Voltage variation detection circuit, semiconductor integrated circuit, and vehicle

Patent metadata

Field	Value
Publication number	US-10830798-B2
Application number	US-201715834241-A
Country	US
Kind code	B2
Filing date	Dec 7, 2017
Priority date	Dec 9, 2016
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

The voltage variation detection circuit includes: a threshold voltage generation circuit arranged to generate a threshold voltage; a comparator arranged to compare a variation detection-target voltage and the threshold voltage to each other; and a controller arranged to control the threshold voltage generation circuit based on output of the comparator. Repeated are operations of: decreasing the threshold voltage stepwise; when the variation detection-target voltage has come to the threshold voltage or more, first increasing the threshold voltage by specified steps and then again decreasing the threshold voltage stepwise; and when the variation detection-target voltage has come to the threshold voltage or more, increasing the threshold voltage by specified steps. The controller detects a variation of the variation detection-target voltage based on control results at time points when the variation detection-target voltage comes to the threshold voltage or more.

First claim

What is claimed is:

1. A voltage variation detection circuit comprising:
a threshold voltage generation circuit arranged to generate a threshold voltage;
a comparator arranged to compare a variation detection-target voltage and the threshold voltage to each other; and
a controller arranged to control the threshold voltage generation circuit based on output of the comparator,
wherein the controller controls the threshold voltage generation circuit in such fashion that the threshold voltage generation circuit repeats operations of: decreasing the threshold voltage stepwise; when the variation detection-target voltage has come to the threshold voltage or more, first increasing the threshold voltage by specified steps to increase the threshold voltage by a fixed value and then again decreasing the threshold voltage stepwise; and when the variation detection-target voltage has come to the threshold voltage or more, increasing the threshold voltage by specified steps to increase the threshold voltage by a fixed value, and
wherein the controller detects a variation of the variation detection-target voltage based on control results at time points when the variation detection-target voltage comes to the threshold voltage or more.

2. The voltage variation detection circuit according to claim 1 , wherein
when the variation detection-target voltage does not come to the threshold voltage or more even by decreasing the threshold voltage stepwise until the threshold voltage reaches a specified decrement or specified value, the threshold voltage generation circuit sets the threshold voltage to a maximum before again decreasing the threshold voltage stepwise.

3. The voltage variation detection circuit according to claim 1 , wherein
the controller
detects that the variation detection-target voltage has become an overvoltage on condition that the variation detection-target voltage is equal to or more than the threshold voltage when the threshold voltage is at a maximum.

4. The voltage variation detection circuit according to claim 1 , wherein
the controller detects at least one of an oscillation of the variation detection-target voltage, a spike of the variation detection-target voltage, and a drift of the variation detection-target voltage.

5. A semiconductor integrated circuit comprising:
the voltage variation detection circuit according to claim 1 ; and
at least part of a voltage generation circuit arranged to generate the variation detection-target voltage.

6. A vehicle comprising:
the semiconductor integrated circuit according to claim 5 .

7. A voltage variation detection circuit comprising:
a threshold voltage generation circuit arranged to generate a threshold voltage;
a comparator arranged to compare a variation detection-target voltage and the threshold voltage to each other; and
a controller arranged to control the threshold voltage generation circuit based on output of the comparator,
wherein the controller controls the threshold voltage generation circuit in such fashion that the threshold voltage generation circuit repeats operations of: increasing the threshold voltage stepwise; when the variation detection-target voltage has come to the threshold voltage or less, first decreasing the threshold voltage by specified steps to decrease the threshold voltage by a fixed value and then again increasing the threshold voltage stepwise; and when the variation detection-target voltage has come to the threshold voltage or less, decreasing the threshold voltage by specified steps to decrease the threshold voltage by a fixed value, and
wherein the controller detects a variation of the variation detection-target voltage based on control results at time points when the variation detection-target voltage comes to the threshold voltage or less.

8. The voltage variation detection circuit according to claim 7 , wherein
when the variation detection-target voltage does not come to the threshold voltage or less even by increasing the threshold voltage stepwise until the threshold voltage reaches a specified increment or specified value, the threshold voltage generation circuit sets the threshold voltage to a minimum before again increasing the threshold voltage stepwise.

9. The voltage variation detection circuit according to claim 7 , wherein
the controller
detects that the variation detection-target voltage has become a low voltage on condition that the variation detection-target voltage is equal to or less than the threshold voltage when the threshold voltage is at a minimum.

10. The voltage variation detection circuit according to claim 7 , wherein
the controller detects at least one of an oscillation of the variation detection-target voltage, a spike of the variation detection-target voltage, and a drift of the variation detection-target voltage.

11. A semiconductor integrated circuit comprising:
the voltage variation detection circuit according to claim 7 ; and
at least part of a voltage generation circuit arranged to generate the variation detection-target voltage.

12. A vehicle comprising:
the semiconductor integrated circuit according to claim 11 .

13. A voltage variation detection circuit comprising:
a threshold voltage generation circuit arranged to generate a first threshold voltage and a second threshold voltage lower than the first threshold voltage;
a first comparator arranged to compare a variation detection-target voltage and the first threshold voltage to each other;
a second comparator arranged to compare the variation detection-target voltage and the second threshold voltage to each other; and
a controller arranged to control the threshold voltage generation circuit based on output of the first comparator and output of the second comparator,
wherein the controller controls the threshold voltage generation circuit in such fashion that the threshold voltage generation circuit repeats operations of: decreasing the first threshold voltage stepwise and increasing the second threshold voltage stepwise; when the variation detection-target voltage has come to the first threshold voltage or more or to the second threshold voltage or less, first increasing the first threshold voltage by specified steps to increase the first threshold voltage by a first fixed value and decreasing the second threshold voltage by specified steps to decrease the second threshold voltage by a second fixed value and then again decreasing the first threshold voltage stepwise and increasing the second threshold voltage stepwise; and when the variation detection-target voltage has come to the first threshold voltage or more or to the second threshold voltage or less, increasing the first threshold voltage by specified steps to increase the first threshold voltage by the first fixed value and decreasing the second threshold voltage by specified steps to decrease the second threshold voltage by the second fixed value, and
wherein the controller detects a variation of the variation detection-target voltage based on control results at time points when the variation detection-target voltage comes to the first threshold voltage or more or to the second threshold voltage or less.

14. The voltage variation detection circuit according to claim 13 , wherein
the threshold voltage generation circuit includes:
a first fixed resistor;
a variable resistor whose resistance value is variable stepwise; and
a second fixed resistor,
wherein a reference voltage is applied to a first terminal of the first fixed resistor,
a first terminal of the variable resistor is connected to a second terminal of the first fixed resistor,
a first terminal of the

Assignees

• Rohm Co Ltd

Inventors

• Nakashima Takayuki

Classifications

• H03K5/02 Primary

  by amplifying (H03K5/04 takes precedence) · CPC title

• G01R19/257

  using analogue/digital converters of the type with comparison of different reference values with the value of voltage or current, e.g. using step-by-step method · CPC title

• H03M1/48

  Servo-type converters · CPC title

• H03K5/24

  the characteristic being amplitude · CPC title

• G01R19/16595 Primary

  with multi level indication (G01R19/16519 and G01R19/16533 take precedence) · CPC title