Photovoltaic solid state relay

摘要

A photovoltaic solid state relay has a light-emitting diode for emitting light in response to an electrical control signal. First and second photovoltaic devices are optically coupled to the light-emitting diode for converting the light to first and second voltages, respectively. First and second unipolar transistors are provided having first and second gate electrodes for respectively receiving the first and second voltages and jointly establishing a first current conducting path between output terminals to which a load circuit will be connected. A bipolar transistor is provided having a base connected to a junction between the first and second unipolar transistors for establishing a second current conducting path in parallel to the first current conducting path in one of opposite directions depending on voltages applied to the output terminals.