Overcurrent/Overdischarge Prot
abstract: this application note describes the use of a current-sense amplifier with internal dual comparators to monitor and protect against too low battery voltage and too high battery current. while written for lead-acid batteries, the circuit and concept can be extended to nicd, li-ion and other battery chemistries. an external power p-channel mosfet is in series with the battery and its load. it works as a normally closed switch which can be opened if the current-sense amplifier and comparators detect either a high load current or a low battery voltage. the high current comparator can be latched to detect brief over currents and reset by an external push button.
the circuit of figure 1 protects a lead-acid battery by disconnecting its load in the presence of excessive current (more than 5a), or a low terminal voltage indicating excessive discharge (
figure 1. a fault condition (battery terminal voltage 5a) causes t1 to open and led1 to illuminate.
ic2 is a micropower device drawing only 50µa of supply current. it contains a dual comparator and a high-side current-sense amplifier whose output current is proportional to the current through r1. the top comparator (c2) senses battery voltage via r2/r3, and drives cout2 low when the voltage falls below 10.5v. that action turns on led1, turns off t3, and allows r4 to turn off t1 by pulling its gate high. thus, the battery load is removed when battery voltage is less than 10.5v. recharging the battery turns t1 back on automatically. c2's internal 1.5% hysteresis prevents output oscillation near the switching threshold.
a high-voltage micropower linear regulator (ic1) provides a stable 5v for pullup resistors r7 and r8. it also sources the 2.25ma required for fault indicator led1. ic1 accepts input voltages as high as 28v, and draws a maximum quiescent supply current of only 8µa.
the output of latched comparator c1 is normally low, which turns off t2 and allows normal operation. when a load current above 5a drives the cin1 voltage above 0.6v, the open-drain output cout1 is latched high (open), allowing r7 to pull t2's gate high. the resulting low on cin2 drives cout2 low, disconnecting the load and illuminating led1 just as an overdischarge does, except the load remains disconnected until ic2's active-low reset input (normally pulled high via r8) is pulled to ground via the normally-open pushbutton switch sw1.
最全PLC输入输出各种回路接线
紫光发布全新一代自主研发人工智能服务器
采用Imagination的OmniShield™多域技术的解决方案
新基建引力 PCB或迎来快速增长
工业智能网关BL110应用之三十五： 如何连接配置金鸽MQTT云服务器
Overcurrent/Overdischarge Prot
leader选举在kubernetes controller中是如何实现的
FPC物料中英文对照表
LG正式发布LG Gram 16笔记本
许斌发表了《RGB全系列突进》的主题演讲
诺基亚Lumia概念机即将问世
Timing Considerations When Usi
海得控制12.78亿元收购新能源工控领域企业75%股权
恩智浦与华为携手成立射频功放联合研发及创新实验中心
高速PCB设计指南---PCB的可靠性设计
汽车连接器的生产技术水平如何？
台湾高技 GAOJ-K与您相约DMP大湾区工博会
使用单片机设计一款功率测试仪
三星W20 5G开启预约该机搭载骁龙855平台辅以12GB+512GB内存组合
哪些将会推动统一通信和协作的发展
the circuit of figure 1 protects a lead-acid battery by disconnecting its load in the presence of excessive current (more than 5a), or a low terminal voltage indicating excessive discharge (
figure 1. a fault condition (battery terminal voltage 5a) causes t1 to open and led1 to illuminate.
ic2 is a micropower device drawing only 50µa of supply current. it contains a dual comparator and a high-side current-sense amplifier whose output current is proportional to the current through r1. the top comparator (c2) senses battery voltage via r2/r3, and drives cout2 low when the voltage falls below 10.5v. that action turns on led1, turns off t3, and allows r4 to turn off t1 by pulling its gate high. thus, the battery load is removed when battery voltage is less than 10.5v. recharging the battery turns t1 back on automatically. c2's internal 1.5% hysteresis prevents output oscillation near the switching threshold.
a high-voltage micropower linear regulator (ic1) provides a stable 5v for pullup resistors r7 and r8. it also sources the 2.25ma required for fault indicator led1. ic1 accepts input voltages as high as 28v, and draws a maximum quiescent supply current of only 8µa.
the output of latched comparator c1 is normally low, which turns off t2 and allows normal operation. when a load current above 5a drives the cin1 voltage above 0.6v, the open-drain output cout1 is latched high (open), allowing r7 to pull t2's gate high. the resulting low on cin2 drives cout2 low, disconnecting the load and illuminating led1 just as an overdischarge does, except the load remains disconnected until ic2's active-low reset input (normally pulled high via r8) is pulled to ground via the normally-open pushbutton switch sw1.
最全PLC输入输出各种回路接线
紫光发布全新一代自主研发人工智能服务器
采用Imagination的OmniShield™多域技术的解决方案
新基建引力 PCB或迎来快速增长
工业智能网关BL110应用之三十五： 如何连接配置金鸽MQTT云服务器
Overcurrent/Overdischarge Prot
leader选举在kubernetes controller中是如何实现的
FPC物料中英文对照表
LG正式发布LG Gram 16笔记本
许斌发表了《RGB全系列突进》的主题演讲
诺基亚Lumia概念机即将问世
Timing Considerations When Usi
海得控制12.78亿元收购新能源工控领域企业75%股权
恩智浦与华为携手成立射频功放联合研发及创新实验中心
高速PCB设计指南---PCB的可靠性设计
汽车连接器的生产技术水平如何？
台湾高技 GAOJ-K与您相约DMP大湾区工博会
使用单片机设计一款功率测试仪
三星W20 5G开启预约该机搭载骁龙855平台辅以12GB+512GB内存组合
哪些将会推动统一通信和协作的发展