1. Technical Field
The disclosed embodiments relate to an electronic device.
2. Description of Related Art
Touch pads are becoming increasingly popular because of their ease of use, versatility, and low price. A touch pad is often incorporated in electronic devices, such as mobile phones, and used as an input device to move a screen pointer.
A capacitive touch pad includes a ground wire, the ground wire is used for discharging electrostatic discharge (ESD) surges applied to the touch pad. A capacitor is formed between the ground wire and the conducting wires of the touch pad, however, if the size of the ground wire is too large, the capacitance of the capacitor is also too large and may affect the performance of the touch pad. If the size of the ground wire is too small, the ground wire cannot discharge ESD surges in time, thus causing the touch pad to malfunction.
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 two views.
Referring to
The processing unit 10 further reads information from the register 24 every predetermined time period, and generates a reset signal when an error is detected. In this embodiment, the error prevents the processing unit 10 from reading any information from the register 24, and the predetermined time period is less than one second. The touch pad 20 is reset according to the reset signal, thus restoring the touch pad 20 to initial conditions.
Referring to
In this embodiment, the touch pad 20 is a capacitive touch pad. The touch pad 20 further includes a ground wire 26, and the ground wire 26 is used for discharging ESD surges applied to the touch pad 20. In effect, a capacitor is formed between the ground wire and conducting wires of the touch pad 20. In this embodiment, the size of the ground wire is small.
Firstly, because the size of the ground wire 26 is small, the ground wire 26 cannot discharge the ESD surges in time, and the touch pad 20 may malfunction due to ESD. Because the processing unit 10 reads information from the register 22 every predetermined time period, when the touch pad 20 malfunctions, the processing unit 10 cannot read information from the register 24 and generates the reset signal, the touch pad 20 is reset according to the reset signal, and then the touch pad 20 is enabled and operates normally. At the same time, during the predetermined time period, the electrostatic surge current is conducted to ground through the ground wire 26, and ESD surges are effectively removed.
Secondly, because the size of the ground wire 24 is small, thus the capacitance of the capacitor is also small, and such a capacitor cannot affect the performance of the touch pad 20.
Alternative embodiments will apparent to those skilled in the art without departing from the spirit and scope of what is claimed. Accordingly, the present invention should be deemed not to be limited to the above detailed description, but rather only by the claims that follow and equivalents thereof.
Number | Date | Country | Kind |
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201010602790.2 | Dec 2010 | CN | national |