Interface circuit and portable electronic device employing the same
AssigneeChi Mei Communication Systems, Inc.
InventorChien-Yao Chao
Life of this patent
Estimating the term…
Abstract
An interface circuit for connecting with a universal serial bus (USB) data cable includes a USB connector for connecting with the USB data cable, an over voltage protection (OVP) circuit connected to the USB connector, and a time delay circuit connected to the USB connector and the OVP circuit to control the OVP circuit. The OVP circuit is switched off in a predetermined delay time of the time delay circuit when the USB data cable is connected to the USB connector, and is then switched on after the delay time of the time delay circuit.
Claims10
An interface circuit for connecting with a universal serial bus (USB) data cable, comprising:
- a USB connector for connecting with the USB data cable;
- an over voltage protection (OVP) circuit connected to the USB connector, the OVP circuit including an input connector, an output connector, and a control connector;
- the input connector connected to the USB connector;
- and
- a time delay circuit connected to the USB connector and the OVP circuit to control the OVP circuit, the time delay circuit being an RC time delay circuit that includes a capacitor, a first resistor and a second resistor connected in series between the USB connector and the ground, the control connector being connected between the first resistor and the second resistor;
- wherein the OVP circuit is switched off in a predetermined delay time of the time delay circuit when the USB data cable is connected to the USB connector, and is then switched on after the delay time of the time delay circuit.
A portable electronic device, comprising:
- a main circuit board;
- and
- an interface circuit for connecting with a universal serial bus (USB) data cable;
- wherein the interface circuit is connected to the main circuit board and includes a USB connector for connecting with the USB data cable, an over voltage protection (OVP) circuit connected to the main circuit board and a time delay circuit connected to the OVP circuit to control the OVP circuit, the OVP circuit including an input connector connected to the USB connector, and output connector connected to the main circuit board, and a control connector connected to the time delay circuit;
- the time delay circuit being an RC time delay circuit that includes a capacitor, a first resistor, and a second resistor connected in series between the USB connector and the ground, the control connector being connected between the first resistor and the second resistor;
- the OVP circuit being switched off in predetermined delay time of the time delay circuit when the USB data cable is connected to the interface circuit to prevent the USB data cable from being connected to the main circuit board, and the OVP circuit being switched on after the delay time of the time delay circuit to connect the USB data cable to the main circuit board.
Dependencies are inferred from the claim text.