Threshold voltage detection circuit, chip and equipment

Abstract

The utility model provides a threshold voltage detection circuit, a chip and equipment, the threshold voltage detection circuit comprises a rectification filter circuit, a voltage division circuit, an operational amplifier comparison circuit and an optocoupler circuit, the rectification filter circuit, the voltage division circuit and the operational amplifier comparison circuit are connected in sequence; the rectifying and filtering circuit is used for converting an externally input alternating current into a direct current and removing clutters in the direct current; the voltage division circuit performs voltage division on the direct current and inputs the divided voltage to the operational amplifier comparison circuit; and the operational amplifier comparison circuit is used for comparing the divided voltage with a reference voltage and outputting high and low levels.

Description

Technical Field

[0001] The utility model relates to the field of circuits, and in particular to a threshold voltage detection circuit, a chip and a device. Background Art

[0002] In the circuit system, voltage detection is usually required for each level, such as bus voltage detection of machinery and equipment, especially the detection of bus voltage after rectification. Because there is instability in the power grid, there are certain fluctuations, sometimes with large amplitudes, and there are also certain ranges of fluctuations when machinery and equipment consume electricity through loads. The heavier the load, the more the voltage drops. There are also certain ranges of fluctuations when machinery and equipment consume electricity through loads. The heavier the load, the more the voltage drops. Therefore, a circuit that can detect voltage changes is needed to prevent damage to machinery and equipment. Utility Model Content

[0003] The utility model aims to provide a circuit which can detect and judge the range of voltage fluctuation and send out corresponding signals in time when the range exceeds the set threshold.

[0004] In a first aspect, the utility model provides a threshold voltage detection circuit, including a rectifier filter circuit, a voltage divider circuit, an operational amplifier comparison circuit and an optical coupler circuit, wherein the rectifier filter circuit, the voltage divider circuit and the operational amplifier comparison circuit are connected in sequence.

[0005] The rectifier and filter circuit is used to convert external input AC power into DC power and remove noise in the DC power; the voltage divider circuit divides the DC power and inputs the divided voltage to the operational amplifier comparison circuit; the operational amplifier comparison circuit is used to compare the divided voltage with a reference voltage and output high and low levels.

[0006] Furthermore, the rectification and filtering circuit includes a rectifier bridge, a first capacitor and a second capacitor;

[0007] The input end of the rectifier bridge is connected to the external AC power supply end; after the first pin and the second pin of the rectifier bridge are connected, they are respectively connected to one end of the first capacitor and the second capacitor, and after the fifth pin and the sixth pin are connected, they are respectively connected to the other end of the first capacitor and the second capacitor.

[0008] Furthermore, the voltage divider circuit includes a first voltage divider circuit, a second voltage divider circuit and a third voltage divider circuit.

[0009] The first voltage-dividing circuit divides the voltage to be measured and inputs the voltage into the operational amplifier comparison circuit. The second voltage-dividing circuit is used to provide a 3.5V reference voltage. The third voltage-dividing circuit is used to provide a 2.5V reference voltage.

[0010] Furthermore, the first voltage divider circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor and a third capacitor.

[0011] The first resistor, the second resistor, the third resistor and the fourth resistor are connected in series in sequence, one end of the first resistor is respectively connected to the HV end and the first pin, one end of the fourth resistor is respectively connected to the fifth pin and the ground end, and the third capacitor is connected in parallel with the fourth resistor.

[0012] Further, the second voltage divider circuit includes a fifth resistor and a sixth resistor, the fifth resistor and the sixth resistor are connected in series, one end of the fifth resistor is connected to a 5V power supply terminal, and one end of the sixth resistor is grounded;

[0013] The third voltage-dividing circuit includes a seventh resistor and an eighth resistor, the seventh resistor and the eighth resistor are connected in series, one end of the seventh resistor is connected to a 5V power supply terminal, and one end of the eighth resistor is grounded.

