Overcurrent protection sampling circuit and three-phase circuit device
By designing an overcurrent protection sampling circuit, utilizing three comparator circuits and one ADC sampling port of a microcontroller, the problem of limited ADC sampling port resources in a three-phase PFC circuit device is solved, achieving low-cost overcurrent protection and preventing failure caused by excessive current.
Patent Information
- Application Number
- CN202422793784.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-15
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2034-11-15
AI Technical Summary
In the existing technology, three-phase PFC circuit devices require six ADC sampling ports for overcurrent protection, resulting in high microcontroller costs.
Design an overcurrent protection sampling circuit that uses three comparator circuits and one ADC sampling port of a microcontroller to implement overcurrent protection for three-phase PFC input. The maximum current phase is selected and the protection signal is output through AND gate logic.
This invention enables overcurrent protection of three-phase PFC input using only one ADC sampling port of a microcontroller, reducing the cost of the microcontroller and effectively preventing failure caused by excessive current.
Smart Images
Figure CN223567293U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the protection of circuit device, especially a kind of overcurrent protection sampling circuit and three-phase circuit device. BACKGROUND
[0002] Due to the application environment of certain circuit device is more and more harsh, in order to guarantee the reliability of product, for example, three-phase switching power supply with PFC function, we need to protect any one phase of three-phase PFC, under normal circumstances, using traditional overcurrent protection circuit, the overcurrent protection sampling of three-phase PFC input needs two signals every phase, respectively indicating that the phase overcurrent or no overcurrent, then ADC needs six sampling ports, in order to meet the demand of six ADC sampling ports, we usually need to select higher specification and more port single-chip microcomputer, higher specification and more port single-chip microcomputer will bring higher cost.
[0003] In order to solve this problem, we design an overcurrent protection circuit, which can realize the overcurrent protection of three-phase PFC input using one-way ADC sampling port of single-chip microcomputer, this overcurrent protection circuit is similar to an AND gate circuit, it can select the phase of the maximum current in three-phase PFC input and send the sampling signal to one-way I / O sampling port of single-chip microcomputer, so as to realize the protection of power module, this overcurrent protection circuit not only has simple structure and low cost, but also can effectively prevent PFC input current from being too large and invalid. SUMMARY
[0004] Therefore, the utility model wants to solve the technical problem to provide a kind of overcurrent protection sampling circuit and three-phase circuit device, alleviate single-chip microcomputer port resource shortage.
[0005] As the first aspect of the utility model, the technical scheme of the embodiment of the overcurrent protection sampling circuit provided is as follows:
[0006] An overcurrent protection sampling circuit is applied to three-phase circuit device, wherein the overcurrent protection sampling circuit comprises:
[0007] First comparison circuit, second comparison circuit and third comparison circuit;
[0008] The first input end of the first comparison circuit is the first input end of the overcurrent protection sampling circuit, used for inputting a first voltage signal representing the magnitude of the first-phase input current of the three-phase circuit device; the first input end of the second comparison circuit is the second input end of the overcurrent protection sampling circuit, used for inputting a second voltage signal representing the magnitude of the second-phase input current of the three-phase circuit device; the first input end of the third comparison circuit is the third input end of the overcurrent protection sampling circuit, used for inputting a third voltage signal representing the magnitude of the third-phase input current of the three-phase circuit device; the second input end of the first comparison circuit, the second input end of the second comparison circuit and the second input end of the third comparison circuit are connected together as the fourth input end of the overcurrent protection sampling circuit, used for inputting a first threshold voltage signal; the third input end of the first comparison circuit, the third input end of the second comparison circuit and the third input end of the third comparison circuit are connected together as the fifth input end of the overcurrent protection sampling circuit, used for inputting a second threshold voltage signal, the first threshold voltage signal being greater than the second threshold voltage signal; the output end of the first comparison circuit, the output end of the second comparison circuit and the output end of the third comparison circuit are connected together as the output end of the overcurrent protection sampling circuit, used for outputting an overcurrent protection signal required by the three-phase circuit device to perform an overcurrent protection action.
[0009] When the voltage signal at the first input end of any one of the first comparison circuit, the second comparison circuit and the third comparison circuit is greater than the voltage signal at the second input end thereof during the operation of the three-phase circuit device, the signal output by the comparison circuit represents that the input current of the corresponding phase of the three-phase circuit device is too large.
[0010] Preferably, the first comparison circuit comprises a first current-limiting device, a first comparator and a second comparator, one end of the first current-limiting device being the first input end of the first comparison circuit, the other end of the first current-limiting device being connected to the inverting input end of the first comparator and the non-inverting input end of the second comparator at the same time, the non-inverting input end of the first comparator being the second input end of the first comparison circuit, the inverting input end of the second comparator being the third input end of the first comparison circuit, and the output end of the first comparator and the output end of the second comparator being connected together as the output end of the first comparison circuit.
