Industrial computer overvoltage and undervoltage protection circuit based on operational amplifier and industrial computer

Abstract

The utility model aims to disclose an industrial computer overvoltage and undervoltage protection circuit based on operational amplifiers and an industrial computer, which relate to the technical field of industrial computer circuit protection and comprise a voltage input end, a reference voltage input end, a first operational amplifier, a second operational amplifier, a first N-type MOS (Metal Oxide Semiconductor) tube, a second N-type MOS tube, a third N-type MOS tube, a P-type MOS tube and a voltage output end, the in-phase input end of the first operational amplifier is connected with a wire between the third resistor and the seventh resistor; the inverting input end of the second operational amplifier is connected with a wire between the second resistor and the sixth resistor; the D pole of the first N-type MOS tube and the D pole of the second N-type MOS tube are both connected with the G pole of the third N-type MOS tube, and the D pole of the P-type MOS tube is connected with the voltage output end, the technical effects are that the industrial computer overvoltage and undervoltage protection circuit is formed by the reference voltage, the two groups of divided voltages, the two groups of operational amplifiers and the plurality of MOS tubes, and the input voltage of the industrial computer works normally within a threshold range.

Description

Operational amplifier-based overvoltage and undervoltage protection circuit for industrial computers and industrial computers. Technical Field

[0001] This utility model relates to the field of industrial computer circuit protection technology, and in particular to an industrial computer overvoltage and undervoltage protection circuit based on operational amplifiers, and an industrial computer. Background Technology

[0002] Currently, industrial computers have insufficient protection against overvoltage or undervoltage conditions. Overvoltage may cause electronic components to break down, while undervoltage may cause the industrial computer system to become unstable, or even crash, lose or damage data.

[0003] Therefore, it is necessary to develop an operational amplifier-based overvoltage and undervoltage protection circuit for industrial computers, as well as an industrial computer, to overcome the aforementioned technical problems. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the purpose of this utility model is to disclose an overvoltage and undervoltage protection circuit for industrial computers based on operational amplifiers, and an industrial computer thereof.

[0005] The first objective of this invention is to provide an overvoltage and undervoltage protection circuit for industrial computers based on operational amplifiers.

[0006] The second objective of this invention is to provide an industrial computer.

[0007] To achieve the first objective mentioned above, this utility model provides an industrial computer overvoltage and undervoltage protection circuit based on operational amplifiers, including a voltage input terminal, a reference voltage input terminal, a first operational amplifier, a second operational amplifier, a first N-type MOSFET, a second N-type MOSFET, a third N-type MOSFET, a P-type MOSFET, and a voltage output terminal;

[0008] A first resistor is connected between the reference voltage input terminal and the voltage input terminal;

[0009] The voltage input terminal is grounded through a second resistor and a sixth resistor connected in series, and the voltage input terminal is also grounded through a third resistor and a seventh resistor connected in series.

[0010] The non-inverting input terminal of the first operational amplifier is connected to the wire between the third resistor and the seventh resistor, the inverting input terminal of the first operational amplifier is connected to the reference voltage input terminal, and the output terminal of the first operational amplifier is connected to the gate of the first N-type MOSFET.

[0011] The non-inverting input of the second operational amplifier is connected to the reference voltage input, the inverting input of the second operational amplifier is connected to the wire between the second resistor and the sixth resistor, and the output of the second operational amplifier is connected to the gate of the second N-type MOSFET.

[0012] The drain of the first N-type MOSFET and the drain of the second N-type MOSFET are both connected to the gate of the third N-type MOSFET. The drain of the third N-type MOSFET is connected to the gate of the P-type MOSFET through the eighth resistor. The drain of the P-type MOSFET is connected to the voltage output terminal.

[0013] The source (S) terminal of the P-type MOSFET is connected to the voltage input terminal. A fifth resistor is connected between the source (S) terminal and the gate (G) terminal of the P-type MOSFET, and a capacitor is connected in parallel with the fifth resistor.

[0014] Preferably, the reference voltage input terminal is grounded through a Zener diode or a reference reference chip.

[0015] Preferably, the VCC terminals of both the first operational amplifier and the second operational amplifier are connected to the voltage input terminal, and the GND terminals of both the first operational amplifier and the second operational amplifier are grounded.

[0016] Preferably, the source (S) terminals of the first N-type MOSFET, the second N-type MOSFET, and the third N-type MOSFET are all grounded.

