输入电流限制电池充电器移动计算应用-Input Curren
additional information:
quick view datasheet for the max1645/max1645a
quick view data sheet for the max1772
technical support: power introductionwith the increasing demand for mobile computing devices, longer battery life and fast charging of batteries are becoming more important. faster microprocessors that control these devices and use more power also require higher-capacity batteries. today's notebooks and palm-computing devices use advanced li-ion and nimh batteries to extend battery life and sophisticated battery chargers to reduce battery-charging time.
the trend in the mobile computing market over the last few years has been one of faster devices and decreasing prices. manufacturers are using sophisticated technology and new methods to minimize the cost of mobile computers.
input current limitinginput current limiting is one such feature that allows mobile computer manufacturers to reduce the cost of ac adapters used with these devices. when an ac adapter is connected to a mobile computer in use, it not only powers the system but also charges the batteries. depending upon the power requirements of the system, the power drawn from the ac adapter will vary. in order to ensure that the ac adapter can safely meet the power requirements of such a system, it has to be able to supply the maximum power required by the system and charge the batteries at the same time, without getting overheated. the result is an ac adapter that is oversized and expensive.
input current limiting is an advanced feature that can help reduce the cost of the ac adapter while meeting the power requirements of the system and charging the batteries. it works by monitoring the power requirement of the system and adjusting the charging current supplied to the batteries to keep the power drawn from the ac adapter within its specified limits. figure 1 shows a simplified schematic of a charger that implements the input-current-limiting feature. when the current drawn by the system increases, causing a corresponding increase in the current drawn from the ac adapter (iinput), the charging current (icharge) supplied to the batteries is reduced, and vice versa.
figure 1.
in the past this feature was implemented using a system power-management microprocessor. the microprocessor would monitor the power drawn by the system and control the battery-charger output current. such a method was complicated, requiring sophisticated firmware and external components including a separate current sense amplifier, making it expensive. in addition, the response time of such a system was slow, because decisions were being made in the firmware.
battery chargers from maxim with input current limitingmaxim has introduced two new chargers, the max1772 and the max1645a, that include the input-current-limiting feature. the max1772 and the max1645a differ in the communication interface used to control the charging voltage and current. whereas the max1772 employs an analog interface for controlling charging parameters, the max1645a uses an smbus interface for the same purpose.
both chargers integrate the input-current-limiting feature using a minimum number of external components. two external sense resistors are used to sense the current being drawn from the ac adapter and the battery-charger output current. the amplifiers required for sensing the currents and associated logic circuitry for making decisions and changing the battery-charger current are fully integrated in the ics. this not only helps in reducing cost but also improves the speed of system response.
both the max1772 and the max1645a work by monitoring the current being drawn from the ac adapter and comparing it to an externally adjustable current limit. typical application circuits for both chargers are given below. the current limit is set based on the current-handling capability of the ac adapter. generally, this limit is chosen to optimally fulfill the system power requirements while achieving a satisfactory charging time for the batteries. if the ac-adapter current exceeds the set threshold, the charger responds by cutting back on the charger current, thereby keeping the current drawn from the ac adapter within the set limit. with such a battery charger, the ac adapter doesn't need to be oversized to meet maximum system and battery-charging requirements simultaneously, reducing ac-adapter cost.
figure 2.
figure 3.
小米10手机充电规格曝光最高支持50W功率有线充电
JK型雷达液位计介绍
华为荣耀为何主动销毁价值2200万元的手机
梯云物联的双屏电梯安全卫士的功能介绍
德国向拥有3.7-3.8GHz许可证的私有5G网络敞开大门
输入电流限制电池充电器移动计算应用-Input Curren
PCB设计裸板测试：夹具测试和飞针测试
汇川技术多款新品展现数自融合，强强战略合作推动可持续生态
直流电动机的常见故障及检修方法
国家政务服务平台成效凸显，网上政务服务能力持续提升
三星这次把电池的优化也做到了极致！不仅不爆炸，而且使用一年损耗率只有5%！
可附着在昆虫上的微型机器人
无线上网卡的最高传输速度
小区电子哨兵健康码+人脸识别，电子哨兵白名单核验登记有必要吗？优势了解一下
光功率计校准
溢流晶片清洗工艺中的流场概述
智云图传功能确实不一般，让用户用起来更舒心
小米MAX3：6．9英寸大屏幕，或将7月推出
专访Altera副总裁胡勇冕：SoC FPGA瓜分嵌入式大饼
led显示屏行业当前及未来发展趋势
quick view data sheet for the max1772
technical support: power introductionwith the increasing demand for mobile computing devices, longer battery life and fast charging of batteries are becoming more important. faster microprocessors that control these devices and use more power also require higher-capacity batteries. today's notebooks and palm-computing devices use advanced li-ion and nimh batteries to extend battery life and sophisticated battery chargers to reduce battery-charging time.
