JPH0455923A - Information processing equipment - Google Patents

Abstract

PURPOSE:To display a screen with low luminance at drive of a battery state and with high luminance at drive of an external power supply respectively by detecting the supply of the drive power received from an external power supply and then switching the drive current of a display device based on the detecting result of the power supply detection means. CONSTITUTION:An AC adaptor 2 is selected and a pin 7 of the AC adaptor 2 is connected to a jack 8 attached to an information processing equipment 1. Thus the output of the adaptor 2 which is set at a level higher than the voltage of a battery 3 is supplied to the equipment 1 via an output switch circuit 9 as the drive power (a). At the same time, a supply detection circuit 10 detects the connection of the adaptor 2 with the output of this adaptor 2. Then a luminance control signal (b) is outputted from the circuit 10 and inputted to a drive circuit 13. Thus an FL tube 12 is driven with high luminance at drive of the adaptor 2 requiring no preference to be given to the low power consumption. Meanwhile the tube 12 is driven with low luminance at drive of the battery 3 so that the low power consumption is maintained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to battery-powered information processing equipment such as personal computers and Japanese word processors, and particularly relates to information processing equipment that controls the brightness of a display device. Regarding processing equipment.

(Prior Art) In recent years, information processing devices such as book-type personal computers and Japanese word processors equipped with flat displays called clamshell or lunchbox types have become popular. Such information processing equipment uses a flat display such as a liquid crystal display and is battery-powered, so it is small and lightweight, making it easy to carry and handle.

In battery-powered information processing equipment such as the book-type personal computer described above, various measures have been taken to reduce the power consumption of loads such as display devices in consideration of extending the usage time of the battery. In these means of reducing power consumption, priority is given to reducing power consumption to extend battery usage time over display screen brightness, and the brightness of the display screen is reduced to the minimum brightness. For this reason, the LCD display can be viewed from behind using E L (Electro-Lumines).
Cold cathode tube (FL tube: Fluoresce)
In a liquid crystal display device using a sidelight lighting method (NT tube), the brightness of the display screen can be made much brighter, but the brightness is lowered to the minimum brightness.

(Problem to be Solved by the Invention) However, in the above-mentioned lighting type liquid crystal display device, lower power consumption is prioritized in order to extend the battery usage time, but it is not only possible to use the battery when it is powered, but also to use an external power source. Low power consumption is prioritized even when powered by an AC adapter, so it is difficult to achieve the required contrast ratio when driven by an AC adapter, which does not require prioritizing low power consumption. has the problem that the entire screen is dim.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an information processing device equipped with a display device that displays a screen with low brightness when driven by a battery and with high brightness when driven by an external power source.

[Structure of the Invention] (Means and Effects for Solving the Problems) In order to achieve the above object, the present invention provides an information processing device to which driving power is supplied from an external power source or an internal battery. A display device driven by drive power from one of the batteries, a supply detection means for detecting that drive power is being supplied from the external power supply, and a display device configured to display the above display based on the detection result of the supply detection means. Since the configuration is equipped with a current switching means for switching the drive current of the device, the display device can be driven with a large drive current when driven by an external power source, and with a small drive current when driven by a battery, thereby reducing power consumption. The screen can be displayed at high brightness when driven by an external power source, which does not require prioritizing electricity use, and the screen can be displayed at low brightness when driven by batteries to maintain low power consumption.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an information processing device according to an embodiment of the present invention.

As shown in the figure, an information processing device 1 such as a personal computer according to an embodiment of the present invention uses an AC adapter 2 as an external power source or a rechargeable battery 3 made of Ni-Cd or the like built into the information processing device 1. The driving power is the power supplied from the CPU, which controls each element constituting the information processing device 1, that is, the entire information processing device 1.
(Central Pr-ocessing Uni
t), ROM (Read 0nl) that stores the program
y Mcvory), RAM that temporarily stores data
(Random Access Memory) etc., a storage section 5 consisting of a hard disk device or a floppy disk device and storing various data, a display consisting of a liquid crystal display device, etc., which displays the results and commands calculated by the main body section 2. Driving power a is supplied to the unit 6 and the like from the AC adapter 2 or the battery 3.

The output power of ACC Tsutata 2 is determined by bin 7 and information processing f! I!
The signal is supplied to the information processing equipment 1 via a jack 8 attached to the trumpet 1 and an output switching circuit 9 in which a diode or the like is inserted in series with the line from the battery 3. The output switching circuit 9 is connected to the AC adapter 2 or the built-in battery 3.
This is to switch which of the following will supply the driving power a to the information processing equipment 1. When the AC adapter 2 is selected and connected, the output voltage of the AC adapter 2 is set higher than the terminal voltage of the battery 3. , the drive power 2 is supplied to the information processing equipment 1 with priority given to the output of the AC adapter 2;
When the C adapter 2 is not connected, the driving power a is supplied from the battery 3 to the information processing equipment l.