[0017] Preferably, a fourth resistor is provided between the gate (G) of the third N-type MOS transistor and the voltage input terminal.

[0018] Preferably, the fourth resistor is a pull-up resistor.

[0019] Preferably, when the input voltage at the voltage input terminal causes the voltage at the non-inverting input terminal of the first operational amplifier to be higher than the voltage at the reference voltage input terminal, and the voltage at the non-inverting input terminal of the first operational amplifier is greater than the voltage at the inverting input terminal of the first operational amplifier, the output terminal of the first operational amplifier is at a high level, the first N-type MOSFET is turned on, the drain terminal of the first N-type MOSFET outputs a low level, the third N-type MOSFET is turned off, the gate terminal of the P-type MOSFET and the source terminal of the P-type MOSFET have equal voltages and are also turned off, and the voltage output terminal has no output, thus achieving overvoltage protection.

[0020] Preferably, when the input voltage at the voltage input terminal causes the voltage at the non-inverting input terminal of the second operational amplifier to be higher than the voltage at the reference voltage input terminal, and the voltage at the non-inverting input terminal of the second operational amplifier is greater than the voltage at the inverting input terminal of the second operational amplifier, the output terminal of the second operational amplifier is at a high level, the second N-type MOSFET is turned on, the drain terminal of the second N-type MOSFET outputs a low level, the third N-type MOSFET is turned off, the gate terminal of the P-type MOSFET and the source terminal of the P-type MOSFET are equal in voltage and thus turned off, and there is no output at the voltage output terminal, thereby achieving undervoltage protection.

[0021] Preferably, when the input voltage at the voltage input terminal is between overvoltage and undervoltage, the voltage at the non-inverting input terminal of the first operational amplifier is less than the voltage at the inverting input terminal of the first operational amplifier, the output terminal of the first operational amplifier is at a low level, and the first N-type MOSFET is cut off; the voltage at the non-inverting input terminal of the second operational amplifier is less than the voltage at the inverting input terminal of the second operational amplifier, the output terminal of the second operational amplifier is at a low level, the second N-type MOSFET is cut off, the gate (G) of the third N-type MOSFET is at a high level and conducts, the gate (G) level of the P-type MOSFET is less than the source (S) level of the P-type MOSFET and conducts, and the voltage output terminal outputs normally.

[0022] Based on the same inventive principle, in order to achieve the second inventive objective mentioned above, this utility model provides an industrial computer, which has the operational amplifier-based overvoltage and undervoltage protection circuit described in the first invention.

[0023] Compared with the prior art, the technical effects of this utility model are as follows:

[0024] This invention comprises a reference voltage, two voltage groups, two operational amplifiers, and several MOSFETs to form an overvoltage and undervoltage protection circuit for an industrial computer. This circuit ensures that the industrial computer operates normally within the threshold voltage range, and prevents it from starting under overvoltage or undervoltage conditions, thus protecting the industrial computer. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 is a circuit block diagram of the industrial computer overvoltage and undervoltage protection circuit based on operational amplifier of this utility model. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent transformations or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the protection scope of the present invention.

[0028] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0029] Example 1

[0030] Referring to Figure 1, this embodiment discloses a specific implementation of an operational amplifier-based overvoltage and undervoltage protection circuit for industrial computers (hereinafter referred to as "circuit").

[0031] Referring to Figure 1, the industrial computer overvoltage and undervoltage protection circuit based on operational amplifiers includes a voltage input terminal VCC-IN, a reference voltage input terminal VREF, a first operational amplifier U1A, a second operational amplifier U1B, a first N-type MOSFET Q2, a second N-type MOSFET Q4, a third N-type MOSFET Q3, a P-type MOSFET Q1, and a voltage output terminal VCC-OUT. A first resistor R1 is connected between the reference voltage input terminal VREF and the voltage input terminal VCC-IN. The voltage input terminal VCC-IN is grounded through a second resistor R2 and a sixth resistor R6 connected in series, and also through a third resistor R3 and a seventh resistor R7 connected in series. The non-inverting input terminal of the first operational amplifier U1A is connected to the wire between the third resistor R3 and the seventh resistor R7, and the inverting input terminal of the first operational amplifier U1A is connected to the reference voltage input terminal VREF. The output of operational amplifier U1A is connected to the gate (G) of the first N-type MOSFET Q2; the non-inverting input of the second operational amplifier U1B is connected to the reference voltage input VREF, and the inverting input of the second operational amplifier U1B is connected to the wire between the second resistor R2 and the sixth resistor R6; the output of the second operational amplifier U1B is connected to the gate (G) of the second N-type MOSFET Q4; the drain (D) of the first N-type MOSFET Q2 and the drain of the second N-type MOSFET Q4 are both connected to the gate (G) of the third N-type MOSFET Q3; the drain of the third N-type MOSFET Q3 is connected to the gate (G) of the P-type MOSFET Q1 through the eighth resistor R8; the drain of the P-type MOSFET Q1 is connected to the voltage output terminal VCC-OUT; the source (S) of the P-type MOSFET Q1 is connected to the voltage input terminal VCC-IN; a fifth resistor R5 is connected between the source (S) and the gate (G) of the P-type MOSFET Q1, and a capacitor C1 is connected in parallel with the fifth resistor R5.

