Input power monitoring circuit

Abstract

To provide an input power supply monitoring circuit capable of accurately determining a change in voltage of an input power supply.SOLUTION: An input power supply monitoring circuit includes: a rectification circuit 2; a divided voltage generation circuit 3; a divided voltage comparison circuit 4; a switching circuit 5; and an arithmetic unit 6. The divided voltage comparison circuit 4 is configured such that the polarity of an output signal outputted from a first comparator 41 when a first rectification divided voltage P2 exceeds a first comparison voltage 43 is opposite to the polarity of an output signal outputted from a second comparator 42 when a second rectification divided voltage P3 exceeds a second comparison voltage 44, and an output terminal OUT-A of the first comparator 41 is connected to an output terminal OUT-B of the second comparator 42. In the switching circuit 5, a connection point 45 of the output terminal OUT-A of the first comparator 41 and the output terminal OUT-B of the second comparator 42 is connected to an input terminal 53. The arithmetic unit 6 measures a frequency of a pulse signal outputted from the switching circuit 5 and determines a voltage state of an input power supply.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an input power supply monitoring circuit. [Background technology]

[0002] Patent Document 1 discloses an input voltage monitoring circuit that receives an AC power supply and monitors its voltage. This input voltage monitoring circuit compares the pulsating voltage generated by rectifying the AC power supply with a predetermined threshold voltage to form a pulse corresponding to the voltage waveform of the AC power supply, and monitors the voltage of the AC power supply by comparing the time width of the pulse with a predetermined time width. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-322192 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the case of the method of determining the voltage of an AC power supply based on the pulse time width as in Patent Document 1, the pulse width fluctuates greatly due to voltage distortion, making it difficult to accurately determine the voltage of the AC power supply. Therefore, there is room for further improvement in terms of accurately monitoring the voltage of the input power supply.

[0005] The present invention provides an input power supply monitoring circuit that can accurately determine changes in the voltage of the input power supply. [Means for solving the problem]

[0006] An input power supply monitoring circuit according to one aspect of the present invention comprises: a rectifier circuit that rectifies a periodic input power supply to generate a rectified voltage; a voltage division generating circuit that divides the rectified voltage to generate a first rectified divided voltage and a second rectified divided voltage that is lower than the first rectified divided voltage; a voltage division comparison circuit including a first comparator that compares the first rectified divided voltage with a first comparison voltage and a second comparator that compares the second rectified divided voltage with a second comparison voltage; a switching circuit that outputs a pulse signal corresponding to a voltage state of the input power supply based on an output signal output from the first comparator and an output signal output from the second comparator; a computing device that determines a voltage state of the input power source based on the pulse signal; Equipped with The voltage division comparison circuit a polarity of an output signal output from the first comparator when the first rectified divided voltage exceeds the first comparison voltage is opposite to a polarity of an output signal output from the second comparator when the second rectified divided voltage exceeds the second comparison voltage, and an output terminal of the first comparator and an output terminal of the second comparator are connected, The switching circuit an input terminal is connected to a connection point between the output terminal of the first comparator and the output terminal of the second comparator; The computing device measuring a frequency of the pulse signal and determining the voltage state of the input power source based on the measured frequency; death , The voltage state of the input power supply is determined by detecting a high period or a low period of the output signal output from the second comparator. do. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an input power supply monitoring circuit that can accurately determine changes in the voltage of the input power supply. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an input power supply monitoring circuit according to an embodiment of the present invention. [Figure 2] 10A and 10B are diagrams illustrating a voltage waveform of a rectified divided voltage when the voltage of an input power supply is not fluctuating, and an output waveform of a switching circuit. [Figure 3]10A and 10B are diagrams illustrating a voltage waveform of a rectified divided voltage when the voltage of an input power supply drops, and an output waveform of a switching circuit. [Figure 4] 10A and 10B are diagrams illustrating the voltage waveform of a rectified divided voltage and the output waveform of a switching circuit when the voltage of the input power supply is further reduced. [Figure 5] 10A and 10B are diagrams illustrating a voltage waveform of a rectified divided voltage when the voltage of an input power supply rises, and an output waveform of a switching circuit. [Figure 6] 10A and 10B are diagrams illustrating the voltage waveform of a rectified divided voltage and the output waveform of a switching circuit when the input power supply voltage is further increased. [Figure 7] 10 is a flowchart showing a voltage determination process of the arithmetic device. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For the sake of convenience, the description of components having the same reference numerals as those already described in the description of the embodiments will be omitted. Furthermore, for the sake of convenience, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component.

[0010] FIG. 1 is a diagram showing an input power supply monitoring circuit according to an embodiment of the present invention. As shown in FIG. 1, the input power supply monitoring circuit 1 includes a rectifier circuit 2, a voltage divider generating circuit 3, a voltage divider comparison circuit 4, a switching circuit 5, and an arithmetic unit 6. The input power supply monitoring circuit 1 also has input terminals Vin1 and Vin2 to which the voltage of the power supply to be monitored is input. For example, an AC voltage (200 V AC at 60 Hz) from a commercial power supply is input to the input terminals Vin1 and Vin2. Note that, in the illustrated example, a case is described in which the voltage of an AC power supply is input, but the power supply to be monitored is not limited to an AC power supply. The input power supply voltage may be a voltage having periodicity such as a sine wave.

[0011] The rectifier circuit 2 is configured as a bridge-type full-wave rectifier circuit made up of rectifier elements of four diodes D1 to D4. An input terminal Vin1 is connected to a terminal 21 of the rectifier circuit 2, and an input terminal Vin2 is connected to a terminal 23. The rectifier circuit 2 full-wave rectifies the AC voltage of the AC power supply input to the input terminals Vin1 and Vin2, and generates a pulsating rectified voltage P1.

