Over-Voltage Automatic Switch off Circuit

Over-voltage Protection circuit using TL431 Shunt Regulator IC

This circuit protects from high voltage. Automatic Equipment disconnect when the power cross the level of a fixed voltage. This is a safety device to overvoltage.

As per datasheet –  TL431A is the three-terminal programmable integrated circuit. This is a shunt regulator diode. Look like a transistor. This monolithic IC voltage references operate as a low-temperature coefficient zener which is programmable from Vref to 36 V with two external resistors. This device exhibit a wide operating current range of 1.0 mA to 100 mA with a typical dynamic impedance of 0.22 W. The characteristics references make it excellent replacements for zener diodes in many applications such as digital voltmeters, power supplies, and op-amp circuitry. The 2.5 V reference makes it convenient to obtain a stable reference from 5.0 V logic supplies, and since the TL431, A, B operates as a shunt regulator, it can be used as either a positive or negative voltage reference. Active output circuitry provides a very sharp turn-on.
• Typical Temperature Drift (TL431B) characteristic,

  • Programmable Output Voltage to 36 V
  • Voltage Reference Tolerance: +/- 0.4%, Typ @ 25°C (TL431B)
  • Low Dynamic Output Impedance, 0.22 W Typical
  • Sink Current Capability of 1.0 mA to 100 mA
  • Equivalent Full-Range Temperature Coefficient of 50 ppm/ °C Typical
  • Temperature Compensated for Operation over Full Rated Operating Temperature Range
  • Low Output Noise Voltage
  • Pb-Free Packages are Available

This is the circuit of over-voltage automatic cut off switch


overvoltage protection circuit diagram

TL431A pin