# US 10,864,720 B2 · Drive circuit and liquid ejecting apparatus

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- Number: US 10,864,720 B2
- Document ID: US10864720B2
- Status: Granted
- Kind: B2
- Application number: 16/751,252
- Filed: 2020-01-24
- Published: 2020-07-30
- Granted: 2020-12-15
- Earliest claimed: 2019-01-25
- Assignees: Seiko Epson Corporation
- Applicants: Seiko Epson Corporation
- Inventors: Hidehiko Yajima; Tetsuo Takagi
- Web page: https://patentgrep.com/patent/US10864720B2

## CPC

- B41J 2/04541: {Specific driving circuit}
- B41J 2/0451: {for detecting failure, e.g. clogging, malfunctioning actuator}
- B41J 2/0452: {reducing demand in current or voltage}
- B41J 2/04581: {controlling heads based on piezoelectric elements}
- B41J 2/04588: {using a specific waveform}
- B41J 2/04593: {Dot-size modulation by changing the size of the drop}
- G01R 31/31715: {Testing of input or output circuits; test of circuitry between the I/C pins and the functional core, e.g. testing of input or output driver, receiver, buffer}
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

There is a provided a drive circuit in which a first drive signal output circuit includes a first control circuit that controls an output of a first drive signal, and a first abnormality detection circuit that detects an abnormality in a first drive signal output circuit, a second drive signal output circuit includes a second control circuit that controls an output of a second drive signal, and a second abnormality detection circuit that detects an abnormality in a second drive signal output circuit, the first drive signal output circuit transmits an occurrence of abnormality to the second drive signal output circuit, when the first abnormality detection circuit detects the abnormality, and the second drive signal output circuit transmits an occurrence of abnormality to the first drive signal output circuit, when the second abnormality detection circuit detects the abnormality.

## Claims

### Claim 1

A drive circuit comprising:
a first drive signal output circuit that outputs a first drive signal for driving a first piezoelectric element; and
a second drive signal output circuit that outputs a second drive signal for driving a second piezoelectric element, wherein
the first drive signal output circuit includes
a first control circuit that controls an output of the first drive signal, and
a first abnormality detection circuit that detects an abnormality in the first drive signal output circuit,
the second drive signal output circuit includes
a second control circuit that controls an output of the second drive signal, and
a second abnormality detection circuit that detects an abnormality in the second drive signal output circuit,
the first drive signal output circuit transmits an occurrence of abnormality to the second drive signal output circuit, when the first abnormality detection circuit detects the abnormality, and
the second drive signal output circuit transmits an occurrence of abnormality to the first drive signal output circuit, when the second abnormality detection circuit detects the abnormality.

### Claim 2 (depends on 1)

The drive circuit according to claim 1, wherein
the first control circuit performs control to stop the output of the first drive signal, when the first abnormality detection circuit detects the abnormality, and
the second control circuit performs control to stop the output of the second drive signal, when the second abnormality detection circuit detects the abnormality.

### Claim 3 (depends on 1)

The drive circuit according to claim 1, wherein
the second control circuit performs control to stop the output of the second drive signal, when the first abnormality detection circuit detects the abnormality and the occurrence of abnormality is transmitted from the first drive signal output circuit to the second drive signal output circuit, and
the first control circuit performs control to stop the output of the first drive signal, when the second abnormality detection circuit detects the abnormality and the occurrence of abnormality is transmitted from the second drive signal output circuit to the first drive signal output circuit.

### Claim 4 (depends on 1)

The drive circuit according to claim 1, wherein
the first control circuit and the first abnormality detection circuit are provided in a first integrated circuit, and
the second control circuit and the second abnormality detection circuit are provided in a second integrated circuit.

### Claim 5 (depends on 4)

The drive circuit according to claim 4, wherein
the first integrated circuit includes a first oscillation circuit that outputs a first oscillation signal,
the second integrated circuit includes a second oscillation circuit that outputs a second oscillation signal,
the first control circuit performs control to stop the output of the first drive signal based on the first oscillation signal, and
the second control circuit performs control to stop the output of the second drive signal based on the second oscillation signal.

### Claim 6 (depends on 5)

The drive circuit according to claim 5, further comprising:
a third oscillation circuit that outputs a third oscillation signal, wherein
the first control circuit performs control to stop the output of the first drive signal based on the third oscillation signal, when the first abnormality detection circuit detects an abnormality in which an output of the first oscillation signal is stopped, and
the second control circuit performs control to stop the output of the second drive signal based on the third oscillation signal, when the second abnormality detection circuit detects an abnormality in which an output of the second oscillation signal is stopped.

### Claim 7 (depends on 1)

The drive circuit according to claim 1, wherein
the first drive signal output circuit transmits a processing state of the first drive signal output circuit to the second drive signal output circuit, and
the second drive signal output circuit transmits a processing state of the second drive signal output circuit to the first drive signal output circuit.

### Claim 8 (depends on 1)

A liquid ejecting apparatus comprising:
the drive circuit according to claim 1; and
a print head that includes the first piezoelectric element and the second piezoelectric element, and ejects a liquid by driving at least one of the first piezoelectric element and the second piezoelectric element.