[0012] The voltage divider circuit 3 resistively divides the rectified voltage generated by the rectifier circuit 2. In the illustrated example, the voltage divider circuit 3 is composed of four resistors, resistors 31 to 34. The resistors 31 to 34 are connected in series between terminal 22 and terminal 24 of the rectifier circuit 2. The connection line between resistor 34 and terminal 24 is connected to ground GND1. The resistance values ​​of the resistors 31 to 34 are determined so that the voltage value at a connection point 35 between resistor 32 and resistor 33 and the voltage value at a connection point 36 between resistor 33 and resistor 34 are predetermined voltage values ​​that are set as input voltages to the voltage divider comparison circuit 4.

[0013] The voltage divider generating circuit 3 resistively divides the rectified voltage P1 generated by the rectifier circuit 2 to generate a first rectified divided voltage P2 and a second rectified divided voltage P3 that is lower than the first rectified divided voltage P2. The first rectified divided voltage P2 is a rectified divided voltage that is output to a connection point 35. The second rectified divided voltage P3 is a rectified divided voltage that is output to a connection point 36.

[0014] The voltage-divided comparison circuit 4 has at least two comparators functioning as comparators. Of the two comparators, the first comparator 41 has an input terminal IN-A and an output terminal OUT-A. The second comparator 42 has an input terminal IN-B and an output terminal OUT-B. The input terminal IN-A of the first comparator 41 receives a first rectified divided voltage P2 output from a connection point 35 of the voltage-divided generation circuit 3. The input terminal IN-B of the second comparator 42 receives a second rectified divided voltage P3 output from a connection point 36 of the voltage-divided generation circuit 3. The first comparator 41 compares the first rectified divided voltage P2 input to the input terminal IN-A with a preset first comparison voltage 43. The second comparator 42 compares the second rectified divided voltage P3 input to the input terminal IN-B with a preset second comparison voltage 44.

[0015] The input terminal IN-A of the first comparator 41, to which the first rectified divided voltage P2 is input, is an inverting input terminal. The input terminal IN-B of the second comparator 42, to which the second rectified divided voltage P3 is input, is a non-inverting input terminal. Therefore, the polarity of the output signal output from the first comparator 41 when the first rectified divided voltage P2 exceeds the first comparison voltage 43 is opposite to the polarity of the output signal output from the second comparator 42 when the second rectified divided voltage P3 exceeds the second comparison voltage 44. Specifically, the first comparator 41 is configured so that when the first rectified divided voltage P2 input to the input terminal IN-A exceeds the first comparison voltage 43, the output of the output terminal OUT-A becomes Low, and when the first rectified divided voltage P2 becomes lower than the first comparison voltage 43, the output of the output terminal OUT-A becomes High. The second comparator 42 is configured so that when the second rectified divided voltage P3 input to the input terminal IN-B exceeds the second comparison voltage 44, the output of the output terminal OUT-B becomes High, and when the second rectified divided voltage P3 becomes lower than the second comparison voltage 44, the output of the output terminal OUT-B becomes Low. The output terminal OUT-A of the first comparator 41 and the output terminal OUT-B of the second comparator 42 are connected at a connection point 45.

[0016] The switching circuit 5 outputs voltage information corresponding to the voltage state of the AC power supply as a pulse signal based on the output signal output from the first comparator 41 and the output signal output from the second comparator 42 of the voltage dividing comparison circuit 4. An input terminal 53 of the switching circuit 5 is connected to a connection point 45 between the output terminal OUT-A of the first comparator 41 and the output terminal OUT-B of the second comparator 42.

[0017] The switching circuit 5 is configured with an insulating element capable of insulating the voltage dividing and comparing circuit 4 side from the arithmetic unit 6 side. The insulating element is, for example, a photocoupler consisting of a light-emitting diode 51 and a phototransistor 52. The light-emitting diode 51 has an anode connected to an input terminal 53 of the switching circuit 5 and a cathode connected to a terminal 54 connected to ground GND1. The phototransistor 52 is disposed opposite the light-emitting diode 51, has a collector connected to an output terminal 55 of the switching circuit 5, and an emitter connected to a terminal 56 connected to ground GND2. The input terminal 53 of the switching circuit 5 is connected to a power supply V1 via a resistor 57 and to ground GND1 via a resistor 58. The output terminal 55 is connected to power supply V2 via a resistor 59. Ground GND1, to which the GND terminal 46 of the voltage dividing and comparing circuit 4 and the cathode of the light-emitting diode 51 in the switching circuit 5 are connected, and ground GND2, to which the emitter of the phototransistor 52 in the switching circuit 5 is connected, are configured as isolated GNDs such that no current flows between them.

[0018] The switching circuit 5 converts the electrical signals output from the first comparator 41 and the second comparator 42 into light using the light-emitting diode 51, receives the light using the phototransistor 52, and converts it back into an electrical signal, thereby transmitting the signal while electrically insulating the voltage dividing comparison circuit 4 side from the arithmetic unit 6 side. When the input terminal 53 of the switching circuit 5 is high, the light-emitting diode 51 turns on, and when it is low, the light-emitting diode 51 turns off. When the light-emitting diode 51 turns on, the phototransistor 52 turns on, and a low signal is output from the output terminal 55 of the switching circuit 5. When the light-emitting diode 51 turns off, the phototransistor 52 turns off, and a high signal is output from the output terminal 55 of the switching circuit 5.

