Over Temperature Protection Ic

White paper intelligent over temperature protection for led lighting applications 01 october 2013 7 4 ic implementation of smart over temperature protection leveraging the key idea of a patent to use the led driver ic as a thermal sensor a patent pending technology has been developed to protect the leds with a slope dimming characteristic and.

Over temperature protection ic.

The secondary protection is composed of the secondary safety ptc tco and nonresettable fuse blocks. Over temperature protection in a power supply is a protection system that shuts down the power supply when the internal temperature exceeded a safe value. Temperature protection devices are used to protect internal circuits or devices from overheating. This will make the exact 7 7 v which is the required cut in voltage in the circuit.

If the power dissipation within the ldo is excessive the internal junction temperature will rise above the typical shutdown threshold of 150 c. The accuracy of a relatively simple temperature detection circuit consisting of an ntc thermistor and fixed resistors is fully sufficient for the protection of an hdd and much more cost efficient than a circuit using a temperature sensor ic. I believe 70 degrees in celsius is good because high power. Over temperature protection otp 6.

Often the primary protection and gas gauge components are combined into a single ic which may include additional protection features not shown above like over under temperature protection and battery authentication. That is why there will be a lot of dissipating heat. Idea super brigth led light will include 100 leds which consume 1 watt per led. Ic data sheets often give some informations about the circuits over temperature protection.

Over operating free air temperature range unless otherwise noted 1 min max unit in pgate with respect to vss 0 3 30. The 1n4007 diode has forward voltage drop of 0 7 v so it will provide the extra 0 7 v drop. I made simple over temperature protection circuit which will shut down leds when a certain temperature is reached. The diagram below shows the replacement of a temperature sensor ic with an ntc thermistor.

The resistance of ptc thermistors rises rapidly when a certain temperature is exceeded thus stopping the flow of current. Usually power supplies have a monitoring integrated circuit on their secondary see figure 1 which is in charge of the power supply protections. This characteristic is self regulating. A circuit is used to monitor and generate a trigger signal that starts the shutdown process at the high temperatures.

For example a zener diode of 7 v can be used in series with a 1n4007 diode. Once the ptc cools down it permits the current to flow again.