JPS6079878A - Power saving control circuit of video camera - Google Patents

Abstract

PURPOSE:To simplify the constitution and to improve the operability by setting forcibly a VTR to the video recording pause mode when the mode is changed over to the power saving position during the video recording running mode. CONSTITUTION:When the 2nd connection changeover switch SW2 is thrown to the 3rd contact III with the mode switched to the power saving position, a negative pulse is fed to a control line L1 and the VTR to be in the video recording running mode is brought into the video recording pause mode. On the other hand, when the 2nd connection changeover switch SW2 is thrown to either the 1st contact I or the 2nd contact II, since a flip-flop 31 is deenergized, an output of the flip-flop 31 goes to a low level the same as the reset state and a circuit 32 generating command output of operating state applies a pause command signal to the 1st and 2nd contacts I , II.

Description

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

(b) Prior Art Conventional video cameras are equipped with a pause switch to control the running of the tape in the recording mode of the VTR, and more recent video cameras are equipped with a pause switch to prevent power consumption. Therefore, a power saving switch is often provided to minimize the power supply to the circuits in the video camera during the recording pause state.

Therefore, with a video camera equipped with a pause switch and a power saving switch, the user can use VTR'4! : There is a risk of accidentally switching the power saving switch to the power saving state while 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 the recording running mode without receiving signal supply.

Therefore, in order to prevent the above-mentioned malfunction,
No. 34664 allows switching to the power saving state only in the recording pause mode. However, in such a conventional example, each time the user operates the power saving switch, the user has to check whether the power saving state has been set or not, and the camera side has to distinguish between the operating state and the power saving state. Requires display means.

(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.

(2) Structure of the Invention The present invention detects switching to a power saving state and tape running mode, and issues a pause command signal to a conventional VTR provided with a tape running mode setting circuit, a power supply switching circuit, and a mode detection circuit. This is characterized by the provision of a circuit for preventing erroneous recording.

(1+>Example Hereinafter, the present invention will be explained according to an illustrative embodiment.

This embodiment corresponds to the three types of VTRs currently on the market, by changing the three-stage connection changeover switch.
The present invention is applied to a video camera configured to be compatible with all connection methods.

First, in the first connection method, a low level output is supplied to the control line (Ll) 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 trigger line (L2) indicating the mode. In addition, in the second connection method, a command signal with a polarity opposite to that in the first connection method is supplied to the control line (Ll), and the recording mode is detected by receiving a low level output from the tarry line (L2). are doing. Furthermore, in the third connection method, a negative pulse is supplied to the control line (Ll) to invert the tape running mode, and a high level output is received from the evening line (L2) to switch the tape to the normal running mode. Detected.

In order to support the three methods mentioned above, a mode detection circuit (10)
The output from the tarry line (L2) is sent to the buffer circuit (1
1), it is supplied to the third contact (I[[) of the first connection switching switch (SWI) and the negative power of the NOR circuit (12). The supply input of this NOR circuit (12) has a low level
When the tape running command signal of ゛ is completely supplied, the Noah circuit (12)
When the output of the output line (L2) becomes low level and the tape running command is not issued (that is, when the recording running mode of the first or second connection method is detected), the high level output is set to the low level. 1 Connection selector switch (Sth) 1st and 2nd
Supplied to contacts (I) and (II). Therefore, by switching the first, second, and third contacts (I), (I[), and (I[), the recording running mode in the corresponding connection system can be detected.

The gate circuit (13) that inputs the switching output is V
When receiving the reproduced video signal from the TR, it enters a blocking state, and this is to prevent switching output in the reproduction mode when the third contact (I) 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 can be displayed in the viewfinder of the video camera.

In addition, the tape running mode setting circuit (30) is configured to operate a normally open pause switch (PS) by pressing the pause button.
) is closed. This closed circuit is connected to the second connection changeover switch (SW2) which is linked to the first connection changeover switch (SWI).
When selects the third terminal (III), a negative pulse is supplied to the high level control line (Ll), and the tape running mode in the third connection method is reversed. This closed circuit also triggers a clip-flop (31) that is initialized (reset) every time the power is turned on. The instruction output generation circuit (32) that inputs the flip-flop output has two stages of transistors (32) as shown in FIG.
A two-stage inverter is configured by Ql) (Q2), and the output of the first transistor (Ql), which is the first inverter, is connected to the first connection terminal (I), and the second transistor (Q2), which is the second inverter, is connected to the first connection terminal (I). The output of is connected to the second connection terminal (n>
are supplied to each. Therefore, when the flip-flop is initialized, the first contact (1) is at high level and the second contact (II) is at high level, and the pause mode is set in the first and second connection methods. There is. Therefore, the trigger causes the flip-flop (31)
When is reversed, the instruction output is also reversed, so that the tape running mode for both connection methods can be set, and thereafter the instruction output is repeatedly inverted every time the pause switch (PS) is closed.

In addition, the power supply circuit (40) is provided with a first power saving switch (SSI) that can be switched between two positions, an operating position and a power saving position. It supplies power to the circuit. In this embodiment, the instruction output circuit (32) is always powered on.

Next, the erroneous recording prevention circuit (50) switches the first power saving switch (
A second power saving switch (SS2) linked to the SSI is installed. This second power saving switch (SS2) is an analog switch (51) that is closed in the recording mode, and has the same function as the pause switch (PS) only in the recording mode. In other words, when switching to the power saving position, if the third contact (II[) is selected by the second connection changeover switch (SW2), the negative pulse is fully supplied to the control line (Ll) and the VTR is supposed to be in the recording mode. goes into recording pause mode. On the other hand, the second connection changeover switch (SW
2), when either the first or second contact (I) (If) is selected, the power to the flip-flop (31) is turned off, so the flip-flop output becomes a low level, similar to a reset. Therefore, the instruction output generation circuit in the operating state <3
2) supplies a pause command signal to the first and second contacts (I) (I). In this embodiment, in order to save as much power as possible, the flip-flop (31) is
However, in terms of operation, even if the power is energized, it is always reset by a trigger caused by switching the second power saving switch (SS2).

Therefore, according to this embodiment, as long as the connection selector switch (SWI) (SW2) is correctly switched in accordance with the connection method of the VTR to be connected, the operation can be guaranteed.

In addition to the three types of connection methods described above, there is also a third connection method which is a special method in which a blinking signal is received from the tarry line (L2) in the recording pause mode. According to 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 mistakenly set the VTR to recording mode. To support such a system, an integrating circuit and a comparator are placed in the line to the analog switch (51), and the configuration is configured so that the average value of the blinking signal does not reach the controller level. Intermittent opening and closing operations of the 7-chi can be prevented.

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 which is simpler in structure and easier to use than the conventional example, and its effects are outstanding.

[Brief explanation of the drawing]

Each figure shows an embodiment of the present invention, with Figure 1 showing a circuit diagram of this embodiment, and Figure 2 showing a specific circuit diagram of a display output generating circuit. Explanation of main drawing numbers (10)...mode detection circuit, (30)...tape running mode setting circuit, (40)...
... Power supply 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 switching the power supply state of the video camera side circuit between an operating state and a power saving state by operating a power saving switch. 11 source switching circuit, a mode detection circuit that detects the recording mode of the VTR, and an erroneous recording prevention circuit that generates the Bose command signal when the power source switching circuit is switched to a power saving state during the mode detection period. , a power saving control circuit for a video camera.