CN211528530U - Overvoltage and undervoltage detection circuit of direct current input power supply - Google Patents
Overvoltage and undervoltage detection circuit of direct current input power supply Download PDFInfo
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- CN211528530U CN211528530U CN201922314288.0U CN201922314288U CN211528530U CN 211528530 U CN211528530 U CN 211528530U CN 201922314288 U CN201922314288 U CN 201922314288U CN 211528530 U CN211528530 U CN 211528530U
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Abstract
The utility model relates to a power supply detection field discloses an overvoltage and undervoltage detection circuit of a direct current input power supply, which comprises a wide power supply window voltage comparator, wherein the wide power supply window voltage comparator is provided with two high-precision comparators with internal 400mV reference and two drain open circuit outputs with 18V rated values; the input voltage adjusting unit is used for adjusting the voltage of the input power supply so as to output the adjusted voltage to the wide power supply window voltage comparator; the output voltage adjusting unit is used for adjusting the voltage output by the wide power supply window voltage comparator into a stable voltage detection signal; the problem that the detection signal is changed from an unstable value to a stable high-low level for output is solved, and therefore the recognition rate of the detection signal is improved.
Description
Technical Field
The utility model relates to a power detects technical field, concretely relates to overvoltage and undervoltage detection circuit of direct current input power supply.
Background
The design of the detection circuit for the overvoltage and undervoltage states of the direct-current input power supply generally adopts a resistance voltage division mode, namely divided voltage is used as a detection signal and input into a single chip microcomputer, and then the single chip microcomputer judges the voltage state of the input power supply according to a signal voltage value. When the voltage of the input detection signal is higher than a certain value, judging that the input detection signal is in an overvoltage state; when the voltage of the input detection signal is lower than a certain value, the voltage is judged to be in an undervoltage state.
The mode adopts a resistance voltage division mode, the design idea is simple, but the actual effect is not good. Because the detection circuit divides the input voltage of the storage battery, the processed voltage signal is used as a circuit check signal and is input into the single chip microcomputer for signal detection and judgment of the voltage state of the input power supply of the storage battery, in practice, firstly: the electric quantity of the storage battery is changed all the time, and the output voltage is also unstable, so that the detection signal obtained by voltage division through the storage battery output power supply is changed all the time; secondly, the method comprises the following steps: the single chip microcomputer has errors in signal detection and judgment, and has larger detection errors in gradual signals, so that the conditions of untimely detection and early warning of the current input voltage state, wrong state judgment and the like easily occur, and unnecessary damage to equipment is caused.
SUMMERY OF THE UTILITY MODEL
In order to overcome the deficiency of the prior art, the utility model aims at providing an overvoltage under-voltage detection circuit of direct current input power supply solves the problem that becomes stable high-low level output with the detected signal by the unstability value to improve the identification rate of detected signal.
In order to achieve the above purpose, the utility model adopts the technical scheme that: an over-voltage and under-voltage detection circuit for providing DC input power comprises
A wide power window voltage comparator having two high precision comparators with an internal 400mV reference and two 18V rated drain open circuit outputs, used for over-voltage and under-voltage detection by setting a monitor voltage using an external resistor;
an input voltage adjusting unit for adjusting a voltage of an input power source to output the adjusted voltage to the wide power source window voltage comparator;
and the output voltage adjusting unit is used for adjusting the voltage output by the wide power supply window voltage comparator into a stable voltage detection signal.
Further, the input voltage adjusting unit includes resistors R1, R2, and R3, capacitors C1, C2, and C3; pin 3 of wide power window voltage comparator connects respectively the one end of R1, the one end of electric capacity C2 and the one end of resistance R2, the other end of resistance R1 with connect input power after electric capacity C1's one end links to each other, pin 4 of wide power window voltage comparator connects respectively the other end of resistance R2, the one end of electric capacity C3 and the one end of resistance R3, the other end ground connection of resistance R3, the other end of electric capacity C1 with electric capacity C2's the other end links to each other the back, connects respectively electric capacity C3's the other end and ground connection.
