智能电池充电器会议设计外文翻译资料

Intelligent Battery Charger Conference Design

INTRODUCTION

Typically, simple battery chargers do not provide the intelligence to charge different battery technologies or batteries with the same technology but different volt-ages and capacities. At best, this may leave the battery improperly charged. At worst, it can pose a serious safety hazard. A microcontroller can provide the intelligence to overcome these problems. In addition to intelligent control, the microcontroller can provide a low-cost, flexible solution for charging batteries. Complete battery charging applications may be developed quickly using a microcontroller. Add to this the serial communication capability of the microcontroller, real-time data logging and monitoring is possible. Simple battery chargers use all analog components to accomplish their function. However, by using a micro-controller, a battery charger can be made intelligent.

Microcontroller Benefits

bull;Flexibility to handle different technologies, voltages and capacities.

bull;Variable Voltage Generation Control

bull;Charge/Discharge Multiple Battery Packs

bull; lsquo;Windowedrsquo; A/D for High Resolution

PICREF-2 OVERVIEW

The Microchip Technology PICREF-2 Intelligent Battery Charger (IBC) Reference Design offers a ready-made battery charger solution. This Reference Design is targeted to battery charger applications such as camcorders, portable audio equipment, portable phones, and portable power tools. With the PICREF-2 Reference Design, the user will be able to simply pick their complete battery charging system by completing the steps listed:

1.Pick the required battery management features from the modular source code provided.

2. Pick the critical battery pack parameters and modify the global constants to those specifications.

The hardware design contains the necessary circuitry to support charging and discharging algorithms, charge termination methods, and RS-232 communications. The modular source code is written in C and consists of the charge termination algorithms, discharge algorithm, interdevice communications, and RS-232 communications modules. The PC based software provides a means for requesting and displaying battery status information.

PICREF-2 Key Features

bull;Compatibility Across Battery Technologies

bull;Low Cost

bull;Flexible Development Environment

bull;Fast Charge Rate

bull;High Charge Current Capability

bull; High Discharge Current Capability for Conditioning

bull;Real-Time Debug

bull;Data Logging

bull;User Selectable Embedded Charge Termination Algorithms

System Overview

The PICREF-2 system block diagram is shown in Figure

1. This reference design can charge or discharge single or dual batteries of the same type. The PIC16C7XX microcontroller contains the embedded charging algorithm and controls the external charging components and buck, or step-down, converter. To develop the charging algorithms, the PICREF-2 has a development mode. Once the algorithm has been developed, the PICREF-2 may be placed in stand-alone mode. The voltage for battery charging is generated through a buck converter, which is controlled by the PIC16C7XXrsquo;s Hardware PWM. The PIC16C7XX controls battery charging and discharging through the Battery Charge Select and Battery Discharge Select lines. Battery Temperature and Battery Voltage lines provide information for charge termination algorithm calculation and status. The Current Sense line monitors the current being delivered to the battery during charge for status information. The A/D functions are implemented using the on-board A/D converter of the PIC16C7XX.

Development Mode

In order to develop the firmware for the PICREF-2 system, a development mode has been included.

This mode supports an RS-232 serial link to a PC for battery status communication. The PIC16C73A also contains the embedded charging algorithm and controls the external charging components and buck converter. Development mode offers real-time debug of charge termination algorithms. In this mode, charging parameters can be changed on the fly via the microcontroller software and battery data can be logged.

Stand-Alone Mode

Once the correct charging algorithm has been developed and charge parameters have been determined, the global constants can to be set for stand-alone mode. There is no RS-232 communication or discharge capacity in this mode.

Hardware Overview

This section describes the PICREF-2 hardware and how it functions in the Intelligent Battery Charger (IBC) system.

Microcontroller

The PIC16C7XX microcontroller gives the PICREF-2 reference design flexibility. Changes can be made using software instead of hardware, and charging algorithms can be easily customized to accommodate the userrsquo;s specific battery packs. The ability to charge and discharge either a single battery or two batteries of the same type means greater flexibility. PWM control of voltage generation (via the buck converter) and A/D monitoring of the voltage means precise control over the voltage used for charging batteries.

Development mode uses the PIC16C73A microcontroller (Figure 1), which provides more memory and a USART (RS-232) communications port for development of firmware. Stand-alone mode uses the PIC16C72 (Figure 2). The PIC16C72 or the PIC16C73A can be inserted in either 28-pin socket (U17 or U19).

Voltage Regulator

The input voltage ( V_FUSED) is used by the voltage regulator to generate the 5 VDC needed by the board. The voltage regulator LT1118CS8-5 (U10) may be replaced by U14 (NJM7805).

