JPH02295389A - Multi-stage connection system - Google Patents

Abstract

PURPOSE:To reduce a rush current while the timing of a power supply rising of each terminal electric equipment by providing a delay circuit retarding a power control signal. CONSTITUTION:When a main power is fed to television receivers 1, 3, 5, the television receivers are in the standby state. When a power supply control signal 7 reaches a high level, the power supply of the television receiver 1 rises. Since the power control signal 8 of the television receiver 3 reaches a high level with a delay more than the power supply control signal 7 by a delay circuit 2, the power supply for the television receiver 3 rises with a delay more than the television receiver 1. The power control signal is inverted by an inverter at the delay circuit 2 and waveform-shaped and then integrated, then the power control signal inverted again by the inverter is retarded more than the input power control signal. Thus, rush current at the start of power supply is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a power supply control method in a multi-stage connection system.

[Conventional technology]

A conventional example of a system for connecting color televisions in multiple stages is shown in FIG.

When the main power supply 33 supplies power to each of the televisions 30, 31, and 32, the televisions are in a standby state, and when the power control signal becomes high level, the televisions 30, 31, and 32 are powered on all at once.

FIG. 4 is a block diagram of the color televisions 30, 31, and 32.

The video mode video signal and the video mode audio signal are directly input to the mode switching circuit 15. The RF signal is selected by an autotuning circuit 11 and a tuner 12, converted into a video signal by an IF circuit 13, and then input to a mode switching circuit 15.

The mode switching circuit 15 switches between television mode and video mode, and the audio signal is sent to the audio processing circuit 14.
Further, the video signal is output to the color signal processing circuit 18.

The color signal processing circuit 18 outputs the RGB signal to the A/D converter 17, converts it into a digital signal, and transmits it to the liquid crystal panel 20 via the control & driver 19, where it is displayed.

FIG. 3 is a detailed circuit diagram of the power switch circuit 21 in FIG. 4.

When the power supply control signal becomes high level, transistor Q1,
Since Q2 becomes conductive, power is supplied to the stabilized power supply circuit.

When the power supply control signal becomes low level, transistor Q1,
Since Q2 becomes non-conductive, power supply to the stabilized power supply circuit is prohibited.

[Problem to be solved by the invention]

However, in such a multi-stage connection system, power supply is permitted to all connected color televisions at the same time, so a very large inrush current flows when power supply starts.

This phenomenon will be explained below using figures.

Figure 5 shows the progress of current consumption when the TV alone is operating properly. t
When power supply is allowed to =To, a rush current lm flows through t-TO, and the current value eventually settles to the steady current 1c.

FIG. 6 shows the progress of current consumption when three televisions are connected in the system shown in FIG. 8. When power supply is permitted to t-To, an inrush current 31m equivalent to three units flows through t-To, and eventually settles down to a steady current 31c.

If a very large inrush current flows at the start of power supply in this way, there is a possibility that the fuse of the main power supply 33 will blow due to the inrush current, so it is necessary to install an inrush current limiting resistor in the main power supply 33, or it will not match the steady current. There was a problem in that a fuse had to be set.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and its purpose is to provide a multi-stage connection system that can reduce inrush current at the start of power supply.

[Means to solve the problem]

The multi-stage connection system of the present invention is a system in which electrical equipment such as a color television is connected in multiple stages, and includes: b) a power control signal that instructs the electrical equipment to turn on the power; and C) a delay circuit that delays the power control signal. It is characterized by comprising the following.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples.

FIG. 1 is a block diagram of a multi-stage connection system of the present invention.

When main power is supplied to the televisions 1, 3, and 5, the televisions enter a standby state. When the power control signal 7 becomes high level, the power of the television 1 is turned on. Since the power control signal 8 of the television 3 becomes high level later than the power control signal 7 due to the delay circuit 2, the power of the television 3 is turned on later than the television 1.