[0032] Specifically, referring to Figure 1, the purpose of this embodiment is to construct an overvoltage and undervoltage protection circuit for an industrial computer by using a reference voltage VREF, two voltage dividers (a voltage divider composed of the second resistor R2 and the sixth resistor R6, and a voltage divider composed of the third resistor R3 and the seventh resistor R7), two operational amplifiers (U1A, U1B), and several MOSFETs (Q1-Q4). This circuit ensures that the input voltage of the industrial computer operates normally within the threshold range, and prevents it from starting under overvoltage and undervoltage conditions, thereby protecting the industrial computer. The reference voltage input terminal VREF is grounded through a Zener diode D1 or a reference reference chip (such as TL431); the VCC terminals of the first operational amplifier U1A and the second operational amplifier U1B are both connected to the voltage input terminal VCC-IN, and the GND terminals of the first operational amplifier U1A and the second operational amplifier U1B are both grounded; the source (S) terminals of the first N-type MOSFET Q2, the second N-type MOSFET Q4, and the third N-type MOSFET Q3 are all grounded; a fourth resistor R4 is provided between the gate (G) terminal of the third N-type MOSFET Q3 and the voltage input terminal VCC-IN; the fourth resistor R4 is a pull-up resistor.

[0033] Referring to Figure 1, the overvoltage protection principle of the industrial computer based on operational amplifiers is as follows: When the input voltage at the voltage input terminal VCC-IN exceeds the threshold Vmax, the voltage at the non-inverting input terminal of the first operational amplifier U1A, DET-OV, is equal to R7 / (R3+R7)*Vmax. That is, when the input voltage at the voltage input terminal VCC-IN makes the voltage at the non-inverting input terminal of the first operational amplifier U1A, DET-OV, higher than the voltage at the reference voltage input terminal VREF, the voltage at the non-inverting input terminal of the first operational amplifier U1A is greater than the voltage at the inverting input terminal of the first operational amplifier U1A. The output terminal of the first operational amplifier U1A is at a high level, the first N-type MOSFET Q2 is turned on, the drain of the first N-type MOSFET Q2 is pulled to a low level, the drain of the first N-type MOSFET Q2 outputs a low level, the third N-type MOSFET Q3 is turned off, the gate and source voltages of the P-type MOSFET Q1 are equal and thus turned off, and the voltage output terminal VCC-OUT has no output, thereby achieving overvoltage protection.

[0034] Referring to Figure 1, the undervoltage protection principle of the industrial computer based on operational amplifiers is as follows: When the input voltage of the voltage input terminal VCC-IN is lower than the threshold Vmin, the voltage DET-UV at the inverting input terminal of the second operational amplifier U1B is R6 / (R2+R6)*Vmin. That is, when the input voltage of the voltage input terminal VCC-IN makes the voltage at the non-inverting input terminal of the second operational amplifier U1B higher than the voltage at the reference voltage input terminal VREF, the voltage at the non-inverting input terminal of the second operational amplifier U1B is greater than the voltage at the inverting input terminal of the second operational amplifier U1B, the output terminal of the second operational amplifier U1B is at a high level, the second N-type MOSFET Q4 is turned on, the drain of the second N-type MOSFET Q4 is pulled to a low level, the drain of the second N-type MOSFET Q4 outputs a low level, the third N-type MOSFET Q3 is turned off, the gate and source voltages of the P-type MOSFET Q1 are equal and thus turned off, and the voltage output terminal VCC-OUT has no output, thereby achieving undervoltage protection.

