JPH03155331A - Circuit power supply controller - Google Patents

Abstract

PURPOSE:To reduce the number of connecting wires between respective devices to each other by using a clamp pulse as a control signal for controlling a power supply. CONSTITUTION:When an image signal regenerating device 10 is set in a working state, then a pulse generating circuit 108 provides a clamp pulse CP to the base of a transistor 110. The clamp pulse CP of output to be outputted to a connecting wire 44 from the collector of the transistor 110 is reversed and inputted to a low-pass filter 212. In the low-pass filter 212, the clamp pulse CP is integrated, and an integrated output Vi is inputted to a comparator 214. As a result, an analog switch 208 is set in an ON-state, and by a regulator 216, line voltage VCC is fed to signal processing circuits, 200, 202. Then, a number of connecting wires can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to circuit power supply control for a system comprising a device having a main function and devices attached thereto.

In a system configured such that a device that has the main function of the entire system and its attached devices are each unitized, and each of these devices is powered by a common power supply, the connection between each device is It is desirable that the number of lines (including signal lines, control lines, and power lines) be as small as possible in order to downsize the system.

Furthermore, if the number of connection wires can be reduced, the number of pins of the connector cover can also be reduced, and as a result, the reliability of the system can be improved.

However, in conventional systems of this type, no consideration has been given to reducing the number of connection lines.

Purpose The present invention solves the problems of the prior art, connects each device with the minimum number of connection lines necessary for signal processing, and controls the supply of circuit power using these connection lines. The purpose of this invention is to provide a circuit power supply control device that can perform the following steps.

DISCLOSURE OF THE INVENTION According to the present invention, a first device that outputs a signal, a second device that includes a signal processing means that processes the signal, and that is attached to the first device are powered from a common power source. The circuit power supply control device of the system configured as above is provided in the first device, and has a control function that outputs control signals necessary for signal processing of the second device to the second device via a signal line during its operation. The signal processing means takes in the control signal and processes the signal output from the first device, and the control device further connects the signal processing means and the power source in the second device. a switch means provided between the second device and configured to turn on/off power supply from the power source to the signal processing means; and an integrating device provided within the second device to integrate the control signal and convert it into a DC signal. , a comparison means provided in the second device for comparing the level of the DC signal with a predetermined reference level and controlling on/off of the switch means according to the comparison result.

EMBODIMENT OF THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of a system including a circuit power supply control device according to the present invention. In the figure, the system includes a video signal reproducing device 1O, and a signal processing device 2 that converts the video signal reproduced by the video signal reproducing device into a predetermined format.
0, and a power supply 30 that supplies power to the video signal reproduction device IO and the signal processing device 20 via a power supply line 32.

The video signal reproducing device M10 and the signal processing device 20 are each formed into a unit, and have connectors 112, 114, 118, 218, 220, 222 and connection lines 40, 42.4.
4, it is configured to be detachable. Similarly, a power source 30 is connected to the video signal reproducing device IO and the signal processing device 20 via a power line 32 via a connector (not shown).

The video signal reproducing device 10 includes a magnetic recording medium (not shown).
For example, a video signal is reproduced from a video disk, video tape, etc.) by a magnetic head. This reproduced video signal is modulated using a predetermined modulation method (eg, FM modulation). This modulated video signal is separated into a luminance signal (Y) and a color signal CG), which are buffered by buffer amplifiers 100 and 1, respectively.
02 is input.

The output terminals of the buffer amplifiers 100 and 102 are connected to capacitors 104. I(+6 via connectors 02, 11
4, and the connectors 112, 114 are each connected to one end of the connection line 40, 42. Furthermore, the other ends of the connection lines 40 and 42 are connected to connectors 218 and 220 provided in the signal processing device 20, respectively.

The pulse generating circuit 108 is necessary for signal processing of the signal processing circuits 200 and 202 in the signal processing device 20 and generates a ramp pulse (cp). The output terminal of the pulse generating circuit 10B is connected to the base of the transistor 110. The transistor 110 constitutes an output circuit of the pulse generating circuit 108, and is an open collector for short-circuit protection. The collector of the transistor 110 is connected to a connector 11B provided in the video signal reproducing device, and the connector 11B is connected to one end of the connection line 44. The other end of the connection line 44 is connected to the connector 2 provided in the signal processing device 20.
22.

The signal processing circuit 200 in the signal processing device 20 is connected to the connector 2
18, connection wire 40, connector 112, capacitor 104
Buffer amplifier 10 in video signal reproducing device 10 via
Connected to 0.

Further, the signal processing circuit 200 is connected to the pulse generating circuit 108 via a transistor 11O, a connector 11B, a connecting line 44, and a connector 222. Signal processing circuit 20
0 performs various processing (for example, demodulation, field/frame conversion, etc.) on the modulated luminance signal input from the buffer amplifier 100 in response to the clamp pulse output from the pulse generation circuit 108.

The signal processing circuit 202 is connected to the buffer amplifier 102 in the video signal reproducing apparatus 0 via a connector 220, a connecting line 42° connector 114, and a capacitor 106. The signal processing circuit 202 performs various processes on the modulated color signal input from the buffer amplifier 102. The output signals of the signal processing circuits ZO0 and 202 are output to output terminals 218 and 220 via drivers 204 and 206, respectively. Output terminals 218, 220 are adapted to be connected to a monitoring device.