[0014] Further, the operational amplifier comparison circuit includes a first comparator, a second comparator, a first diode, a second diode and a ninth resistor;

[0015] The first pin of the first comparator is connected between the third resistor and the fourth resistor, the second pin is connected between the seventh resistor and the eighth resistor, the fifth pin is grounded, the seventh pin is connected to the anode of the first diode, and the eighth pin is connected to the 5V power supply terminal; the third pin of the second comparator is connected between the fifth resistor and the sixth resistor, the fourth pin is connected to the first pin of the first comparator, and the sixth pin is connected to the anode of the second diode;

[0016] The cathode of the first diode is connected to the cathode of the second diode, and then connected in series with a ninth resistor and grounded.

[0017] Furthermore, the optocoupler circuit includes an optocoupler, a tenth resistor and an eleventh resistor. The first pin of the optocoupler is connected in series with the tenth resistor and then connected to the cathode of the second diode. The second pin and the third pin are grounded respectively. The fourth pin is connected in series with the eleventh resistor and then connected to the external power supply terminal.

[0018] In a second aspect, the utility model provides a chip, which adopts the threshold voltage detection circuit as described in any one of the above items.

[0019] In a third aspect, the utility model provides a device, which adopts the threshold voltage detection circuit as described in any one of the above items.

[0020] Compared with the prior art, the utility model includes at least the following beneficial effects: this detection circuit can check and send out an alarm signal when the mains power fluctuation is too high or too low, and can stop the operation of the machine and issue an alarm in time or turn off the control switch of the equipment to prevent damage to the machine equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0022] Figure 1 It is the detailed circuit diagram of the operational amplifier comparison circuit of the utility model;

[0023] Figure 2 This is the overall circuit diagram of the threshold voltage detection circuit of the utility model. DETAILED DESCRIPTION

[0024] A threshold voltage detection circuit, chip and device of the present invention will be described in more detail below in conjunction with a schematic diagram, wherein preferred embodiments of the present invention are shown, and it should be understood that those skilled in the art can modify the present invention described herein and still achieve the beneficial effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art and not as a limitation to the present invention.

[0025] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0026] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are in very simplified form and in non-precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0027] In a first aspect, the utility model provides a threshold voltage detection circuit, including a rectifier filter circuit, a voltage divider circuit, an operational amplifier comparison circuit and an optocoupler circuit, wherein the rectifier filter circuit, the voltage divider circuit and the operational amplifier comparison circuit are connected in sequence.

[0028] The rectifier and filter circuit is used to convert external input AC power into DC power and remove noise in the DC power; the voltage divider circuit divides the DC power and inputs the divided voltage to the operational amplifier comparison circuit; the operational amplifier comparison circuit is used to compare the divided voltage with a reference voltage and output high and low levels.

[0029] Furthermore, the rectification and filtering circuit includes a rectifier bridge DR1, a first capacitor C1 and a second capacitor C2.

[0030] The input end of the rectifier bridge DR1 is connected to the external AC power supply end. Figure 1 As shown, the input end is connected to the three-phase AC voltage terminals J1, J2 and J3. After the first pin and the second pin of the rectifier bridge DR1 are connected, they are respectively connected to one end of the first capacitor C1 and the second capacitor C2, and after the fifth pin and the sixth pin are connected, they are respectively connected to the other end of the first capacitor C2 and the second capacitor C2.

[0031] Please refer to Figure 2 The rectifier bridge DR1 is used to convert an AC signal into a pulsating DC signal. In this embodiment, the rectifier bridge DR1 is composed of six diodes, so that the input current can flow in the same direction regardless of the positive or negative polarity of the input voltage. The first capacitor C1 and the second capacitor C2 are used for filtering, smoothing the pulsating DC output by the rectifier bridge DR1, reducing voltage fluctuations and ripples, and thus obtaining a more stable DC voltage. The first capacitor C1 and the second capacitor C2 are connected in parallel to improve the filtering effect.

[0032] Specifically, the input end of the rectifier bridge DR1 is directly connected to the external AC power supply, so that the AC power can enter the rectifier bridge DR1 for rectification. The output end of the rectifier bridge DR1, i.e., the first pin and the second pin, the fifth pin and the sixth pin, are respectively connected to two capacitors, so that the rectified current can flow to the capacitor for filtering.