[0019] The arithmetic unit 6 determines the voltage state of the AC power supply based on the output signal output from the output terminal 55 of the switching circuit 5. The arithmetic unit 6 detects the rising edge or falling edge of the output signal output from the output terminal 55. The arithmetic unit 6 measures the frequency (pulse interval) of the output signal (pulse signal) that switches between High and Low based on the rising edge or falling edge of the output signal. The arithmetic unit 6 also measures the pulse width of the High pulse or Low pulse of the output signal. The arithmetic unit 6 determines the voltage state of the AC power supply based on the measured frequency of the pulse signal or the pulse width of the output signal. The arithmetic unit 6 can be configured, for example, by a microcomputer, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or the like.

[0020] Next, the operation of the input power supply monitoring circuit 1 in each voltage state of the AC power supply will be described with reference to Figures 2 to 6. In the present embodiment, the case where the AC power supply is a commercial power supply of 200V will be described below.

[0021] FIG. 2 is a diagram illustrating operation when the AC power supply voltage is a stable standard voltage of 200 V AC. When 200 V AC is not fluctuating, the peak value of the rectified voltage P1A, a pulsating current full-wave rectified by the rectifier circuit 2, is 200 × √2 = 282.8 Vp. The waveform shown in the upper part of FIG. 2 is the waveform of the second rectified divided voltage P3A obtained by resistively dividing the rectified voltage P1A. The waveform of the second rectified divided voltage P3A is input to the input terminal IN-B of the second comparator 42 of the voltage-dividing comparison circuit 4. The waveform shown in the lower part of FIG. 2 is the pulse signal waveform Q1 output to the output terminal 55 of the switching circuit 5.

[0022] As shown in FIG. 2, when the voltage value of second rectified divided voltage P3A input to input terminal IN-B exceeds a preset second comparison voltage 44 (for example, when it reaches the voltage value of rectified voltage-divider node 71 at second rectified divided voltage P3A), the output of output terminal OUT-B of second comparator 42 goes High. On the other hand, first comparator 41 is set so that the voltage value of first rectified divided voltage P2A input to input terminal IN-A does not exceed first comparison voltage 43 when AC 200V is not fluctuating. Therefore, the output of output terminal OUT-A of first comparator 41 is always High at AC 200V. Therefore, with the voltage value of rectified voltage-divider node 71 in FIG. 2, the outputs of output terminals OUT-A and OUT-B are both High, and therefore, connection node 45 between output terminals OUT-A and OUT-B goes High. As a result, the light emitting diode 51 of the switching circuit 5 lights up, the phototransistor 52 turns on, and the pulse signal waveform Q1 output from the output terminal 55 of the switching circuit 5 goes low.

[0023] Furthermore, when the voltage value of the second rectified divided voltage P3A input to the input terminal IN-B becomes lower than the preset second comparison voltage 44 (for example, when it falls below the voltage value of the rectified voltage-divider node 72 of the second rectified divided voltage P3A), the output of the output terminal OUT-B of the second comparator 42 becomes low. On the other hand, the output of the output terminal OUT-A of the first comparator 41 is always high, as described above. Therefore, with the voltage value of the rectified voltage-divider node 72 in FIG. 2, the output of the output terminal OUT-B becomes low, and the connection node 45 between the output terminals OUT-A and OUT-B becomes low. As a result, the light-emitting diode 51 of the switching circuit 5 is turned off, the phototransistor 52 is turned off, and the pulse signal waveform Q1 output from the output terminal 55 of the switching circuit 5 switches from low to high.

[0024] As described above, when the voltage of the AC power supply is not fluctuating, the pulse signal waveform Q1 output from the switching circuit 5 switches between a high state and a low state depending on the output state of the output terminal OUT-B of the second comparator 42. The frequency of the pulse signal waveform Q1 is 120 Hz because it is based on the rectified voltage P1 of the pulsating current generated by full-wave rectification. The high / low duty ratio at this time is set to about 50%.

[0025] 3 is a diagram illustrating the operation when the voltage of the AC power supply drops to AC 150V. When the voltage drops to AC 150V, the waveform peak value of the rectified voltage P1B of the pulsating current that has been full-wave rectified in the rectifier circuit 2 becomes 150×√2=212.1Vp. 。

[0026] As shown in FIG. 3, the waveform peak value of the second rectified divided voltage P3B is lower than the waveform peak value of the second rectified divided voltage P3A (see FIG. 2) in accordance with the voltage drop of the AC power supply (from AC 200V to AC 150V). When the voltage value of the second rectified divided voltage P3B input to the input terminal IN-B exceeds a predetermined second comparison voltage 44 (for example, when it reaches the voltage value of the rectified voltage-divider point 73 of the second rectified divided voltage P3B), the output of the output terminal OUT-B of the second comparator 42 becomes High. On the other hand, the voltage value of the first rectified divided voltage P2B input to the input terminal IN-A of the first comparator 41 does not exceed the first comparison voltage 43 even when AC 200V drops to AC 150V. Therefore, the output of the output terminal OUT-A of the first comparator 41 is always High even at AC 150V. 3, the output from output terminal OUT-A and the output from output terminal OUT-B are both High, so that connection point 45 between output terminal OUT-A and output terminal OUT-B is High. As a result, light-emitting diode 51 of switching circuit 5 is lit, phototransistor 52 is turned on, and pulse signal waveform Q2 output from output terminal 55 of switching circuit 5 is Low.

