JPH043711B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a power saving control circuit for a video camera provided with a power saving switch.

(b) Prior Art Video cameras are usually equipped with a pause switch to control tape running in the VTR's recording mode.Furthermore, recent video cameras are equipped with a pause switch to control tape running in the VTR's recording mode. A power saving switch is often provided to minimize the power supply to the circuitry within the video camera when in a pause state.

Therefore, in a video camera equipped with both a pause switch and a power saving switch, there is a risk that the user may accidentally switch the power saving switch to the power saving state while the VTR is in recording mode. The power saving state of a video camera differs somewhat depending on the model, but at least the captured video signal is not derived. Therefore,
The VTR enters recording mode without receiving signal supply.

Therefore, in order to prevent the above-mentioned malfunction, Japanese Utility Model Application Publication No. 57-34664 allows switching to the power saving state only in the recording pause mode. but,
In such a conventional example, each time the user operates the power saving switch, the user must check whether the power saving state is set or not, and the camera side requires display means to identify the operating state and the power saving state. Requires.

(c) Object of the Invention In view of the above-mentioned points, the present invention is characterized in that when the VTR is switched to the power saving state during the recording running mode, the VTR is forcibly set to the recording pause mode.

(d) Structure of the Invention The present invention is directed to a conventional VTR equipped with a tape running mode setting circuit, a power supply switching circuit, and a mode detection circuit.
In contrast, the present invention is characterized by being provided with an erroneous recording prevention circuit that detects switching to a power saving state and tape running mode and issues a pause command signal.

(E) Embodiment The present invention will be described below with reference to an illustrative embodiment.

This example uses three methods currently on the market.
The present invention is applied to a video camera configured to be compatible with all connection methods by switching a three-stage connection changeover switch in accordance with VTR.

First, in the first connection method, a low level output is supplied to the control line L1 that sets the tape running of the VTR to issue a tape running command, and a high level output is supplied to issue a pause command.
The recording mode is detected by receiving a low level output from the Tarley line L2 indicating the mode. In addition, in the second connection method, the control line L1 is connected to the first
In addition to supplying a command signal with a polarity opposite to that of the connection method, the recording drive mode is detected by receiving a low level output from the Tally line L2. Furthermore, in the third connection method, a negative pulse is supplied to the control line L1 to invert the tape running mode, and
The normal running mode of the tape is detected by receiving a high level output from the tarley line L2.

In order to support the three methods described above, the mode detection circuit 10 supplies the output from the Tally line L2 to the third contact of the first connection switching switch SW1 and one input of the NOR circuit 12 via the buffer circuit 11. . A low level tape running command signal is supplied to the other inputs of this NOR circuit 12.
When the output of the tally line L2 becomes low level and a tape running command is issued (that is, when the recording running mode of the first and second connection methods is detected), the high level output is switched to the first connection. It is supplied to the first and second contacts of switch SW1. Therefore, by switching the first, second, and third contacts, it is possible to detect the recording running mode in the corresponding connection system. The gate circuit 13 to which the switching output is input enters a blocking state upon receiving the reproduced video signal from the VTR, and this is to block the switching output in the reproduction mode when the third contact is selected. Therefore, the detection output of the recording running mode is derived from the gate 13.
When this detection output is input to the display circuit 2, the recording running mode is displayed in the viewfinder of the video camera.

Further, the tape running mode setting circuit 30 closes the normally open pause switch PS by pressing the pause button. This closed circuit supplies a negative pulse to the high-level control line L1 when the second connection changeover switch SW2, which is interlocked with the first connection changeover switch SW1, selects the third terminal. Inverts the tape running mode. This closed circuit also triggers the clip-flop 31, which is initialized (reset) each time the power is turned on. The instruction output generation circuit 32 inputting the flip-flop output has a second
As shown in the figure, a two-stage inverter is configured by two-stage transistors Q1 and Q2, and the output of the first transistor Q1, which is the first inverter, is
The output of the second transistor Q2, which is a second inverter, is also supplied to the second connection terminals. Therefore, when the flip-flop is initialized, the first contact is at high level and the second contact is at low level, setting the pause mode in the first and second connection systems. Therefore, the trigger triggers the flip-flop 31.
When is reversed, the instruction output is also reversed, so the tape running mode for both connection methods is set, and thereafter, the instruction output repeats inversion every time the pause switch PS is closed.

Further, the power supply circuit 40 has two positions, an operating position and a power saving position.
A first power saving switch SS1 is provided which can be switched to the operating position, and the flip-flop 31 is switched to the operating position.
and many other circuits except for some. In this embodiment, the instruction output circuit 32 is always in a power-energized state.

Next, the erroneous recording prevention circuit 50 is provided with a second power saving switch SS2 that is interlocked with the first power saving switch SS1. This second power saving switch SS2 is a pause switch only in the recording mode by the analog switch 51 which is closed in the recording mode.
Performs the same function as PS. In other words, when switched to the power saving position, the third contact is switched to the second connection changeover switch.
If SW2 is selected, control line L1
A negative pulse is supplied to the VCR, which should have been in recording run mode, but falls into recording pause mode. On the other hand, the second
Connection changeover switch SW2 switches the first and second contacts,
When any one of them is selected, the power to the flip-flop 31 is turned off, and the flip-flop output goes to a low level similar to a reset, so the instruction output generation circuit 32 in the operating state is
A pause command signal will be supplied to the contact. In this embodiment, in order to save as much power as possible, the flip-flop 31 is de-energized in the power-saving state, but in terms of operation, even if the power is energized,
It is always reset by the trigger caused by switching the second power saving switch SS2.

Therefore, according to this embodiment, the connection changeover switch SW1,
As long as SW2 is switched correctly, its operation is guaranteed.

In addition to the three types of connection methods mentioned above, in the third connection method, in the recording pause mode, the Tali line L2
There are also special methods that receive more blinking signals. In this method, the display circuit 2 operates intermittently in the recording pause mode, causing the display element to blink. Further, the analog switch 51 is also intermittently closed, and there is a risk that the second power saving switch SS2 may erroneously set the VTR to the recording mode. To support such a system, an integrating circuit and a comparator are placed in the line to the analog switch 51, and if the configuration is configured so that the average value of the blinking signal does not reach the comparator level, the intermittent opening and closing of the analog switch can be avoided. Actions can be prevented.

(F) Effects of the Invention Therefore, according to the present invention, since the power saving operation is prioritized over the setting operation of the tape running mode, it is possible to provide a power saving control circuit that is simpler in structure and easier to use than the conventional example, and its effects are significant. be.

[Brief explanation of drawings]

Each figure shows an embodiment of the present invention, with FIG. 1 showing a circuit block diagram of this embodiment, and FIG. 2 showing a specific circuit diagram of a display output generating circuit. Explanation of main figure numbers, 10...Mode detection circuit, 3
0... Tape running mode setting circuit, 40... Power switching circuit, 50... Erroneous recording prevention circuit.

Claims (1)

[Claims] 1. A tape running mode setting circuit that supplies a tape running command signal and a pause command signal to the VTR by operating a pause switch, and changing the power supply state of the circuit on the video camera side to an operating state and a power saving state by operating a power saving switch. a mode detection circuit that detects a recording running mode of the VTR; and an erroneous recording prevention circuit that generates the pause command signal when the power supply switching circuit is switched to a power saving state during the mode detection period. A power saving control circuit for a video camera consisting of the following.