CN208621682U - A kind of mains failure detection circuit - Google Patents
A kind of mains failure detection circuit Download PDFInfo
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- CN208621682U CN208621682U CN201821330414.0U CN201821330414U CN208621682U CN 208621682 U CN208621682 U CN 208621682U CN 201821330414 U CN201821330414 U CN 201821330414U CN 208621682 U CN208621682 U CN 208621682U
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- high pressure
- nmos pipe
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- pressure nmos
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Abstract
The utility model relates to power cut detection circuit technical fields, specially a kind of mains failure detection circuit, including power supply, high pressure NMOS pipe N1, high pressure NMOS pipe N2, resistance R1, resistance R2 and capacitor C1, the grid of high pressure NMOS pipe N1 one end with resistance R1 respectively, the grid of high pressure NMOS pipe N2, one end of capacitor C1, the inverting input terminal of comparator is connected and is grounded, source electrode is connect with the other end of resistance R1, drain electrode is used as alternating current firewire connecting pin, the source electrode of the high pressure NMOS pipe N2 other end with capacitor C1 respectively, one end of resistance R2 is connected with the non-inverting input terminal of comparator, drain electrode is used as alternating current zero curve connecting pin, the other end of resistance R2 is connect with power supply VCC, the substrate of high pressure NMOS pipe N1 and high pressure NMOS pipe N2 are grounded, The output end of comparator is as detection signal output end.The utility model circuit structure is simple, and accuracy in detection is high, easy of integration, at low cost.
Description
Technical field
The utility model relates to power cut detection circuit technical field, specially a kind of mains failure detection circuit.
Background technique
In many applications, it would be desirable to be detected to the power supply state of alternating current.When blackout condition occurs, adopt
Corresponding emergency measure is taken, to avoid secondary accident.For example, in unexpected have a power failure, need to cut off electric equipment with prevent its
Restart when sending a telegram here again；When power failure, it is also desirable to start emergency lighting.Due to the electric network monitoring device of profession, typically cost is higher,
Thus it is unfavorable for popularization and application.
Utility model content
For the problems of the prior art, the utility model provides that a kind of circuit structure is simple, the low alternating current of manufacturing cost
Power cut detection circuit.
To realize the above technical purpose, the technical solution of the utility model is:
A kind of mains failure detection circuit, it is characterised in that: including power supply, high pressure NMOS pipe N1, high pressure NMOS pipe N2, electricity
Hinder R1, resistance R2 and capacitor C1, the grid of high pressure NMOS pipe N1 grid with one end of resistance R1, high pressure NMOS pipe N2 respectively
Pole, one end of capacitor C1, the inverting input terminal connection of comparator and ground connection, source electrode are connect with the other end of resistance R1, the height
The source electrode of pressure NMOS tube N2 is connect with the non-inverting input terminal of the other end of capacitor C1, one end of resistance R2 and comparator respectively, institute
The other end for stating resistance R2 is connect with power supply VCC, and the substrate of the high pressure NMOS pipe N1 and high pressure NMOS pipe N2 are grounded, described
The drain electrode of high pressure NMOS pipe N1 is connected as alternating current firewire connecting pin, the drain electrode of the high pressure NMOS pipe N2 as alternating current zero curve
End, the output end of the comparator is as detection signal output end.
From the above, it can be seen that the utility model has following advantages:
1. the utility model circuit structure is simple, it is easy to accomplish, only switch S1 conducting make detection circuit access alternating current into
When going and detect, and mains failure occurs, the output logic signal of comparator can just change, and issue the warning that has a power failure；It is disconnected in switch S1
It opens, will not be reported by mistake when detection circuit does not access alternating current, circuit accuracy in detection is high.
2. the utility model when it is implemented, the mains failure detection circuit due to the utility model all devices in inside
Can realize on an integrated circuit die, thus can by entire circuit integration in same IC chip, so as to
To produce the mains failure detection circuit in single ic core on piece of realization, level of integrated system is not only increased, is improved
Reliability, and reduce circuit manufacturing cost.
Detailed description of the invention
Fig. 1 is the circuit diagram of the utility model；
Fig. 2 is that capacitor C1 is charged and discharged time diagram；
Fig. 3 is capacitor C1 charge path schematic diagram when not having a power failure；
Fig. 4 is capacitor C1 discharge path schematic diagram when not having a power failure；
Fig. 5 is capacitor C1 discharge path schematic diagram when having a power failure.
Specific embodiment
In conjunction with Fig. 1 to Fig. 5, a specific embodiment of the utility model is described in detail, but not to the power of the utility model
Benefit requires to do any restriction.
