JPS6234357Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a setting display circuit that displays power supply of an auxiliary power source to a memory having an auxiliary power source.

[Technical background of the invention and its problems]

BACKGROUND ART Conventionally, a method is well known in which various types of data are written and stored in a writable and readable memory (RAM) and read out at a desired timing.
Also, low power consumption type RAM (C-MOS type, etc.)
While the portable power source (obtained by converting the commercial power source) is being supplied, the portable power source is
Power is supplied to the RAM for data retention, writing, and read operations, and while the portable power supply is cut off due to a power outage, etc., the power is supplied to the RAM by switching to an auxiliary power source such as an attached battery, and data retention is performed. The power backup method used is also well known.

As the auxiliary power source used in this power backup method, a relatively long-life primary battery, such as a lithium battery, is used to improve maintenance, workability, and long life, thereby achieving maintenance-free operation for several years or more. Some have. Such batteries are generally RAM
It is mounted on a printed circuit board. For example, many of the printed circuit boards used in button telephone devices are of this type. Further, on the printed circuit board on which this battery is mounted, a battery selection switch is mounted together with the battery to connect or disconnect the battery from the power input terminal of the RAM. This switch is set when the printed circuit board is handed over to the user and used for actual use, and the battery is connected to the RAM to enable battery backup. This is because the circuit may be shorted due to an unexpected accident before the printed circuit board is put into actual use.
This is to keep the battery in an unloaded state for unnecessary periods in order to prevent battery consumption as much as possible due to long-term storage.

However, since this changeover switch is set after being handed over to the user, the changeover setting is not always carried out reliably, and there is a possibility that the changeover setting may be forgotten.

On the other hand, in a system that uses a printed circuit board handed over to the user and requires writing semi-fixed data desired by the user into the RAM on this printed circuit board, the writing state can be set using, for example, a setting switch. We are working on writing this semi-fixed data. Therefore, when using a printed circuit board, the user must write data and set the switch for connecting the battery.

However, as mentioned above, if the switch setting is forgotten, the semi-permanent data written using the power backup method described above will disappear when the power supply to the portable power source is cut off due to a power outage, etc., and the battery backup function is required. It has the disadvantage of causing This semi-fixed data disappears when the power supply to the portable power supply is cut off, so the data is often written at a different time, and after this data disappears, the user realizes that they have forgotten to set the switch and has to rewrite the data. Various inconveniences occurred.

In addition, if you forget to set the switch, please use the display (for example,
One possible method is to use an LED (e.g. LED) to indicate the forgetting setting, but it would be necessary to use an indicator that lights up only in the special case of forgetting the setting.
This results in very poor usage efficiency of the display.

[Purpose of invention]

The present invention has been developed in view of the above-mentioned circumstances, and aims to provide a setting display circuit that can reliably display a forgotten switching setting and notify the user of this fact without using a dedicated display. purpose.

[Summary of the idea]

Therefore, the present invention has achieved the above object by using a display that lights up when data is written to the memory, and by displaying an indication that the switching setting has been forgotten.

[Example of idea]

Hereinafter, the present invention will be explained in detail with reference to the drawings.

The figure is a circuit block diagram showing one embodiment of the present invention, where 1 is a setting switch, 2 is a resistor, and 3 is an LED.
4 is a power outage control signal input terminal, 5 is a setting data output terminal, 6 is a first battery backup circuit, and 7 is a second battery backup circuit.
The LED display 3 has one end connected to the portable DC power supply Vcc and the other end connected to one end of the resistor 2.
The other end is connected to the terminal 5 and one end of the setting switch 1, and the other end of the setting switch 1 is grounded. Further, the first and second battery backup circuits 6 and 7 have the same configuration, and the transistors 61 and 7 have the same configuration.
71, resistor 62, 72, capacitor 63, battery selector switch 64, 74, diode 65, 75,
Resistor 66, 76, primary battery 67, 77, RAM
(Random access memory) It consists of 68 and 78. The emitters of these transistors 61 and 71 are connected to the portable DC power supply Vcc, and the bases are connected to the resistor 6.
2 and 72 to the terminal 4. Collectors of the transistors 61 and 71 are connected to battery selector switches 64 and 74, one ends of capacitors 63 and 73, and power input terminals of RAMs 68 and 78. Further, the other ends of the capacitors 63 and 73 are grounded. A series circuit consisting of diodes 65, 75, resistors 66, 76, and batteries 67, 77 is connected to the a contacts (power contacts) of the battery selector switches 64, 74, and the b contacts are connected to the LED display 3 and resistor 2. connected to a connection point.

