JP2003033034A - Ac adaptor and power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AC adaptor and a power supply system wherein output of direct-current voltage is controlled with accuracy and power-off operation is performed with reliability. SOLUTION: The AC adaptor is for supplying direct current to various kinds of electric equipment (200) which operates on direct-current power supply. The AC adaptor is provided with an AC-DC converting portion (AC-DC conversion circuit 101) which converts alternating-current voltage from a commercial power supply into direct-current voltage; a DC output adjusting portion (DC output adjustment circuit 102) which adjusts the direct-current voltage and then outputs the adjusted voltage to the electric equipment; and a DC output adjusting portion control circuit (microcomputer 103) which controls the DC output adjusting portion. With the AC adaptor and the electric equipment connected, the DC output adjusting portion control circuit increases and decreases direct-current voltage outputted from the DC output adjusting portion based on digitized information about voltage change on the side of the electric equipment transmitted therefrom, and further stops DC output from the DC output adjusting portion based on a digitized power-off signal transmitted from the electric equipment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC adapter and a power supply system for supplying a DC current through an output line to various electric devices that operate on a DC power supply.

[0002]

2. Description of the Related Art An AC adapter converts an AC voltage from a commercial power source into a DC voltage and supplies a predetermined DC power to various electric devices which operate at the DC voltage. The AC adapter generally includes a transformer that reduces the amplitude of the AC voltage, a rectifier that rectifies the AC and converts it into a pulsating flow, and a smoother that converts the pulsating flow into a smooth DC. Still further, there is also one provided with a stabilizing circuit for stabilizing the output voltage. An AC adapter and an electric device (for example, a notebook personal computer) are connected by an output line (cable) that supplies DC power, and supplies a voltage of a rating determined for each electric device. .

By the way, the voltage output from the AC adapter drops due to the resistance of the cable.
Cause Therefore, the conventional AC adapter is provided with a comparator on the electric device side and outputs a predetermined DC voltage based on the voltage value fed back from the electric device side (Japanese Patent Laid-Open No. 56-56). -13741
3 gazette, Unexamined-Japanese-Patent No. 6-113553, etc.).

[0004]

However, in the conventional AC adapter, since the voltage value fed back from the electric equipment side is an analog signal, a voltage drop due to the cable also occurs in the analog signal itself, and the DC voltage is reduced. There was a problem that the output of could not be controlled accurately.

When an abnormal rise in temperature is detected on the electric equipment side, it may be desired to cut off the direct current output from the AC adapter for safety, but it is transmitted via a cable. In the control by the analog signal that is
It was not possible to perform a highly reliable power-off process due to the influence of signal interference or noise.

The present invention has been devised to solve the above problems, and AC capable of accurately controlling the output of a DC voltage and performing highly reliable power-off processing. It is intended to provide an adapter and a power supply system.

[0007]

In order to achieve the above object, the present invention provides a variety of electric equipment (20) operated by a DC power supply.
AC) that converts a DC voltage from a commercial power source into a DC voltage in an AC adapter that supplies a DC current to 0)
/ DC conversion unit (AC / DC conversion circuit 101) and D for adjusting the converted DC voltage and outputting the adjusted DC voltage to an electric device
The C output adjustment unit (DC output adjustment circuit 102), and the DC
A DC output adjusting unit control circuit (microcomputer 103) that controls the output adjusting unit, wherein the DC output adjusting unit control circuit is in a state in which the AC adapter and the electric device are connected to each other on the electric device side. The DC voltage output from the DC output adjusting unit is increased / decreased based on the digitized information about the voltage change of the electric device transmitted from the electric device, and the digitized power cutoff transmitted from the electric device is cut off. The DC output from the DC output adjusting unit is stopped based on the signal.

As a result, the output of the DC voltage can be accurately controlled without being affected by the voltage drop due to the cable unlike the conventional control by the analog signal. In addition, it is possible to eliminate the influence of signal interference and noise, and perform highly reliable power-off processing.

Further, the DC output adjusting section control circuit may be composed of a microcomputer. As a result, it is possible to process the digitized information regarding the voltage change and the power cutoff signal at high speed.

Another aspect of the present invention is a power supply system having an electric device that operates on a DC power supply and an AC adapter that supplies a DC current to the electric device, wherein the electric device controls the power supply of the electric device. And a power cutoff command means for generating a digitized power cutoff signal based on a signal from the abnormality detection means. The adapter controls an AC / DC converting unit that converts an AC voltage from a commercial power source into a DC voltage, an output adjusting unit that adjusts the converted DC voltage, and then outputs the electric device, and the output adjusting unit. A DC output adjusting unit control circuit, wherein the power supply control device detects a voltage change of the electric device, digitizes the detection signal, and then controls the control circuit of the AC adapter. In response, the DC output adjustment unit control circuit increases or decreases the DC voltage output from the DC output adjustment unit based on the digitized information regarding the voltage change on the electric device side transmitted from the power supply control device. In addition, the DC output adjuster control circuit controls the DC output adjuster based on the digitized power cutoff signal transmitted from the power cutoff command means of the electric device.
Controlled to stop the output.