As shown in Figure 1, a kind of mains failure detection circuit, including power supply, high pressure NMOS pipe N1, high pressure NMOS pipe N2, electricity
Hinder R1, resistance R2 and capacitor C1, the grid of high pressure NMOS pipe N1 respectively with one end of resistance R1, high pressure NMOS pipe N2 grid,
One end of capacitor C1, the inverting input terminal connection of comparator and ground connection, source electrode are connect with the other end of resistance R1, high pressure NMOS pipe
The source electrode of N2 is connect with the non-inverting input terminal of the other end of capacitor C1, one end of resistance R2 and comparator respectively, and resistance R2's is another
One end is connect with power supply VCC, and the substrate of high pressure NMOS pipe N1 and high pressure NMOS pipe N2 are grounded, and the drain electrode of high pressure NMOS pipe N1 is made
For alternating current firewire connecting pin, the drain electrode of high pressure NMOS pipe N2 is as alternating current zero curve connecting pin, the output end conduct of the comparator
Signal output end is detected, the warning that has a power failure is used as.
The working principle of the utility model is as follows:
Mains ac power supply is usually connected to the load in each electricity utilization site by distrbution network by power distribution station.Distrbution network
Electric wire it is usually long, can have faint electric leakage between the zero curve and firewire of distrbution network, equivalent can think zero curve and fire
The biggish resistance R3 of a resistance value is connected between line.
After alternating current is linked into each electricity consumption occasion, it will usually it is connected in parallel multichannel resistive load, such as motor, light bulb, it can
These shunt loads are equivalent to resistance R4.
The connection terminal VN and high pressure of the drain electrode of the high pressure NMOS pipe N1 of the mains failure detection circuit of the utility model
The connection terminal VL of the drain electrode of NMOS tube N2 is connected between zero curve and firewire by switch S1, it is believed that with above-mentioned resistance R3
It is in parallel with resistance R4.Whether switch S1, which accesses alternating current for controlling mains failure detection circuit, is detected, when switch S1 conducting
When, mains failure detection circuit detects the power supply state of alternating current, and the warning that has a power failure is issued when having a power failure, when switch S1 is disconnected
When opening, mains failure detection circuit will not issue power failure warning.
For 220V alternating current, the ceiling voltage generated between VN and VL is 311V, and NMOS tube N1 and N2 are high-voltage tube, leakage
The breakdown voltage of pole to source electrode should be greater than 311V.For 110V alternating current, the ceiling voltage generated between VN and VL is 155V,
The breakdown voltage of NMOS tube N1 and N2 drain-to-source should be greater than 155V.And so on, according to specific city's electrical parameter, selection
The breakdown voltage of drain-to-source sufficiently large high pressure NMOS pipe N1 and high pressure NMOS pipe N2.
Diode D1 is the parasitic diode between the substrate and drain electrode of high pressure NMOS pipe N1, and the substrate of N1 is connected to detection
The ground wire of circuit；Diode D2 is the parasitic diode between the substrate and drain electrode of high pressure NMOS pipe N2, and the substrate of N2 is connected to
The ground wire of detection circuit.The gate voltage values of high pressure NMOS pipe N1 are VG1, VG1Turn-on threshold voltage V higher than N1TH1, make at N1
In open state.The gate voltage values of high pressure NMOS pipe N2 are VG2, VG2Turn-on threshold voltage V higher than N2TH2, it is in N2 and opens
Open state.The source electrode of high pressure NMOS pipe N1 is connected to the ground wire of detection circuit by resistance R1, and the source electrode of high pressure NMOS pipe N2 is logical
Cross the ground wire that capacitor C1 is connected to detection circuit.The voltage signal V of the tie point of the source electrode and capacitor C1 of high pressure NMOS pipe N2C1Make
For the input signal of comparator, the reference voltage signal of comparator is VR.Comparator is to VC1 and VRVoltage value size compared
Compared with, and output logic signal.
The power supply VCC of one end connection detection circuit of resistance R2, the other end are connected to capacitor C1.Detection circuit power supply VCC
Voltage VCCMeet VCC=VG2-VTH2, wherein VTH2For the turn-on threshold voltage of N2.
It is illustrated in figure 2 when not having a power failure, the opposite voltage between an exchange cycle of oscillation inner terminal VL and terminal VN
Relation schematic diagram.Within the t1 period, terminal VN voltage is higher than terminal VL voltage；Within the t2 period, terminal VN voltage is lower than
Terminal VL voltage；Within the t2 period, mains failure, without applied voltage source between VN and VL, so the voltage between VN and VL
It is approximately equal.
Voltage absolute value of the difference between the zero curve and firewire of AC power source is VAC× | sin θ |, wherein θ is AC power source
Phase angle changes over time.
Within the t1 period, capacitor C1 is electrically charged, and charging current path is as shown in Figure 3.When capacitor C1 is electrically charged, charging electricity
Stream passes through the parasitic diode D1 of NMOS tube N1, and the drain voltage of high pressure NMOS pipe N1 is VNt1=-VD1, wherein VD1It is two
Pole pipe D1 forward conduction voltage drop；The drain voltage of high pressure NMOS pipe N2 is VLt1=VAC×|sinθ|-VD1.At this point, high pressure NMOS
Higher voltage is born between the drain electrode and source electrode of pipe N1.The charging current of capacitor C1 is determined by the saturation current of N2, usually should
Electric current is very big, so capacitor C1 is charged rapidly.When capacitor C1 voltage rises above VC1_t1=VG2-VTH2When, NMOS tube N2
Because voltage difference is lower than its threshold voltage V between grid and source electrodeTH2And turn off, capacitor C1 voltage keeps V laterC1_t1Until t1
Period terminates.The voltage V of power supply VCCCCMeet VCC=VG2-VTH2, thus the voltage between the both ends resistance R2 is equal, passes through electricity
The electric current of resistance R2 can be ignored.
Within the t2 period, capacitor C1 is discharged, and discharge current path is as shown in Figure 4.Discharge current passes through resistance R1, puts
Electric current value is determined by the resistance value of resistance R1.In order to make capacitor C1 discharge at a slow speed, the resistance value needs of R1 select larger, so that logical
Cross the electric current very little of resistance R1.High pressure NMOS pipe N1 is in lightly conducting state, and the drain voltage of high pressure NMOS pipe N1 is about VNt2=
VG1-VTH1, the drain voltage of high pressure NMOS pipe N2 is VLt2=VAC×|sinθ|+VNt2=VAC×|sinθ|+VG1-VTH1.At this point,
Higher voltage is born between the drain electrode and source electrode of NMOS tube N2.Voltage between the source electrode and drain electrode of high pressure NMOS pipe N1 is approximate
It is equal, the discharge current of capacitor C1 are as follows:By selecting biggish resistance value to resistance R1, so that capacitor C1
Discharge current very little can approximatively think, t2 so the voltage of capacitor C1 only reduces the value of very little within the t2 period
At the end of period, the voltage of capacitor C1 is equal to the voltage at the end of the above-mentioned t1 period.The voltage V of power supply VCCCCMeet VCC
=VG2-VTH2, thus the voltage between the both ends resistance R2 is equal, can be ignored by the electric current of resistance R2.
The reference voltage V of comparator is setRMeet 0V < VR< VG2-VTH2, then under not power-off condition, capacitor C1 with
Ac period quick charge, discharge at a slow speed, capacitance voltage value VC1It maintains to be greater than comparator reference voltage VR, comparator is defeated
It is out 1 logical signal, which does not issue power failure warning.
If Fig. 5 is the discharge path schematic diagram of capacitor C1 when AC outage happens.When AC outage situation
When generation, capacitor C1 will not be by alternating current charging.The discharge current of capacitor C1 after testing the high pressure NMOS pipe N1 inside circuit,
Resistance R1, capacitor C1, high pressure NMOS pipe N2, while also by the resistance R3 and the equivalent electricity of other shunt loads between distrbution network
Hinder R4.The equivalent conducting resistance of high pressure NMOS pipe N1 and N2 very little compared with resistance R1, can ignore.Resistance R1 and distrbution network
Between resistance R3 and other shunt load equivalent resistance R4 series connection.So the discharge current of capacitor C1 are as follows:In the process, the voltage value of capacitor C1 is lower than the voltage vcc of detection circuit power supply VCC, electricity
Hold the power supply VCC charging of C1 meeting detected circuit, charging current isIt is larger by being selected to resistance R2
Resistance value so that when AC outage happens capacitor C1 charging current be less than discharge current, i.e.,Then capacitor C1 is discharged by continuous slow, and the voltage on capacitor slowly declines.When on capacitor C1
After voltage drops below reference voltage VR, the logical signal of comparator output changes, and becomes 0 from 1 logical signal
Logical signal, the mains failure detection circuit issue the warning that has a power failure.