Next, this operation will be explained. Transportable DC power supply
When Vcc is being supplied, the potential of the power failure control signal input from terminal 4 is 0V, transistors 61 and 71 are conductive, and portable DC power Vcc is supplied to RAMs 68 and 78. ing. In this state, RAM68,78
When attempting to write semi-permanent data, close setting switch 1 and connect terminal 5.
A switch signal indicating the switch state (here, closed state) of the setting switch 1 is transmitted to a control circuit (for example, a CPU, etc.) not shown. The control circuit controls RAM68, 78 based on the switch signal.
Allow data to be written to and perform that operation.

By the way, when the setting switch 1 is closed, the LED display 3 is turned on by power supplied from the portable DC power supply Vcc. However, if either of the battery selector switches 64, 74 is switched to the contact b side, the LED display 3 is shunted by the transistor 61 or the transistor 71, and therefore remains off without being turned on. Therefore, at least one of the battery selector switches 64 and 74 is connected to the contact a.
If the setting switch 1 is closed without being switched to the side, the LED display 3 will not light up, so the user can be informed that the setting has been forgotten. still,
Even if the LED indicator does not light up, terminal 5
Since it has no effect on the switch signal output from the switch, it does not interfere with the setting operation itself.

Furthermore, if the supply of the portable DC power supply Vcc is cut off, the power failure control signal input via the terminal 4 becomes a high impedance signal, so the transistor 6
1 and 71 are in the OFF state (non-conducting state), and the diodes 65 and 75 and the resistor 6 are connected from the batteries 67 and 77.
Electric power for holding data contents is supplied to the RAMs 68 and 78 via the RAMs 6 and 76. diode 6
5 and 75 are for backflow prevention.

[Effects of the invention] As explained above, according to the invention, the display that displays the write setting status of RAM has the function of displaying the switching connection setting of the auxiliary power source such as a battery, thereby eliminating the need for an unnecessary display. You can easily switch and confirm forgotten connection settings without adding any additional settings.
Further, since the switch signal itself of the setting switch means is not affected in any way, no problem occurs even if semi-fixed data is written into the memory regardless of the switch state of the changeover switch means. Furthermore, since the display operation can be performed with a configuration that does not affect the power supplied to the battery, there is no problem with battery consumption, and the power consumption is also reduced because the display turns on only when necessary. I can do it. Furthermore, even if it is necessary to switch a plurality of auxiliary power sources, it is possible to monitor whether all the auxiliary power sources have been forgotten to switch using one display.

[Brief explanation of the drawing]

The figure is a circuit block diagram showing one embodiment of the present invention. Vcc...Transportable DC power supply, 1...Setting switch,
3...LED display, 61,71...Transistor, 64,74...Battery selection switch, 67,7
7...Battery, 68,78...RAM.

Claims (1)

[Claims for Utility Model Registration] (1) A memory in which data can be written, an auxiliary power source for this memory, and a switch that connects the auxiliary power source to the power input terminal of the memory by switching to the power contact side. a switch means, a setting switch means which allows data writing to the memory by being switched to the setting contact side, a display, and a switch state of the changeover switch means and the setting switch means;
and a display drive means for controlling blinking of the display, the display drive means having the changeover switch means switched to the power contact side, and the setting switch means switched to the setting contact side. A setting display circuit characterized in that the display device is turned on when the display device is turned on. (2) A plurality of memories and corresponding auxiliary power sources and changeover switch means are provided, and the display drive means causes the display to light up when all the changeover switch means are switched to the power contact side. A setting display circuit as set forth in claim (1) of the utility model registration claim.