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.