TC) and constant current (CC) stages but also prevents from damaging multiple batteries. Thus, the VCC control realizes safe charging and reduces charging time for parallel battery packs in the TC and CC stages. Owing to the battery’s parasitic resistance, a conventional charger changes from CC to constant voltage (CV) stage without approaching the rated voltage of the battery packs. The AVC control estimates the parasitic resistance and determines the proper transition timing from the CC to CV stage. Therefore, the duration of CC stage is prolonged and the CV charging time is reduced. Thanks to the VCC and AVC controls, the proposed battery charger can achieve charging time reduction and charging safety simultaneously. The experimental results verify that the periods of CC and CV stages are extended and shortened, respectively, and charging currents are maximized to the predefined values in the TC and CC stages. The maximum efficiencies in the CC and CV stages are up to 96.4%. Furthermore, compared to charging dual battery packs with conventional control, the proposed controls can save about half of total charging time.

This paper proposes a new and improved fast-transient-response low-transient-voltage boost converter with pseudo-current hysteresis-controlled techniques (PCHC). The converter uses the rail-to-rail current-sensing circuit to provide a hysteresis-controlled signal, helping to speed up the transient response and improve the overall efficiency. The proposed boost converter has been fabricated with TSMC $0.18~\mu \text{m}$ CMOS 1P6M technology, and the chip area is $1.18\times 1.18$ mm2 (include PADs). The measured results show that the input voltage range is from 0.5 V to 1 V, the output voltage is set as 1.8 V, and the output load current range is from 10 mA to 100 mA. When the output load current changes from 10 mA to 100mA and 100 mA to 10 mA, the transient responses are both 2 $\mu \text{s}$ , and peak power efficiency is 88.5% at the output load current of 75 mA.

This paper presents a pulse-modulated RF power amplifier system with the aliasing-free digital pulse-width modulation employing direct connection of an absorptive bandpass filter as the output reconstruction filter. This implementation is capable of keeping the system linearity by reducing the out-of-band spurs reflection back to the power amplifiers. A prototype transmitter system including the absorptive filter is constructed with commercially available components. Measurements using a 16-QAM 20-MHz bandwidth LTE signal at 836.5 MHz, it achieves 4 to 6-dB ACLRs linearity improvement as compared with direct connection of an output SAW filter and without using any calibration or pre-distortion.

This study aimed to explore the effects of mulberry leaf powder on glucose metabolism as well as the underlying mechanisms. The largemouth bass (initial body weight: 10.12 ± 0.06 g) were randomly allotted into three treatments, fed low-starch diet (LS, 5%), high-starch diet (HS, 15 %) and high-starch diet with mulberry leaf powder (SM, 50 g/kg diet) for 8 weeks, respectively. Biochemistry parameters were tested using commercial biochemical kits, immune and antioxidant related genes expression were assessed using Q-PCR.The SM group exhibited significantly higher specific growth rate (SGR) and protein efficiency ratio (PER), and lower hepatosomatic index (HSI), liver lipid and glycogen contents than HS treatment. Simultaneously, the suppressed growth accompanied by impaired liver function was found in fish fed the HS diet compared to the LS group. However, supplementation with mulberry leaf diet (SM) significantly reduced plasma glucose, triglyceride (TG) and total cholesterol (TC) contents, the activities of alanine aminotransferase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) compared with the HS group. Accordingly, the liver histological investigation showed an improvement of liver histostructure in the SM group. Furthermore, hepatic SOD and CAT were significantly up-regulated by SM supplementation. Meanwhile, the superoxide dismutase (SOD) and catalase (CAT) activities of SM group were significantly increased, while malondialdehyde (MDA) content significantly reduced in liver compared with the HS group. In addition, SM supplementation significantly down-regulated the expression levels of nf-kb, tnf-a and il-8 in the liver, while il-10 showed significant improvement in the LS group compared to the HS group. Mulberry leaves could alleviate hepatic injuries by regulating inflammation and oxidative stress, providing a theoretical basis for the development of mulberry leaves as a drug against high starch-induced liver disease.

This paper presents a wideband power recycling technique for pulse-modulated polar transmitters (PMPTs). The technique allows unwanted out-of-band modulation spurs in PMPTs to be rectified and recovered back to the power supply for efficiency improvement. By configuring the power amplifiers as a balanced amplifier with dual-phase digital pulse-width modulation, the odd modulation spurs can be extracted directly from the isolation port of the output-combining quadrature coupler. Using the proposed architecture, the prototype transmitter achieved 59.1% drain efficiency at an output channel power of 26.2 dBm using a 10-MHz bandwidth long-term evolution 16-quadrature amplitude modulation test signal at 836.5 MHz. After output signal restoration by a surface-acoustic-wave filter, an output power level of 24.8 dBm and 42.8% drain efficiency were achieved while passing the spectral and receive-band-noise requirements without using any digital pre-distortion techniques.

This paper presents a highly symmetric ${1\! :\! {n}}$ concentric vortical transformer (CVT) technology, which can be implemented with slab inductors. The CVT and several widely used planar transformer structures are analyzed to show the characteristic distinction of the CVT. The proposed CVT was developed in an integrated passive device technology along with the popular distributed active transformer (DAT) for comparison. Under the same real-part impedance transformation ratio at 2.4 GHz, the outer diameter of the CVT is only 48% of the DAT. Moreover, 89.4% transformation efficiency and 191% $- {\hbox{1-dB}}$ fractional bandwidth are achieved by the CVT from a high coupling coefficient of 0.9. The symmetric nature of the CVT makes it capable of achieving far less variation than the DAT in resistance and reactance among multiple input ports when used for power combining.