[0027] Furthermore, when the voltage value of the second rectified divided voltage P3B input to the input terminal IN-B becomes lower than the preset second comparison voltage 44 (for example, when it falls below the voltage value of the rectified voltage-divider node 74 of the second rectified divided voltage P3B), the output of the output terminal OUT-B of the second comparator 42 becomes low. As described above, the output of the output terminal OUT-A of the first comparator 41 is always high. Therefore, with the voltage value of the rectified voltage-divider node 74 in FIG. 3, the output of the output terminal OUT-B becomes low, and the connection node 45 between the output terminals OUT-A and OUT-B becomes low. As a result, the light-emitting diode 51 of the switching circuit 5 is turned off, the phototransistor 52 is turned off, and the pulse signal waveform Q2 output from the output terminal 55 of the switching circuit 5 switches from low to high.

[0028] In this way, when the voltage of the AC power supply drops to AC 150V, the pulse signal waveform Q2 output from the switching circuit 5 switches between a high state and a low state depending on the output state of the output terminal OUT-B of the second comparator 42. The frequency of the pulse signal waveform Q2 is 120 Hz, the same as the frequency of the pulse signal waveform Q1. Note that the high / low duty ratio at this time has a longer high period than the duty ratio described in FIG. 2.

[0029] 4 is a diagram illustrating the operation when the voltage of the AC power supply drops below AC 135V. When the voltage drops to AC 135V, the waveform peak value of the rectified voltage P1C of the pulsating current that has been full-wave rectified in the rectifier circuit 2 becomes 135×√2=190.9Vp. 。

[0030] As shown in FIG. 4, the waveform peak value of the second rectified divided voltage P3C becomes lower than the waveform peak value of the second rectified divided voltage P3A (see FIG. 2) in accordance with the voltage drop of the AC power supply (from AC 200V to AC 135V). When the voltage drops to AC 135V, the voltage value of the second rectified divided voltage P3C input to the input terminal IN-B of the second comparator 42 does not exceed the preset second comparison voltage 44. Therefore, the output of the output terminal OUT-B of the second comparator 42 is constantly low. On the other hand, the voltage value of the first rectified divided voltage P2C input to the input terminal IN-A of the first comparator 41 does not exceed the first comparison voltage 43, even when the voltage drops from AC 200V to AC 135V. Therefore, the output of the output terminal OUT-A of the first comparator 41 is constantly high, even at AC 135V. Therefore, when the voltage drops to AC 135V, the output of output terminal OUT-B is constantly low, so that connection point 45 between output terminals OUT-A and OUT-B is constantly low. This causes light-emitting diode 51 of switching circuit 5 to turn off, phototransistor 52 to turn off, and pulse signal waveform Q3 output from output terminal 55 of switching circuit 5 to be constantly high.

[0031] In this way, when the voltage of the AC power supply drops below AC 135V, the pulse signal waveform Q3 output from the switching circuit 5 is always in a high state in accordance with the output state of the output terminal OUT-B of the second comparator 42.

[0032] 2 to 4, when the voltage of the AC power supply (AC 200V) is not fluctuating or when the voltage drops, there is no change in the output of the output terminal OUT-A of the first comparator 41, and the output of the switching circuit 5 changes depending on the output state of the output terminal OUT-B of the second comparator 42. Therefore, when the voltage of the AC power supply is not fluctuating or when the voltage drops, it is possible to detect a voltage drop state by detecting the High period or Low period in the output signal from the output terminal OUT-B of the second comparator 42.

[0033] Next, the operation of the input power supply monitoring circuit 1 when the voltage of the AC power supply (AC 200V) rises will be described. Figure 5 shows the voltage of the AC power supply. AC264V 1 is a diagram illustrating the operation when the voltage rises to AC264V When the voltage rises to 1 V, the waveform peak value of the rectified voltage P1D of the pulsating current that has been full-wave rectified in the rectifier circuit 2 is 264×√2=373.3Vp become 。

[0034] As shown in Figure 5, the waveform peak value of the second rectified divided voltage P3D increases with the voltage rise of the AC power supply (from AC200V to AC264V When the voltage value of the second rectified divided voltage P3D input to the input terminal IN-B exceeds the preset second comparison voltage 44 (for example, when it reaches the voltage value of the rectified voltage-dividing point 75 of the second rectified divided voltage P3D), the output of the output terminal OUT-B of the second comparator 42 becomes High. On the other hand, although not shown, the waveform peak value of the first rectified divided voltage P2D increases with the increase in the voltage of the AC power supply (from AC 200V to AC264VTherefore, the voltage value of the first rectified divided voltage P2D input to the input terminal IN-A of the first comparator 41 becomes higher than the waveform peak value of the first rectified divided voltage P2A in accordance with the voltage rise of AC 200V. AC264V If the voltage rises to a value higher than the first comparison voltage 43, the voltage may become higher than the first comparison voltage 43.

[0035] Incidentally, the waveform peak values ​​of the rectified voltage P1 of the pulsating current that has been full-wave rectified in the rectifier circuit 2 vary between the odd-numbered waveform peak values ​​and the even-numbered waveform peak values ​​due to variations in elements such as diodes D1 to D4 in the rectifier circuit 2. This causes similar variations in the first rectified divided voltage P2 and the second rectified divided voltage P3 that are generated by resistively dividing the rectified voltage P1. Here, in the example shown in FIG. 5, it is assumed that variations occur such that the waveform peak values ​​of the odd-numbered (2m+1) first rectified divided voltage P2D and the second rectified divided voltage P3D are higher than the waveform peak values ​​of the even-numbered (2m) first rectified divided voltage P2D and the second rectified divided voltage P3D.

