Power supply circuit having protection circuit against electrostatic discharge stress and semiconductor device having the power supply circuit

Patent metadata

Field	Value
Publication number	US-12444922-B2
Application number	US-202217896647-A
Country	US
Kind code	B2
Filing date	Aug 26, 2022
Priority date	Nov 11, 2021
Publication date	Oct 14, 2025
Grant date	Oct 14, 2025

Abstract

According to the present embodiment, a power supply circuit includes a first transistor, a feedback voltage generation circuit, a first voltage generation circuit, and a protection circuit. The first transistor is connected between an input terminal and an output terminal. The feedback voltage generation circuit divides the output voltage to generate a feedback voltage. The first voltage generation circuit supplies a voltage to a first control terminal of the first transistor via a first node based on the feedback voltage and a reference voltage. The protection circuit outputs a voltage that makes the first transistor non-conducting or places the first transistor in a state where the first transistor has a predetermined high resistance value to the first control terminal, when the input voltage increases above a first threshold voltage within a predetermined time.

First claim

The invention claimed is:

1. A power supply circuit comprising:
a first transistor connected between an input terminal and an output terminal;
a feedback voltage generation circuit configured to divide an output voltage to generate a feedback voltage;
a first voltage generation circuit configured to supply a voltage to a first control terminal of the first transistor via a first node based on the feedback voltage and a reference voltage; and
a protection circuit configured to, when an input voltage increases above a first threshold voltage within a predetermined time, output a voltage that makes the first transistor non-conducting or places the first transistor in a state where the first transistor has a predetermined resistance value, to the first control terminal,
wherein the protection circuit includes
a second transistor connected between the input terminal and the first node, and
a second voltage generation circuit configured to supply a voltage to a second control terminal of the second transistor in accordance with time change of the input voltage, and
wherein the second voltage generation circuit includes
a first capacitor connected between the input terminal and a second node,
a first resistor connected between the second node and a ground terminal,
a third transistor with a third control terminal connected to the second node, connected between the ground terminal and a third node, and
a second resistor connected between the input terminal and the third node, and wherein
the third node is connected to the second control terminal of the second transistor.

2. The circuit of claim 1 , further comprising a fourth transistor in which a gate and a source are connected to the ground terminal and a drain is connected to the input terminal, wherein
the first threshold voltage is set to be lower than a snapback voltage of the fourth transistor, and
the protection circuit outputs the voltage that makes the first transistor non-conducting or places the first transistor in a state where the first transistor has the predetermined resistance value, to the first control terminal, when a potential at the second node reaches a first potential corresponding to the first threshold voltage.

3. The circuit of claim 1 , wherein the second voltage generation circuit further includes a fifth transistor with a fifth control terminal connected to the second node, connected between the ground terminal and the output terminal.

4. The circuit of claim 3 , wherein the first transistor, the second transistor, the third transistor, and the fifth transistor are configured as an integrated circuit, the integrated circuit includes a first element group and a second element group arranged to be closer to an end of the integrated circuit than the first element group, the first transistor is an element of the first element group, and at least either the third transistor or the fifth transistor is an element of the second element group.

5. The circuit of claim 1 , wherein, when the input voltage increases above the first threshold voltage within the predetermined time, a voltage that makes the third transistor conducting or places the third transistor in a state where the third transistor has a predetermined resistance value is applied to the third control terminal in accordance with transition characteristics provided by a combination of the first capacitor and the first resistor.

6. A semiconductor device that modulates a logic signal input to a signal input terminal and outputs a demodulated logic signal from a signal output terminal, comprising a power supply circuit configured to supply an output voltage used for driving the semiconductor device, wherein the power supply circuit includes
a first transistor connected between an input terminal and an output terminal,
a feedback voltage generation circuit configured to divide the output voltage to generate a feedback voltage,
a first voltage generation circuit configured to supply a voltage to a first control terminal of the first transistor via a first node based on the feedback voltage and a reference voltage, and
a protection circuit configured to, when an input voltage increases above a first threshold voltage within a predetermined time, output a voltage that makes the first transistor non-conducting or places the first transistor in a state where the first transistor has a predetermined resistance value, to the first control terminal,
wherein the protection circuit includes
a second transistor connected between the input terminal and the first node, and
a second voltage generation circuit configured to supply a voltage to a second control terminal of the second transistor in accordance with time change of the input voltage, and
wherein the second voltage generation circuit includes
a first capacitor connected between the input terminal and a second node,
a first resistor connected between the second node and a ground terminal,
a third transistor with a third control terminal connected to the second node, connected between the ground terminal and a third node, and
a second resistor connected between the input terminal and the third node, and wherein
the third node is connected to the second control terminal of the second transistor.

7. A power supply circuit supplying an output voltage between a first terminal and a second terminal, comprising:
a first transistor connected between a third terminal inputting an input voltage and the first terminal outputting the output voltage;
an electrostatic protection circuit connected between the third terminal and the second terminal, and configured to electrically conduct between the third terminal and the second terminal when a voltage between the third terminal and the second terminal exceeds a predetermined voltage; and
a protection circuit configured to output a voltage that makes the first transistor non-conducting or places the first transistor in a state where the first transistor has a predetermined resistance value to a first control terminal of the first transistor via a first node, when the input voltage increases above a first threshold voltage within a predetermined time,
wherein the first threshold voltage is set to be lower than the predetermined voltage,
wherein the protection circuit includes
a second transistor connected between the third terminal and the first node, and
a second voltage generation circuit configured to supply a voltage to a second control terminal of the second transistor in accordance with time change of the input voltage, and
wherein the second voltage generation circuit includes
a first capacitor connected between the third terminal and a second node,
a first resistor connected between the second node and the second terminal,
a third transistor with a third control terminal connected to the second node, connected between the second terminal and a third node, and
a second resistor connected between the third terminal and the third node, and wherein
the third node is connected to the second control terminal of the second transistor.

8. The circuit of claim 7 , wherein the second voltage generation circuit further includes a fifth transistor with a fifth control terminal connected to the second node, connected between the first terminal and the second terminal.

9. The circuit of claim 7 , wherein a voltage that makes the third transistor conducting or places the third transistor in a state where the third transistor has a predetermined resistance value is applied to the third control terminal in accordance with transition characteristics provided by a combination of the first capacitor and the first resistor, when the input voltage increases above the first threshold voltage within a pr

Assignees

• Toshiba Kk
• Toshiba Electronic Devices & Storage Corp

Inventors

• Maruyama Tatsuhiko
• Uo Toyoaki

Classifications

• H02H3/22 Primary

  of short duration, e.g. lightning · CPC title

• H02H9/046 Primary

  responsive to excess voltage appearing at terminals of integrated circuits · CPC title

• G05F1/625 Primary

  wherein it is irrelevant whether the variable actually regulated is AC or DC · CPC title