公开(公告)号：US20240113731A1

公开(公告)日：2024-04-04

申请号：US18093501

申请日：2023-01-05

Applicant: Primax Electronics Ltd.

Inventor： Chih-Chen Chang ,  Yi-Liang Chen ,  Yu-Ting Lo

IPC: H03M11/00 ,  G06F3/02

CPC classification number: H03M11/003 ,  G06F3/0202

Abstract: A ghost key preventing circuit includes plural driving lines, plural sensing lines, plural key switches, plural bias resistors and a controller. The plural driving lines and the plural sensing lines are collaboratively formed as a matrix circuit. The plural key switches are included in the matrix circuit. The plural bias resistors are connected with the corresponding sensing lines. When the key switch of a specified switch circuit is turned on, a divided voltage is generated and outputted from the specified switch circuit. The controller judges whether the key switch of the specified switch circuit is normally turned on or the key switch is a ghost key according to the divided voltage.

公开(公告)号：US20240310926A1

公开(公告)日：2024-09-19

申请号：US18143552

申请日：2023-05-04

Applicant: Primax Electronics Ltd.

Inventor： Yi-Liang Chen ,  Chih-Chen Chang ,  Chien-Ming Li

IPC: G06F3/023 ,  H01H13/703 ,  H01H13/785 ,  H01H13/79 ,  H01H13/80 ,  H03K17/96

CPC classification number: G06F3/0233 ,  G06F3/0238 ,  H01H13/703 ,  H01H13/785 ,  H01H13/79 ,  H01H13/80 ,  H03K17/9625

Abstract: A composite function keyboard circuit includes a first matrix circuit, a first bias resistor group, a second matrix circuit, a second bias resistor group and a controller. Each switch unit in the first matrix circuit is an ink-type force sensing switch. A resistance of the ink-type force sensing switch is variable according to a pressing mode of a keypress action. An electrical connection path is formed between the ink-type force sensing switch and the corresponding bias resistor of the second bias resistor group. When the ink-type force sensing switch is electrically conducted, a divided sensing voltage is generated by the electrical connection path, and the controller generates a corresponding key control instruction according to a level of the divided sensing voltage. Furthermore, the cooperation of the first matrix circuit and the first bias resistor group can achieve a ghost key preventing function.