Over Temperature Protection Circuit

The resistance of ptc thermistors rises rapidly when a certain temperature is exceeded thus stopping the flow of current.

Over temperature protection circuit.

This characteristic is self regulating. That is why there will be a lot of dissipating heat. 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. When an overcurrent flows the temperature of the ntc thermistor rises and its resistance decreases thus suppressing the drive voltage of the microcontroller.

The transistor must be attached physically closest to the heat source ideally it should be attached to the heatsink of the power transistors. I believe 70 degrees in celsius is good because high power. I made simple over temperature protection circuit which will shut down leds when a certain temperature is reached. 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.

Idea super brigth led light will include 100 leds which consume 1 watt per led. 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. The 1n4007 diode has forward voltage drop of 0 7 v so it will provide the extra 0 7 v drop.

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. A wide variety of over temperature protection circuit options are available to you such as power tools. This will make the exact 7 7 v which is the required cut in voltage in the circuit. 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.

The same method is used in the design of this battery over charging protection circuit. For example a zener diode of 7 v can be used in series with a 1n4007 diode. Over temperature protection otp 6. 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.