JPS61822A - Electronic device with display of warning for fluctuation of power supply voltage - Google Patents

Abstract

PURPOSE:To detect the fluctuation of power supply voltage with various types of electronic devices by using a circuit which detects the fluctuation of the power supply voltage and displays an alarm for generation of a fault in case the detected voltage fluctuation exceeds a prescribed level. CONSTITUTION:The fluctuated voltage of an AC line power supply 1 are held by holding circuits 8 and 9 after the reduction of voltage and the full-wave rectification. This held voltage VC27 is supplied to operational amplifiers 13 and 14 through a voltage follower 10 and set at logic 1 when it is higher or lower than the voltage levels set by variable resistors 11 and 12 respectively. A delay circuit 19 delays a zero cross pulse TZ25 by a prescribed period of time and delivers a timing signal TS26 that detects the abnormal fluctuated voltage. Therefore, the output of an OR circuit 15 secures an AND with the signal TS26 and is turned into an interruption signal TB29 of a microprocessor 17. The processor 17 produces a voltage read pulse TR18 when an interruption is applied and reads the output voltage of the follower 10 through an A/D converter 20 to transfer data to a display device 21 for display of an alarm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to means for detecting abnormalities in power supply fluctuations in commonly used equipment, particularly electronic equipment, and displaying a warning.

[Prior art]

BACKGROUND ART Conventionally, almost no devices for general users, especially electronic devices of the stand-alone type, have a means for detecting power fluctuations, and furthermore, there is no device that displays a warning when abnormal power fluctuations have occurred. For this reason, problems such as equipment malfunctions and deterioration of performance and quality (for example, blurred images in the case of electronic copying machines) due to the above-mentioned abnormal voltage fluctuations have been caused. This has the disadvantage that it is difficult to ascertain the cause of the problem and gives the user or service personnel a sense of distrust that the device is simply unstable.

〔the purpose〕

The present invention has been made in view of the above problems, and it not only clarifies the cause of the trouble by displaying a warning when there is an abnormal fluctuation in the power supply, but also helps users and service personnel to solve the problem. It also aims to improve confidence in the equipment.

〔Example〕

The present invention will be explained below based on the drawings. FIG. 1 shows an embodiment of a circuit configuration according to the present invention. FIG. 2 is a waveform diagram of each part of the signal. In Fig. 1, 1 is an AC line power supply, 2 is a power switch for the equipment, 3 is a pressure reducing transformer for detecting the fluctuating voltage of the power supply, 4 is a full-wave rectifier circuit for AC/DC conversion, and 5 is a full-wave rectifier circuit for AC/DC conversion. , zero cross pulse Tz
25, 8 and 9 are circuits for holding the peak value of the full-wave rectified sales voltage, and 7
is a circuit for discharging the holding voltage, and the discharge timing is performed by supplying a zero cross signal '14rT z 25 to the circuit 7 through the driver 6. Therefore, the holding voltage Vc27 becomes as shown in FIG.

Next, this holding voltage Vc27 is supplied to each operational amplifier 13.14 through the voltage follower 10, but when it is higher or lower than the voltage set by each variable resistor 11.12, operational amplifier 13.1
The output of 4 logically becomes ki 1. The operational amplifier 13 is
The operational amplifier 14 performs the detection when the input voltage is smaller than the set value and when it is larger than the set value. 15 is the OR of the outputs of each operational amplifier 13 and 14
It is a 01% circuit that takes . Reference numeral 19 denotes a delay circuit that delays the zero-crossing pulse Tz25 by a predetermined time, and is used to generate a timing signal Ts26 for detecting an abnormally fluctuating voltage. Therefore, the output of the OR circuit 15 is
It is ANDed with the signal Ts26 through the AND circuit 16, and then supplied to the microprocessor 17 as an interrupt signal TB29.

When an interrupt occurs to the microprocessor 17, the processor 17 performs necessary interrupt processing, issues a voltage read pulse TR1B, reads the output voltage of the voltage follower 10 through the A/D converter 20, and then displays the display device 21. Then, data for displaying a warning to report that an abnormal voltage has occurred is transferred, or data is transferred to the printer 22 in order to save the contents of the warning.

If this warning display occurs during the device's normal operating sequence, it can be displayed after the operating sequence continues, or it can be displayed immediately at the time of occurrence, such as by transferring necessary data. It is also possible to immediately stop the sequence and display a warning.

Next, the signal waveforms of each part will be explained with reference to FIG.

23 is the input AC line voltage waveform in FIG.
In Japan, the rated value is 100V effective value. 24 VR
is a waveform obtained by rectifying the voltage reduced by the pressure reducing transformer 3 at a predetermined ratio by the full-wave rectifier circuit 4, and the pressure reduction ratio is stored in the microprocessor 17 in advance. Tz of 25 is the zero cross pulse generated from the voltage VR24, TsU of 26 is this zero cross pulse Tz2
6 is delayed by a predetermined period of time, and is used to set the timing for interrupting the microprocessor 17. VC 27 is a signal that holds the peak value of the reduced voltage, and because it is discharged at timing Tz, it has a waveform as shown in the figure.

28 Vo is the waveform when the signal Vc is lower than the set voltage by half a cycle, and in this case, the interrupt signal T
s29 occurs at the timing shown in FIG.

〔effect〕

As explained above, according to the present invention, the circuit is configured to display a warning when the fluctuation value of the power supply voltage exceeds a predetermined value, so by incorporating this circuit into the equipment,
Since the state of abnormal fluctuations in the power supply voltage can be accurately grasped, the corrective action can be taken without guessing as required in the past, which in turn increases the user's or service personnel's confidence in the equipment. can also be improved.

[Brief explanation of the drawing]

FIG. 1 shows an example of a circuit configuration according to the present invention. FIG. 2 is a waveform diagram of each part of the signal. 1... AC line power supply 3... Voltage reducing transformer 5... Zero cross circuit 13.14... Operational amplifier 16...
...AND circuit 17...Microprocessor 21...Display device

Claims (1)

[Claims] A power supply voltage fluctuation warning display comprising means for detecting and storing power supply voltage fluctuations, and means for displaying a warning of the occurrence of abnormal power supply fluctuations when the detected fluctuation value exceeds a predetermined value. Electronic equipment with.