[0033] Furthermore, the voltage divider circuit includes a first voltage divider circuit, a second voltage divider circuit and a third voltage divider circuit.

[0034] The first voltage-dividing circuit divides the voltage to be measured and inputs the voltage into the operational amplifier comparison circuit. The second voltage-dividing circuit is used to provide a 3.5V reference voltage. The third voltage-dividing circuit is used to provide a 2.5V reference voltage.

[0035] Furthermore, the first voltage divider circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a third capacitor C3.

[0036] The first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are connected in series in sequence, one end of the first resistor R1 is respectively connected to the HV end and the first pin, one end of the fourth resistor R4 is respectively connected to the fifth pin and the ground end, and the third capacitor C3 is connected in parallel with the fourth resistor R4.

[0037] For details, please refer to Figure 1 . The first voltage divider circuit is used to divide the voltage to be measured. These resistors are connected in series to gradually reduce the voltage to be measured so as to match the input range of the subsequent operational amplifier comparison circuit. The third capacitor C3 is connected in parallel with the fourth resistor R4 for further filtering to reduce voltage fluctuations. In this embodiment, the resistance values ​​of resistors R1, R2, and R3 are 33K, and the resistance value of R4 is 1K, then the voltage 3V after voltage division will be input into the operational amplifier comparison circuit. HV represents the voltage to be detected, and capacitor C3 is used as a filter to filter out spike interference signals.

[0038] Furthermore, the second voltage-dividing circuit includes a fifth resistor R5 and a sixth resistor R6, the fifth resistor R5 and the sixth resistor R6 are connected in series, one end of the fifth resistor R5 is connected to a 5V power supply terminal, and one end of the sixth resistor R6 is grounded.

[0039] The third voltage-dividing circuit includes a seventh resistor R7 and an eighth resistor R8, wherein the seventh resistor R7 and the eighth resistor R8 are connected in series, one end of the seventh resistor R7 is connected to a 5V power supply terminal, and one end of the eighth resistor R8 is grounded.

[0040] Please continue to refer to Figure 1 In this embodiment, the resistance of resistor R5 is 2.4K, and the resistance of R6 is 5.6K. After voltage division, the reference voltage is 3.5V. This reference voltage will be used as a reference value for comparison by the operational amplifier comparison circuit to determine whether the voltage to be measured has reached 3.5V. Resistors R7 and R8 are 2K respectively, and the voltage after voltage division is 2.5V. Similarly, this reference voltage is also a reference value for the operational amplifier comparison circuit to determine whether the voltage to be measured has reached 2.5V.

[0041] The voltage divider circuit allows the voltage to be compared with different reference voltages, thereby achieving accurate detection of the voltage range. By comparing the voltage to be measured with different reference voltages, it can be determined whether the voltage to be measured falls within a specific voltage range, increasing the flexibility and accuracy of voltage detection.

[0042] Furthermore, the operational amplifier comparison circuit includes a first comparator U1A, a second comparator U1B, a first diode D2, a second diode D1 and a ninth resistor R9.

[0043] The first pin of the first comparator U1A is connected between the third resistor R3 and the fourth resistor R4, the second pin is connected between the seventh resistor R7 and the eighth resistor R8, the fifth pin is grounded, the seventh pin is connected to the anode of the first diode D2, and the eighth pin is connected to the 5V power supply terminal.

[0044] The third pin of the second comparator U1B is connected between the fifth resistor R5 and the sixth resistor R6, the fourth pin is connected to the first pin of the first comparator U1A, and the sixth pin is connected to the anode of the second diode D1;

[0045] The cathode of the first diode D2 is connected to the cathode of the second diode D1, and then connected in series with a ninth resistor R9 and grounded.

