Semiconductor relay device

Patent metadata

Field	Value
Publication number	US-2022311436-A1
Application number	US-202117473889-A
Country	US
Kind code	A1
Filing date	Sep 13, 2021
Priority date	Mar 23, 2021
Publication date	Sep 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 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 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; 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 a transistor having a gate coupled to the first node.

2 . The semiconductor relay device according to claim 1 , 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−1, 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.

3 . The semiconductor relay device according to claim 2 , wherein
the conversion circuit outputs 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 input signal, and a breakdown voltage of the zener diode is lower than the first voltage.

4 . The semiconductor relay device according to claim 3 , wherein
the breakdown voltage is higher than a threshold voltage of the transistor.

5 . The semiconductor relay device according to claim 4 , wherein
each of the n diodes has a forward voltage having a first magnitude when the diode has a first temperature, and has a forward voltage having a second magnitude smaller than the first magnitude when the diode has a second temperature higher than the first temperature.

6 . The semiconductor relay device according to claim 5 , further comprising:
a transmission circuit configured to output the input signal.

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

8 . The semiconductor relay device according to claim 4 , wherein
the n diodes generate, between the second end and the first end, a first forward voltage when the diodes have a first temperature, and a second forward voltage when the diodes have a second temperature higher than the first temperature, the first forward voltage is higher than the breakdown voltage, and the second forward voltage is lower than the breakdown voltage.

9 . The semiconductor relay device according to claim 3 , wherein
each of the n diodes has a forward voltage having a first magnitude when the diode has a first temperature, and has a forward voltage having a second magnitude smaller than the first magnitude when the diode has a second temperature higher than the first temperature.

10 . The semiconductor relay device according to claim 3 , wherein
the n diodes generate, between the second end and the first end, a first forward voltage when the diodes have a first temperature, and a second forward voltage when the diodes have a second temperature higher than the first temperature, the first forward voltage is higher than the breakdown voltage, and the second forward voltage is lower than the breakdown voltage.

11 . The semiconductor relay device according to claim 2 , wherein
each of the n diodes has a forward voltage having a first magnitude when the diode has a first temperature, and has a forward voltage having a second magnitude smaller than the first magnitude when the diode has a second temperature higher than the first temperature.

12 . The semiconductor relay device according to claim 1 , wherein
the conversion circuit outputs 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 input signal, and a breakdown voltage of the zener diode is lower than the first voltage.

13 . The semiconductor relay device according to claim 12 , wherein
the breakdown voltage is higher than a threshold voltage of the transistor.

14 . The semiconductor relay device according to claim 13 , wherein
each of the n diodes has a forward voltage having a first magnitude when the diode has a first temperature, and has a forward voltage having a second magnitude smaller than the first magnitude when the diode has a second temperature higher than the first temperature.

15 . The semiconductor relay device according to claim 14 , further comprising:
a transmission circuit configured to output the input signal.

16 . The semiconductor relay device according to claim 15 , wherein
the transmission circuit is a light emitting diode, and the conversion circuit includes a photodiode.

17 . The semiconductor relay device according to claim 13 , wherein
the n diodes generate, between the second end and the first end, a first forward voltage when the diodes have a first temperature, and a second forward voltage when the diodes have a second temperature higher than the first temperature, the first forward voltage is higher than the breakdown voltage, and the second forward voltage is lower than the breakdown voltage.

18 . The semiconductor relay device according to claim 12 , wherein
each of the n diodes has a forward voltage having a first magnitude when the diode has a first temperature, and has a forward voltage having a second magnitude smaller than the first magnitude when the diode has a second temperature higher than the first temperature.

19 . The semiconductor relay device according to claim 12 , wherein
the n diodes generate, between the second end and the first end, a first forward voltage when the diodes have a first temperature, and a second forward voltage when the diodes have a second temperature higher than the first temperature, the first forward voltage is higher than the breakdown voltage, and the second forward voltage is lower than the breakdown voltage.

20 . The semiconductor relay device according to claim 1 , wherein
each of the n diodes has a forward voltage having a first magnitude when the diode has a first temperature, and has a forward voltage having a second magnitude smaller than the first magnitude when the diode has a second temperature higher than the first temperature.

Assignees

• Toshiba Kk
• Toshiba Electronic Devices & Storage Corp

Inventors

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

Classifications

• H02H5/044

  using a semiconductor device to sense the temperature · CPC title

• H03K17/08 Primary

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

• H02H3/08

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

• H03K2017/0806

  against excessive temperature · CPC title

• H03K2017/515

  Mechanical switches; Electronic switches controlling mechanical switches, e.g. relais · CPC title