Semiconductor relay device

Patent metadata

Field	Value
Publication number	US-2022416787-A1
Application number	US-202217902737-A
Country	US
Kind code	A1
Filing date	Sep 2, 2022
Priority date	Mar 23, 2021
Publication date	Dec 29, 2022
Grant date	—

Abstract

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.

First claim

1 . A semiconductor relay device comprising:
a transmission circuit that outputs a first signal; a conversion circuit configured to output a second signal that is based on the first signal over a period of receiving the first signal; an overheat protection circuit that keeps outputting a control signal having a first magnitude using the second signal over a period of receiving the second signal and having a temperature lower than a first temperature, transitions to a state in which the overheat protection circuit outputs the control signal having a second magnitude using the second signal when the overheat protection circuit has a temperature higher than or equal to the first temperature during a period of receiving the second signal, and keeps outputting the control signal having the second magnitude once the overheat protection circuit has a temperature higher than or equal to the first temperature; and a switch circuit that electrically connects a first terminal and a second terminal over a period of receiving the control signal having the first magnitude, and electrically disconnects the first terminal and the second terminal over a period of receiving the control signal having the second magnitude.

2 . The semiconductor relay device according to claim 1 , wherein:
the overheat protection circuit keeps outputting the control signal having the second magnitude regardless of whether the overheat protection circuit is receiving the second signal once the overheat protection circuit has a temperature higher than or equal to the first temperature.

3 . The semiconductor relay device according to claim 1 , wherein:
the conversion circuit outputs the second signal at a first node, the overheat protection circuit includes:
a zener diode having an anode coupled to a 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, and
the switch circuit includes a first transistor having a gate coupled to the first node.

4 . The semiconductor relay device according to claim 3 , wherein:
the n diodes include a first to an n th diode, an anode of an i th diode is coupled to a cathode of an (i−1) th diode for all cases of i where i is a natural number larger than or equal to 2 and smaller than or equal to n, an anode of the first diode is coupled to the first node, and an anode of the n th diode is coupled to a cathode of the (n−1) th diode, and a cathode of the n th diode is coupled to the third node.

5 . The semiconductor relay device according to claim 4 , wherein:
the conversion circuit outputs the second signal having a first voltage across the first node and a fourth node coupled to the second node via a diode over a period of receiving the first signal, and a breakdown voltage of the zener diode is lower than the first voltage.

6 . The semiconductor relay device according to claim 5 , wherein:
the breakdown voltage is higher than a threshold voltage of the first transistor.

7 . The semiconductor relay device according to claim 6 , wherein:
each of the n diodes has a forward voltage having a first magnitude when the each of the n diodes has a second temperature smaller than the first temperature, and has a forward voltage having a second magnitude smaller than the first magnitude when the diode has a third temperature higher than the first temperature.

8 . The semiconductor relay device according to claim 6 , wherein:
the transmission circuit is a light emitting diode, and the conversion circuit includes a photodiode.

9 . The semiconductor relay device according to claim 7 , wherein:
the n diodes generate, between the second end and the first end, a first forward voltage when the diodes have the second temperature, and a second forward voltage when the diodes have the third temperature, the first forward voltage is higher than the breakdown voltage, and the second forward voltage is lower than the breakdown voltage.

10 . The semiconductor relay device according to claim 3 , wherein:
the switch circuit includes:
a second transistor coupled between the first node and the gate of the first transistor; and
a third transistor coupled between the gate of the first transistor and the second node.

11 . The semiconductor relay device according to claim 1 , wherein:
the switch circuit includes:
a fourth transistor having a third end coupled to the first terminal and a fourth end;
a fifth transistor having a fifth end coupled to the fourth end and a sixth end coupled to the second terminal;
a second zener diode having a cathode coupled to the third end;
a third zener diode having an anode coupled to an anode of the second zener diode and having a cathode coupled to a gate of the fourth transistor;
a fourth zener diode having a cathode coupled to the fourth end;
a fifth zener diode having an anode coupled to an anode of the fourth zener diode and having a cathode coupled to the gate of the fourth transistor;
a sixth zener diode having a cathode coupled to the fifth end;
a seventh zener diode having an anode coupled to an anode of the sixth zener diode and having a cathode coupled to a gate of the fifth transistor;
an eighth zener diode having a cathode coupled to the sixth end; and
a ninth zener diode having an anode coupled to an anode of the eighth zener diode and having a cathode coupled to the gate of the fifth transistor.

12 . 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.

13 . The semiconductor relay device according to claim 12 , 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.

14 . The semiconductor relay device according to claim 12 , 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.

15 . The semiconductor relay device according to claim 12 , 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.

Assignees

• Toshiba Kk
• Toshiba Electronic Devices & Storage Corp

Inventors

• Takai Naoya
• Takifuji Yukihiro
• Saito Keita
• Tanaka Kazuki

Classifications

• H03K2017/0806

  against excessive temperature · CPC title

• H03K17/08 Primary

  Modifications for protecting switching circuit against overcurrent or overvoltage · CPC title

• H02H5/044

  using a semiconductor device to sense the temperature · CPC title

• H02H3/08

  responsive to excess current (responsive to abnormal temperature caused by excess current H02H5/04) · CPC title

• H03K17/08108 Primary

  in thyristor switches (H03K17/0812, H03K17/0814 take precedence) · CPC title