Amending circuit of correcting bouncing misjudgment of a keyswitch

Patent metadata

Field	Value
Publication number	US-10659077-B2
Application number	US-201715597110-A
Country	US
Kind code	B2
Filing date	May 16, 2017
Priority date	Jan 25, 2017
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

An amending circuit of correcting bouncing misjudgment of a keyswitch includes a comparing unit, a predetermined voltage generating unit and a controlling unit. The comparing unit has a first input terminal, a second input terminal and an output terminal. The first input terminal is adapted to receive a triggering signal generated by the keyswitch. The predetermined voltage generating unit is electrically connected to the second input terminal and adapted to generate a first predetermined voltage. The controlling unit is electrically connected to the output terminal. The controlling unit is adapted to determine whether to execute polling application according to a comparison result of the comparing unit, and to generate a confirming signal while a polling result of the polling application is kept at a specific level. The confirming signal is used by an external processor to confirm that the keyswitch is actually triggered.

First claim

What is claimed is:

1. An amending circuit for correcting bouncing misjudgment of a keyswitch, the amending circuit comprising:
a comparator having a first input terminal, a second input terminal and an output terminal, the first input terminal being adapted to receive a plurality of triggering signals generated by the keyswitch;
a predetermined voltage generator electrically connected to the second input terminal and adapted to generate a first predetermined voltage and a second predetermined voltage, the first predetermined voltage being larger than the second predetermined voltage, and a critical region being defined between the first predetermined voltage and the second predetermined voltage; and
a controller electrically connected to the output terminal, the controller being adapted to determine the triggering signals are generated by an actual triggering of the keyswitch when the triggering signals are higher than the critical region and further determine the keyswitch is bounced when the triggering signals are at the critical region and further determine the keyswitch is not triggered when the triggering signals are lower than the critical region, and to generate a confirming signal according to variation in an operation frequency of a polling application while a polling result of the polling application is kept at a specific level, wherein the confirming signal is used by an external processor to perform a function related to the keyswitch, variation of the triggering signals generated by the actual triggering of the keyswitch is larger than variation of the triggering signals generated by bouncing of the keyswitch due to environmental vibration.

2. The amending circuit of claim 1 , further comprising:
an edge trigger electrically connected to the first input terminal and the keyswitch and adapted to determine whether transition of at least one triggering signal of the plurality of triggering signals has occurred.

3. The amending circuit of claim 2 , wherein the comparator is actuated to determine whether the polling application is actuated while electrical potential of the at least one triggering signal is changed, and the controller is further adapted to determine that the keyswitch is not actually triggered while the electrical potential of the at least one triggering signal is not changed.

4. The amending circuit of claim 1 , wherein the controller is further adapted to actuate the polling application while a voltage value of at least one triggering signal of the plurality of triggering signals is higher than the first predetermined voltage, and to output a prompting signal while the voltage value is lower than or equal to the first predetermined voltage.

5. The amending circuit of claim 4 , wherein the controller is further adapted to determine that the keyswitch is not actually triggered while the voltage value is lower than or equal to the first predetermined voltage.

6. The amending circuit of claim 1 , wherein the controller is further adapted to record an accumulative quantity of some of the plurality of triggering signals having a voltage value lower than the first predetermined voltage, and to output a prompting signal in accordance with the accumulative quantity.

7. The amending circuit of claim 2 , wherein the predetermined voltage generator is further adapted to generate a second predetermined voltage, the comparator compares the at least one triggering signal with the second predetermined voltage to determine whether the keyswitch is actually triggered while electrical potential of the at least one triggering signal is not changed.

8. The amending circuit of claim 7 , wherein the controller is further adapted to output a prompting signal while a voltage value of the at least one triggering signal is higher than or equal to the second predetermined voltage.

9. The amending circuit of claim 1 , wherein the controller is further adapted to generate the confirming signal while the polling result is kept at the specific level during a predetermined period or within a predetermined amount.

10. The amending circuit of claim 9 , wherein a length of the predetermined period or a number of the predetermined amount is varied in accordance with an operation frequency of the controller.

Assignees

• Pixart Imaging Inc

Inventors

• Wang Tsung-Fa
• Kuo Shih-Wei

Classifications

• H03M11/00

  Coding in connection with keyboards or like devices, i.e. coding of the position of operated keys (keyboard switch arrangements, structural association of coders and keyboards H01H13/70, H03K17/94) · CPC title

• H03K5/1254 Primary

  specially adapted for pulses generated by closure of switches, i.e. anti-bouncing devices (debouncing circuits for electronic time-pieces G04G5/00) · CPC title

• H03M11/20 Primary

  Dynamic coding, i.e. by key scanning (H03M11/26 takes precedence) · CPC title