Further, the output voltage adjusting unit includes resistors R4 and R5, capacitors C4 and C5; connect respectively after wide power window voltage comparator's pin 6 links to each other with pin 1 resistance R4's one end, voltage detection signal output end and electric capacity C4's one end, electric capacity C4's other end ground connection, resistance R4's another termination power 3.3V, wide power window voltage comparator's pin 5 is connected respectively resistance R5's one end with electric capacity C5's one end, resistance R5's another termination power 3.3V, electric capacity C5's another termination ground connection.
Further, pin 2 of the wide power window voltage comparator is grounded.
Further, the wide power window voltage comparator is a TPS3700 chip.
Further, pin 1 and pin 2 of the wide power supply window voltage comparator are input voltage terminals, and pin 1 and pin 6 of the wide power supply window voltage comparator are output voltage terminals.
Further, the capacitance C1 is 100 nanofarads, the capacitance C2 is 1 nanofarad, and the capacitance C3 is 1 nanofarad.
Further, the capacitance C4 is 100 picofarads, and the capacitance C5 is 100 nanofarads.
Further, the operating voltage range of the wide power window voltage comparator is 1.8V to 18V.
Compared with the prior art, the beneficial effects of the utility model reside in that, the utility model provides a direct current input power's excessive pressure undervoltage detection circuit, input voltage through input voltage adjustment unit to the battery adjusts, the voltage output after will adjusting is to wide power window voltage comparator, it takes the high accuracy comparator of inside 400mV benchmark and two rated values to be 18V's drain electrode output of opening a way to have through wide power window voltage comparator, use external resistance to set up monitoring voltage, be used for excessive pressure and undervoltage detection with wide power window voltage comparator, make the voltage of the output after wide power window voltage comparator handles, adjust to stable detection signal output through output voltage adjustment unit, the problem of changing detection signal into stable high-low level output by unstable value has been solved, thereby detection signal's identification rate has been improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a functional block diagram of an overvoltage/undervoltage detection circuit of a dc input power supply according to an embodiment of the present invention.
Fig. 2 is a schematic circuit diagram of an overvoltage/undervoltage detection circuit of a dc input power supply according to an embodiment of the present invention.
Fig. 3 is an under-voltage logic diagram of the under-voltage and over-voltage detection circuit of the dc input power supply provided by the embodiment of the present invention.
Fig. 4 is an overvoltage logic diagram of an overvoltage and undervoltage detection circuit of a dc input power supply according to an embodiment of the present invention.
The wide power window voltage comparator, labeled U1 in the above figure; 2. an input voltage adjusting unit; 3. an output voltage adjusting unit.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The same or similar reference numerals in the drawings of the present embodiment correspond to the same or similar components; in the description of the present invention, it should be understood that if there are the terms "upper", "lower", "left", "right", etc. indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of the description, but it is not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore the terms describing the positional relationship in the drawings are only for illustrative purposes and are not to be construed as limitations of the present patent, and those skilled in the art can understand the specific meanings of the terms according to specific situations.
The technical solution of the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1 to 2, the present invention provides a preferred embodiment.
Referring to fig. 1, the overvoltage and undervoltage detection circuit of the dc input power supply provided in this embodiment includes a wide power window voltage comparator U1, the wide power window voltage comparator U1 has two high-precision comparators with internal 400mV reference and two 18V-rated open-drain outputs, and the wide power window voltage comparator U1 is used for overvoltage and undervoltage detection by setting a monitor voltage using an external resistor; an input voltage adjusting unit 2, wherein the input voltage adjusting unit 2 is configured to adjust a voltage of an input power source so that the adjusted voltage is output to the wide power source window voltage comparator U1; and an output voltage adjusting unit 3, wherein the output voltage adjusting unit 3 is used for adjusting the voltage output by the wide power window voltage comparator U1 into a stable voltage detection signal.
According to the overvoltage and undervoltage detection circuit of the direct-current input power supply, the input voltage of the battery is adjusted through the input voltage adjusting unit 2, the adjusted voltage is output to the wide power window voltage comparator U1, the wide power window voltage comparator U1 is provided with two high-precision comparators with internal 400mV reference and two drain open circuit outputs with rated values of 18V, the external resistor is used for setting monitoring voltage, the wide power window voltage comparator U1 is used for overvoltage and undervoltage detection, the voltage of the output processed by the wide power window voltage comparator U1 is adjusted to be stable detection signal output through the output voltage adjusting unit 3, the problem that the detection signal is changed from an unstable value to stable high and low level output is solved, and the identification rate of the detection signal is improved.