As a result, the output of the DC voltage can be accurately controlled without being affected by the voltage drop due to the cable unlike the conventional control by the analog signal. Further, it is possible to provide a power supply system capable of performing highly reliable power-off processing by eliminating the influence of signal interference and noise.

The abnormality detecting means may be a temperature sensor for detecting a temperature change in the electric device. This makes it possible to stop the output from the DC output adjusting unit when the temperature rises abnormally in the electric device, and ensure the safety of the electric device.

Further, the DC output adjusting section control circuit of the AC adapter, the power supply control device of the electric equipment, and the power supply cutoff command means may each be configured by a microcomputer. As a result, it is possible to process the digitized information regarding the voltage change and the power cutoff signal at high speed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention will be described below with reference to FIG. FIG. 1 illustrates electrical equipment (eg,
FIG. 3 is a block diagram showing a schematic configuration of a power supply system S including a notebook type personal computer or the like) and an AC adapter connected to the electric device. In the figure, reference numeral 10
Reference numeral 0 is an AC adapter body, and reference numeral 200 is an electric device that receives a DC power supply from the AC adapter body.

The AC adapter body 100 adjusts an AC / DC conversion circuit 101 for converting an AC voltage from a commercial power source (for example, 100 V AC) into a DC voltage, and a DC voltage converted by the AC / DC conversion circuit 101. After that, the DC output adjusting circuit 102 that outputs the electric power to the electric device 200 and the microcomputer 103 that configures the DC output adjusting unit control circuit that controls the DC output adjusting circuit 102 are provided.

The AC / DC conversion circuit 101 is adapted to be connected to a commercial power source via an AC connector 101a. The DC power output from the DC output adjustment circuit 102 is supplied to the electric device 200 side via the cable C1 and a connector (not shown).

On the other hand, the electric device 200 generates a comparator 201 for detecting a voltage change of the electric device itself and a voltage adjustment signal digitized based on information from the comparator 201, and the voltage adjustment signal is supplied to the AC adapter body. A microcomputer 202 for controlling transmission to the 100 side via the signal line C2 and a temperature sensor 203 for inputting temperature information in the electric device 200 to the microcomputer 203 are provided. It should be noted that in practice, the cable C1 and the signal line C2 can be combined into a single power cable.

Next, the operation of the power supply system S will be described. AC connector 10 of AC adapter body 100
When 1a is connected to a commercial power source, the AC / DC conversion circuit 10
1 converts alternating current of 100V into direct current of 15V or the like. The direct current is supplied to the electric device 200 via the cable C1 after the waveform is smoothed and the current is adjusted by the DC output adjusting circuit 102.

When a power switch (not shown) on the electric equipment 200 side is turned on, the DC power input from the AC adapter body 100 is supplied to each device D. The comparator 201 constantly monitors the voltage of the DC power source input from the adapter body 100, and inputs information regarding the monitoring result to the microcomputer 202. Based on the information of the voltage change from the comparator 201, the microcomputer 202 is instructed to increase the voltage when the voltage is lower than the rated voltage of the electric device 200, and the voltage is decreased when the voltage is higher than the rated voltage. A voltage adjustment signal to be instructed is generated, and this voltage adjustment signal is converted into a digital signal to obtain the signal line C.
2 to the AC adapter body 100 side.

The microcomputer 103 on the side of the AC adapter body 100 analyzes the voltage adjustment signal input from the side of the electric device 200, and when the content of the instruction is step-up of the voltage, the DC output adjustment circuit 102 is instructed. And outputs a step-up instruction signal, and outputs a step-down instruction signal in the case of step-down.

The DC output adjusting circuit 102 adjusts the voltage based on the step-up instruction signal or the step-down instruction signal from the microcomputer 103, and then supplies the direct current to the electric device 200.

As a result, the output of the DC voltage can be accurately controlled without being affected by the voltage drop caused by the cable as in the prior art in which the voltage value is fed back and controlled by an analog signal.

Further, the microcomputer 202 on the side of the electric device 200 monitors the temperature fluctuation condition in the electric device 200 based on the temperature information input from the temperature sensor 203, and when it detects a sudden temperature rise, Generates a power cutoff signal, converts the power cutoff signal into a digital signal, and transmits the digital signal to the AC adapter body 100 side.

The microcomputer 103 on the AC adapter main body 100 side controls so as to stop the supply of DC power from the DC output adjusting circuit 102 based on the power cutoff signal received from the electric device 200 side. This allows
Like the conventional control using an analog signal, the influence of signal interference and noise can be eliminated, and highly reliable power-off processing can be performed.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments and can be modified without departing from the scope of the invention.