[0046] Specifically, the first pin of the first comparator U1A is connected between the third resistor R3 and the fourth resistor R4, which is the voltage dividing point of the voltage to be measured. The second pin is connected between the seventh resistor R7 and the eighth resistor R8, which is the voltage dividing point of the 2.5V reference voltage. The fifth pin (ground terminal) is grounded, the seventh pin (output terminal) is connected to the positive electrode of the first diode D2, and the eighth pin (power supply terminal) is connected to the 5V power supply terminal. The function of the first comparator U1A is to compare the voltage to be measured with the 2.5V reference voltage, and output a high or low level according to the comparison result.

[0047] The third pin of the second comparator U1B is connected between the fifth resistor R5 and the sixth resistor R6, which is the voltage dividing point of the 3.5V reference voltage. The fourth pin is connected to the first pin of the first comparator U1A, which is the voltage dividing point of the voltage to be measured. The sixth pin (output end) is connected to the positive electrode of the second diode D1. The function of the second comparator U1B is to compare the voltage to be measured with the 3.5V reference voltage, and output a high or low level according to the comparison result.

[0048] When the bus voltage is divided and input to the first and fourth pins, and the voltage is between 2.5V and 3.5V, both comparators output low level. When the bus voltage is higher than 350V, the voltage of the first and fourth pins is also higher than 3.5V. When the bus voltage is lower than 250V, the voltage of pins 1 and 4 is lower than 2.5V. No matter it is higher or lower, a high level signal will be output.

[0049] The anodes of the two diodes are connected to the output terminals of the first comparator U1A and the second comparator U1B respectively. After the cathodes of the diodes are connected, the ninth resistor R9 is connected in series and grounded. This connection method forms a logic circuit, which can be turned on or off through the diode according to the output level of the comparator, thereby forming a high or low level on the ninth resistor R9.

[0050] Taking the power supply system as an example, J1, J2, and J3 input three-phase AC voltage, DR1 is a rectifier bridge, HV is the bus voltage after rectification, and the capacitance of capacitors C1 and C2 is 100uF, which is used as bus filter capacitors. The bus voltage after filtering is about 300V. The op amp is powered by 5V, which means that as long as the bus voltage is not between the threshold range of 250-350V, it will output a high level. This high-level signal can be directly used for control circuits or connected to other control devices, such as optocouplers.

[0051] Furthermore, the optocoupler circuit includes an optocoupler U2, a tenth resistor R10 and an eleventh resistor R11, the first pin of the optocoupler U2 is connected in series with the tenth resistor R10 and then connected to the cathode of the second diode D1, the second pin and the third pin are grounded respectively, and the fourth pin is connected in series with the eleventh resistor R11 and then connected to the external power supply end.

[0052] Specifically, the optocoupler U2 includes a light emitting diode (LED) and a photosensitive transistor, which are used to achieve circuit isolation through photoelectric conversion. The tenth resistor R10 is connected between the first pin of the optocoupler U2 and the cathode of the second diode D1, and is used to limit the current flowing through the LED to ensure that the LED works normally without exceeding its maximum allowable current. The eleventh resistor R11 is connected between the fourth pin of the optocoupler U2 and the external power supply terminal, and is used to limit the current at the output terminal of the optocoupler to protect the subsequent circuit from overcurrent.

[0053] To sum up, in this embodiment, when the voltage of the fourth pin of the second comparator U1B is lower than the voltage of the third pin, the sixth pin outputs a high level, and is still a high level signal after being unidirectionally conducted by the diode D1; if the voltage of the fourth pin is lower than the voltage of the third pin, a low level signal is output.

[0054] When the voltage of the first pin of the first comparator U1A is higher than the voltage of the second pin, the seventh pin outputs a high level; when the voltage of the first pin is lower than the voltage of the second pin, the seventh pin outputs a low level.

[0055] When one of the seventh pin or the sixth pin outputs a high-level signal, the high-level signal can be directly used for other control signals or to trigger optocouplers and other devices. Resistor R9 is a pull-down resistor. When the two groups of op amps output a low level, the pull-down resistor plays a pull-down role to prevent interference and stabilize at a low level.

[0056] In a second aspect, the utility model provides a chip, which adopts the threshold voltage detection circuit as described in any one of the above items.

[0057] In a third aspect, the utility model provides a device, which adopts the threshold voltage detection circuit as described in any one of the above items.

