JPH0269727A - Power failure detection method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a power failure detection method.

(Prior art) Fig. 3 is a partially cutaway exploded plan view showing the battery loading section of a camera using a conventional battery power source, and Fig. 4 is a partially cutaway exploded plan view showing the connection between the conventional camera and an external power source. 3, 1 is the camera body, 2 is the battery, 3 is the battery cover, 4 is a battery cover open detection switch that detects when the battery 2 is removed from the main body 1, and FIG. Inside, 5 is a device having the same shape as a battery 2 that supplies power to the main body 1 from an external power source via an AC adapter 6.

Next, we will discuss the third issue regarding devices that use battery power, such as cameras.
This will be explained using FIG.

Traditionally, battery-powered devices, such as cameras,
For devices that can cause problems if the battery is suddenly removed and the power is cut off during operation, a non-volatile memory element (E" F
When it is necessary to write to the E"FROM), the battery cover opening detection switch 4 detects that the battery cover 3 is opened to remove the battery, and the current state (number of shots) is immediately written to the E"FROM. A device is known in which the device is equipped so that the next time the battery 2 is inserted, the continuation can be carried out without any trouble.Furthermore, as shown in Fig. 4, instead of the battery 2, a device having the same shape as the battery is used. 5 is configured to receive power supply from an external power supply device such as an AC adapter 6. Similarly to the above, even if the battery-shaped device 5 is removed and the power is turned off, the battery cover 3 can be opened. There is a device known that can detect the battery with the detection switch 4 in the same manner as described above, take the same measures as in the case of the battery 2, and continue without any trouble. A camera device is shown in which a battery ejecting prevention member is added near the battery storage chamber to lengthen the time it takes to remove the battery.

(Problems to be Solved by the Invention) As described above, in the conventional example, as shown in FIG. If the outlet is unplugged or the connection cord 7 between the AC adapter 6 and the battery-shaped device 5 is disconnected, the battery cover open detection switch 4 of the battery cover 3 will not operate, so the current state of the camera 1 will not be activated. There was a problem that no writing was done to the E2FROM, which caused errors and hindered operation when the power was turned on again.

This invention has been made in order to solve the problems of the conventional example as described above. It is an object of the present invention to obtain a device that can operate without any trouble even when the power is cut off due to disconnection.

[Means to solve the problem]

Therefore, in the present invention, in a device using a battery power supply, when the device is operated by being supplied with power from an external source via a device having the same shape as the battery, a power supply is provided that supplies power when the power is cut off. The above object is achieved by predicting an external power outage by providing means and a voltage detecting means for constantly monitoring the power supply voltage at regular time intervals and detecting a drop in the voltage.

[Effect]

In the power failure detection method of the present invention, when a power failure occurs, the power supply means supplies power, the voltage detection means constantly monitors the power supply voltage at fixed time intervals, detects a voltage drop, and detects an external power failure. Predict.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing a power failure detection system according to an embodiment of the present invention, and FIG. 2 is a flowchart for controlling the operation of this embodiment. Components are represented by the same reference numerals, and duplicate explanations will be omitted.

Further, in FIG. 1, 8 is a camera control device which is an embodiment of the present invention, and the power supply voltage is divided by a resistor 10.
The converter 8a performs A/D conversion, reads data, and constantly monitors the power supply voltage. Next, 9 is a battery cover open detection switch, and 12 is a power supply means (L) that supplies power by charged charges when the power is cut off, and its capacity is approximately determined by the following equation (1).

In the above formula (1), the power supply monitoring interval is tlee, and the interval during camera operation is 70. The maximum value of the average current at is denoted by {circle around (2)}, the minimum power supply voltage at which the camera can continue to operate is denoted by VMin, and the voltage supplied from the AC adapter 6 to the battery-shaped device 5 is denoted by vIn. 13 is a diode, 14 is a film feeding device,
15 is a shutter, 16 is a photometer, 17 is a 22F ROM in which the current state, for example, the number of shots is written when a drop in power supply voltage is detected, in preparation for the next power-on, 18 is an operation switch, and 19 is a power regulator. The voltage detection means (M) is the control device 8. Battery cover open detection switch9. It is composed of resistors to and tt, and as described above, the control device 8
This is a means of constantly monitoring the power supply voltage at regular intervals and detecting a drop in the power supply voltage.