[0036] When such a variation occurs, the voltage value of the even-numbered (2m) first rectified divided voltage P2D input to the input terminal IN-A of the first comparator 41 is AC 200V. AC264V However, there may be a case where the voltage value of the odd-numbered (2m+1) first rectified divided voltage P2D exceeds the first comparison voltage 43.

[0037] Therefore, when an even-numbered (2m) first rectified divided voltage P2D is input to the input terminal IN-A of the first comparator 41, the output of the output terminal OUT-A of the first comparator 41 is AC264V 5, the output from output terminal OUT-A and the output from output terminal OUT-B are both High, so that the connection point 45 between output terminal OUT-A and output terminal OUT-B is High. As a result, the light-emitting diode 51 of the switching circuit 5 lights up, the phototransistor 52 is turned on, and the pulse signal waveform Q4 output from output terminal 55 of the switching circuit 5 is Low.

[0038] Furthermore, when the voltage value of the second rectified divided voltage P3D input to the input terminal IN-B falls below the preset second comparison voltage 44 (for example, when it falls below the voltage value of the rectified voltage-divider node 76 of the second rectified divided voltage P3D), the output of the output terminal OUT-B of the second comparator 42 goes low. As described above, the output of the output terminal OUT-A of the first comparator 41 is always high when an even-numbered (2m) first rectified divided voltage P2D is input to the input terminal IN-A. Therefore, with the voltage value of the rectified voltage-divider node 76 in FIG. 5 , the output of the output terminal OUT-B goes low, and the connection node 45 between the output terminals OUT-A and OUT-B goes low. This turns off the light-emitting diode 51 of the switching circuit 5, turns off the phototransistor 52, and switches the pulse signal waveform Q4 output from the output terminal 55 of the switching circuit 5 from low to high.

[0039] However, when the above-described variations occur, the first comparator 41 and the second comparator 42 operate as follows when the odd-numbered (2m+1) first rectified divided voltage P2D and the odd-numbered (2m+1) second rectified divided voltage P3D are input.

[0040] The operation of the second comparator 42 is the same as the operation when an even-numbered (2m) second rectified divided voltage P3D is input. On the other hand, when an odd-numbered (2m+1) first rectified divided voltage P2D is input to the input terminal IN-A of the first comparator 41, the waveform crest value of the odd-numbered (2m+1) first rectified divided voltage P2D is higher than the waveform crest value of the even-numbered (2m) first rectified divided voltage P2D, and therefore the voltage value near the peak voltage of the odd-numbered (2m+1) first rectified divided voltage P2D exceeds the first comparison voltage 43. Therefore, when an odd-numbered (2m+1) first rectified divided voltage P2D is input to the input terminal IN-A, the output of the output terminal OUT-A of the first comparator 41 becomes low near the peak voltage of the first rectified divided voltage P2D. 5, the output of the output terminal OUT-B of the second comparator 42 becomes High and the output of the output terminal OUT-A becomes Low, so that the connection point 45 between the output terminals OUT-A and OUT-B becomes Low. As a result, the light-emitting diode 51 of the switching circuit 5 turns off, the phototransistor 52 turns off, and the pulse signal waveform Q4 output from the output terminal 55 of the switching circuit 5 becomes High.

[0041] In this way, the voltage of the AC power supply AC264V When the voltage comparison circuit 4 receives an odd-numbered (2m+1) rectified partial voltage P2D, P3D, the pulse signal waveform Q4 output from the switching circuit 5 switches between High and Low depending on the output state of the output terminal OUT-B of the second comparator 42 when the even-numbered (2m) rectified partial voltage P2D, P3D is input. When the odd-numbered (2m+1) rectified partial voltage P2D, P3D is input to the voltage comparison circuit 4, the pulse signal waveform Q4 switches between High and Low depending on the output state of the output terminal OUT-A of the first comparator 41 near the peak voltage of the rectified partial voltage P2D, P3D. The frequency of the pulse signal waveform Q4 is 180 Hz because the pulse waveform based on the pulsating rectified voltage P1 generated by full-wave rectification is added to the pulse waveform for the odd-numbered (2m+1) rectified partial voltage P2D, P3D.

[0042] Figure 6 shows the voltage of the AC power supply. AC275V 1 is a diagram illustrating the operation when the voltage rises to AC275V When the voltage rises to 0V, the peak value of the waveform of the rectified voltage P1E of the pulsating current that has been full-wave rectified in the rectifier circuit 2 is 275×√2=388.9Vp become 。

[0043] As shown in Figure 6, the waveform peak value of the second rectified divided voltage P3E increases with the voltage rise of the AC power supply (from AC200V to AC275V The voltage is higher than the peak value of the waveform of the second rectified divided voltage P3A (see Figure 2). AC275V The operation of the second comparator 42 when the voltage rises to AC264V This is the same as the operation of the second comparator 42 when the voltage rises to

[0044] On the other hand, if the voltage AC275V When the voltage rises to the level shown in FIG. AC264V In addition to the operation of the first comparator 41 when the voltage rises to 1, when an even-numbered (2m) first rectified divided voltage P2E (not shown) is input to the input terminal IN-A, the voltage value near the peak voltage exceeds the first comparison voltage 43, and the output of the output terminal OUT-A becomes Low. AC275V When the voltage of the first comparator 41 rises to 1, the output of the output terminal OUT-A becomes Low at a voltage value near the respective peak voltages, regardless of whether an even-numbered (2m) first rectified divided voltage P2E or an odd-numbered (2m+1) first rectified divided voltage P2E is input to the input terminal IN-A.