Also, when AC adapter 2 is connected, AC adapter 2
The connection of the AC adapter 2 is detected by the supply detection circuit 10, which detects the connection state of the AC adapter 2 by, for example, measuring the terminal voltage of the resistor, and the detection output is outputted to the display section 6 as a brightness control signal. . The supply detection circuit 10 is A
The brightness control signal is set to be output at the voltage measured when AC adapter 2 is connected, and
Even if the battery 3 is not connected, the supply detection circuit I
Current flows through O, but because the output voltage of AC adapter 2 is set higher than the terminal voltage of battery 3, the voltage measured at this time is lower than the set voltage when AC adapter 2 is connected, and the brightness No control signal is output.

The brightness control signal has the function of controlling the current that drives the display device of the display unit 6 and switching the brightness of the display device.When driven by the AC adapter 2, the drive current is increased to increase the brightness, and when the battery 3 When driving, priority is given to lower power consumption in order to extend the usage time of the battery 3, so the drive current is reduced and the brightness is lowered. FIG. 2 shows an example of this. As shown in the figure, a cold cathode tube (FL tube) 12 used as a light source in a lighting type liquid crystal display device 11 has a tube current controlled by a drive circuit 13 such as an inverter. The drive circuit 13 receives drive power a from the AC adapter 2 or battery 3, and also receives a brightness control signal from the supply detection circuit 10, and controls the brightness based on the brightness control signal. The brightness of the cold cathode tube (FL tube) 12 is controlled by increasing or decreasing the tube current. Further, a display control signal C is output from the main body 4 to the liquid crystal display device 11, and the liquid crystal display device 11 visually outputs various data based on the display control signal C.

Next, the operation of one embodiment of the present invention having the above configuration will be explained.

When the AC adapter 2 is not connected, the driving power a to the information processing device 1 is supplied from the battery 3 via the output switching circuit 9. At this time, since the measured voltage in the supply detection circuit IO is lower than the set voltage, no brightness control signal is output from the supply detection circuit 10, and the drive circuit 13 drives the FL tube 12 at the minimum brightness that can be observed by the operator. Outputs less tube current. Therefore, the FL tube 12 is driven at low brightness, low power consumption is maintained, and the usage time of the battery 3 can be extended.

On the other hand, when the AC adapter 2 is selected and the pin 7 of the AC adapter 2 is connected to the jack 8 attached to the information processing equipment l, the AC
The output of the adapter 2 is supplied as drive power a to the information processing device 1 via the output switching circuit 9. At this time, the supply detection circuit 10 detects the AC adapter 2 based on the output of the AC adapter 2.
is detected to be connected. When the connection of the AC adapter 2 is detected, the brightness control signal Suga supply detection circuit 1
It is output from 0 and input to the drive circuit 13. When driven by the AC adapter 2, there is no need to give priority to reducing power consumption to extend the usage time of the battery 3, so the drive circuit 13
has sufficient brightness and outputs a tube current that drives the FL tube 12, for example, twice the tube current when driven by the battery 3. Therefore, AC adapter 2 does not require consideration of low power consumption.
When driven by this, the FL tube 12 is driven with sufficient brightness.

Note that when the AC adapter 2 is connected, the battery 3 is charged with the output power of the AC adapter 2 by a charging circuit (not shown).

In this way, by driving the FL tube 12 with a large tube current when driven by the AC adapter 2, and by driving the FL tube 12 with a small tube current when driven by the battery 3, there is no need to prioritize lower power consumption. When driven by the AC adapter 2, the FL tube 12 can be driven at high brightness, and when driven by the battery 3, the FL tube 12 can be driven at low brightness to maintain low power consumption.

Note that in the above embodiment, the brightness of the light source that illuminates the display device is controlled rather than the brightness of the display device, but the invention is not limited to this, and the brightness of the display device itself may be controlled.

Further, in the above embodiments, a cold cathode tube (FL tube) has been described, but the present invention is not limited to a cold cathode tube (FL tube), and may be a surface light emitter such as an EL panel.

Furthermore, it goes without saying that the present invention is not limited to the above embodiments, and can be modified in various ways without departing from the gist of the present invention.

[Effects of the Invention] As detailed above, according to the information processing device of the present invention,
By detecting that drive power is being supplied from an external power supply and switching the drive current of the display device based on the detection result of the supply detection means, the display device can be driven with a large drive current when driven by the external power supply. In addition, since the display device is driven with a small drive current when powered by batteries, the screen can be displayed at high brightness when driven by an external power source, which does not require prioritizing low power consumption, and the screen can be displayed at low brightness when powered by batteries. This has the effect of maintaining low power consumption.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an information processing device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a display section of the present invention. DESCRIPTION OF SYMBOLS 1... Information processing equipment, 2... AC adapter (external power supply), 3... Battery (built-in battery), 6... Display unit (display device), 10... Supply detection circuit (supply detection means), 11...
Liquid crystal display device (display device), 12... cold cathode tube (display device), 13... drive circuit (current switching means). Agent Patent Attorney Norio Ogo

Claims (1)

[Claims] In an information processing device to which driving power is supplied from an external power source or an internal battery, a display device driven by driving power selected from the external power source or the internal battery, and a display device to which driving power is supplied from the external power source. 1. An information processing device comprising: a supply detecting means for detecting that the supply detecting means is present; and a current switching means for switching a driving current of the display device based on a detection result of the supply detecting means.