As an implementation manner of the present embodiment, referring to fig. 2, the input voltage adjusting unit 2 includes resistors R1, R2, and R3, capacitors C1, C2, and C3; the pin 3 of the wide power window voltage comparator U1 is connected with one end of the resistor R1, one end of the capacitor C2 and one end of the resistor R2 respectively, the other end of the resistor R1 is connected with one end of the capacitor C1 and then connected with an input power supply, the pin 4 of the wide power window voltage comparator U1 is connected with the other end of the resistor R2, one end of the capacitor C3 and one end of the resistor R3 respectively, the other end of the resistor R3 is grounded, and the other end of the capacitor C1 is connected with the other end of the capacitor C2 and then connected with the other end of the capacitor C3 and the ground respectively.
As an implementation of the present embodiment, referring to fig. 2, the output voltage adjusting unit 3 includes resistors R4 and R5, capacitors C4 and C5; the pin 6 of the wide power window voltage comparator U1 is connected with the pin 1 and then is respectively connected with one end of a resistor R4, a voltage detection signal output end and one end of a capacitor C4, the other end of the capacitor C4 is grounded, the other end of the resistor R4 is connected with a power supply 3.3V, the pin 5 of the wide power window voltage comparator U1 is respectively connected with one end of a resistor R5 and one end of a capacitor C5, the other end of the resistor R5 is connected with the power supply 3.3V, and the other end of the capacitor C5 is grounded.
Specifically, referring to fig. 2, pin 2 of the wide supply window voltage comparator U1 is connected to ground.
Preferably, the wide power window voltage comparator U1 is a TPS3700 chip, the pins 1 and 2 of the wide power window voltage comparator U1 are input voltage terminals, the pins 1 and 6 of the wide power window voltage comparator U1 are output voltage terminals, and the operating voltage range of the wide power window voltage comparator U1 is 1.8V to 18V.
Preferably, the capacitor C1 is 100 nanofarads, the capacitor C2 is 1 nanofarad, the capacitor C3 is 1 nanofarad, the capacitor C4 is 100 picofarads, and the capacitor C5 is 100 nanofarads.
Referring to fig. 2, pin 1 of the wide supply window voltage comparator U1 is denoted by INA +, pin 2 by INB-, pin 3 by OUTA, pin 4 by OUTB, and pin 5 by VDD, and the undervoltage overvoltage detection principle is described as follows:
VITP: indicating a forward input threshold voltage, VITN: indicating a negative input threshold voltage, VHYS: denotes hysteresis, Vmon: representing the input supply voltage, VMON(UV): representing the target voltage at which the under-voltage condition was detected, as shown in the following table:
referring to FIGS. 3 and 4, when the voltage at the INA + pin is reduced to (V)ITP–VHYS) In the following, the pin OUTA is driven low, and when the voltage returns to the respective threshold (V)ITP) In the above, the pin OUTA is driven to a high level; when the voltage on pin INB-rises above VITPAt this time, pin OUTB is driven low; when the voltage drops to the corresponding threshold value (V)ITP–VHYS) Hereinafter, OUTB is driven high. Because both comparators of the TPS3700 have built-in hysteresis functions, filtering can be performed to suppress transient glitches, thereby ensuring stable output operation without causing false triggering;
because the working voltage of the 12V vehicle-mounted 2V vehicle-mounted host is generally 8-18V, the working voltage is higher than 18V and is in an overvoltage state, the working voltage is lower than 8V and is in an undervoltage state, and the working voltage is in a normal voltage state in 8-18V.
Referring to fig. 2, VBAT is the input power voltage, BATT _ DET is the voltage detection signal, and the circuit detects and judges the current power supply operating state through the voltage values of the overvoltage and undervoltage detection pins INB-, INA + of U1; the resistor divider value and the target threshold voltage can be adjusted by equations one through four:
the formula I is as follows: rTOTAL＝R1+R2+R3
Selection of RTOTALThe current through the voltage divider is made approximately 100 times higher than the input current on the INA + and INB-pins. Because of the low input bias current, these resistors can have higher resistance values to minimize current consumption without significant error to the resistor divider.
