Semiconductor relay device
A semiconductor relay device includes a conversion circuit configured to receive an input signal from outside and pass a first current to a first node based on the input signal. A zener diode has an anode coupled to a second node and a cathode coupled to the first node. A resistor is coupled between the second node and a third node. A number n of diodes are serially coupled. A thyristor has an anode coupled to the first node, a cathode coupled to the second node, and a control terminal coupled to the third node. A transistor has a gate coupled to the first node. An anode of a diode at a first end of the n diodes is coupled to the first node, and a cathode of a diode at a second end of the n diodes is coupled to a third node.
1 . A semiconductor relay device comprising:
a conversion circuit configured to receive an input signal from outside, and pass a first current to a first node based on the input signal;
an overheat protection circuit provided between the first node and a second node and configured to short the first node to the second node while a temperature in the semiconductor relay device is higher than a predetermined temperature; and
a transistor having a gate coupled to the first node, wherein
the overheat protection circuit includes:
a zener diode having an anode coupled to the second node and a cathode coupled to the first node;
a resistor coupled between the second node and a third node;
a number n of diodes that are serially coupled, wherein an anode of a diode at a first end of the n diodes is coupled to the first node, and a cathode of a diode at a second end of the n diodes is coupled to the third node, where n is a natural number larger than or equal to 2; and
a thyristor having an anode coupled to the first node, a cathode coupled to the second node, and a control terminal coupled to the third node.
2 . The semiconductor relay device according to claim 1 , further comprising a transmission circuit configured to output the input signal, wherein:
the transmission circuit is a light emitting diode, and
the conversion circuit includes a photodiode.
3 . The semiconductor relay device according to claim 1 , further comprising a transmission circuit configured to output the input signal, wherein:
the input signal is a magnetic signal generated from a coil included in the transmission circuit, and
the conversion circuit includes a coil detecting the input signal.
4 . The semiconductor relay device according to claim 1 , further comprising a transmission circuit configured to output the input signal, wherein:
the transmission circuit connected to the conversion circuit via a capacitor, and
the input signal is an electric signal generated from the transmission circuit and transmitted to the conversion circuit via the capacitor.