It should be noted that when the battery cover open detection switch 9 is operated, the control device 8 determines that the battery or the battery-shaped device 5 will be removed soon, and writes the current state to the E2P ROM 17, as described in the conventional example. There is, but this E
'Rewriting FROM usually requires several tens of m5ec, so the mechanism and arrangement of the battery cover, battery cover open detection switch 9, and battery or battery shape device 5 should be changed after the battery cover open detection switch is activated. The structure is such that it always takes several tens of m5ec or more until the instrument 5 is removed.

Next, the operation of this embodiment will be explained using FIG.

In FIG. 1, when a device using a battery power source, such as a camera, is operated by being supplied with power from an AC adapter 6, which is an external power source, through a device 5 having the same shape as the battery, the control device 8 is kept constant. A/D converter 8a converts the divided voltage obtained by dividing the power supply voltage by resistor 10.11 at time intervals, that is, at fixed cycles, for example, every few m5ec,
It is constantly monitored by reading it (voltage detection means (M)).

In this way, during monitoring, if the connection cord 7 between the AC adapter 6 and the battery-shaped appliance is suddenly cut, or if the outlet 6b is suddenly pulled out, that is, if the power is cut off, the power supply means Since the capacitor 12 (L) supplies power to the camera using the charged electric charge, the camera continues to operate normally for a while. During this time, if the voltage detection means (M) detects a drop in the power supply voltage, the control device 8
predicts that the external power will be turned off, writes the current state, for example, the number of images to be taken, in the E2FROM 17, and prepares for the next power-on.

In this case, since the capacitance of the capacitor 12 is configured to the above-mentioned value, it is possible to hold the number of hours + m5ec for writing the current state into the E2F ROM 17 after the voltage detection means (M) detects a power drop. .

Next, the operation of this embodiment will be further explained with reference to the flowchart of FIG. 2, focusing on the voltage detection means.

In Figure 2, start and step 2a resistor 10
．． The input power supply voltage divided by 11 is A/D converted by the A/D converter 8a (Fig. 1), and then step 2b
The A/D converted and input voltage is read every few m5ec, and then it is determined whether the voltage has decreased below the standard voltage (Step 2c). If it has decreased, the current state is stored in the E"P ROM 17. (Fig. 1) (step 2d). If it has not decreased, return to step 2C. Step 2d advances to step 2e, determines whether the voltage has recovered, and if it has recovered, returns to step 2b,
If it has not recovered, proceed to step 2f and turn the power to 0FFL.
, and if the power is OFFFFL/, it ends and the power is OFF.
If it is not FF, return to step 2e.

(Effects of the Invention) As explained above, according to the present invention, in a device using a battery power source, when the device operates by being supplied with power from the outside via a device having the same shape as the battery,
In the case of a power outage, a power supply means for supplying power and a voltage detection means for constantly monitoring the power supply voltage at regular time intervals and detecting a drop in the voltage are provided to predict the external power outage, so it is not necessary to open the battery cover. It is possible to obtain a device that can operate without any trouble even when the power is cut off due to disconnection of the AC outlet 6b on the side of the AC adapter 6 or disconnection of the cord 7, etc., when the detection switch 9 does not operate.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a power failure detection method according to an embodiment of the present invention, Fig. 2 is a flowchart for controlling the operation of this embodiment, and Fig. 3 is a battery of a camera using a conventional battery power source. FIG. 4 is a partially cutaway exploded plan view showing the loading section, and FIG. 4 is a partially cutaway exploded plan view showing the connection between a conventional camera and an external power source. 1.---Camera 2---Battery 4.9---One battery cover open detection switch 5---One battery shaped device 8---Control device 10.11---Resistance ! 2. Capacitor 17 --- E'F ROM L --- Power supply means M --- Voltage detection means

Claims (1)

[Claims] In a device using a battery as a power source, when the device operates by being supplied with power from an external source via a device having the same shape as the battery, a power supply means for supplying power when the power is cut off, and a power supply voltage and a voltage detection means for constantly monitoring the voltage at regular time intervals and detecting a drop in the voltage, thereby predicting a power outage of the external power supply.