Physical quantity detection circuit, physical quantity detection device, electronic apparatus, and vehicle

Patent metadata

Field	Value
Publication number	US-10116275-B2
Application number	US-201715646376-A
Country	US
Kind code	B2
Filing date	Jul 11, 2017
Priority date	Jul 15, 2016
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

A physical quantity detection device includes a switched capacitor filter circuit having a first sample-and-hold circuit adapted to sample and hold a first signal, which is based on an output signal of a physical quantity detection element, an amplifier circuit to which an output signal of the first sample-and-hold circuit is input, and a first switched capacitor circuit to which a first output signal of the amplifier circuit is input, wherein an output signal of the first switched capacitor circuit is input to the amplifier circuit, and an A/D conversion circuit adapted to perform an A/D conversion on an output signal of the switched capacitor filter circuit.

First claim

What is claimed is:

1. A physical quantity detection circuit comprising:
a switched capacitor filter circuit having a first sample-and-hold circuit adapted to sample and hold a first signal, which is based on an output signal of a physical quantity detection element, an amplifier circuit to which an output signal of the first sample-and-hold circuit is input, and a first switched capacitor circuit to which a first output signal of the amplifier circuit is input, wherein an output signal of the first switched capacitor circuit is input to the amplifier circuit; and
an A/D conversion circuit adapted to perform an A/D conversion on an output signal of the switched capacitor filter circuit,
wherein the A/D conversion circuit performs the A/D conversion on a plurality of signals including an output signal of the switched capacitor filter circuit in a time-sharing manner.

2. The physical quantity detection circuit according to claim 1 , wherein
the amplifier circuit includes:
a first chopping circuit to which an output signal of the first sample-and-hold circuit is input,
an operational amplifier to which an output signal of the first chopping circuit is input, and
a second chopping circuit to which an output signal of the operational amplifier is input.

3. The physical quantity detection circuit according to claim 2 , wherein
chopping frequencies in the first chopping circuit and the second chopping circuit are equal to or lower than a half of a sampling frequency with which the A/D conversion circuit samples an output signal of the switched capacitor filter circuit.

4. The physical quantity detection circuit according to claim 2 , further comprising:
a drive circuit adapted to generate a drive signal for driving the physical quantity detection element based on a first clock signal,
wherein the switched capacitor filter circuit has a frequency divider circuit adapted to divide a frequency of the first clock signal to generate a second clock signal, and
the first chopping circuit and the second chopping circuit operate based on the second clock signal.

5. The physical quantity detection circuit according to claim 1 , wherein
the switched capacitor filter circuit includes
a second sample-and-hold circuit adapted to sample and hold a second signal, which is based on the output signal of the physical quantity detection element, and
a second switched capacitor circuit to which a second output signal of the amplifier circuit is input,

an output signal of the first sample-and-hold circuit and an output signal of the second sample-and-hold circuit are input to the amplifier circuit, and
the amplifier circuit operates on the first signal and the second signal in a differential manner.

6. A physical quantity detection device comprising:
the physical quantity detection circuit according to claim 1 ; and
a physical quantity detection element.

7. A physical quantity detection device comprising:
the physical quantity detection circuit according to claim 2 ; and
a physical quantity detection element.

8. A physical quantity detection device comprising:
the physical quantity detection circuit according to claim 3 ; and
a physical quantity detection element.

9. A physical quantity detection device comprising:
the physical quantity detection circuit according to claim 4 ; and
a physical quantity detection element.

10. An electronic apparatus comprising:
the physical quantity detection device according to claim 6 .

11. An electronic apparatus comprising:
the physical quantity detection device according to claim 7 .

12. An electronic apparatus comprising:
the physical quantity detection device according to claim 8 .

13. An electronic apparatus comprising:
the physical quantity detection device according to claim 9 .

14. A vehicle comprising:
the physical quantity detection device according to claim 6 .

15. A vehicle comprising:
the physical quantity detection device according to claim 7 .

16. A vehicle comprising:
the physical quantity detection device according to claim 8 .

17. A vehicle comprising:
the physical quantity detection device according to claim 9 .

Assignees

• Seiko Epson Corp

Inventors

• Murashima Noriyuki

Classifications

• H03G3/20

  Automatic control ({H03G3/005 takes precedence;} combined with volume compression or expansion H03G7/00) · CPC title

• G01D5/2417

  by varying separation · CPC title

• G01D21/00

  Measuring or testing not otherwise provided for · CPC title

• H03G1/0094

  using switched capacitors · CPC title

• H03F3/387 Primary

  with semiconductor devices only · CPC title