R3 is determined by equation two:
the formula II is as follows: r3 ═ RTOTAL/VMON(OV)×VITPVMON(OV)Indicating a target voltage at which an overvoltage condition is detected
R2 is determined by formula three or formula four:
the formula III is as follows: r2 ═ (R)TOTAL/VMON(noUV)×VITP)–R3
VMON(noUV)Indicates following with VMONRaising target voltage to eliminate undervoltage condition
The formula four is as follows: r2 ═ RTOTAL/VMON(UV)×(VITP-VHYS)]–R3
VMON(UV)Indicating a target voltage at which an under-voltage condition is detected.
The embodiments of the present invention have been described in detail, but the invention is not limited to the embodiments, and those skilled in the art can make many equivalent modifications or substitutions without departing from the spirit of the present invention, and the equivalent modifications or substitutions are included in the scope of protection defined by the claims of the present application.
Claims (9)
1. The overvoltage and undervoltage detection circuit of the DC input power supply is characterized by comprising
A wide power window voltage comparator having two high precision comparators with an internal 400mV reference and two 18V rated drain open circuit outputs, used for over-voltage and under-voltage detection by setting a monitor voltage using an external resistor;
an input voltage adjusting unit for adjusting a voltage of an input power source to output the adjusted voltage to the wide power source window voltage comparator;
and the output voltage adjusting unit is used for adjusting the voltage output by the wide power supply window voltage comparator into a stable voltage detection signal.
2. The under-voltage and over-voltage detection circuit of a DC input power supply of claim 1, wherein the input voltage adjustment unit comprises resistors R1, R2 and R3, capacitors C1, C2 and C3; pin 3 of wide power window voltage comparator connects respectively the one end of R1, the one end of electric capacity C2 and the one end of resistance R2, the other end of resistance R1 with connect input power after electric capacity C1's one end links to each other, pin 4 of wide power window voltage comparator connects respectively the other end of resistance R2, the one end of electric capacity C3 and the one end of resistance R3, the other end ground connection of resistance R3, the other end of electric capacity C1 with electric capacity C2's the other end links to each other the back, connects respectively electric capacity C3's the other end and ground connection.
3. The under-voltage and over-voltage detection circuit of a DC input power supply of claim 1, wherein the output voltage adjustment unit comprises resistors R4 and R5, capacitors C4 and C5; connect respectively after wide power window voltage comparator's pin 6 links to each other with pin 1 resistance R4's one end, voltage detection signal output end and electric capacity C4's one end, electric capacity C4's other end ground connection, resistance R4's another termination power 3.3V, wide power window voltage comparator's pin 5 is connected respectively resistance R5's one end with electric capacity C5's one end, resistance R5's another termination power 3.3V, electric capacity C5's another termination ground connection.
4. The undervoltage detection circuit for the over-voltage and under-voltage of the DC input power supply according to any one of claims 1 to 3, wherein the pin 2 of the wide power window voltage comparator is grounded.
5. The under-voltage and over-voltage detection circuit for the DC input power supply of claim 4, wherein the wide power window voltage comparator is a TPS3700 chip.
6. The under-voltage and over-voltage detection circuit for the direct current input power supply of claim 5, wherein the pins 1 and 2 of the wide power window voltage comparator are input voltage terminals, and the pins 1 and 6 of the wide power window voltage comparator are output voltage terminals.
7. The under-voltage and over-voltage detection circuit of claim 2, wherein the capacitor C1 is 100 nFarad, the capacitor C2 is 1 nFarad, and the capacitor C3 is 1 nFarad.
8. The under-voltage/overvoltage detection circuit for a DC input power supply of claim 3, wherein the capacitor C4 is 100 picofarads and the capacitor C5 is 100 nanofarads.
9. The under-voltage and over-voltage detection circuit for the direct-current input power supply of claim 6, wherein the operating voltage range of the wide power window voltage comparator is 1.8V to 18V.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201922314288.0U CN211528530U (en) | 2019-12-20 | 2019-12-20 | Overvoltage and undervoltage detection circuit of direct current input power supply |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201922314288.0U CN211528530U (en) | 2019-12-20 | 2019-12-20 | Overvoltage and undervoltage detection circuit of direct current input power supply |
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| CN211528530U true CN211528530U (en) | 2020-09-18 |
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