[0045] 6, the output of the output terminal OUT-B of the second comparator 42 is High, the output of the output terminal OUT-A is Low, and the connection point 45 between the output terminals OUT-A and OUT-B is Low. As a result, the light-emitting diode 51 of the switching circuit 5 is turned off, the phototransistor 52 is turned off, and the pulse signal waveform Q5 output from the output terminal 55 of the switching circuit 5 is set to a High state.

[0046] In this way, the voltage of the AC power supply AC275V When the voltages P2D and P3D rise to 100 V, the pulse signal waveform Q5 output from the switching circuit 5 becomes a pulse signal that switches between High and Low in accordance with the output state of the output terminal OUT-A of the first comparator 41 near the peak voltages of the rectified partial voltages P2D and P3D when the rectified partial voltages P2D and P3D are input to the voltage division comparison circuit 4. The frequency of the pulse signal waveform Q5 is 240 Hz because the pulse waveform based on the pulsating rectified voltage P1 generated by full-wave rectification is added to the pulse waveform for each of the rectified partial voltages P2D and P3D (both even-numbered and odd-numbered).

[0047] 5 and 6, when the voltage of the AC power supply (AC 200V) rises, a change occurs in the output state of the output terminal OUT-A of the first comparator 41, and a pulse waveform accompanying this change in output state appears in the pulse signal waveform Qn output from the switching circuit 5. Therefore, when the voltage of the AC power supply rises, it is possible to detect the voltage rise state by measuring the frequency (pulse interval) of the pulse signal waveform Qn.

[0048] Next, the operation of determining the voltage state of the AC power supply in the arithmetic device 6 will be described with reference to FIG.

[0049] When a pulse signal is input to the arithmetic unit 6 from the output terminal 55 of the switching circuit 5, the arithmetic unit 6 detects the rising edge of the input pulse signal and measures the high period of the pulse signal. The arithmetic unit 6 determines whether the high period of the pulse signal continues for a predetermined warning detection period or longer (step S10).

[0050] In step S10, if the High period of the pulse signal is not equal to or longer than the warning detection period (NO in step S10), the calculation device 6 calculates the frequency of the pulse signal based on the rising edge of the pulse signal (step S11).

[0051] On the other hand, in step S10, if the High period of the pulse signal is equal to or longer than the warning detection period (YES in step S10), the arithmetic unit 6 sets a power supply voltage drop warning to warn that the voltage of the AC power supply is dropping (step S12).

[0052] Following step S12, the calculation device 6 determines whether the High period of the pulse signal continues for at least the voltage drop alarm detection time (step S13).

[0053] In step S13, if the high period of the pulse signal is equal to or longer than the voltage drop alarm detection period (YES in step S13), the calculation device 6 sets a voltage drop alarm to warn that the voltage of the AC power supply is dropping (step S14), and then proceeds to step S11.

[0054] On the other hand, in step S13, if the High period of the pulse signal is not equal to or longer than the alarm detection period for voltage drop (NO in step S13), the process proceeds directly to step S11.

[0055] Following step S11, the calculation device 6 determines whether the calculated frequency of the pulse signal is 90 Hz or less (step S15). The pulse signal is detected based on a pulsating rectified voltage P1 generated by full-wave rectifying the AC power supply voltage. Therefore, a pulse signal frequency of 90 Hz or less means that the frequency of the AC power supply is 90 / 2=45 Hz or less. Therefore, if the AC power supply is AC 200V at 50 Hz, it is determined whether the frequency is lower than 50 Hz by 5 Hz or more.

[0056] In step S15, if the frequency of the pulse signal is 90 Hz or less (YES in step S15), the calculation device 6 sets a power supply frequency drop warning to warn that the frequency of the AC power supply is dropping (step S16), and ends this determination process.

[0057] On the other hand, in step S15, if the frequency of the pulse signal is not 90 Hz or less (NO in step S15), the calculation device 6 performs a moving average process on the calculated frequency of the pulse signal (step S17).

[0058] Next, the arithmetic unit 6 determines whether the frequency of the pulse signal subjected to the moving average process is 180 Hz or more, and determines whether the state of 180 Hz or more continues for the overvoltage alarm detection time or more (step S18).

[0059] In step S18, if the state where the frequency is 180 Hz or higher continues for more than the overvoltage alarm detection time (YES in step S18), the calculation device 6 sets an overvoltage alarm / warning to alert that the voltage of the AC power supply is rising (step S19), and ends this determination process.

[0060] On the other hand, in step S18, if the state where the frequency is 180 Hz or higher has not continued for the overvoltage alarm detection time or longer (NO in step S18), the calculation device 6 ends this determination process. After this determination process is completed, if a voltage drop alarm and an overvoltage alarm / warning are set, the calculation device 6 proceeds to data protection processing, in which the data being processed is stored in memory.

