MOS tube state detection and threshold voltage detection circuit

Abstract

The utility model relates to an MOS tube state detection and threshold voltage detection circuit, which comprises a signal input isolation circuit, a switch circuit and a voltage division circuit, the signal input isolation circuit is used for controlling the on or off of an MOS tube in the switch circuit and simultaneously realizing the adaptation and electrical isolation connection of a level signal; the signal isolation circuit and the voltage division circuit are used for detecting a threshold voltage, the circuit realizes dual detection of the state of the MOS tube and the threshold voltage, the detection mode is easy to realize, the signal is controllable, the reliability and the stability are high, the requirements of input and output interfaces of various logic level signals can be met, the flexibility of circuit application is improved, and the circuit is suitable for popularization and application. And development engineers can conveniently realize functions and requirements.

Description

Technical Field

[0001] The utility model relates to the technical field of MOS tubes, and more specifically, to a MOS tube state detection and threshold voltage detection circuit. Background Art

[0002] In industrial systems in the safety field, increasing system complexity has, on the one hand, fulfilled the multifunctional requirements of the entire equipment, but on the other hand, it has also brought difficulties to system commissioning, troubleshooting, and maintenance. Controllable MOS transistor status detection and threshold voltage detection circuits with isolation functions can monitor the operating status of important functions or components in the entire system. When these components have problems or are operating abnormally, they will issue a fault indication and restore the system to a safe state. Engineering and technical personnel can use the feedback of the fault indication to track and locate the system fault.

[0003] Existing MOS transistor state detection and threshold voltage detection circuits are complex and costly to implement. They detect the operating status of the MOS transistor by sampling the current flowing through the transistor, amplifying it through a current detection amplifier, and comparing it with a given reference value in a circuit. However, these circuits have limited applications and cannot meet the input and output interface requirements of various logic level signals, making them unsuitable for diverse circuit systems. Utility Model Content

[0004] In order to solve the above-mentioned problems of the prior art, the utility model provides a MOS tube state detection and threshold voltage detection circuit. Under the action of a signal input isolation circuit, a switch circuit and a voltage divider circuit, dual detection of the MOS tube state and threshold voltage can be achieved. The detection method is easy to implement, the signal is controllable, the reliability is high, and the input and output interface requirements of various logic level signals can be met.

[0005] According to one aspect of the present invention, a MOS tube state detection and threshold voltage detection circuit is provided, comprising a signal input isolation circuit, a switch circuit, and a voltage divider circuit. The signal input isolation circuit is used to control the on or off state of the MOS tube in the switch circuit, and the signal isolation circuit and the voltage divider circuit are used to detect the threshold voltage.

[0006] Preferably, the signal isolation input circuit includes a first logic level signal and a first optocoupler, the first logic level signal is connected to the first optocoupler, and the first optocoupler is connected to the input voltage after being turned on.

[0007] Preferably, a first resistor is connected between the first logic level signal and the first optocoupler.

[0008] Preferably, the switch circuit includes a fourth resistor and a MOS transistor, the input voltage is divided by the fourth resistor, the fourth resistor is connected in series with the gate of the MOS transistor, and the input voltage is connected to the source of the MOS transistor.

[0009] Preferably, a second resistor is connected in parallel between the gate and the source.

[0010] Preferably, the drain of the MOS tube is connected to a filter network, and the filter network is convenient for stabilizing the output threshold voltage.

[0011] Preferably, the filtering network includes a ninth resistor, a third capacitor, a fourth capacitor, a fifth capacitor and a magnetic bead, the ninth resistor and the third capacitor are connected to form a first filter, the fourth capacitor and the fifth capacitor are connected to form a second filter, and the magnetic bead is connected between the first filter and the second filter.

[0012] Preferably, the voltage divider circuit includes a fifth resistor, a sixth resistor and a second optocoupler, the fifth resistor and the sixth resistor are connected in series, the fifth resistor and the sixth resistor are connected to the second optocoupler, and the second optocoupler outputs a second logic level signal when turned on.

[0013] The technical effect of the present utility model is that the MOS tube state detection and threshold voltage detection circuit can simultaneously achieve level signal adaptation and electrical isolation connection. When the output threshold voltage received by the external circuit is less than the set threshold value, the external control terminal receives a second logic level signal that changes from a high level to a low level, so that the external control circuit determines that the output threshold voltage does not meet the requirement. In this case, it can be indicated that the state of the MOS tube is not fully turned on or disconnected. Further measurement of the voltage between the source and gate of the MOS tube can determine the state of the MOS tube, thereby achieving dual detection of the MOS tube state and threshold voltage. The detection method is easy to implement, the signal is controllable, and the reliability is high. It can also meet the input and output interface requirements of various logic level signals, improve the flexibility of circuit application, and facilitate development engineers to realize functions and requirements.

