# US 11,442,553 B2 · Apparatus and method for detecting actuation of a switch

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- Number: US 11,442,553 B2
- Document ID: US11442553B2
- Status: Granted
- Kind: B2
- Application number: 16/015,111
- Filed: 2018-06-21
- Published: 2019-12-26
- Granted: 2022-09-13
- Earliest claimed: 2015-12-21
- Assignees: Cherry GmbH
- Applicants: Cherry GmbH
- Inventors: Erwin Koeferl
- Web page: https://patentgrep.com/patent/US11442553B2

## CPC

- G06F 3/0227: {Cooperation and interconnection of the input arrangement with other functional units of a computer (G06F3/023 - G06F3/037 take precedence)}
- H01H 13/70: having a plurality of operating members associated with different sets of contacts, e.g. keyboard (mounting together a plurality of independent switches H02B)
- H03K 5/1254: specially adapted for pulses generated by closure of switches, i.e. anti-bouncing devices (debouncing circuits for electronic time-pieces G04G5/00)
- H01H 2231/008: Video game
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)

## Abstract

The invention relates to a method and an apparatus with circuitry comprising at least one mechanical switch serving to open and/or close an electric contact and a processor unit serving to perform first query and a second query of a contact state of the contact, with the processor unit further serving to provide an output signal on the basis of information on a change of the contact state of the contact detected by means of the first and second queries, wherein the processor unit is configured to perform the second query after the first query with a timing so that the second query precedes an expected bounce of the contact.

## Claims

### Claim 1

An apparatus with circuitry comprising:
at least one mechanical switch serving to open and/or close an electric contact and
a processor unit serving to perform a first query and a second query of a contact state of the contact, the processor unit further serving to provide an output signal on the basis of information on a change of the contact state of the contact detected by way of the first and second queries,
wherein the processor unit is configured to perform the second query after the first query with a timing so that the second query precedes a first bounce of the contact,
wherein the processor unit is configured to perform the second query immediately after the first query,
wherein the processor unit is configured to provide the output signal immediately after the second query,
wherein the processor unit is configured to detect another change of the contact state only when a default debounce time of the contact has lapsed, and
wherein the apparatus comprises several mechanical switches, wherein the mechanical switches are implemented as keys in a keyboard.

### Claim 2 (depends on 1)

The apparatus according to claim 1, wherein that if the apparatus comprises more than one mechanical switch, the processor unit is configured to perform a second query of a first switch before performing a first query of a second switch.

### Claim 3 (depends on 1)

The apparatus according to claim 1, wherein the processor unit interrupts a query of other contacts in order to perform the second query.

### Claim 4 (depends on 1)

The apparatus according to claim 1, wherein the second query is performed about 47 nanoseconds after the first query.

### Claim 5

A method of detecting change of a contact state of a contact a mechanical switch, comprising:
opening and/or closing the contact,
performing a first query and a second query of the contact state of the contact,
providing an output signal on the basis of information on a change of the contact state of the contact detected by way of the first and second queries,
performing the second query after the first query with a timing so that the second query precedes a first bounce of the contact,
wherein the second query is performed immediately after the first query,
wherein the output signal is provided immediately after the second query,
wherein another change of the contact state is detected only when a default debounce time of the contact has lapsed, and
wherein the mechanical switch is implemented as a key in a keyboard.