For example, in this embodiment, the temperature sensor 20
The case where the temperature of the electric device 200 is monitored by 3 and the power supply cutoff process is performed when the temperature rises sharply has been described, but the present invention is not limited to this. It can also be applied to power-off processing when any abnormality is detected by other abnormality detecting means.

Further, instead of the signal line C2, infrared rays or electromagnetic waves may be used to transmit and receive digital signals for voltage adjustment and power interruption by a wireless system.

[0028]

According to the present invention, an AC / DC converter for converting an AC voltage from a commercial power source into a DC voltage in an AC adapter for supplying a DC current through an output line to various electric equipments operated by a DC power source. A DC output adjustment unit that adjusts the converted DC voltage and outputs the adjusted DC voltage to an electric device; a DC output adjustment unit control circuit that controls the DC output adjustment unit; and the AC adapter and the electric device. In this state, the DC output adjusting unit control circuit has a signal line for exchanging a digitized signal between the DC output adjusting unit control circuit and the power supply control device provided on the electric device side. Based on the digitized information about the voltage change on the electric device side transmitted via the line,
Since the DC voltage output from the DC output adjustment unit is increased or decreased, the output from the DC output adjustment unit is stopped based on the digitized power cutoff signal transmitted via the signal line. There is an effect that the output of the DC voltage can be accurately controlled without being affected by the voltage drop in the cable unlike the conventional control by the analog signal. Further, there is an effect that the influence of signal interference and noise can be eliminated, and the power supply disconnection processing with high reliability can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a power supply system including an electric device and an AC adapter connected to the electric device.

[Explanation of symbols]

S power supply system 100 AC adapter body 101 AC / DC conversion circuit 101a AC connector 102 DC output adjustment circuit 103 Microcomputer 200 electrical equipment 201 comparator 202 microcomputer 203 temperature sensor C1 cable C2 signal line

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Claims (6)

[Claims] 1. An AC adapter for supplying a DC current to various electric devices which are operated by a DC power supply, the AC / D converting an AC voltage from a commercial power supply into a DC voltage.
A C conversion unit, a DC output adjustment unit that adjusts the converted DC voltage and then outputs the DC voltage to an electric device, and a microcomputer that controls the DC output adjustment unit, and the microcomputer includes the AC adapter. While the electric device is connected, the DC voltage output from the DC output adjusting unit is increased or decreased based on the digitized information about the voltage change on the electric device side transmitted from the electric device side. An AC adapter characterized in that the DC output from the DC output adjusting unit is stopped based on a digitized power cutoff signal transmitted from the electric device. 2. An AC adapter for supplying a DC current to various electric devices that operate from a DC power supply, the AC / D converting an AC voltage from a commercial power supply into a DC voltage.
The DC output adjustment unit includes a C conversion unit, a DC output adjustment unit that adjusts the converted DC voltage and outputs the adjusted DC voltage to an electric device, and a DC output adjustment unit control circuit that controls the DC output adjustment unit. The control circuit outputs from the DC output adjustment unit based on the digitized information regarding the voltage change on the electric device side transmitted from the electric device side in a state where the AC adapter and the electric device are connected. DC voltage is increased / decreased, and DC is generated based on the digitized power cutoff signal transmitted from the electric device.
An AC adapter characterized by stopping DC output from an output adjusting unit. 3. The AC adapter according to claim 2, wherein the DC output adjusting section control circuit is configured by a microcomputer. 4. A power supply system having an electric device that operates on a direct-current power supply and an AC adapter that supplies a direct current to the electric device, wherein the electric device includes a power supply control device that controls power supply to the electric device. An abnormality detection unit that detects an abnormality of the electric device, and a power cutoff command unit that generates a power cutoff signal that is digitized based on a signal from the abnormality detection unit. AC / DC converter for converting AC voltage from DC to DC voltage, output adjuster for adjusting the converted DC voltage and then outputting it to electric equipment, and DC output adjuster control for controlling the output adjuster A circuit, the power supply control device detects a voltage change of the electric device, digitizes the detection signal, and then transmits the detection signal to the control circuit of the AC adapter; The output adjustment unit control circuit increases or decreases the DC voltage output from the DC output adjustment unit based on digitized information regarding the voltage change on the electric device side transmitted from the power supply control device, and The DC output adjuster control circuit controls to stop the DC output from the DC output adjuster based on the digitized power cutoff signal transmitted from the power cutoff command means of the electric device. Power supply system to operate. 5. The power supply system according to claim 4, wherein the abnormality detecting means is a temperature sensor that detects a temperature change in the electric device. 6. The DC output adjusting section control circuit of the AC adapter, the power supply control device of the electric device and the power supply cutoff command means are each configured by a microcomputer. The power supply system according to item 5.