1. Technical Field
The present disclosure relates to a card reader.
2. Description of Related Art
Most card readers include universal serial bus (USB) interfaces. When a USB card reader is connected to an electronic device, such as a computer, a card received in the card reader communicates with the computer. When a user no longer need to read or write to the card, the user may use the operating system to “eject” the card. The card is not physically removed from the card reader but is shown as not present or ignored by the operating system. For the operating system to access the card again, the card reader must be physically disconnected and reconnected to the computer.
Moreover, the card may not be detected by the computer when the card reader is initially plugged in, so the card reader must be unplugged and replugged from the computer, maybe even for several times until the card is detected by the computer.
Having to repeatedly insert the card reader each time may wear out the USB interfaces of the computer and the card reader more quickly. Therefore there is room for improvement in the art.
Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
The disclosure, including the accompanying drawings in which like references indicate similar elements, is illustrated by way of examples and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one.
Referring to
The housing 10 defines a hole 12 in a top of the housing 10, and defines a card space 13 to receive a card 30.
The PCB 20 includes a universal serial bus (USB) interface 22, a card interface 24, a control chip 26, and a normally-closed switch 28. The control chip 26 is connected between the USB interface 22 and the card interface 24. The switch 28 is connected in-line in the wire connecting a positive differential signal pin D+of the USB interface 22 to the control chip 26. A wire connecting a negative differential signal pin D- of the USB interface 22 to the control chip 26 includes a backward “s” curve portion 27, to have the same length as the circuit path of the differential signal pin D+of the USB interface 22, the switch 28, and the control chip 26, to ensure timing of signals. The switch 28 is exposed out of the housing 10 through the hole 12.
Referring to
It is to be understood, however, that even though numerous characteristics and advantages of the present disclosure have been set forth in the foregoing description, together with details of the structure and function of the disclosure, the disclosure is illustrative only, and changes may be made in details, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
Number | Date | Country | Kind |
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201010152620.9 | Apr 2010 | CN | national |