[0014] Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0016] Figure 1 FIG. 1 is a schematic diagram of the structure of the MOS tube state detection and threshold voltage detection circuit in this embodiment.

[0017] In the drawings, the same components are denoted by the same reference numerals; the drawings are not drawn to scale. DETAILED DESCRIPTION

[0018] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0019] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present invention, its application, or uses.

[0020] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0021] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0022] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0023] Example

[0024] like Figure 1 As shown, the MOS transistor state detection and threshold voltage detection circuit in this embodiment includes a signal input isolation circuit, a switch circuit and a voltage divider circuit. The signal input isolation circuit is used to control the conduction or shutdown of the MOS transistor in the switch circuit, and at the same time realizes the adaptation of the level signal and the electrical isolation connection. The signal isolation circuit and the voltage divider circuit are used to detect the threshold voltage.

[0025] Furthermore, the signal isolation input circuit includes a first logic level signal S1 and a first optocoupler U1 . The first logic level signal S1 is connected to the first optocoupler U1 . The first optocoupler U1 is connected to the input voltage Vin after being turned on.

[0026] Specifically, an externally input first logic level signal S1 controls the on / off switching of the first optocoupler U1. When the first optocoupler U1 is turned on, a path is established between the input voltage Vin and pins 3 and 4 of the first optocoupler U1. The first optocoupler U1 isolates the input external first logic level signal S1, ensuring that the signal type after the first optocoupler U1 is turned on is consistent with the input voltage Vin. The isolation function of the first optocoupler U1 ensures that the input external first logic level signal S1 is not restricted by its logic level type.

[0027] Furthermore, a first resistor R1 is connected between the first logic level signal S1 and the first optocoupler U1. Specifically, pins 1 and 2 of the first optocoupler U1 are connected in parallel to the first resistor R1 to prevent the first optocoupler U1 from being mis-conducted when the first logic level signal S1 is 0, thereby promoting further stability and reliability of the circuit.

[0028] Furthermore, the switching circuit includes a fourth resistor R4 and a MOS transistor Q1. The MOS transistor Q1 is a P-MOS. The input voltage Vin is divided by the fourth resistor R4. The fourth resistor R4 is connected in series with the gate of the MOS transistor Q1. The input voltage Vin is connected to the source of the MOS transistor Q1.

[0029] Specifically, after the externally input first logic level signal S1 controls the first optocoupler U1 to turn on, the input voltage Vin is divided by the fourth resistor R4. The voltage applied to the gate of the MOS transistor Q1 is equal to the voltage across the fourth resistor R4. The source voltage of the MOS transistor Q1 is equal to the input voltage Vin. At this time, the source voltage is higher than the gate voltage. The positive voltage of the gate attracts holes in the P-type channel, gradually forming a conductive channel. This causes current to flow from the source to the drain, and the MOS transistor Q1 is in the on state.

[0030] Furthermore, the first capacitor C1 filters the input voltage Vin.

[0031] Furthermore, a second resistor R2 is connected in parallel between the gate and the source. The second resistor R2 connected in parallel to the gate and source of the MOS transistor Q1 can keep the VGS voltage of the MOS transistor Q1 within the rated voltage range, ensuring application reliability.

[0032] Furthermore, the drain of the MOS transistor is connected to a filter network, which is convenient for stabilizing the output threshold voltage Vout and making the output threshold voltage Vout smooth. The output threshold voltage Vout can be used to determine the working state of the MOS transistor Q1.

[0033] Furthermore, the filtering network includes a ninth resistor R9, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5 and a magnetic bead FB1. The ninth resistor R9 and the third capacitor C1 are connected to form a first filter, the fourth capacitor C4 and the fifth capacitor C5 are connected to form a second filter, and the magnetic bead FB1 is connected between the first filter and the second filter.

[0034] Furthermore, the voltage divider circuit includes a fifth resistor R5, a sixth resistor R6 and a second optocoupler U2, the fifth resistor R5 and the sixth resistor R6 are connected in series, the fifth resistor R5 and the sixth resistor R6 are connected to the second optocoupler U2, and the second optocoupler U2 outputs a second logic level signal S2 after being turned on. The isolation effect of the second optocoupler U2 ensures that the output second logic level signal S2 does not limit the level type of the external control interface.