the trend in the mobile computing market over the last few years has been one of faster devices and decreasing prices. manufacturers are using sophisticated technology and new methods to minimize the cost of mobile computers.
input current limitinginput current limiting is one such feature that allows mobile computer manufacturers to reduce the cost of ac adapters used with these devices. when an ac adapter is connected to a mobile computer in use, it not only powers the system but also charges the batteries. depending upon the power requirements of the system, the power drawn from the ac adapter will vary. in order to ensure that the ac adapter can safely meet the power requirements of such a system, it has to be able to supply the maximum power required by the system and charge the batteries at the same time, without getting overheated. the result is an ac adapter that is oversized and expensive.
input current limiting is an advanced feature that can help reduce the cost of the ac adapter while meeting the power requirements of the system and charging the batteries. it works by monitoring the power requirement of the system and adjusting the charging current supplied to the batteries to keep the power drawn from the ac adapter within its specified limits. figure 1 shows a simplified schematic of a charger that implements the input-current-limiting feature. when the current drawn by the system increases, causing a corresponding increase in the current drawn from the ac adapter (iinput), the charging current (icharge) supplied to the batteries is reduced, and vice versa.
figure 1.
in the past this feature was implemented using a system power-management microprocessor. the microprocessor would monitor the power drawn by the system and control the battery-charger output current. such a method was complicated, requiring sophisticated firmware and external components including a separate current sense amplifier, making it expensive. in addition, the response time of such a system was slow, because decisions were being made in the firmware.
battery chargers from maxim with input current limitingmaxim has introduced two new chargers, the max1772 and the max1645a, that include the input-current-limiting feature. the max1772 and the max1645a differ in the communication interface used to control the charging voltage and current. whereas the max1772 employs an analog interface for controlling charging parameters, the max1645a uses an smbus interface for the same purpose.
both chargers integrate the input-current-limiting feature using a minimum number of external components. two external sense resistors are used to sense the current being drawn from the ac adapter and the battery-charger output current. the amplifiers required for sensing the currents and associated logic circuitry for making decisions and changing the battery-charger current are fully integrated in the ics. this not only helps in reducing cost but also improves the speed of system response.
both the max1772 and the max1645a work by monitoring the current being drawn from the ac adapter and comparing it to an externally adjustable current limit. typical application circuits for both chargers are given below. the current limit is set based on the current-handling capability of the ac adapter. generally, this limit is chosen to optimally fulfill the system power requirements while achieving a satisfactory charging time for the batteries. if the ac-adapter current exceeds the set threshold, the charger responds by cutting back on the charger current, thereby keeping the current drawn from the ac adapter within the set limit. with such a battery charger, the ac adapter doesn't need to be oversized to meet maximum system and battery-charging requirements simultaneously, reducing ac-adapter cost.
figure 2.
figure 3.
小米10手机充电规格曝光最高支持50W功率有线充电
JK型雷达液位计介绍
华为荣耀为何主动销毁价值2200万元的手机
梯云物联的双屏电梯安全卫士的功能介绍
德国向拥有3.7-3.8GHz许可证的私有5G网络敞开大门
输入电流限制电池充电器移动计算应用-Input Curren
PCB设计裸板测试：夹具测试和飞针测试
汇川技术多款新品展现数自融合，强强战略合作推动可持续生态
直流电动机的常见故障及检修方法
国家政务服务平台成效凸显，网上政务服务能力持续提升
三星这次把电池的优化也做到了极致！不仅不爆炸，而且使用一年损耗率只有5%！
可附着在昆虫上的微型机器人
无线上网卡的最高传输速度
小区电子哨兵健康码+人脸识别，电子哨兵白名单核验登记有必要吗？优势了解一下
光功率计校准
溢流晶片清洗工艺中的流场概述
智云图传功能确实不一般，让用户用起来更舒心
小米MAX3：6．9英寸大屏幕，或将7月推出
专访Altera副总裁胡勇冕：SoC FPGA瓜分嵌入式大饼
led显示屏行业当前及未来发展趋势