基于单片机的智能手机充电器的设计英文版doc 11页.docx

1、基于单片机的智能手机充电器的设计英文版doc 11页基于单片机的智能手机充电器的设计(英文版)(doc 11页)更多企业学院： 中小企业管理全能版183套讲座+89700份资料总经理、高层管理49套讲座+16388份资料中层管理学院46套讲座+6020份资料国学智慧、易经46套讲座人力资源学院56套讲座+27123份资料各阶段员工培训学院77套讲座+ 324份资料员工管理企业学院67套讲座+ 8720份资料工厂生产管理学院52套讲座+ 13920份资料财务管理学院53套讲座+ 17945份资料销售经理学院56套讲座+ 14350份资料销售人员培训学院72套讲座+ 4879份资料更多企业学院：

2、conventional linear chargers, one of the great advantages of using switching chargers solution is the capability to boost the charge current from what supplied by the source. This is especially important when powering off of a USB port where the current available might be limited to less than 500mA.

3、 Higher charge currents equate to shorter charge cycles thus satisfying customer expectations.There are two kinds of battery chargers used in most handhelds now linear chargers and switching devices. Linear chargers have a longer history. They have typically provided a relatively efficient, simple w

4、ay to charge portable devices, creating minimal noise without many external components. But as portable devices become more complex and add layers of new features, they need higher battery capacity. Linear chargers present liabilities due to power dissipation, which become clear if a user wants to c

5、harge a device while using at the same time. The heat generated while simultaneously using and charging can damage the system or battery. Not a good outcome. The alternative is a switching device, or switch mode battery charger IC, that can deliver higher current levels to a battery while requiring

6、as little power as possible. Historically, there have been some noise issues with these kinds of ICs. In addition, some early generations of switch mode devices have required several external components. However, the benefits of the switched mode battery topology are clear. They include higher effic

7、iency and lower power dissipation, along with fast charging cycles. These devices also are capable of charging from higher input voltages, which allows the use of lower cost unregulated adapters. They can increase the charging current from current restricted sources. The noise from switching charger

8、s usually comes during light load operation, particularly during preconditioning. As it decreases, many switching chargers move into an operation known as pulse skipping. In pulse skipping, the PWM frequency changes asynchronously. There have been battery charger ICs developed that supply high charg

9、e current with minimal thermal impact to the system using a switching charger, then switch into a linear charger during low current charging modes to minimize noise. This type of PWM switch mode charger with a linear mode has been a good development, providing high efficiency at the full constant cu

10、rrent (fast charge) rate. The switching charger controls large constant current charge (up to 2A) with a PWM switching regulator. It automatically moves to linear mode while the battery is preconditioning and near the end of constant voltage taper charge mode, which lowers the noise while the switch

11、 mode speeds up charging. Once the charge current level dips below 300 mA, the linear mode kicks in completely and noise generated by the switching converter is eliminated. But now there are further advances. For example, an ideal solution for new handhelds is a complete charger for single cell Li+/

12、 Polymer batteries with up to 1A charge current and advanced indication capabilities for full charge system monitoring. USB Compliant 100mA/500mA charge current settings are beneficial as are programmable pre-charge and fast charge. Many products also include battery temperature monitoring, which en

13、sures safe charging. Companies such as Intersil are leading the development effort for new generations of charger ICs. These fully integrated solutions serve compact applications and provide charge controllers for higher power applications. Charge voltage accuracy is now at 0.5 percent, an improveme

14、nt over just a few years ago, when an accuracy rating of 1 percent was considered good. Switching frequencies are up to 3 MHz and new switching chargers now provide up to 2A charge current, with one recent example being the ISL9220, which is suitable for both 1 and 2 cells Li Ion applications. In ad

15、dition, new designs restrict leakage - there is no less than 0.5uA typical leakage current off the battery when no input power is attached. These improvements also have become available in smaller and smaller packages, such as 4 x 4mm QFNs or 2 x 2mm CSPs, which save real estate in space-constrained

