Over Temperature Protection Circuit

The diagram below shows a microcontroller temperature protection circuit that employs a voltage dividing circuit consisting of a combination of ntc thermistor and fixed resistors r s.

Over temperature protection circuit.

I made simple over temperature protection circuit which will shut down leds when a certain temperature is reached. Frequently the monitoring circuit is built on a small printed circuit board that is attached to the main printed circuit board from the power supply. The 1n4007 diode has forward voltage drop of 0 7 v so it will provide the extra 0 7 v drop. Once the ptc cools down it permits the current to flow again.

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. When an overcurrent flows the temperature of the ntc thermistor rises and its resistance decreases thus suppressing the drive voltage of the microcontroller. This characteristic is self regulating. Simplified block diagram of the smart over temperature protection circuit it is important to note that the v drive signal is compared with an internal sawtooth signal to generate an internal pwm signal for the dimming.

That is why there will be a lot of dissipating heat. Temperature protection devices are used to protect internal circuits or devices from overheating. 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.

The same method is used in the design of this battery over charging protection circuit. The resistance of ptc thermistors rises rapidly when a certain temperature is exceeded thus stopping the flow of current. The transistor must be attached physically closest to the heat source ideally it should be attached to the heatsink of the power transistors. This will make the exact 7 7 v which is the required cut in voltage in the circuit.

A wide variety of over temperature protection circuit options are available to you such as power tools. The temperature monitor circuit works by comparing the voltage drop of a cold diode t1 with the base emitter voltage of a warm transistor t2. Over temperature protection otp 6. When the over temperature protection otp is present we usually find a thermistor attached to the secondary heat sink the fan control unit usually uses a thermistor in the same heat sink.