Patent Application
20100103566
1. Technical Field
The disclosure generally relates to protection circuits, more particularly, to a protection circuit used for protecting a portable electronic device.
2. Description of the Related Art
Portable electronic devices, such as mobile telephones and personal digital assistants (PDAs), may accidentally become wet or damp, which may cause a short in the inner circuits, resulting in serious damage to the portable electronic device. Therefore, it is necessary to prevent water or dampness from damaging the portable electronic device.
At present, to protect the portable electronic device from water or dampness, the designer may improve design processes of the portable electronic device to tightly seal the housings of the portable electronic device. However, after long period of usage, the water or dampness may enter into the housing from the junctions of housings due to abrasion, which may still damage the inner circuits of the portable electronic device.
Therefore, there is room for improvement within the art.
Many aspects of a protection circuit and a portable electronic device employing the same 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 exemplary protection circuit and the portable electronic device employing the same. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment.
The protection circuit 100 includes a power unit 10, a protecting unit 20 electrically connected to the power unit 10, a detecting unit 30 electrically connected to the protecting unit 20, and a processor 40. The processor 40 is electrically connected to the protecting unit 20 and the detecting unit 30.
The power unit 10, can be a lithium ion (Li+) battery of the portable electronic device 200, is rechargeable, and configured to provide power to the protection circuit 100 and the portable electronic device 200.
The protecting unit 20 can be a fuse, which can ensure safe operation of the protection circuit 100. When the protection circuit 100 is abnormal, accompanied by rising current, the protecting unit 20 can cut off the current to protect the protection circuit 100.
The detecting unit 30 includes a first coil 32 and a second coil 34. When water or moisture enters between the first coil 32 and the second coil 34, the first coil 32 and the second coil 34 are electrically connected with each other. Referring to
The processor 40 can be a central processing unit (CPU) of the portable electronic device 200 and includes a signal input pin 42 electrically connected to the second coil 34, a power input pin 44, and a signal output pin 46 electrically connected to the protecting unit 20. The power input pin 44 is electrically connected to the first coil 32 and the protecting unit 20, and configured for receiving power from the power unit 10.
The power level of the signal output pin 46 is consistent with the power level of the signal input pin 42. The protecting unit 20 is controlled by the power level of the signal output pin 46, when the power level of the signal output pin 46 is low, the protecting unit 20 works normally, and the power unit 10 provides power to the processor 40. When the power level of the signal output pin 46 is high, the protecting unit 20 is cut off, and the power unit 10 stops providing power to the processor 40. Under normal circumstances (where there is no water or moisture between the firs coil 32 and the second coil 34), the power levels of the signal input pin 42 and the signal output pin 46 are low.
In use, when water or moisture from outside enters between the first coil 32 and the second coil 34, the first coil 32 and second coil 34 become electrically connected with each other. The signal input pin 42 is electrically connected to the power input pin 44 and receives a level signal from a detecting result. The power level of the signal input pin 42 is changed into high level from low level, and the power level of the signal output pin 46 is also changed into high level in response to the power level of the signal input pin 42. The signal output pin 46 outputs the high level signal as a control signal to the protecting unit 20, and the protecting unit 20 cuts off according to the control signal. Thus, the power unit 10 stops providing power to the processor 40 for protecting the portable electronic device 200.
The protecting unit 20 can be designed as all in one and a removable module. When the water or moisture in the portable electronic device 200 is cleaned up, a new fuse can be use to replace the damaged fuse, and the protecting unit 20 can be reset into the protection circuit 100.
The first coil 32 can be electrically connected to the power input pin 44, and the second coil 34 can be electrically connected to the signal input pin 42 simultaneously.
The protection circuit 100 has a simple structure and manufacturing process. When the portable electronic device 200 is in a wet environment or falls into water, the protection circuit 100 can automatically power off to prevent the inner circuits from damage. Thus, the protection circuit 100 can protect the portable electronic device 200.
It is to be understood, however, that even though numerous characteristics and advantages of the exemplary invention have been set forth in the foregoing description, together with details of the structure and function of the exemplary invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of exemplary invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200810305276.5 | Oct 2008 | CN | national |
