Hon Hai Precision Industry Co., Ltd.

Hong-Fu Jin Precision Industry (Shenzhen) Co., Ltd.

Xiang-Ping Zhou

Lin-Kun Ding

Shih-Fang Wong

Jiang-Feng Shan

Gui-Rong Zhou

Tsung-Jen Chuang

Ren-Wen Huang

Li-Sheng Shu

A portable electronic device includes a player, a speaker, a control circuit, a switch circuit, and a current limiter. The player is for outputting analog audio signals. The speaker is for transforming the analog audio signals into sound. The control circuit is for generating a first control signal when ambient light intensity is lower than a predetermined value. The switch circuit is for turning on and transmitting the analog audio signals to the speaker when receiving the first control signal. The current limiter is for transmitting the analog audio signals to the speaker when the switch circuit turns off, and for limiting a current flowing through the speaker.

Portable electronic device

A scanning circuit includes n rows L&#x2dc;Ln, 2n columns P-&#x2dc;P-and P-&#x2dc;P-, and the n rows L&#x2dc;Ln and the n columns P-&#x2dc;P-cooperatively form a switch matrix comprising n*n switches S-&#x2dc;Sn-n, with ends of the switches in the same row electrically connected to one of n I/O ports K&#x2dc;Kn, respectively, the ends of the switches in the same column are electrically connected to ground via one resistor R-&#x2dc;R-, respectively, each of resistors R-&#x2dc;R-is electronically connected in one column of the columns P-&#x2dc;P-, and connected between one of the I/O ports K&#x2dc;Kn and ground via one of the resistors R-&#x2dc;R-, respectively. A keyboard and a scanning method are also provided.

Scanning circuit and scanning method for keyboard

A telephone line monitoring device is connected to a telephone line and adjacent to a telephone device using the telephone line. The telephone line monitoring device includes a rectifying circuit for generating a corresponding direct current voltage according to an effective voltage of the telephone line; a first controller for generating a first control signal when the direct current voltage is lower than a predetermined voltage; a second controller for detecting an operating state of the telephone device and generating a second control signal when the telephone device is operated; a load booster for pulling down the effective voltage of the telephone line when enabled; and a first switch circuit for disabling the load booster whenever receiving the second control signal, and enabling the load booster when receiving the first control signal while not receiving the second control signal. A monitoring method and a telephone device are also provided.

Telephone device, telephone line monitoring device and method

An interface circuit and an electronic device are used for expanding an output port of a micro processing unit. The interface circuit includes an input port electrically connected to the output port of the micro processing unit for receiving a control signals, and a plurality of output ports selectively driven to control external circuits by inputting different values of the control signal at the input port.

Growing community of inventors

Shenzhen, China

Xiang-Ping Zhou