FIG. 2 shows a specific circuit example of the delay circuit.

The power supply control signal is inverted and waveform-shaped by an inverter 9. Thereafter, since it is integrated by R1 and C1, the power supply control signal that is inverted again by the inverter 10 is delayed by 01 and R1 from the human power supply control signal.

The televisions 1, 3, and 5 are constructed as shown in FIG. 4, similar to the conventional example. The video mode video signal and the video mode audio signal are directly input to the mode switching circuit 15.

The RF signal is selected by an auto-tuning circuit 11 and a tuner 12, converted into a video signal by an IF circuit 13, and then inputted to a mode switching circuit 15.

The mode switching circuit 15 performs switching 1 between television mode and video mode, and outputs the audio signal to the audio processing circuit 14 and the video signal to the color signal processing circuit 18. The color signal processing circuit 18 outputs RGB signals to the A/D converter 17, converts them into digital signals, and transmits them to the liquid crystal panel 20 via the control and driver 19 for display.

The power switch circuit has the circuit configuration shown in FIG. 3, similar to the conventional example. When the power supply control signal becomes high level, transistors Q1 and Q2 become conductive, so that power is supplied to the stabilized power supply circuit. When the power supply control signal becomes low level, transistors Q1 and Q2 become non-conductive, and therefore, power supply flooding to the stabilized power supply circuit is prohibited.

FIG. 7 shows the progress of current consumption when three televisions are connected in the multi-stage system of the present invention. When conduction occurs at t=To,
An inrush current lm for one vehicle flows at t-To. Assuming that the power control signal is delayed by T due to the power control signal at the previous stage due to the delay circuit, at t=To+T, an inrush current corresponding to the consumption current of the first TV at t=To+7+1 unit flows. At t-To+2T, an inrush current corresponding to the consumption current of the first and second television sets plus one unit flows at t-To+2T.

〔Effect of the invention〕

As described above, by providing a delay circuit, the multi-stage connection system of the present invention can shift the power-on timing of each terminal electrical device and reduce inrush current. It is no longer necessary to take measures such as inrush current limiting resistors and fuse selection that take into account inrush current, and costs can be reduced, which is extremely effective.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a multi-stage connection system of the present invention. FIG. 2 is a circuit diagram of a delay circuit. FIG. 3 is a circuit configuration diagram of a power switch circuit in a conventional example and in the present invention. FIG. 4 is a block configuration diagram of a television in a conventional example and in the present invention. FIG. 5 is a graph showing the progress of current consumption when the television is turned on. FIG. 6 is a graph of current consumption when three televisions are connected using a conventional multi-stage connection system. FIG. 7 is a diagram showing the progress of current consumption when three televisions are connected using the multi-stage connection system of the present invention. FIG. 8 is a configuration diagram of a conventional multi-stage connection system. Working●TV...delay circuit a#TV...delay circuit...TV...main power supply...power control signal 8...power control signal 9...●inverter 10●fist Φ inverter 11...auto tuning circuit 12...Tuner 13...IF circuit 14...Audio processing circuit 15...Mode switching circuit 16...Synchronization circuit 17...A/D converter 18...Color signal processing circuit 19...・Control & driver 20...LCD panel 21...Power switch circuit 22...Stabilized power supply circuit 24...Fluorescent tube drive circuit 25...Fluorescent tube 30...φ TV 31・●・Television 32φφ/TV 33...Main power supply 34...Power control signal and above Applicant Seiko Epson Co., Ltd. Agent Patent attorney Kisaburo Suzuki (and 1 other person) Fig. 2 Fig. 5 Fig. 6 Fig. 7 -----Ichiden Nanazushu Fig. 4 S+

Claims (1)

[Claims] (1) In a system that connects electrical equipment such as a color television in multiple stages, it is recommended to include: b) a power control signal that instructs the electrical equipment to turn on the power; and c) a delay circuit that delays the power control signal. Features a multi-stage connection system.