1. Technical Field
The present disclosure relates to a power enabling control circuit and an electronic device using the power enabling control circuit.
2. Description of Related Art
It is known that most electronic devices, such as VCD players or DVD players, include power integrated circuits (POWER IC). The POWER IC has a power enabling port connected to a processor (a CPU or a MCU for example) of the electronic device. The processor is powered by an independent power source to make the processor work. When working, the processor provides a high level voltage to the power enabling port to enable the POWER IC to provide power to internal components of the electronic device. However, when the processor is restarted, for example, an application installed in the electronic device is updated to cause the processor to be restarted, the processor cannot provide a high level voltage to the power enabling port, thus causes the POWER IC to be shut down.
If the applications installed in the electronic device are updated frequently, it is necessary to make the power enabling port in a high level voltage all the time to save starting time of the POWER IC.
The power enabling control circuit 40 includes a first Bipolar Junction Transistor (BJT) Q1 and a second BJT Q2. The first BJT Q1 is a NPN BJT and the second BJT is a PNP BJT. A base of the first BJT Q1 is connected to ground through a first resistor R1 and a second resistor R2, a collector of the BJT Q1 is connected to a base of the second BJT Q2 through a third resistor R3, and further connected a high level voltage port VH through a fourth resistor R4, and an emitter of the BJT Q1 is grounded. A collector of the second BJT Q2 is connected to the power enabling port 201 through a fifth resistor R5, and an emitter of the second BJT Q2 is connected to the high level voltage port VH. The MPEG chip 30 is grounded through the second resistor R2.
When the processor 10 is working, the processor 10 provides a high level voltage to the power enabling port 201. When being restarted, the processor 10 sends the restarted signal to the MPEG chip 30, and the MPEG chip 30 outputs a high level voltage to the power enabling control circuit 40 in response to the restarted signal. Because the base of the first BJT Q1 is in a high level voltage, the first BJT Q1 is turned on, causing the base of the second BJT Q2 to ground through the third resistor R3 and the BJT Q1, thus, the second BJT Q2 is turned on. The power enabling port 201 is connected to the high level voltage port VH through the BJT Q2 and the fifth resistor R5. Thus, the power enabling port 201 is in a high level voltage no matter if the processor 10 is working or restarted. However, the power enabling control circuit 40 includes a first BJT Q1 and a second BJT Q2 which make the structure of the power enabling control circuit 40 be complex and take much space of the electronic device 100.
The components in the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure.
The disclosure is illustrated by way of example 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 power enabling control circuit 40′ includes a first diode D1 and a second diode D2. An anode of the first diode D1 is connected to the MPEG chip 30. An anode of the second diode D2 is connected to the processor 10. A cathode of the first diode D1 and an cathode of the second diode D2 are both connected to the power enabling port 201.
When the processor 10 is working, the processor 10 outputs a high level voltage, the second diode D2 is turned on to make the power enabling port 201 in a high level voltage. When the processor 10 is restarted, the MPEG chip 30 outputs a high level voltage in response to the restarting signal from the processor 10, the first diode D1 is turned on to make the power enabling port 201 in a high level voltage. Therefore, no matter if the processor 10 is working or being restarted, the power enabling port 201 is in a high level voltage.
The power enabling control circuit 40′ solves the same problem as the problem solved by the power enabling control circuit 40 in the prior art and reaches the same effect. However, the components of the power enabling control circuit 40′ are less than that of the power enabling control circuit 40 and takes up less space in the electronic device 100.
Although the present disclosure has been specifically described on the basis of the exemplary embodiment thereof, the disclosure is not to be construed as being limited thereto. Various changes or modifications may be made to the embodiment without departing from the scope and spirit of the disclosure.
Number | Date | Country | Kind |
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201210059394.9 | Mar 2012 | CN | national |