On the other hand, the pulse generation circuit 108 in the video signal reproducing device IO
is a transistor 110, a connector 116, and a connecting wire 44.
, are connected to the input end of the low-pass filter 212 via the connector 222. The low-pass filter 212 integrates the input clamp pulse CP and converts it into a DC signal. The output terminal of the low-pass filter 212 is the comparator 2
14. Comparator 2
A reference voltage vO is set to the other input terminal of 14.

The comparator 214 is composed of an operational amplifier or the like, and its output is connected to the drive circuit of the switch 20.

Comparator 214 closes switch 208 when input voltage Vi satisfies Vi≦vO, and opens switch 208 when Vi>VO.

Power is supplied from the power source 30 to the regulators 2!8 via the power line 32. A stabilized power supply voltage VDD is supplied from the regulator 2113 to the comparator 214 and the connection line 44 via the resistor 210. Here, since the connection line 44 is detachable between the video signal reproducing device IO and the signal processing device 20 through the connectors 118 and 220, the input of the low-pass filter 212 is connected to the power supply voltage V
It is pulled up to the level of DD.

Also, the stabilized power supply voltage vC from the regulator 21B
C is connected to the signal processing circuit 20 via the analog switch 20B.
0.202.

The operation of the circuit power supply control device having the above configuration will be explained with reference to the timing chart shown in FIG.

Now, suppose that the video signal reproducing device 10 is in a non-operating state, and therefore the clamp pulse CP is not output from the pulse generating circuit 108 (FIG. 2(a)). Power supply voltage VDD is supplied to comparator 214 and connection line 44 .

At this time, the transistor 110 is in a cutoff state,
The power supply voltage VDD is directly input to the low-pass filter 212. Therefore, comparator 214
A voltage Vi such that Vi > VO is input to (FIG. 2(C)), and a low level signal is output from the comparator 214 to the analog switch 208. As a result, the analog switch 208 is in the off state, and the signal processing circuits 200 and 202 are connected to the regulator 21G.
is not supplied with power supply voltage VCC.

Thereafter, when the video signal reproducing device 1O enters the operating state at time 0 10, a clamp pulse CP is generated from the pulse generation circuit 108.
is input to the base of transistor 110. (FIG. 2(a)), ) Connection l! from the collector of the transistor 110! The clamp pulse CP output to 44 is inverted (
In FIG. 2(b)), the signal is input to a low-pass filter 212.

The clamp pulse CP is integrated in the Lohas filter 212 (FIG. 2(C)), and the integrated output Vi is input to the comparator 214.

The comparator 214 compares the integral output Vi with the reference voltage vO. In this state, since Vi is less than vO, a high level signal is output from the comparator 214 to the analog switch 208 (see FIG. 2(d)). ), as a result, the analog switch 20 is turned on, and the power supply voltage vCC is applied to the signal processing circuit 20 by the regulator 216.
0,202.

In this way, according to this embodiment, the necessary connection lines are connected between each device of the system without providing a control line for turning on and off the power, and the image is transmitted after providing short-circuit protection. It becomes possible to control the power supply to the signal reproducing device 10 and the signal processing device 20 in synchronization.

Note that in this embodiment, a clamp pulse (pulse train signal) is used as a control signal to control the supply of power, but the present invention is not limited to this, and it is possible to use various signals.

Effects According to the present invention, the minimum necessary connection lines are connected between the device having the main function of the system and the devices attached to it, without providing a control line for turning on and off the power, and these According to the present invention, since the power supply supplied to each device is synchronized and controlled based on the necessary signal in processing the signals transmitted through the connection line, the devices constituting the system can be connected. The number of connection wires can be reduced, and a power switch is not required on the side of the accessory device, thereby making it possible to downsize the system and improve reliability.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the configuration of a system including a circuit IT source control device according to the present invention, and FIG. 2 is a timing chart showing the operation of each part of the circuit power source control device shown in FIG. Explanation of symbols for the end portion 1O...Video signal reproducing device 20...Signal processing device 30...Power supply 10B...Pulse generation circuit 200.202...Signal processing circuit 20th...Analog switch 2 !2...Low pass filter 214...Comparator 216...Regulator

Claims (1)

[Scope of Claims] A first device that outputs a signal and a second device that has signal processing means that processes the signal and is attached to the first device are configured to be powered from a common power source. In the circuit power supply control device for the system, the control device is provided in the first device and sends control signals necessary for signal processing of the second device to the second device via a signal line during its operation. the signal processing means takes in the control signal and processes the signal output from the first device, and the control device further performs the signal processing in the second device. a switch means provided between the means and the power source for turning on/off the power supply from the power source to the signal processing means; and a switch means provided in the second device for integrating the control signal into a DC signal. an integrating means for converting; and a comparing means provided in the second device for comparing the level of the DC signal with a predetermined reference level and controlling on/off of the switching means according to the comparison result. A circuit power supply control device characterized by: