CN117459033A - Hysteresis comparison circuit, voltage detection device and overvoltage and undervoltage detection device - Google Patents
Hysteresis comparison circuit, voltage detection device and overvoltage and undervoltage detection device Download PDFInfo
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- CN117459033A CN117459033A CN202311252818.8A CN202311252818A CN117459033A CN 117459033 A CN117459033 A CN 117459033A CN 202311252818 A CN202311252818 A CN 202311252818A CN 117459033 A CN117459033 A CN 117459033A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K5/00—Manipulating of pulses not covered by one of the other main groups of this subclass
- H03K5/22—Circuits having more than one input and one output for comparing pulses or pulse trains with each other according to input signal characteristics, e.g. slope, integral
- H03K5/24—Circuits having more than one input and one output for comparing pulses or pulse trains with each other according to input signal characteristics, e.g. slope, integral the characteristic being amplitude
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16528—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values using digital techniques or performing arithmetic operations
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/2503—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques for measuring voltage only, e.g. digital volt meters (DVM's)
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Abstract
The invention provides a hysteresis comparison circuit, a voltage detection device and an overvoltage and undervoltage detection device. The hysteresis comparison circuit comprises: the hysteresis voltage comparison unit is characterized in that a first input end receives a signal to be detected, and a second input end receives a reference voltage signal; comparing the signal to be detected with a reference voltage, and when the voltage of the signal to be detected is greater than the reference voltage, outputting a logic signal as a first logic signal by an output end; when the voltage of the signal to be detected is not greater than the reference voltage, the logic signal is a second logic signal; the logic signal feedback acts on a hysteresis voltage comparison unit, and the hysteresis voltage comparison unit generates a reference voltage based on a reference voltage signal and the logic signal; and the isolation unit receives the logic signal at the input end and outputs a comparison result signal to the logic signal in an isolated manner at the output end. The invention is provided with the isolation unit, and the hysteresis voltage comparison unit is isolated from the rear end, so that the load effect is avoided, and the output of the analog quantity of the rear end is prevented from being influenced.
Description
Technical Field
The invention relates to the technical field of comparators, in particular to a hysteresis comparison circuit, a voltage detection device and an overvoltage and undervoltage detection device.
Background
The hysteresis comparator is a common comparator and is widely applied to the field of industrial control. The voltage comparison threshold of the hysteresis comparator is determined according to the output state, when the output is high level, the voltage comparison threshold is higher, and when the output is low level, the voltage comparison threshold is lower, and a voltage hysteresis interval is generated. The hysteresis comparator has wide application in the field of industrial control due to strong anti-interference capability
In the prior art, a hysteresis comparator is usually formed by using an operational amplifier, and referring to fig. 1, a load effect exists in the hysteresis comparator circuit due to the existence of a resistor, so that the output of the analog quantity of the rear end is affected.
Disclosure of Invention
The embodiment of the invention provides a hysteresis comparison circuit, a voltage detection device and an overvoltage and undervoltage detection device, which are used for solving the problem that the output of a hysteresis comparator in the prior art has a load effect and affects the output of a rear-end analog quantity.
In a first aspect, an embodiment of the present invention provides a hysteresis comparison circuit, including:
the hysteresis voltage comparison unit is characterized in that a first input end receives a signal to be detected, and a second input end receives a reference voltage signal; comparing the signal to be detected with a reference voltage, and when the voltage of the signal to be detected is greater than the reference voltage, outputting a logic signal as a first logic signal by an output end; when the voltage of the signal to be detected is not greater than the reference voltage, the logic signal is a second logic signal; the logic signal feedback acts on a hysteresis voltage comparison unit, and the hysteresis voltage comparison unit generates a reference voltage based on a reference voltage signal and the logic signal; the logic signals are different in reference voltage corresponding to the first logic signal and the second logic signal;
and the isolation unit receives the logic signal at the input end and outputs a comparison result signal to the logic signal in an isolated manner at the output end.
Optionally, when the logic signal is the first logic signal, the value of the reference voltage generated by the hysteresis voltage comparing unit is the first voltage value; when the logic signal is a second logic signal, the value of the reference voltage generated by the hysteresis voltage comparison unit is a second voltage value;
when the logic signal is switched from the first logic signal to the second logic signal, the value of the reference voltage is switched from the first voltage value to the second voltage value; when the logic signal is switched from the second logic signal to the first logic signal, the value of the reference voltage is switched from the second voltage value to the first voltage value; wherein the first voltage value is different from the second voltage value.
Optionally, the hysteresis voltage comparing unit includes: a first comparator and a first resistor;
the first input end of the first comparator is coupled to the first input end of the hysteresis voltage comparison unit, the second input end of the first comparator is coupled to the second input end of the hysteresis voltage comparison unit, and the output end of the hysteresis voltage comparison unit is coupled to the second input end of the first comparator through a first resistor feedback;
the logic signal is fed back to the second input end of the first comparator through the first resistor and is overlapped with the reference voltage signal to obtain the reference voltage.
Optionally, when the voltage of the signal to be detected is not greater than the reference voltage, the logic signal is at a high level, and the value of the reference voltage is a second voltage value;
when the voltage of the signal to be detected is larger than the reference voltage, the logic signal is in a low level, and the value of the reference voltage is a first voltage value;
when the logic signal is switched from a high level to a low level, the value of the reference voltage is switched from a second voltage value to a first voltage value; when the logic signal is switched from low level to high level, the value of the reference voltage is switched from a first voltage value to a second voltage value;
wherein the second voltage value is greater than the first voltage value.
Optionally, the hysteresis voltage comparing unit includes: the second resistor, the third resistor and the fourth resistor;
the second input end of the first comparator is respectively connected with the first end of the second resistor, the first end of the first resistor and the first end of the third resistor, the first input end of the first comparator is connected with the first input end of the hysteresis voltage comparison unit, and the output end of the first comparator is respectively connected with the second end of the first resistor, the first end of the fourth resistor and the output end of the hysteresis voltage comparison unit;
the second end of the second resistor is connected with the second input end of the hysteresis voltage comparison unit;
the second end of the fourth resistor is connected to a pull-up power supply;
the second end of the third resistor is grounded.
Optionally, the isolation unit includes: a second comparator;
the first input end of the second comparator is connected with the input end of the isolation unit, the second input end of the second comparator is respectively connected with the second input end of the first comparator, the first end of the first resistor, the first end of the second resistor and the first end of the third resistor, and the output end of the second comparator is connected with the output end of the isolation unit.
Optionally, when the logic signal is switched from the first logic signal to the second logic signal, the comparison result signal is switched to the first result signal for indicating abnormal protection;
when the logic signal is switched from the second logic signal to the first logic signal, the comparison result signal is switched to the second result signal for indicating abnormal recovery.
In a second aspect, an embodiment of the present invention provides a voltage detection apparatus, including: at least one hysteresis comparison circuit as provided in the first aspect of the embodiments of the present invention.
In a third aspect, an embodiment of the present invention provides an overvoltage and undervoltage detection device, including: two hysteresis comparison circuits connected in parallel and provided in the first aspect of the embodiment of the invention;
wherein, two reference voltages corresponding to the first hysteresis comparison circuit are different from two reference voltages corresponding to the second hysteresis comparison circuit.
Optionally, in the first hysteresis comparison circuit, a first input end of the first comparator is a negative input end, a second input end of the first comparator is a positive input end, a first input end of the second comparator is a positive input end, and a second input end of the second comparator is a negative input end;
in the second hysteresis comparison circuit, the first input end of the first comparator is a negative input end, the second input end of the first comparator is a positive input end, the first input end of the second comparator is a negative input end, and the second input end of the second comparator is a positive input end.
The embodiment of the invention provides a hysteresis comparison circuit, a voltage detection device and an overvoltage and undervoltage detection device. The hysteresis comparison circuit comprises: the hysteresis voltage comparison unit is characterized in that a first input end receives a signal to be detected, and a second input end receives a reference voltage signal; comparing the signal to be detected with a reference voltage, and when the voltage of the signal to be detected is greater than the reference voltage, outputting a logic signal as a first logic signal by an output end; when the voltage of the signal to be detected is not greater than the reference voltage, the logic signal is a second logic signal; the logic signal feedback acts on a hysteresis voltage comparison unit, and the hysteresis voltage comparison unit generates a reference voltage based on a reference voltage signal and the logic signal; and the isolation unit receives the logic signal at the input end and outputs a comparison result signal to the logic signal in an isolated manner at the output end. According to the embodiment of the invention, the hysteresis voltage comparing unit is isolated from the rear end by the isolating unit, so that the load cannot influence the circuit, and the load effect is avoided, and the output of the analog quantity of the rear end is prevented from being influenced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic circuit diagram of a prior art hysteretic comparator;
FIG. 2 is a schematic diagram of a hysteresis comparator circuit according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of reference voltage variation according to an embodiment of the present invention;
FIG. 4 is a schematic circuit diagram of a hysteresis voltage comparing unit according to an embodiment of the present invention;
FIG. 5 is a schematic circuit diagram of a hysteresis comparator circuit according to an embodiment of the present invention;
FIG. 6 is a schematic circuit diagram of a hysteresis comparator circuit according to an embodiment of the present invention;
fig. 7 is a schematic circuit diagram of an overvoltage and undervoltage detection device according to an embodiment of the present invention;
fig. 8 is a waveform diagram of two hysteresis comparison circuits in an overvoltage and undervoltage detection device according to an embodiment of the present invention.
Detailed Description
In order to make the present solution better understood by those skilled in the art, the technical solution in the present solution embodiment will be clearly described below with reference to the accompanying drawings in the present solution embodiment, and it is obvious that the described embodiment is an embodiment of a part of the present solution, but not all embodiments. All other embodiments, based on the embodiments in this solution, which a person of ordinary skill in the art would obtain without inventive faculty, shall fall within the scope of protection of this solution.
The term "comprising" in the description of the present solution and the claims and in the above-mentioned figures, as well as any other variants, means "including but not limited to", intended to cover a non-exclusive inclusion, and not limited to only the examples listed herein. Furthermore, the terms "first" and "second," etc. are used for distinguishing between different objects and not for describing a particular sequential order.
The implementation of the invention is described in detail below with reference to the specific drawings:
fig. 2 is a schematic structural diagram of a hysteresis comparison circuit according to an embodiment of the present invention. Referring to fig. 2, the hysteresis comparison circuit includes:
the hysteresis voltage comparing unit 11, the first input end receives the signal to be detected Uin, and the second input end receives the reference voltage signal Vref1; comparing the magnitude of a signal Uin to be detected with the magnitude of a reference voltage, and when the voltage of the signal Uin to be detected is larger than the reference voltage, outputting a logic signal Uout1 as a first logic signal by an output end; when the voltage of the signal Uin to be detected is not greater than the reference voltage, the logic signal Uout1 is a second logic signal; the logic signal Uout1 is fed back to the hysteresis voltage comparing unit 11, and the hysteresis voltage comparing unit 11 generates a reference voltage based on the reference voltage signal Vref1 and the logic signal Uout 1; wherein, when the logic signal Uout1 is the first logic signal and the second logic signal, the corresponding reference voltages are different;
the isolation unit 12 has an input terminal receiving the logic signal Uout1 and an output terminal isolating the logic signal Uout1 and outputting the comparison result signal Uout2.
In the embodiment of the invention, the hysteresis voltage comparing unit 11 is arranged, and generates the reference voltage based on the reference voltage signal Vref1 and the logic signal Uout1, when the logic signal Uout1 changes, the reference voltage also changes, so that hysteresis is formed. Meanwhile, the isolation unit 12 isolates the hysteresis voltage comparison unit 11 from a rear-end load, the rear-end load does not influence the output of the hysteresis comparison circuit, no load effect exists, and the stability of the circuit output is improved.
In one possible implementation, when the logic signal Uout1 is the first logic signal, the value of the reference voltage generated by the hysteresis voltage comparing unit 11 is the first voltage value; when the logic signal Uout1 is the second logic signal, the value of the reference voltage generated by the hysteresis voltage comparing unit 11 is the second voltage value;
when the logic signal Uout1 is switched from the first logic signal to the second logic signal, the value of the reference voltage is switched from the first voltage value to the second voltage value; when the logic signal Uout1 is switched from the second logic signal to the first logic signal, the value of the reference voltage is switched from the second voltage value to the first voltage value; wherein the first voltage value is different from the second voltage value.
The logic signal Uout1 is fed back to the hysteresis voltage comparing unit 11, and the hysteresis voltage comparing unit 11 generates a reference voltage based on the reference voltage signal Vref1 and the logic signal Uout1. When the logic signal Uout1 is the first logic signal, the reference voltage has a first voltage value (U 1 ) The method comprises the steps of carrying out a first treatment on the surface of the When the logic signal Uout1 is the second logic signal, the reference voltageThe value is a second voltage value (U 2 ) The method comprises the steps of carrying out a first treatment on the surface of the Referring to fig. 3, when the logic signal Uout1 is switched, the reference voltage is also switched, thereby forming a hysteresis.
In one possible implementation, referring to fig. 4, the hysteresis voltage comparing unit 11 may include: a first comparator U1 and a first resistor R1;
the first input end of the first comparator U1 is coupled to the first input end of the hysteresis voltage comparing unit 11, the second input end of the first comparator U1 is coupled to the second input end of the hysteresis voltage comparing unit 11, and the output end of the hysteresis voltage comparing unit 11 is coupled to the second input end of the first comparator U1 in a feedback manner through the first resistor R1;
the logic signal Uout1 is fed back to the second input end of the first comparator U1 through the first resistor R1 and is superimposed with the reference voltage signal Vref1 to obtain a reference voltage.
In the embodiment of the invention, the first comparator U1 outputs the logic signal Uout1, and the logic signal Uout1 is fed back to the second input end of the first comparator U1, that is, the reference level input end, through the first resistor R1, so as to influence the reference voltage of the first comparator U1, thereby forming a hysteresis.
In one possible implementation manner, when the voltage of the signal Uin to be detected is not greater than the reference voltage, the logic signal Uout1 is at a high level, and the value of the reference voltage is a second voltage value;
when the voltage of the signal Uin to be detected is larger than the reference voltage, the logic signal Uout1 is in a low level, and the value of the reference voltage is a first voltage value;
when the logic signal Uout1 is switched from high level to low level, the value of the reference voltage is switched from the second voltage value to the first voltage value; when the logic signal Uout1 is switched from low level to high level, the value of the reference voltage is switched from the first voltage value to the second voltage value;
wherein the second voltage value is greater than the first voltage value.
Referring to fig. 3 and 4, the hysteresis voltage comparing circuit 11 is formed by a comparator, the first comparator U1 outputs a high level or a low level, and feedback is applied to the second input terminal of the first comparator U1 to form two reference voltages with different voltage values. When the logic signal Uout1 switches, the reference voltages switch synchronously, thereby forming a hysteresis.
Illustratively, the first input of the first comparator U1 is a negative input and the second input of the first comparator U1 is a positive input. Thus, when the voltage of the signal to be detected Uin is smaller than the reference voltage, the logic signal Uout1 is at a high level; and conversely, is low.
In one possible implementation, referring to fig. 5, the hysteresis voltage comparing unit 11 may include: the second resistor R2, the third resistor R3 and the fourth resistor R4;
the second input end of the first comparator U1 is respectively connected with the first end of the second resistor R2, the first end of the first resistor R1 and the first end of the third resistor R3, the first input end of the first comparator U1 is connected with the first input end of the hysteresis voltage comparison unit 11, and the output end of the first comparator U1 is respectively connected with the second end of the first resistor R1, the first end of the fourth resistor R4 and the output end of the hysteresis voltage comparison unit 11;
the second end of the second resistor R2 is connected with the second input end of the hysteresis voltage comparing unit 11;
the second end of the fourth resistor R4 is connected to a pull-up power supply Vref2;
the second end of the third resistor R3 is grounded.
The hysteresis voltage comparing unit 11 is formed of a first comparator U1, and outputs a high impedance when the voltage of the positive input terminal is greater than the voltage of the negative input terminal. The fourth resistor R4 is a pull-up resistor, and is used for pulling up the voltage of the output terminal to a high level. The second resistor R2 and the third resistor R3 are used for dividing the voltage of the reference voltage signal Vref1 to obtain a proper level, and the proper level is matched with the voltage of the signal Uin to be detected.
Specifically, the reference voltage of the first comparator U1 can be adjusted by adjusting the second resistor R2 and the third resistor R3.
The resistance values of the resistors can be set according to practical application requirements, and are not described herein.
In one possible implementation, the reference voltage signal Vref1 may be provided by a pull-up power supply Vref 2.
In one possible embodiment, referring to fig. 5, the isolation unit 12 includes: a second comparator U2;
the first input end of the second comparator U2 is connected with the input end of the isolation unit 12, the second input end of the second comparator U2 is respectively connected with the second input end of the first comparator U1, the first end of the first resistor R1, the first end of the second resistor R2 and the first end of the third resistor R3, and the output end of the second comparator U2 is connected with the output end of the isolation unit 12.
In the embodiment of the invention, the isolated output of the logic signal Uout1 is realized by adopting a comparator as well. Referring to fig. 5, the reference voltage of the first comparator U1 is used as the reference voltage of the second comparator U2 to be input to the second input terminal of the second comparator U2, and the first input terminal of the second comparator U2 is input with the logic signal Uout1.. Referring to fig. 5, when the logic signal Uout1 is at a high level, greater than the reference voltage, the second comparator U2 outputs a high level; when the logic signal Uout1 is at a low level, the second comparator U2 outputs a low level, less than the reference voltage. And no resistor is arranged between the input and the output of the second comparator U2, the output of the rear-end analog signal is not influenced, and the effective isolation of the logic signal Uout1 is realized.
In one possible implementation, when the logic signal Uout1 is switched from the first logic signal to the second logic signal, the comparison result signal Uout2 is switched to the first result signal for indicating an abnormal protection;
when the logic signal Uout1 is switched from the second logic signal to the first logic signal, the comparison result signal Uout2 is switched to the second result signal for indicating an abnormal recovery.
In the embodiment of the invention, the hysteresis comparison circuit can be adopted to perform voltage abnormality indication, and the first result signal and the second result signal are respectively used for indicating abnormality protection and abnormality recovery.
For example, referring to fig. 5, when the signal to be detected Uin is larger than the reference voltage (U 2 ) When the logic signal Uout1 is switched from high level to low level, the output signal is switched from high level to low level, and the logic signal Uout1 is used for indicating overvoltage protection; when the signal to be detected Uin decreases, it is smaller than the reference voltage (U 1 ) At the time, logic signal Uout1 switches from low to high, and as a result the output signal also switches from low to high, indicating an over-voltage anomaly recovery.
Specifically, the first result signal and the second result signal may be further used to indicate an abnormal recovery and an abnormal protection, respectively, and may be specifically set according to an application requirement of an actual circuit.
Referring to fig. 6, the hysteresis voltage comparing circuit 11 may further include: a voltage conditioning unit 13;
the input end of the voltage conditioning unit 13 is used for receiving an original voltage signal, and the output end of the voltage conditioning unit 13 is connected with the first input end of the first comparator U1;
the voltage conditioning unit 13 is used for conditioning the original voltage signal to obtain a signal to be detected.
In one possible embodiment, referring to fig. 6, the voltage conditioning unit 13 may include: a fifth resistor R5 and a sixth resistor R6;
the first end of the fifth resistor R5 is connected with the input end of the voltage conditioning unit 13, and the second end of the fifth resistor R5 is respectively connected with the first end of the sixth resistor R6 and the output end of the voltage conditioning unit 13;
the second terminal of the sixth resistor R6 is grounded.
The fifth resistor R5 and the sixth resistor R6 divide the original voltage signal and match the input voltage range of the first comparator U1 and the reference voltage signal.
In one possible embodiment, referring to fig. 6, the voltage conditioning unit 13 may further include: a first diode D1;
the anode of the first diode D1 is connected to the input end of the voltage conditioning unit 13 and the first end of the fifth resistor R5, and the cathode of the first diode D1 is connected to the regulated power supply Vref 3.
The first diode D1 is used for voltage stabilization, when the original voltage signal is mixed with the peak voltage, the first diode D1 is turned on, the original voltage signal is stabilized at Vref3, and the first comparator U1 is prevented from being damaged by high voltage.
The voltage of the regulated power supply Vref3 and the voltage of the pull-up power supply Vref2 may be the same.
In one possible implementation, referring to fig. 6, the hysteresis comparison circuit may further include: an input filtering unit 14;
an input terminal of the input filter unit 14 is connected to an output terminal of the voltage conditioning unit 13, and an output terminal of the input filter unit 14 is connected to a first input terminal of the first comparator U1.
In one possible implementation, referring to fig. 6, the input filtering unit 14 may include: a first capacitor C1;
the first end of the first capacitor C1 is connected to the input end of the input filter unit 14 and the output end of the input filter unit 14, respectively, and the second end of the first capacitor C1 is grounded.
Corresponding to the above embodiment, the embodiment of the present invention further provides a voltage detection device, including: at least one hysteresis comparison circuit as provided in the above embodiments.
In the embodiment of the invention, a hysteresis comparison circuit can be adopted for voltage detection.
Meanwhile, as the hysteresis comparison circuit provided by the embodiment of the invention has no load effect, the hysteresis comparison circuits can be directly connected in parallel, the voltage detection device can also be formed by a plurality of hysteresis comparison circuits, the output ends of the hysteresis comparison circuits are connected, the input ends of the hysteresis comparison circuits are respectively used for connecting corresponding voltages to be detected, and therefore, the simultaneous detection of a plurality of voltages is realized at the same time, and the hysteresis comparison circuits cannot be affected mutually.
Based on the above embodiment, the embodiment of the present invention further provides an overvoltage and undervoltage detection device, including: two hysteresis comparison circuits connected in parallel as shown in fig. 5;
wherein, two reference voltages corresponding to the first hysteresis comparison circuit are different from two reference voltages corresponding to the second hysteresis comparison circuit.
The reference voltages of the two hysteresis comparison circuits are different and are respectively used for realizing the detection of overvoltage and undervoltage.
In one possible implementation, referring to fig. 7, in the first hysteresis comparison circuit, the first input end of the first comparator U1 is a negative input end, the second input end of the first comparator U1 is a positive input end, the first input end of the second comparator is a positive input end, and the second input end of the second comparator is a negative input end;
in the second hysteresis comparison circuit, the first input end of the first comparator U1 is a negative input end, the second input end of the first comparator U1 is a positive input end, the first input end of the second comparator is a negative input end, and the second input end of the second comparator is a positive input end.
Referring to fig. 7, the resistances of the resistors in the two hysteresis comparison circuits are different, and the settings of the reference voltages of the two first comparators U1 are different. Exemplary, referring to FIG. 8, two reference voltages (U 1 And U 2 ，U 2 >U 1 ) Are each larger than two reference voltages (U 3 And U 4 ，U 4 >U 3 ) U, i.e. U 2 >U 1 >U 4 >U 3 ；
Referring to FIG. 8, when the voltage of the signal to be detected Uin is greater than U 2 When the first hysteresis comparison circuit outputs a low level, the second hysteresis comparison circuit outputs a high level, and the second hysteresis comparison circuit outputs a low level in parallel to indicate abnormality (overvoltage);
when the voltage of the signal Uin to be detected is smaller than U 3 When the first hysteresis comparison circuit outputs a high level, the second hysteresis comparison circuit outputs a low level, and the second hysteresis comparison circuit outputs a low level in parallel to indicate abnormality (under-voltage);
when the voltage of the signal Uin to be detected is greater than U 4 And is smaller than U 1 And when the voltage is normal, the first hysteresis comparison circuit and the second hysteresis comparison circuit both output high level, and the high level is output in parallel, so that the detection of overvoltage and undervoltage is realized.
U 3 And U 4 U is a hysteresis interval when the under-voltage is recovered 3 And U 4 The interval still indicates under-voltage, when the voltage of the signal Uin to be detected is larger than U 4 When the normal state is restored, the normal state is indicated; when under-voltage is normally entered, U 3 And U 4 The interval still indicates normal, when the voltage of the signal Uin to be detected is smaller than U 3 Only indicating the undervoltage; reserving hysteresis intervals to avoid frequent switching of indication statesAnd (5) changing.
Also U 2 And U 1 The principle is the same as that of the hysteresis interval, and the hysteresis interval is reserved and frequent switching of the indication state is avoided.
The above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A hysteresis comparator circuit, comprising:
the hysteresis voltage comparison unit is characterized in that a first input end receives a signal to be detected, and a second input end receives a reference voltage signal; comparing the signal to be detected with a reference voltage, and when the voltage of the signal to be detected is larger than the reference voltage, outputting a logic signal as a first logic signal by an output end; when the voltage of the signal to be detected is not greater than the reference voltage, the logic signal is a second logic signal; the logic signal feedback acts on the hysteresis voltage comparison unit, and the hysteresis voltage comparison unit generates the reference voltage based on the reference voltage signal and the logic signal; the logic signals are the first logic signals and the second logic signals, and the reference voltages corresponding to the logic signals are different in magnitude;
and the isolation unit receives the logic signal at the input end and outputs a comparison result signal to the logic signal at the output end in an isolated manner.
2. The hysteresis comparison circuit according to claim 1, wherein when the logic signal is the first logic signal, the value of the reference voltage generated by the hysteresis voltage comparison unit is a first voltage value; when the logic signal is the second logic signal, the value of the reference voltage generated by the hysteresis voltage comparison unit is a second voltage value;
when the logic signal is switched from the first logic signal to the second logic signal, the value of the reference voltage is switched from the first voltage value to the second voltage value; when the logic signal is switched from the second logic signal to the first logic signal, the value of the reference voltage is switched from the second voltage value to the first voltage value; wherein the first voltage value is different from the second voltage value.
3. The hysteresis comparison circuit of claim 2, wherein the hysteresis voltage comparison unit comprises: a first comparator and a first resistor;
the first input end of the first comparator is coupled to the first input end of the hysteresis voltage comparison unit, the second input end of the first comparator is coupled to the second input end of the hysteresis voltage comparison unit, and the output end of the hysteresis voltage comparison unit is coupled to the second input end of the first comparator through the first resistor in a feedback manner;
the logic signal is fed back to the second input end of the first comparator through the first resistor and is overlapped with the reference voltage signal to obtain the reference voltage.
4. The hysteresis comparison circuit of claim 3, wherein said logic signal is high when the voltage of said signal to be detected is not greater than said reference voltage, said reference voltage having said second voltage value;
when the voltage of the signal to be detected is larger than the reference voltage, the logic signal is in a low level, and the value of the reference voltage is the first voltage value;
when the logic signal is switched from a high level to a low level, the value of the reference voltage is switched from the second voltage value to the first voltage value; when the logic signal is switched from a low level to a high level, the value of the reference voltage is switched from the first voltage value to the second voltage value;
wherein the second voltage value is greater than the first voltage value.
5. The hysteresis comparison circuit of claim 3, wherein said hysteresis voltage comparison unit comprises: the second resistor, the third resistor and the fourth resistor;
the second input end of the first comparator is respectively connected with the first end of the second resistor, the first end of the first resistor and the first end of the third resistor, the first input end of the first comparator is connected with the first input end of the hysteresis voltage comparison unit, and the output end of the first comparator is respectively connected with the second end of the first resistor, the first end of the fourth resistor and the output end of the hysteresis voltage comparison unit;
the second end of the second resistor is connected with the second input end of the hysteresis voltage comparison unit;
the second end of the fourth resistor is connected to a pull-up power supply;
the second end of the third resistor is grounded.
6. The hysteresis comparison circuit of claim 5, wherein said isolation unit comprises: a second comparator;
the first input end of the second comparator is connected with the input end of the isolation unit, the second input end of the second comparator is respectively connected with the second input end of the first comparator, the first end of the first resistor, the first end of the second resistor and the first end of the third resistor, and the output end of the second comparator is connected with the output end of the isolation unit.
7. The hysteresis comparison circuit according to any one of claims 1 to 6, wherein when said logic signal is switched from said first logic signal to said second logic signal, said comparison result signal is switched to a first result signal for indicating an abnormal protection;
when the logic signal is switched from the second logic signal to the first logic signal, the comparison result signal is switched to a second result signal for indicating abnormal recovery.
8. A voltage detection device, comprising: at least one hysteresis comparison circuit according to any one of claims 1 to 7.
9. An overvoltage and undervoltage detection device, comprising: two hysteresis comparison circuits according to claim 6 connected in parallel;
wherein, two reference voltages corresponding to the first hysteresis comparison circuit are different from two reference voltages corresponding to the second hysteresis comparison circuit.
10. The overvoltage/undervoltage detection device of claim 9, wherein in the first hysteresis comparator circuit, a first input terminal of the first comparator is a negative input terminal, a second input terminal of the first comparator is a positive input terminal, a first input terminal of the second comparator is a positive input terminal, and a second input terminal of the second comparator is a negative input terminal;
in the second hysteresis comparison circuit, the first input end of the first comparator is a negative input end, the second input end of the first comparator is a positive input end, the first input end of the second comparator is a negative input end, and the second input end of the second comparator is a positive input end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311252818.8A CN117459033A (en) | 2023-09-26 | 2023-09-26 | Hysteresis comparison circuit, voltage detection device and overvoltage and undervoltage detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311252818.8A CN117459033A (en) | 2023-09-26 | 2023-09-26 | Hysteresis comparison circuit, voltage detection device and overvoltage and undervoltage detection device |
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| Publication Number | Publication Date |
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| CN117459033A true CN117459033A (en) | 2024-01-26 |
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| CN202311252818.8A Pending CN117459033A (en) | 2023-09-26 | 2023-09-26 | Hysteresis comparison circuit, voltage detection device and overvoltage and undervoltage detection device |
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| Country | Link |
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| CN (1) | CN117459033A (en) |
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2023
- 2023-09-26 CN CN202311252818.8A patent/CN117459033A/en active Pending
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