This paper presents an aliasing-free pulse modulated polar transmitter under fewer harmonics condition for the 4G long term evolution (LTE) femtocell base stations. Compared between two kinds of harmonic conditions K = 1 and 3, the fewer K implementation is capable of reducing the complexity and the number of modulation spurs resulted from the pulse modulator. However, the other outside modulation spurs will still be revealed after non-linear amplification. Based on this reason, the dual-phase digital pulse-width modulation and balanced configuration were adopted to suppress the undesired modulation spurs at the combination output port. A prototype transmitter system was constructed with commercially available components. Measuring using a 10-MHz bandwidth LTE 16-QAM signal at 836.5 MHz for application, it achieves 28% efficiency at 21.2-dBm power level. The condition of K = 3 also has more than 4.3 dB better adjacent channel leakage power ratio than the one of K = 1 under the same memoryless digital pre-distortion based on lookup tables.

The pulse-modulated polar transmitter (PMPT) uses the envelope information to pulse modulate the phase information to implement a highly linear and highly efficient polar transmitter. The bandwidth of the PMPT is primarily determined by the pulsewidth modulation sampling frequency of the envelope information. For wide bandwidth applications such as long-term evolution (LTE), finite rise and fall times of the RF pulses distort the envelope information. In this paper, the nonideal RF pulses are analyzed and an envelope correction method is proposed to reduce the distortion in wide bandwidth applications using the PMPT architecture. For validation, a cellular-band prototype transmitter system was constructed using commercially available components. Using a 20-MHz bandwidth 16-QAM LTE signal at 836.5 MHz, the prototype transmitter achieved an output power of 22.7 dBm and drain efficiency of 33% while passing the spectral requirements of the LTE standard.

This paper presents a 90-nm fully integrated CMOS linear power amplifier (PA) using a coupled L-shape concentric vortical transformer (CL-CVT) for the fourth-generation long-term evolution (LTE) communication standard. Using the proposed output combining CL-CVT architecture, the outer diameter required by the power combiner is reduced by 66% compared to the distributed active transformer with similar performance. Moreover, the PA is able to efficiently combine four push-pull output stages and achieve nearly constant power over several LTE bands with a total chip area less than 1 mm 2 . With a 1.2-V supply voltage, the PA delivers 27.3-dBm maximum output power with a peak drain efficiency of 47% at 2.4 GHz. Using a 20-MHz LTE 16-QAM test signal, the PA achieves 24.6% power-added efficiency at an output power level of 22 dBm and passes the spectral requirements defined by the LTE standard without using any pre-distortion or calibration techniques.

This letter presents a high-isolation absorptive 1.9 GHz on-off keying (OOK) modulator in 90 nm CMOS process. The RF leakage-canceling technique is developed to suppress the RF leakage by combining it with its inverse replica at the output. The transform-typed baluns are used for the input and output matching such that the modulator input and output return losses change only slightly between the on and off states. The measured off-isolation of the CMOS OOK modulator is higher than 39.2 dB and the modulator has the on-state signal gain of 3.6 dB.

This paper presents a wide bandwidth fully integrated CMOS power amplifier (PA) suitable for pulse-mode operation. The CMOS PA was implemented in a 90-nm process with core size of 1 mm2. A pulse-modulated polar transmitter for LTE femtocell applications was constructed with this switching CMOS PA using the aliasing-free digital pulse-width modulation technique. With conventional memoryless digital predistortion, the polar transmitter achieved 23.5% efficiency and 19.5-dBm output power at 2.4 GHz. Moreover, the proposed transmitter can also pass the −45-dBc ACLR requirement over a wide frequency range from the first channel in downlink band-1 to the last channel in downlink band-7 for LTE home femtocell base stations.

This paper presents a highly efficient polar transmitter using interleaving pulse modulation for multiple communication standards. Using the proposed interleaving pulse modulation technique, a polar transmitter can suppress the odd-order output spurs deeply with a feasible value of essential sampling frequency and keep the residual spurs from falling into the receive bands. To validate the proposed technique, a prototype polar transmitter was constructed and evaluated. Using global system for mobile communications, enhanced data rates for GSM evolution, and wideband code division multiple access (WCDMA) signals at 836.5 MHz, the polar transmitter achieved 68%, 45.5%, and 41.2% power-added efficiency at output power levels of 28, 26, and 25 dBm, respectively. The measurement results were able to pass the spectral requirements defined by the respective standards without the use of any pre-distortion or calibration techniques. Moreover, the polar transmitter was able to achieve an output dynamic range of 80 dB required by the WCDMA standard.

This paper presents a transmitter architecture based on a pulse-modulated polar transmitter using multiphase pulsewidth modulation. The modulation to the radio-frequency input signal, instead of conventional drain modulation, significantly reduces the circuit complexity, while the multiphase modulation technique reduces the out-of-band emissions. An 836.5-MHz four-phase prototype transmitter using four class-C power amplifiers in parallel was constructed. Using the transmitter, single-phase, two-phase, and four-phase pulsewidth modulated signals were tested to verify the benefits of using the proposed multiphase architecture. Using a CDMA2000 1X signal, 46.8% efficiency at a 29-dBm output power level was measured while passing the spectral-mask requirements without using any kind of digital predistortion or calibration.