[0035] Specifically, after the externally input first logic level signal S1 controls the first optocoupler U1 to turn on, when the output threshold voltage Vout is less than the set threshold value, the MOS transistor Q1 is in the off state. The threshold voltage Vout is the voltage obtained by dividing the fifth resistor R5, the sixth resistor R6, and the ninth resistor R9. At this time, the second optocoupler U2 is turned on, and the second logic level signal S2 received by the external control system changes from 1 to 0. At this time, the system determines that the MOS transistor Q1 is in the off state, and the threshold voltage Vout does not meet the set threshold voltage requirement, thereby achieving detection of the MOS transistor state and threshold voltage.

[0036] The working principle of this embodiment is as follows:

[0037] The external control circuit sends a first logic level signal S1 of 0 and 1. The low-level first logic level signal S1 of 0 does not turn on the first optocoupler U1 under the action of the first resistor R1. The high-level first logic level signal S1 of 1 turns on the first optocoupler U1, thereby forming a path between the input voltage Vin line and pins 3 and 4 of the first optocoupler U1. The input voltage Vin is divided by the fourth resistor R4, so that the voltage at the source of the MOS transistor Q1 is higher than the voltage at the gate. Current flows from the source to the drain of the MOS transistor, turning on the MOS transistor Q1. After passing through the filtering network, the threshold voltage Vout is output. At this time, the threshold voltage Vout meets the set threshold value and meets the requirement.

[0038] When the output threshold voltage Vout received by the external circuit is less than the set threshold value, the threshold voltage Vout is the voltage obtained by dividing the voltages of the fifth resistor R5, the sixth resistor R6, and the ninth resistor R9. The external control terminal receives the second logic level signal S2 that changes from a high level 1 to a low level 0, causing the external control circuit to determine that the output threshold voltage Vout does not meet the requirement. In this case, it can be indicated that the state of the MOS transistor Q1 is not fully turned on or is turned off. Further measurement of the voltage between the source and gate of the MOS transistor can determine the state of the MOS transistor Q1, thereby achieving dual detection of the MOS transistor state and the threshold voltage. The detection method is easy to implement, the signal is controllable, and the reliability and stability are high. It can also meet the input and output interface requirements of various logic level signals, improve the flexibility of circuit application, and facilitate development engineers to realize functions and requirements.

[0039] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art will appreciate that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art will appreciate that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A MOS tube state detection and threshold voltage detection circuit, characterized in that: It includes a signal input isolation circuit, a switch circuit and a voltage divider circuit. The signal input isolation circuit is used to control the on or off of the MOS tube in the switch circuit. The signal input isolation circuit and the voltage divider circuit are used to detect the threshold voltage.

2. The MOS tube state detection and threshold voltage detection circuit according to claim 1, characterized in that: The signal input isolation circuit includes a first logic level signal and a first optocoupler. The first logic level signal is connected to the first optocoupler. The first optocoupler is connected to the input voltage after being turned on.

3. The MOS tube state detection and threshold voltage detection circuit according to claim 2, characterized in that: A first resistor is connected between the first logic level signal and the first optical coupler.

4. The MOS tube state detection and threshold voltage detection circuit according to claim 2, characterized in that: The switch circuit includes a fourth resistor and a MOS transistor. The input voltage is divided by the fourth resistor. The fourth resistor is connected in series with the gate of the MOS transistor. The input voltage is connected to the source of the MOS transistor.

5. The MOS tube state detection and threshold voltage detection circuit according to claim 4, characterized in that: A second resistor is connected in parallel between the gate and the source.

6. The MOS tube state detection and threshold voltage detection circuit according to claim 4, characterized in that: The drain of the MOS tube is connected to a filter network, and the filter network is convenient for stabilizing the output threshold voltage.

7. The MOS tube state detection and threshold voltage detection circuit according to claim 6, characterized in that: The filtering network includes a ninth resistor, a third capacitor, a fourth capacitor, a fifth capacitor and a magnetic bead. The ninth resistor and the third capacitor are connected to form a first filter, the fourth capacitor and the fifth capacitor are connected to form a second filter, and the magnetic bead is connected between the first filter and the second filter.

8. The MOS tube state detection and threshold voltage detection circuit according to claim 1, characterized in that: The voltage divider circuit includes a fifth resistor, a sixth resistor and a second optocoupler. The fifth resistor and the sixth resistor are connected in series. The fifth resistor and the sixth resistor are connected to the second optocoupler. When the second optocoupler is turned on, it outputs a second logic level signal.

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