Simple Circuit Activates Fan W
abstract: a circuit is shown that senses the temperature of a remote thermal diode on the die of a cpu, fpga, gpu, or other high-performance ic. when the thermal diode temperature exceeds a pre-defined trip point, a cooling fan switches on, thereby providing a simple fan control function.
cooling fans are common in pcs, workstations, and other systems that can generate significant heat during normal operation. in many such systems, however, cooling isn't needed 100% of the time. in these systems, it is preferable to operate the fan only when cooling is needed, rather than full time. operating the fan only when needed increases fan lifetime and reduces system noise.
the circuit shown below uses a very simple, low-cost approach to controlling a fan's operation based on the die temperature of a microprocessor, fpga, or other high-power chip. the target ic must have a temperature-sensing pn junction (typically the base and the emitter of a substrate pnp) available. the circuit is based on a max6513 remote temperature switch (ic1). ic1 forces current with precisely controlled ratios through the sense junction on the target ic, measures the junction's forward voltage at each current, and calculates the temperature of the remote junction based on this information. if the measured temperature exceeds the factory-programmed threshold temperature, the max6513's output pin (tover) goes active, turning on the n-channel mosfet and supplying power to the fan.
the threshold temperature can be chosen to match the needs of the target ic. in the circuit shown here, ic1 has a threshold of 55°c. typical values for fan control range from about 45°c to about 65°c, but higher values can also be accommodated. after activating the fan, hysteresis keeps the fan on until the temperature drops 10°c below the trip temperature. if 5°c hysteresis is preferred, connect the hyst pin to ground. for best results, locate ic1 close to the target ic and keep high-speed digital traces away from the dxp and dxn traces to avoid noise coupling.
figure 1. this simple fan controller activates the fan when the temperature of the target ic exceeds 55°c.
figure 2. the fan turns on when the trip temperature is exceeded. temperature has to fall below the trip temperature minus the hysteresis before the fan turns off. by connecting the hyst pin to ground or vcc, 5°c or 10°c hysteresis can be selected.
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Simple Circuit Activates Fan W
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cooling fans are common in pcs, workstations, and other systems that can generate significant heat during normal operation. in many such systems, however, cooling isn't needed 100% of the time. in these systems, it is preferable to operate the fan only when cooling is needed, rather than full time. operating the fan only when needed increases fan lifetime and reduces system noise.
the circuit shown below uses a very simple, low-cost approach to controlling a fan's operation based on the die temperature of a microprocessor, fpga, or other high-power chip. the target ic must have a temperature-sensing pn junction (typically the base and the emitter of a substrate pnp) available. the circuit is based on a max6513 remote temperature switch (ic1). ic1 forces current with precisely controlled ratios through the sense junction on the target ic, measures the junction's forward voltage at each current, and calculates the temperature of the remote junction based on this information. if the measured temperature exceeds the factory-programmed threshold temperature, the max6513's output pin (tover) goes active, turning on the n-channel mosfet and supplying power to the fan.
the threshold temperature can be chosen to match the needs of the target ic. in the circuit shown here, ic1 has a threshold of 55°c. typical values for fan control range from about 45°c to about 65°c, but higher values can also be accommodated. after activating the fan, hysteresis keeps the fan on until the temperature drops 10°c below the trip temperature. if 5°c hysteresis is preferred, connect the hyst pin to ground. for best results, locate ic1 close to the target ic and keep high-speed digital traces away from the dxp and dxn traces to avoid noise coupling.
figure 1. this simple fan controller activates the fan when the temperature of the target ic exceeds 55°c.
figure 2. the fan turns on when the trip temperature is exceeded. temperature has to fall below the trip temperature minus the hysteresis before the fan turns off. by connecting the hyst pin to ground or vcc, 5°c or 10°c hysteresis can be selected.
理想二极管的应用实例及主要规格
R&S TS7810测试系统主要面向汽车胎压监测
讯飞智能录音笔SR502焕新上市，持续提升转写体验
开赛倒计时！vivo X21世界杯非凡版胜利红限量开售
分析采用GD32 MCU设计LCD显示屏背光驱动方案的实用性和应用
Simple Circuit Activates Fan W
关于ADC应用100Msps的数字示波器的案例分析
小米平板3和小米平板2对比：憋了这么久 就这么点升级？
菲力尔推出适用于易爆环境下的保护系统——FLIR A310ex
4通道DC-DC转换器LX3476的功能特点和典型应用分析
车载手持吸尘器方案芯片
分享一个经典的5W电子管放大器的电路图
可穿戴设备的“跨界”神器！微型压电气泵：打造高精度的“腕上血压计”
气体泄漏和烟雾探测器的制作教程
亚马逊终推线上药店，正式向连锁药店宣战
内网专线和外网专线有什么区别？
PCI背板的VIO电源实作
一个基于PyTorch的几何深度学习扩展库，为GNN的研究和应用再添利器
锤子科技450万存款被冻结 锤子还能不能挨过年关
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