[0058] The above specific examples are used to illustrate the present invention, which are only used to help understand the present invention and are not intended to limit the present invention. For those skilled in the art of the present invention, some simple deductions, deformations or substitutions can be made based on the idea of ​​the present invention.

Claims

1. A threshold voltage detection circuit, characterized in that: It includes a rectifier filter circuit, a voltage divider circuit, an operational amplifier comparison circuit and an optical coupler circuit, wherein the rectifier filter circuit, the voltage divider circuit and the operational amplifier comparison circuit are connected in sequence. The rectifier and filter circuit is used to convert external input AC power into DC power and remove noise in the DC power; the voltage divider circuit divides the DC power and inputs the divided voltage to the operational amplifier comparison circuit; the operational amplifier comparison circuit is used to compare the divided voltage with a reference voltage and output high and low levels.

2. The threshold voltage detection circuit according to claim 1, characterized in that: The rectification and filtering circuit comprises a rectifier bridge, a first capacitor and a second capacitor; The input end of the rectifier bridge is connected to the external AC power supply end; after the first pin and the second pin of the rectifier bridge are connected, they are respectively connected to one end of the first capacitor and the second capacitor, and after the fifth pin and the sixth pin are connected, they are respectively connected to the other end of the first capacitor and the second capacitor.

3. The threshold voltage detection circuit according to claim 2, characterized in that: The voltage divider circuit includes a first voltage divider circuit, a second voltage divider circuit and a third voltage divider circuit. The first voltage-dividing circuit divides the voltage to be measured and inputs the voltage into the operational amplifier comparison circuit. The second voltage-dividing circuit is used to provide a 3.5V reference voltage. The third voltage-dividing circuit is used to provide a 2.5V reference voltage.

4. The threshold voltage detection circuit as claimed in claim 3, characterized in that: The first voltage divider circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor and a third capacitor. The first resistor, the second resistor, the third resistor and the fourth resistor are connected in series in sequence, one end of the first resistor is respectively connected to the HV end and the first pin, one end of the fourth resistor is respectively connected to the fifth pin and the ground end, and the third capacitor is connected in parallel with the fourth resistor.

5. The threshold voltage detection circuit according to claim 4, characterized in that: The second voltage divider circuit includes a fifth resistor and a sixth resistor, the fifth resistor and the sixth resistor are connected in series, one end of the fifth resistor is connected to a 5V power supply terminal, and one end of the sixth resistor is grounded; The third voltage-dividing circuit includes a seventh resistor and an eighth resistor, the seventh resistor and the eighth resistor are connected in series, one end of the seventh resistor is connected to a 5V power supply terminal, and one end of the eighth resistor is grounded.

6. The threshold voltage detection circuit as claimed in claim 5, characterized in that: The operational amplifier comparison circuit includes a first comparator, a second comparator, a first diode, a second diode and a ninth resistor; The first pin of the first comparator is connected between the third resistor and the fourth resistor, the second pin is connected between the seventh resistor and the eighth resistor, the fifth pin is grounded, the seventh pin is connected to the anode of the first diode, and the eighth pin is connected to the 5V power supply terminal; the third pin of the second comparator is connected between the fifth resistor and the sixth resistor, the fourth pin is connected to the first pin of the first comparator, and the sixth pin is connected to the anode of the second diode; The cathode of the first diode is connected to the cathode of the second diode, and then connected in series with a ninth resistor and grounded.

7. The threshold voltage detection circuit according to claim 6, characterized in that: The optocoupler circuit includes an optocoupler, a tenth resistor and an eleventh resistor. The first pin of the optocoupler is connected in series with the tenth resistor and then connected to the cathode of the second diode. The second pin and the third pin are grounded respectively. The fourth pin is connected in series with the eleventh resistor and then connected to the external power supply terminal.

8. A chip, characterized in that: A threshold voltage detection circuit as described in any one of claims 1 to 7 is adopted.

9. A device, characterized in that: A threshold voltage detection circuit as described in any one of claims 1 to 7 is adopted.

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