Buck (Step-Down) Converter

The most critical parameter in charging batteries is the control of the power source. Whether current or voltage charging is being used (PICREF-2 uses a constant current method), control of the power source is imperative to proper battery c

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智能电池充电器会议设计

简介
通常情况下，简单的电池充电器不给不同的电池或有不同电压和容量的电池提供智能充电技术。最好的情况下，这可能会造成电池充电不当的结果。在最坏的情况下，它可能会对电池构成一个严重的安全隐患。微控制器智即单片机能智能地解决这些问题。单片机除了提供智能技术外，还可以提供一种低成本、灵活的解决方案来解决电池充电的问题。如果使用单片机，电池充电应用可以得到快速全面的发展。单片机的串行通信、实时数据记录和监控对电池充电的智能技术都是有利的。简单的电池充电器会尽可能利用模拟组件来完成它们的功能。但是，电池充电器和单片机结合可以使其智能化。

单片机的优势
1.灵活处理不同的技术、电压和容量。
2.控制可变电压产生
3.充电/放电复合电池组
4.“窗口”A/D分辨率高

PICREF -2概述
微芯片技术PICREF -2智能电池充电器（IBC）参考设计提供了一个现成的电池充电器解决方案。该参考设计是针对如摄像机、便携式音频设备、移动电话、便携式电动工具等电池充电器应用。对比PICREF -2参考设计，用户可以通过完成以下步骤简单地选择完善的电池充电系统：
1.从模块源代码中选择所需的电池管理功能。
2.选择关键的电池参数并且修改相应的全局常量。硬件设计包括支持充电和放电算法的电路，充电终止方法和RS-232通信。源代码是用C写的，模块包括充电终止算法，流量算法，元件通信和RS-232通信模块。计算机的软件提供了一种显示电池状态信息的装置。
PICREF -2关键特征
1.电池技术的兼容性
2.成本低
3.灵活的开发环境
4.充电速度快
5.高充电电流
6.高放电电流调节力
7.实时调试
8.数据记录
9.用户可选择嵌入式电荷终止算法

系统概述
PICREF -2系统框图如图所示

1.本参考设计可为同一类型的单或双电池充电或放电。PIC16C7XX单片机内含充电算法和控制外部充电组件和降压电路或降压转换器。PICREF -2有一种发展模式开发充电算法。一旦这种算法被开发出来，PICREF -2可能被放置在独立模式。电池充电电压由PIC16C7XX硬件PWM控制的降压变换器产生。PIC16C7XX通过电池充电选择和电池放电选择来控制电池充放电。电池温度和电池电压线为充电终止算法的计算和状态提供信息。电流检测线检测充电状态的电流传递给电池。A/D功能通过PIC16C7XX内部的A/D转换器实现。

发展模式
开发模式主要是为了提高PICREF -2系统的精确度。这种模式支持RS-232串口连接到计算机实现电池状态通信。PIC16C73A还包含嵌入式充电算法、控制外部充电组件和Buck变换器。开发模式提供实时调试的充电终止算法。在这种模式下，单片机软件系统可以改变电池的充电参数，电池的各项数据也可以实时记录。
独立模式
正确的充电算法和充电参数一旦被开发及确定，在独立模式中可以设置全局变量。但是在这个模式中并没有RS-232通信和放电功能。

硬件概述
本节介绍了在智能电池充电系统（IBC）中，PICREF -2硬件如何实现它的功能。

单片机
PIC16C7XX单片机给PICREF -2提供了灵活的参考设计。如果用软件代替硬件，可以简易的定制充电算法来适应用户有特殊要求的电池。充电和放电是一节还是两节相同类型的电池意味着更大的灵活性。电压产生的脉宽调制（通过降压转换器）和A/D检测电压对充电电池的电压进行精确控制。
发展模式采用PIC16C73A单片机（图1），因为PIC16C73A单片机提供了更多的内存和一个串口（RS-232）通信端口来开发固件。独立模式采用PIC16C72 单片机（图2）。PIC16C72或PIC16C73A可插入28针插座（U17和U19）。

电压调节器
电压调节器根据输入电压产生电路所需的5V直流电。LT1118CS8-5 (U10)电压调节器可能会被U14 (NJM7805)取代。
降压转换器
充电电池中最关键的参数是电源控制参数。无论是使用电流充电还是电压充电（PICREF -2采用恒流充电法），想要对电池进行恰当的充电必须控制电源电压。本设计的电源是一个降压转换器。之所以会选择降压转换器是因为其简单、效率高和低散热的优点。图3所示的简化电路图。

降压转换器的基本知识
PIC16C7XX单片机通过硬件PWM模块和外部电流检测电阻来控制Buck转换器。PWM和电流检测电阻的反馈不能提供精确的和可重复充电的方法。降压转换器工作如下：当脉宽调制输出高电平时，电流通过晶体管和电感到达电池。此时，电感通电，电容充电。当脉宽调制输出低电平时，电感的电压反转，二极管提供电流。电感和电容作为输出电压和电流的滤波器。
Buck转换器可操作的两种模式：（1）连续的，电流持续不断，或（2）不连续的，在一段时间内电流下降到零。对于大电流负载，转换器将在连续模式工作。然而，在小负载条件下，降压转换器的电流可能会在一段时间内降至零。在本参考设计中的转换器因为被控制使得它始终工作在连续模式。因此，它产生的锯齿波形如图4所示。

对于一个给定的输入电压和输出电压，此电感电流波形的峰值幅度保持恒定。当负载电流上升或下降，整个锯齿波电流波形也上升或下降。此波形的平均直流电压等于直流负载电流。

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