16、 handheld equipment. The latest battery charger ICs also are able to monitor the input voltage, the battery voltage, and the charge current. When any of the three parameters exceeds specific limits, the IC turns off an internal N-channel MOSFET to remove the power from the charging system to the bat

17、tery. This kind of flexible efficiency is another of the improvements now available in these important devices, which are vital to the continuing growth and feature set expansion of mobile, handheld products.【作 者】Marino, Giampaolo; Schmitz, Tamara【刊 名】Electronic Component News【出版日期】2010【卷 号】Vol.54【期

18、 号】No.1【页 码】16DESIGN AND IMPLEMENTATION OF A MICROCOMPUTER 8051 SYSTEM POWERED BY DUAL BATTERIES CHARGED BY SOLAR CELLSAbstractSingle-chip microcomputer systems are becoming increasingly popular in current control and information applications. However, due to their battery energy limitations, these

19、systems have a very restricted operation time or recharge cycle if a single rechargeable battery supplies their power. We propose a design and implementation for the software and hardware of a microcomputer 8051 system powered by a dual rechargeable battery that is charged by solar cells. From a fea

20、sibility analysis of the queueing model for the stochastic charging and discharging process of the dual battery system, due to the random characteristics of weather conditions and users operational behavior, we confirm that the average operation time for this model can be much longer than that of a

21、single rechargeable battery power supply. The experimental results of our design also show approximately the same results as our model. With a two-thirds utilization ratio, we can obtain an average operation time four times as long in theoretical results, and three and half times as long in experime

22、ntal results than with a single rechargeable battery power supply. In addition, the technology trend shows that the power consumption rate for a typical microcomputer system is decreasing and the power generation efficiency for typical solar cells is increasing. Hence, solar cells as the power charg

23、ing sources for a microcomputer 8051 system supplied by a dual rechargeable battery can be feasible in the near future.Over the past few years, microcomputer system design researchers have been working with different levels of low-power technology. In terms of system, circuits, and device power savi

24、ng, the results show that every year from 1992 to 1997 the average power consumption of a microcomputer computer decreased more than 20%,and from 1998 to 2001 it decreased by 10%.Reducing power consumption is important because of its potential to extend the recharge period of portable information ap

25、plications. The longer the battery operation time before a recharge is needed, the more convenient it is for mobile users to operate a portable microcomputer system.Eventually, the power consumption of a single-chip microcomputer system will be small enough to be supplied or recharged by other power

26、 sources. One of the proposed power sources is mechanical vibration. Among others, we previously proposed solar cells that can be used as power supply sources. Although current mc-Si solar cell power generation efficiency is not high enough, their efficiency increased from 14.2% to 16.8%from 1990 to

27、 1997.This improvement can reduce the gap between the charging and discharging rate of the power supply of a microcomputer system, so the probability of power exhaustion within a certain operational time is reduced each year.To prolong the battery operation time before recharging, in this article we

28、 present the software and hardware module for a single-chip microcomputer 8051 system with a dual battery charged by solar cells. Based on its design and implementation, this work also presents the estimation for power exhaustion probability and the experimental measurement for operation time that d

29、epends on the power generation efficiency of solar cells and the power consumption rate of a microcomputer. In addition, due to the overlapping of the charging and the discharging period, if the ratio between the charging and discharging rate is two thirds, then the operation time can potentially be

30、 prolonged four times in comparison with a single rechargeable battery.The rest of this is organized as follows. In Section 2, the technology trends with respect to the power consumption of a microcomputer and the power generation efficiency of solar cells are discussed. In Section 3, the queueing m

31、odel for the stochastic charging and discharging behavior for the dual rechargeable battery in a single-chip microcomputer system is presented. In addition, the feasibility estimation for the dual rechargeable battery in a single chip microcomputer system is given. In Sections 4 and 5, the design an

32、d implementation of the software and hardware modules for this system are provided. In Section 6, the experimental results of this system are given. The last section presents conclusions.7. ConclusionsWe have presented the design and implementation of a microcomputer 8051 system powered by dual batteries charged by solar cells. The hardware components used are very common and are of low cost. The control program designed uses a common variety of assembly language. The experimental system has shown a very stable