Wake up system for electronic device

This application claims priority to Chinese Patent Application No. 201410625054.7 filed on Nov. 10, 2014, the contents of which are incorporated by reference herein.

The subject matter herein generally relates to power-saving techniques in electronic devices.

Conventional personal computers usually go into a sleep mode when the computer is not used for a period of time. Users need to wake up the computer using the mouse or the keyboard.

Implementations of the present technology will now be described, by way of example only, with reference to the attached figures.

FIG. 1 is a block diagram of an embodiment of a wake up system for electronic device.

FIG. 2 is a circuit diagram of the wake up system for electronic device of FIG. 1 .

It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure.

Several definitions that apply throughout this disclosure will now be presented.

The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series, and the like.

FIG. 1 illustrates a wake up system for electronic device in accordance with an embodiment. The wake up system includes a detecting circuit 100 , an amplifier circuit 200 , a switch circuit 300 , and a south bridge chip 400 .

FIG. 2 illustrates that the detecting circuit 100 includes a detector 110 , a first resistor R 1 , a second resistor R 2 , and a capacitor C. The detector 110 includes a gate, a source, and a drain. The gate of the detector 110 is grounded. The source of the detector 110 is grounded via the first resistor R 1 . The drain of the detector 110 receives a first DC voltage via the second resistor R 2 . The drain of the detector 110 is grounded via the capacitor C. In one embodiment, the detector 110 is a heat detector. The first DC voltage is +5 volts.

The amplifier circuit 200 includes an amplifier 210 , a third resistor R 3 , a fourth resistor R 4 , and a fifth resistor R 5 . The amplifier 210 includes an inverting input terminal, a non-inverting input terminal, an output terminal, and a power terminal. The non-inverting input terminal of the amplifier 210 is electrically coupled to the source of the detector 110 via the third resistor R 3 . The inverting input terminal of the amplifier 210 is grounded via the fourth resistor R 4 . The inverting input terminal of the amplifier 210 is electrically coupled to the output terminal of the amplifier 210 via the fifth resistor R 5 . The power terminal of the amplifier 210 receives the first DC voltage.

The switch circuit 300 includes a MOSFET Q, a sixth resistor R 6 , and a seventh resistor R 7 . The MOSFET Q includes a gate, a source, and a drain. The gate of the MOSFET Q is electrically coupled to the output terminal of the amplifier 210 . The source of the MOSFET Q is grounded. The drain of the MOSFET Q is electrically coupled to a wake up terminal of the south bridge chip 400 via the sixth resistor R 6 . The wake up terminal of the south bridge chip 400 receives a second DC voltage via the seventh resistor R 7 . In one embodiment, the MOSFET Q is an n-channel MOSFET. The second DC voltage is +3.3 volts.

In use, when the user gets close to the electronic device which is in a sleep mode, the detector 110 detects a temperature change caused by the user. The detector 110 converts the temperature change to a weak voltage signal and amplifies the voltage signal for the first time. The non-inverting input terminal of the amplifier 210 receives the amplified voltage signal and amplifies the voltage signal for the second time. The gate of the MOSFET Q receives the voltage signal that is amplified for the second time. The MOSFET Q turns on. The drain of the MOSFET Q outputs a low voltage level wake up signal to the wake up terminal of the south bridge chip 400 . The south bridge chip 400 wakes up the electronic device.

In one embodiment, an amplification factor of the amplifier 210 and a turn-on voltage of the MOSFET Q can be adjusted as required. In that case, the MOSFET Q is turned on when the user gets physically closer than a predetermined distance to the electronic device. The MOSFET Q outputs the low voltage level wake up signal to the south bridge chip 400 . The south bridge chip 400 wakes up the electronic device.

The embodiments shown and described above are only examples. Many details are often found in the art such as the other features of a wake up system for electronic device. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the details, including in matters of shape, size, and arrangement of the parts within the principles of the present disclosure, up to and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the claims.