[0061] As described above, the input power supply monitoring circuit 1 of this embodiment includes: a rectifier circuit 2 that rectifies a periodic input power supply to generate a rectified voltage P1; a voltage divider generation circuit 3 that divides the rectified voltage P1 to generate a first rectified divided voltage P2 and a second rectified divided voltage P3 that is lower than the first rectified divided voltage P2; a voltage divider comparison circuit 4 that has a first comparator 41 that compares the first rectified divided voltage P2 with a first comparison voltage 43 and a second comparator 42 that compares the second rectified divided voltage P3 with a second comparison voltage 44; a switching circuit 5 that outputs a pulse signal corresponding to the voltage state of the input power supply based on the output signal output from the first comparator 41 and the output signal output from the second comparator 42; and a calculation device 6 that determines the voltage state of the input power supply based on the pulse signal output from the switching circuit 5. The first comparator 41 and the second comparator 42 in the voltage division comparison circuit 4 are configured so that the polarity of the output signal output from the first comparator 41 when the first rectified divided voltage P2 exceeds the first comparison voltage 43 is opposite to the polarity of the output signal output from the second comparator 42 when the second rectified divided voltage P3 exceeds the second comparison voltage 44. The output terminal OUT-A of the first comparator 41 and the output terminal OUT-B of the second comparator 42 are connected to each other. The switching circuit 5 has an input terminal 53 connected to a connection point 45 between the output terminal OUT-A of the first comparator 41 and the output terminal OUT-B of the second comparator 42. The computing device 6 measures the frequency of the pulse signal and determines the voltage state of the input power supply based on the measured frequency. With this configuration, a pulse signal is generated based on the output signals from the first comparator 41 and the second comparator 42, and the voltage state of the input power supply is determined based on the pulse width and frequency of the generated pulse signal. As a result, when the voltage of the input power supply drops, the voltage state can be determined based on the pulse width of the pulse signal. Therefore, during a power outage, the pulse signal remains high, preventing erroneous power outage detection. Furthermore, if the input power supply voltage rises, the voltage status can be determined based on the frequency of the pulse signal. This prevents erroneous determinations due to pulse width fluctuations caused by voltage distortion, enabling accurate determination of the voltage status.

[0062] Furthermore, according to the input power supply monitoring circuit 1, the first comparator 41 outputs a low signal when the first rectified divided voltage P2 exceeds a first comparison voltage 43, and outputs a high signal when the first rectified divided voltage P2 becomes lower than the first comparison voltage 43. The second comparator 42 outputs a high signal when the second rectified divided voltage P3 exceeds a second comparison voltage 44, and outputs a low signal when the second rectified divided voltage P3 becomes lower than the second comparison voltage 44. By setting the first comparator 41 and the second comparator 42 to have such output states, and by connecting the output terminal OUT-A of the first comparator 41 and the output terminal OUT-B of the second comparator 42, it is possible to appropriately determine the voltage state of the input power supply with a single signal output from the switching circuit 5.

[0063] Furthermore, according to the input power supply monitoring circuit 1, the first comparator 41 is configured so that, at least when the voltage of the input power supply drops, the first rectified divided voltage P2 does not exceed the first comparison voltage 43. By setting the first comparator 41 to be in this output state and connecting the output terminal OUT-A of the first comparator 41 and the output terminal OUT-B of the second comparator 42, it is possible to appropriately determine the voltage state of the input power supply with a single signal output from the switching circuit 5.

[0064] Furthermore, according to the input power supply monitoring circuit 1, the arithmetic device 6 determines the voltage state of the input power supply by detecting only the High period or the Low period of the output signal output from the second comparator 42. By setting the rectified divided voltage and the comparison voltage so that only the output signal output from the second comparator 42 switches to the Low state for a normal voltage level of the input power supply, it is possible to determine whether the voltage of the input power supply is abnormal (a voltage drop) simply by monitoring the output signal of the second comparator 42.

[0065] Furthermore, according to the input power supply monitoring circuit 1, the arithmetic device 6 notifies that the voltage of the input power supply is abnormal when the frequency of the pulse signal output from the switching circuit 5 exceeds a predetermined threshold. This makes it possible to determine whether the voltage of the input power supply is abnormal (voltage rise) and to notify that a voltage abnormality has occurred.

[0066] Furthermore, according to the input power supply monitoring circuit 1, the arithmetic device 6 determines that the voltage of the input power supply has dropped when the output from the switching circuit 5 is constantly High. By utilizing the fact that the output of the switching circuit 5 is always at a High level when the voltage of the input power supply drops, it is possible to detect a drop in the input voltage even when the input power supply is a non-periodic DC input.

[0067] Furthermore, according to the input power supply monitoring circuit 1, the switching circuit 5 is configured with an insulating element that can insulate the voltage dividing comparison circuit 4 side from the arithmetic unit 6 side. This makes it possible to suppress the influence of voltage fluctuations of the input power supply on the arithmetic processing of the arithmetic unit 6.

[0068] Although the embodiments of the present invention have been described above, it goes without saying that the technical scope of the present invention should not be construed as being limited by the description of the present embodiments. The present embodiments are merely examples, and it will be understood by those skilled in the art that various modifications of the embodiments are possible within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and its equivalents. [Explanation of symbols]

[0069] 1 Input power monitoring circuit 2 Rectifier circuit 3 Voltage divider circuit 4 Voltage divider comparison circuit 5 Switching Circuits 6 Arithmetic unit 31~34 Resistance 35,36 Connection points 41 First Comparator 42 Second Comparator 43 First comparison voltage 44 Second comparison voltage 45 Connection Points 46 GND terminal 51 Light-emitting diode 52 Phototransistor 53 Input terminal 54,56 terminals 55 Output terminal 57~59 Resistance 71~76 Rectification voltage dividing point D1~D4 Diodes IN-A, IN-B input terminals OUT-A, OUT-B output terminals P1 Pulsating rectified voltage P2 First rectifier voltage divider P3 Second rectifier voltage divider P1A~P1E rectified voltage P2A~P2E First rectifier voltage divider P3A~P3E Second rectifier voltage divider Q1~Q5 Pulse signal waveform Vin1, Vin2 input terminals

