JPH09231050A - Notebook type personal computer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need of adjusting an output voltage each time corresponding to the kind of external equipments or the like even in the case of sharing a single output connector for the plural external equipments by providing a resistance body serially interposed between an amplifier circuit and an output terminal. SOLUTION: This notebook type personal computer is composed of a data input part 1 such as a keyboard or the like, a ROM 2 storing prescribed control data and control programs, a RAM 3 used as a work area, a display part 4 composed of an LCD or the like for displaying a prescribed arithmetic result or the like, a sound controller 5 for performing the output control of sound, a CPU 6 connected to respective components for performing a prescribed arithmetic operation and managing the respective components and an output part 7 for outputting the sound from the sound controller 5 as main parts. Then, for the output part 7, the resistance body 10 is serially interposed between the amplifier circuit 8 and the output connector 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a notebook personal computer (hereinafter referred to as "notebook personal computer"), and more particularly to a notebook personal computer having a sound function.

[0002]

In recent years, it has become essential for personal computers to have a multimedia function in order to increase commercial value, and not only for desktop type personal computers but also for notebook type personal computers. It is becoming important for products to incorporate an FM sound source and a PCM voice recording / playback function.

In the meantime, note that a notebook personal computer is required to be downsized, so that there is a limit to the space for arranging the output connectors. Originally, a single output connector should be divided into a plurality of output connectors. It is often used for both. For example, a typical example is that one output connector also serves as the headphone output connector and the line output connector.

However, the output voltage for headphones is generally less than 1 Vpp, while the output voltage for lines is about 2 to 3 Vpp, depending on the type of external device connected to the output connector. Since the appropriate value of the output voltage is different, the output voltage is adjusted by operating the output adjusting volume in the conventional notebook computer having the sound function. In other words, when a single output connector is used for both line output and headphone output, it is necessary to perform volume adjustment by the output adjustment volume one by one according to the type of external device connected to the output connector. There was a problem.

Further, when headphones are connected and used for line output while the volume is adjusted, the headphones have an excessive output, which may lead to headphone failure or damage to the hearing of the user. There was a problem. The present invention has been made in view of such problems, and even when a single output connector is also used for a plurality of external devices and the like, the output voltage is adjusted one by one according to the types of these external devices and the like. The purpose is to provide a laptop computer that does not need to.

[0006]

In order to achieve the above object, among the notebook computers according to the present invention, the invention according to claim 1 is an audio signal control means for controlling an audio signal, and an audio signal control means. In a notebook personal computer provided with an output unit connected to output a plurality of different output voltages, the output unit has an output terminal connected to an external device, an amplifier circuit for amplifying a sound signal, and the amplifier circuit. And a resistor interposed in series between the output terminal and the output terminal.

According to a second aspect of the present invention, in addition to the first aspect of the invention, a voice output means connected to the output terminal is built in, and the output terminal is the external device and the voice output. It is characterized in that it comprises a switching means capable of switching the connection with the means.

The invention according to claim 3 is characterized in that the external equipment connected to the output terminal includes at least an audio amplifier and a headphone.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a notebook computer according to the present invention. The notebook computer stores a data input section 1 such as a keyboard and predetermined control data and control programs. A ROM 2, a RAM 3 used as a work area, a display unit 4 including an LCD for displaying a predetermined calculation result, a sound controller 5 for controlling audio output, and the components described above. A CPU 6 which performs predetermined arithmetic processing and controls each of the above-described components, and an output unit 7 which outputs a sound from the sound controller 5 are mainly configured.

FIG. 2 is an electric circuit diagram showing a first embodiment of the output section 7, wherein the output section 7 is an amplifier circuit 8.
The resistor 10 is interposed in series between the output connector 9 and the output connector 9.

FIG. 3 shows the case where the output connector 9 of the notebook computer is connected to the input section 12 of the audio amplifier via the connection cable 11. The input section 12 has an input connector 13 and a first stage amplifier circuit 14, and the first stage amplifier circuit 14 has an input impedance 1
Five.

In the case where the notebook computer is connected to the audio amplifier as described above, if the output voltage value of the amplifier circuit 8 is V1, the resistance value of the resistor 10 is R, and the impedance value of the input impedance 15 is I, the first stage amplification is performed. The input voltage V2 of the circuit 14 is represented by Expression (1).

V2 = V1 × I / (R + I) (1) Here, for example, V1 = 2Vpp, R = 50Ω, I = 1
Substituting these values into Equation (1) assuming 0 KΩ, V
2≈1.99 Vpp, and the output voltage V1 of the amplifier circuit 8
(= 2Vpp), which is almost the same.