When switch S1 is disconnected, capacitor C1 discharge off path.No matter at this time alternating current whether normal power supply, by resistance R2's
Electric current slowly charges to capacitor C1, and the voltage on capacitor C1 is finally made to be equal to VCC.Because of VCC=VG2-VTH2, comparator is set
Reference voltage VRMeet 0V < VR< VG2-VTH2, VCCValue be greater than comparator reference voltage VRValue, so comparator export
For 1 logical signal, which does not issue power failure warning, i.e., in switch S1 disconnection, no matter alternating current whether
Normal power supply, the mains failure detection circuit will not all issue power failure warning.
In conclusion mains failure detection circuit described in the utility model is only in switch S1 conducting, (i.e. mains failure is examined
Slowdown monitoring circuit access alternating current is when being detected) and when having a power failure, output logic signal just can become 0 from 1, the mains failure detection circuit
The warning that has a power failure is issued, so as to apply in emergency lighting, have a power failure the occasions such as alarm.(i.e. mains failure inspection is disconnected in switch S1
Slowdown monitoring circuit does not access alternating current and is detected) when, no matter alternating current whether normal power supply, output logic be still maintained 1, Bu Huifa
Raw wrong report.
The utility model when it is implemented, due to the utility model mains failure detection circuit all devices in inside all
Can realize on an integrated circuit die, thus can by entire circuit integration in same IC chip, so as to
The mains failure detection circuit is produced in single ic core on piece of realization, level of integrated system is not only increased, improves
Reliability, and reduce circuit manufacturing cost.
In conclusion the utility model has the advantage that
1. the utility model circuit structure is simple, it is easy to accomplish, only switch S1 conducting make detection circuit access alternating current into
When going and detect, and mains failure occurs, the output logic signal of comparator can just change, and issue the warning that has a power failure；It is disconnected in switch S1
It opens, will not be reported by mistake when detection circuit does not access alternating current, circuit accuracy in detection is high.
2. the utility model when it is implemented, the mains failure detection circuit due to the utility model all devices in inside
Can realize on an integrated circuit die, thus can by entire circuit integration in same IC chip, so as to
To produce the mains failure detection circuit in single ic core on piece of realization, level of integrated system is not only increased, is improved
Reliability, and reduce circuit manufacturing cost.
It is understood that being merely to illustrate the utility model above with respect to the specific descriptions of the utility model and not being
It is limited to technical solution described in the utility model embodiment.Those skilled in the art should understand that still can be with
It modifies to the utility model or equivalent replacement, to reach identical technical effect；Needs are used as long as meeting, all in this reality
Within novel protection scope.
Claims (1)
1. a kind of mains failure detection circuit, it is characterised in that: including power supply, high pressure NMOS pipe N1, high pressure NMOS pipe N2, resistance
R1, resistance R2 and capacitor C1, the grid of high pressure NMOS pipe N1 grid with one end of resistance R1, high pressure NMOS pipe N2 respectively
Pole, one end of capacitor C1, the inverting input terminal connection of comparator and ground connection, source electrode are connect with the other end of resistance R1, the height
The source electrode of pressure NMOS tube N2 is connect with the non-inverting input terminal of the other end of capacitor C1, one end of resistance R2 and comparator respectively, institute
The other end for stating resistance R2 is connect with power supply VCC, and the substrate of the high pressure NMOS pipe N1 and high pressure NMOS pipe N2 are grounded, described
The drain electrode of high pressure NMOS pipe N1 is connected as alternating current firewire connecting pin, the drain electrode of the high pressure NMOS pipe N2 as alternating current zero curve
End, the output end of the comparator is as detection signal output end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821330414.0U CN208621682U (en) | 2018-08-17 | 2018-08-17 | A kind of mains failure detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821330414.0U CN208621682U (en) | 2018-08-17 | 2018-08-17 | A kind of mains failure detection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN208621682U true CN208621682U (en) | 2019-03-19 |
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ID=65715366
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| Application Number | Title | Priority Date | Filing Date |
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| CN201821330414.0U Active CN208621682U (en) | 2018-08-17 | 2018-08-17 | A kind of mains failure detection circuit |
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| CN (1) | CN208621682U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108957108A (en) * | 2018-08-17 | 2018-12-07 | 无锡麟力科技有限公司 | A kind of mains failure detection circuit |
-
2018
- 2018-08-17 CN CN201821330414.0U patent/CN208621682U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108957108A (en) * | 2018-08-17 | 2018-12-07 | 无锡麟力科技有限公司 | A kind of mains failure detection circuit |
| CN108957108B (en) * | 2018-08-17 | 2024-03-12 | 无锡麟力科技有限公司 | Commercial power outage detection circuit |
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