[0035] Referring to Figure 1, the normal operating principle of the operational amplifier-based industrial computer is as follows: When the input voltage of the voltage input terminal VCC-IN is between overvoltage Vmax and undervoltage Vmax, the voltage at the non-inverting input terminal of the first operational amplifier U1A is less than the voltage at the inverting input terminal of the first operational amplifier U1A, the output terminal of the first operational amplifier U1A is at a low level, and the first N-type MOSFET Q2 is cut off; the voltage at the non-inverting input terminal of the second operational amplifier U1B is less than the voltage at the inverting input terminal of the second operational amplifier U1B, the output terminal of the second operational amplifier U1B is at a low level, the second N-type MOSFET Q4 is cut off, the gate of the third N-type MOSFET Q3 is pulled up to a high level by the fourth resistor and conducts, the gate level of the P-type MOSFET Q1 is R8 / (R5+R8)*VCC_IN, the gate level of the P-type MOSFET Q1 is less than the source level of the P-type MOSFET Q1 and conducts, and the voltage output terminal VCC-OUT outputs normally.

[0036] Example 2

[0037] This embodiment discloses a specific implementation of an industrial computer. The industrial computer has the operational amplifier-based overvoltage and undervoltage protection circuit described in Embodiment 1, which protects the input voltage of the industrial computer under both overvoltage and undervoltage conditions.

[0038] Example 2 describes the overvoltage and undervoltage protection circuit of the industrial computer based on operational amplifiers. For details, please refer to Example 1, which will not be repeated here.

Claims

1. An industrial computer overvoltage and undervoltage protection circuit based on operational amplifiers, characterized in that, The system includes a voltage input terminal, a reference voltage input terminal, a first operational amplifier, a second operational amplifier, a first N-type MOSFET, a second N-type MOSFET, a third N-type MOSFET, a P-type MOSFET, and a voltage output terminal. A first resistor is connected between the reference voltage input terminal and the voltage input terminal. The voltage input terminal is grounded through a second resistor and a sixth resistor connected in series, and also through a third resistor and a seventh resistor connected in series. The non-inverting input terminal of the first operational amplifier is connected to the wire between the third and seventh resistors, the inverting input terminal of the first operational amplifier is connected to the reference voltage input terminal, and the output terminal of the first operational amplifier is connected to the first N-type MOSFET. The gate (G) of the first N-type MOSFET is connected to the reference voltage input terminal; the inverting input terminal of the second operational amplifier is connected to the wire between the second resistor and the sixth resistor; the output terminal of the second operational amplifier is connected to the gate (G) of the second N-type MOSFET; the drain (D) of the first N-type MOSFET and the drain of the second N-type MOSFET are both connected to the gate (G) of the third N-type MOSFET; the drain of the third N-type MOSFET is connected to the gate (G) of the P-type MOSFET through the eighth resistor; the drain of the P-type MOSFET is connected to the voltage output terminal; the source (S) of the P-type MOSFET is connected to the voltage input terminal; a fifth resistor is connected between the source (S) and the gate (G) of the P-type MOSFET, and a capacitor is connected in parallel with the fifth resistor.

2. The operational amplifier-based industrial computer overvoltage and undervoltage protection circuit as described in claim 1, characterized in that, The reference voltage input terminal is grounded through a Zener diode or a reference reference chip.

3. The operational amplifier-based industrial computer overvoltage and undervoltage protection circuit as described in claim 1, characterized in that, The VCC terminals of both the first operational amplifier and the second operational amplifier are connected to the voltage input terminal, and the GND terminals of both the first operational amplifier and the second operational amplifier are grounded.

4. The operational amplifier-based industrial computer overvoltage and undervoltage protection circuit as described in claim 1, characterized in that, The source (S) terminals of the first N-type MOSFET, the second N-type MOSFET, and the third N-type MOSFET are all grounded.

5. The operational amplifier-based industrial computer overvoltage and undervoltage protection circuit as described in claim 4, characterized in that, A fourth resistor is provided between the gate (G) of the third N-type MOS transistor and the voltage input terminal.

6. The operational amplifier-based industrial computer overvoltage and undervoltage protection circuit as described in claim 5, characterized in that, The fourth resistor is a pull-up resistor.

7. An industrial computer, characterized in that, The industrial computer has the operational amplifier-based overvoltage and undervoltage protection circuit described in any one of claims 1-6.

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