Opto-Isolator Multi-Voltage Detection Circuit

An opto-isolator multi-voltage detection circuit comprising:

• a voltage input, the voltage input arranged for connection to the voltage source;
• an opto-isolator having a light-emitting diode (LED), the opto-isolator configured to detect the presence of an input voltage applied to the voltage input from the voltage source;
• a rectifier, the rectifier arranged for connection to the voltage input;
• and
• a first transistor and a second transistor operatively coupled in series, each transistor having a gate, a source, and a drain, the source of the first transistor operatively coupled to the drain of the second transistor, and the drain of the first transistor operatively coupled to the rectifier;
• wherein a current output from the rectifier biases the LED, and wherein the first and second transistors are configured to dissipate a first power level across the first and second transistors, the first power level different than a second power level dissipated across the circuit.

An opto-isolator multi-voltage detection circuit comprising:

• a voltage input, the voltage input arranged for connection to the voltage source;
• an opto-isolator having a light-emitting diode (LED), the opto-isolator configured to detect the presence of an input voltage applied to the voltage input from the voltage source;
• a diode, a resistor, and a capacitor connected in series and cooperating to define a rectifier, the rectifier connected to the voltage input;
• a first transistor and a second transistor operatively coupled in series, each transistor having a gate, a source, and a drain, the source of the first transistor connected to the drain of the second transistor, and the drain of the first transistor connected to the rectifier;
• a voltage divider connected to the gates of the first and second transistors, the voltage divider configured to divide the input voltage across the first and second transistors;
• and
• a DC to DC converter connected to the source of the second transistor and the opto-isolator;
• wherein a current output from the DC to DC converter biases the LED, and wherein the first and second transistors are configured to dissipate a first power level across the first and second transistors, the first power level different than a second power level dissipated across the circuit.

A method for handling a variety of input voltages from a voltage source comprising:

• operatively coupling an opto-isolator to a voltage input to detect the presence of the input voltage applied to the voltage input from the voltage source;
• forward biasing a light-emitting diode (LED) of the opto-isolator when a current from a diode operatively to the voltage input is detected;
• and
• operatively coupling a first transistor to the diode and the opto-isolator;
• wherein maintaining any power dissipated through the first transistor at or below an acceptable level.