FIG. 4 shows a case where the output connector 9 of the notebook computer is connected to the headphones 16. That is, the headphone 16 includes a headphone cable 17 connected to the output connector 9,
The headphone body 18 has an input impedance 19.

When the notebook personal computer is thus connected to the headphones, the output voltage value V1 of the amplifier circuit 8 is 2 Vpp, the resistance value R of the resistor 10 is 50 Ω, and the input impedance 19 of the headphones is the same as described above. If the value I of the headphone 16 is 16Ω, the input voltage V2 of the headphone 16 is V2≈0.48Vpp by the formula (1).
Is about 1/4 of that when connected to an audio amplifier.

As described above, in the output section 7 of the present notebook computer, the resistor 10 is interposed in series between the amplifier circuit 8 and the output connector 9, so that the input impedance of the external equipment such as the audio amplifier and the headphone. 15, 19
The output voltage changes through the partial pressure action of. Therefore,
There is no need for the user to adjust the volume each time according to the type of external device connected to the output connector, and it is possible to obtain a notebook computer with a sound function that is easy to use.

FIG. 5 is an electric circuit diagram of the output section 7 showing the second embodiment. The connector of the output section 7 is composed of an output connector 20 having a switch function, and a speaker is provided on the main body of the notebook computer. 23 is provided, and the speaker 23
Is connected to the output connector 20 via an amplifier circuit 22 having an input impedance 21 built therein.

In the second embodiment, when no external device is connected to the output connector 20 with a switch function, the switch 24 is turned on, and the signal from the amplifier circuit 8 passes through the amplifier circuit 22 and the speaker 23. Is output to. In this case, as in the first embodiment, the output voltage value V1 of the amplifier circuit 8 is 2 Vpp, the resistance value R of the resistor 10 is 50Ω, and the value I of the input impedance 21 is 10K.
If Ω, the input voltage V2 of the amplifier circuit 22 becomes V2≈1.99Vpp from the formula (1), and the amplifier circuit 8
Of the output voltage V1 (= 2Vpp).

Further, as shown in FIG. 6, when the headphone 16 is connected to the output connector 20 with the switch function, the switch 24 of the output connector 20 with the switch function is turned off, and the output from the amplifier circuit 18 is output. The signal is output to the headphones 16. Therefore, the output voltage value V of the amplifier circuit 8 is the same as in the first embodiment.
1 is 2 Vpp, the resistance value R of the resistor 10 is 50Ω, the value I of the input impedance 19 of the headphones is 16Ω, and these numerical values are substituted into the formula (1). The input voltage V2 of the headphones 16 is V2≈0. 48Vpp,
It is about 1/4 of that when connected to the speaker 23.

As described above, in the second embodiment, there is no need to adjust the volume each time according to the connection status of the output connector, and a notebook computer with a sound function having good usability can be obtained. it can.

[0022]

As described above in detail, according to the notebook computer of the present invention, the output voltage is connected to the output terminal by the voltage dividing action of the resistor (in the case where the audio output means is built-in. Since it changes according to the voice output means), it is possible to save the user the trouble of re-adjusting the volume according to the type of external device, etc., and obtain a notebook computer with good usability.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing an embodiment of a notebook computer according to the present invention.

FIG. 2 is an electric circuit diagram showing details of an output unit of the notebook computer.

FIG. 3 is a diagram showing a state in which an output unit is connected to an audio amplifier.

FIG. 4 is a diagram showing a state in which an output unit is connected to headphones.

FIG. 5 is an electric circuit diagram showing details of an output section of the second embodiment.

FIG. 6 is a diagram showing a state in which an output unit according to a second embodiment is connected to headphones.

[Explanation of symbols]

 5 sound controller (audio signal control means) 7 output section (output means) 8 amplifier circuit 9 output connector (output terminal) 10 resistor 12 audio amplifier input section 16 headphone 20 output connector (output terminal) 23 speaker (audio output means) ) 24 switches (switching means)

Claims (3)

[Claims] 1. A notebook personal computer comprising: an audio signal control means for controlling an audio signal; and an output means connected to the audio signal control means for outputting a plurality of different output voltages, wherein the output means comprises: A notebook computer comprising an output terminal connected to an external device, an amplifier circuit for amplifying an audio signal, and a resistor interposed in series between the amplifier circuit and the output terminal. Type personal computer. 2. An audio output means connected to the output terminal is built-in, and the output terminal is provided with a switching means capable of switching connection between the external device and the audio output means. The notebook personal computer according to claim 1. 3. The notebook personal computer according to claim 1, wherein the external device connected to the output terminal includes at least an audio amplifier and a headphone.