Claims

1. a rectifier circuit that rectifies a periodic input power supply to generate a rectified voltage; a voltage division generating circuit that divides the rectified voltage to generate a first rectified divided voltage and a second rectified divided voltage that is lower than the first rectified divided voltage; a voltage division comparison circuit including a first comparator that compares the first rectified divided voltage with a first comparison voltage and a second comparator that compares the second rectified divided voltage with a second comparison voltage; a switching circuit that outputs a pulse signal corresponding to a voltage state of the input power supply based on an output signal output from the first comparator and an output signal output from the second comparator; a computing device that determines a voltage state of the input power source based on the pulse signal; Equipped with The voltage division comparison circuit a polarity of an output signal output from the first comparator when the first rectified divided voltage exceeds the first comparison voltage is opposite to a polarity of an output signal output from the second comparator when the second rectified divided voltage exceeds the second comparison voltage, and an output terminal of the first comparator and an output terminal of the second comparator are connected, The switching circuit an input terminal is connected to a connection point between the output terminal of the first comparator and the output terminal of the second comparator; The computing device measuring a frequency of the pulse signal and determining the voltage state of the input power source based on the measured frequency; determining the voltage state of the input power supply by detecting a High period or a Low period of the output signal output from the second comparator; Input power monitoring circuit.

2. the first comparator outputs a Low signal when the first rectified divided voltage exceeds the first comparison voltage, and outputs a High signal when the first rectified divided voltage becomes lower than the first comparison voltage; the second comparator outputs a High signal when the second rectified divided voltage exceeds the second comparison voltage, and outputs a Low signal when the second rectified divided voltage becomes lower than the second comparison voltage.

2. The input power supply monitoring circuit of claim 1.

3. a voltage value of the first rectified divided voltage input to the first comparator is configured so that the first rectified divided voltage does not exceed the first comparison voltage when the voltage of the input power supply drops; 3. The input power supply monitoring circuit of claim 2.

4. a rectifier circuit that rectifies a periodic input power supply to generate a rectified voltage; a voltage division generating circuit that divides the rectified voltage to generate a first rectified divided voltage and a second rectified divided voltage that is lower than the first rectified divided voltage; a voltage division comparison circuit including a first comparator that compares the first rectified divided voltage with a first comparison voltage and a second comparator that compares the second rectified divided voltage with a second comparison voltage; a switching circuit that outputs a pulse signal corresponding to a voltage state of the input power supply based on an output signal output from the first comparator and an output signal output from the second comparator; a computing device that determines a voltage state of the input power source based on the pulse signal; Equipped with The voltage division comparison circuit a polarity of an output signal output from the first comparator when the first rectified divided voltage exceeds the first comparison voltage is opposite to a polarity of an output signal output from the second comparator when the second rectified divided voltage exceeds the second comparison voltage, and an output terminal of the first comparator and an output terminal of the second comparator are connected, The switching circuit an input terminal is connected to a connection point between the output terminal of the first comparator and the output terminal of the second comparator; The computing device measuring a frequency of the pulse signal and determining the voltage state of the input power source based on the measured frequency; If the frequency of the pulse signal exceeds a predetermined threshold, a notification is given that the voltage of the input power supply is abnormal. Input power monitoring circuit.

5. a rectifier circuit that rectifies a periodic input power supply to generate a rectified voltage; a voltage division generating circuit that divides the rectified voltage to generate a first rectified divided voltage and a second rectified divided voltage that is lower than the first rectified divided voltage; a voltage division comparison circuit including a first comparator that compares the first rectified divided voltage with a first comparison voltage and a second comparator that compares the second rectified divided voltage with a second comparison voltage; a switching circuit that outputs a pulse signal corresponding to a voltage state of the input power supply based on an output signal output from the first comparator and an output signal output from the second comparator; a computing device that determines a voltage state of the input power source based on the pulse signal; Equipped with The voltage division comparison circuit a polarity of an output signal output from the first comparator when the first rectified divided voltage exceeds the first comparison voltage is opposite to a polarity of an output signal output from the second comparator when the second rectified divided voltage exceeds the second comparison voltage, and an output terminal of the first comparator and an output terminal of the second comparator are connected, The switching circuit an input terminal is connected to a connection point between the output terminal of the first comparator and the output terminal of the second comparator; The computing device measuring a frequency of the pulse signal and determining the voltage state of the input power source based on the measured frequency; When the output from the switching circuit is always High, it is determined that the voltage of the input power supply has dropped. Input power monitoring circuit.

6. the switching circuit is configured with an insulating element capable of insulating the voltage dividing comparison circuit side from the arithmetic unit side.

2. The input power supply monitoring circuit of claim 1.

7. a rectifier circuit that rectifies an input power supply to generate a rectified voltage; a voltage division generating circuit that divides the rectified voltage to generate a first rectified divided voltage and a second rectified divided voltage that is lower than the first rectified divided voltage; a voltage division comparison circuit including a first comparator that compares the first rectified divided voltage with a first comparison voltage and a second comparator that compares the second rectified divided voltage with a second comparison voltage; a switching circuit to which the output signal output from the first comparator and the output signal output from the second comparator are input; a computing device that determines a voltage state of the input power supply based on an output signal output from the first comparator and an output signal output from the second comparator; Equipped with The voltage division comparison circuit a polarity of an output signal output from the first comparator when the first rectified divided voltage exceeds the first comparison voltage is opposite to a polarity of an output signal output from the second comparator when the second rectified divided voltage exceeds the second comparison voltage, and an output terminal of the first comparator and an output terminal of the second comparator are connected, The switching circuit an input terminal is connected to a connection point between the output terminal of the first comparator and the output terminal of the second comparator; The computing device determining the voltage state of the input power supply by detecting whether the output signal output from the first comparator or the second comparator is High or Low; Input power monitoring circuit.

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