On-state voltage measurement circuit

Patent metadata

Field	Value
Publication number	US-12451880-B2
Application number	US-202218546741-A
Country	US
Kind code	B2
Filing date	Feb 22, 2022
Priority date	Feb 25, 2021
Publication date	Oct 21, 2025
Grant date	Oct 21, 2025

Abstract

An on-state voltage measurement circuit includes a detecting switch element, a control unit, a resistive element, and a voltage detection unit. The control unit includes a signal output terminal and a reference potential terminal and controls the detecting switch element. The resistive element is connected between a source terminal of the detecting switch element and the reference potential terminal. A resistance value of the resistive element is greater than an on-state resistance of the detecting switch element. The control unit turns the detecting switch element on when the semiconductor switch element is turned on. The voltage detection unit detects, based on a voltage across the resistive element when the semiconductor switch element and the detecting switch element are both on, the on-state voltage of the semiconductor switch element connected between a drain terminal of the detecting switch element and the reference potential terminal.

First claim

The invention claimed is:

1. An on-state voltage measurement circuit configured to measure an on-state voltage of a semiconductor switch element, the semiconductor switch element including a first control terminal, a first main terminal corresponding to the first control terminal, a second control terminal, and a second main terminal corresponding to the second control terminal, the on-state voltage being a voltage between the first main terminal and the second main terminal of the semiconductor switch element in an on state, the on-state voltage measurement circuit comprising:
a first detecting switch element including a first drain terminal, a first source terminal, and a first gate terminal;
a first control unit including a first signal output terminal and a first reference potential terminal and configured to control the first detecting switch element;
a first resistive element connected between the first source terminal and the first reference potential terminal;
a first voltage detection unit;
a second detecting switch element including a second drain terminal, a second source terminal, and a second gate terminal;
a second control unit including a second signal output terminal and a second reference potential terminal and configured to control the second detecting switch element;
a second resistive element connected between the second source terminal and the second reference potential terminal; and
a second voltage detection unit,
the first drain terminal of the first detecting switch element and the second drain terminal of the second detecting switch element being connected to each other,
a resistance value of the first resistive element being greater than an on-state resistance of the first detecting switch element,
a resistance value of the second resistive element being greater than an on-state resistance of the second detecting switch element,
the first voltage detection unit being configured to detect, based on a voltage across the first resistive element when the semiconductor switch element and the first detecting switch element are both on, the on-state voltage of the semiconductor switch element connected between the first reference potential terminal and the second reference potential terminal, and
the second voltage detection unit being configured to detect, based on a voltage across the second resistive element when the semiconductor switch element and the second detecting switch element are both on, the on-state voltage of the semiconductor switch element connected between the first reference potential terminal and the second reference potential terminal.

2. The on-state voltage measurement circuit of claim 1 , further comprising:
a first diode connected to the first resistive element in parallel; and
a second diode connected to the second resistive element in parallel, wherein
the first diode includes a first anode and a first cathode, the first anode is connected to the first reference potential terminal, and the first cathode is connected to the first source terminal of the first detecting switch element,
the second diode includes a second anode and a second cathode, the second anode is connected to the second reference potential terminal, and the second cathode is connected to the second source terminal of the second detecting switch element.

3. The on-state voltage measurement circuit of claim 1 , further comprising:
a first capacitor connected to the first resistive element in parallel; and
a second capacitor connected to the second resistive element in parallel.

4. The on-state voltage measurement circuit of claim 1 , wherein
the first control unit is a first constant voltage source, and
the second control unit is a second constant voltage source.

5. An on-state voltage measurement circuit configured to measure an on-state voltage of a semiconductor switch element, the semiconductor switch element including a first control terminal, a first main terminal corresponding to the first control terminal, a second control terminal, and a second main terminal corresponding to the second control terminal, the on-state voltage being a voltage between the first main terminal and the second main terminal of the semiconductor switch element in an on state, the on-state voltage measurement circuit comprising:
a first detecting switch element including a first drain terminal, a first source terminal, and a first gate terminal;
a first control unit including a first signal output terminal and a first reference potential terminal and configured to control the first detecting switch element;
a second detecting switch element including a second drain terminal, a second source terminal, and a second gate terminal;
a second control unit including a second signal output terminal and a second reference potential terminal and configured to control the second detecting switch element;
a resistive element connected between the first source terminal of the first detecting switch element and the second source terminal of the second detecting switch element; and
a voltage detection unit,
the first signal output terminal of the first control unit being connected to the first gate terminal of the first detecting switch element,
the first reference potential terminal of the first control unit being connected to the second source terminal of the second detecting switch element,
the second signal output terminal of the second control unit being connected to the second gate terminal of the second detecting switch element,
the second reference potential terminal of the second control unit being connected to the first source terminal of the first detecting switch element,
a resistance value of the resistive element being greater than any one of an on-state resistance of the first detecting switch element or an on-state resistance of the second detecting switch element, and
the voltage detection unit being configured to detect, based on a voltage across the resistive element when the semiconductor switch element is on, the on-state voltage of the semiconductor switch element connected between the first reference potential terminal and the second reference potential terminal.

6. The on-state voltage measurement circuit of claim 5 , wherein
the first control unit is a first constant voltage source, and
the second control unit is a second constant voltage source.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Maeda Ryosuke
• Kinoshita Yusuke
• Nakazawa Satoshi

Classifications

• H03K17/08

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

• H03K17/0822 Primary

  in field-effect transistor switches · CPC title

• H03K17/08122 Primary

  in field-effect transistor switches · CPC title