[0011] Preferably, the first current-limiting device is a resistor.
[0012] Preferably, the second comparison circuit comprises a second current-limiting device, a third comparator and a fourth comparator, one end of the second current-limiting device is a first input end of the second comparison circuit, the other end of the second current-limiting device is connected to the inverting input end of the third comparator and the non-inverting input end of the fourth comparator at the same time, the non-inverting input end of the third comparator is a second input end of the second comparison circuit, the inverting input end of the fourth comparator is a third input end of the second comparison circuit, the output end of the third comparator and the output end of the fourth comparator are connected together to be an output end of the second comparison circuit.
[0013] Preferably, the second current-limiting device is a resistor.
[0014] Preferably, the third comparison circuit comprises a third current-limiting device, a fifth comparator and a sixth comparator, one end of the third current-limiting device is a first input end of the third comparison circuit, the other end of the third current-limiting device is connected to the inverting input end of the fifth comparator and the non-inverting input end of the sixth comparator at the same time, the non-inverting input end of the fifth comparator is a second input end of the third comparison circuit, the inverting input end of the sixth comparator is a third input end of the third comparison circuit, the output end of the fifth comparator and the output end of the sixth comparator are connected together to be an output end of the third comparison circuit.
[0015] Preferably, the third current-limiting device is a resistor.
[0016] Preferably, the first comparison circuit comprises a first current limiting device, a first comparator and a second comparator, one end of the first current limiting device is a first input end of the first comparison circuit, the other end of the first current limiting device is connected to the inverting input end of the first comparator and the non-inverting input end of the second comparator at the same time, the non-inverting input end of the first comparator is a second input end of the first comparison circuit, the inverting input end of the second comparator is a third input end of the first comparison circuit, the output end of the first comparator and the output end of the second comparator are connected together to be an output end of the first comparison circuit; the second comparison circuit comprises a second current limiting device, a third comparator and a fourth comparator, one end of the second current limiting device is a first input end of the second comparison circuit, the other end of the second current limiting device is connected to the inverting input end of the third comparator and the non-inverting input end of the fourth comparator at the same time, the non-inverting input end of the third comparator is a second input end of the second comparison circuit, the inverting input end of the fourth comparator is a third input end of the second comparison circuit, the output end of the third comparator and the output end of the fourth comparator are connected together to be an output end of the second comparison circuit; the third comparison circuit comprises a third current limiting device, a fifth comparator and a sixth comparator, one end of the third current limiting device is a first input end of the third comparison circuit, the other end of the third current limiting device is connected to the inverting input end of the fifth comparator and the non-inverting input end of the sixth comparator at the same time, the non-inverting input end of the fifth comparator is a second input end of the third comparison circuit, the inverting input end of the sixth comparator is a third input end of the third comparison circuit, the output end of the fifth comparator and the output end of the sixth comparator are connected together to be an output end of the third comparison circuit.
[0017] As a second aspect of the present application, the technical scheme of the embodiment of the three-phase circuit device is as follows:
[0018] A three-phase circuit device, wherein: comprising the overcurrent protection sampling circuit of any one of the first aspect.
[0019] Further, the three-phase circuit device is a switching power supply.
[0020] The beneficial effects of the present application compared with the prior art are as follows:
[0021] The output end of the first comparison circuit, the output end of the second comparison circuit and the output end of the third comparison circuit in the overcurrent protection sampling circuit embodiment of the present application are connected together to be an output end of the overcurrent protection sampling circuit, so that when the output current of any phase of the three-phase circuit device is too large, the output end of the overcurrent protection sampling circuit will output an overcurrent protection signal that the three-phase circuit device needs to perform an overcurrent protection action. BRIEF DESCRIPTION OF DRAWINGS
[0022] Figure 1 The principle block diagram of the overcurrent protection sampling circuit of the first embodiment of the utility model;
[0023] Figure 2 The single-chip microcomputer is connected with a specific circuit diagram of the utility model Figure 1 The specific circuit diagram of the utility model Specific implementation
[0024] In order to make the above-mentioned purpose, features and advantages of the utility model more obvious and easy to understand, the specific implementation of the utility model will be described in detail below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor shall belong to the scope of protection of the present application.
[0025] It should be noted that the terms "include" and "have" and any variations thereof described in the specification and claims of the present application are intended to cover non-exclusive inclusion, for example, a series of components, unit circuits or control sequences need not be limited to those components, unit circuits or control sequences clearly listed, but can include components, unit circuits or control sequences not clearly listed or inherent to these circuits.
[0026] In addition, the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.
[0027] It should be understood that in the specification and claims, when describing that an element is "connected" to another element, the element can be "directly connected" to the other element, or "connected" to the other element through a third element; when describing that a step is connected to another step, the step can be directly connected to the other step, or connected to the other step through a third step.
[0028] First embodiment
[0029] The embodiment provides a kind of overcurrent protection sampling circuit, it is applied to three-phase circuit device, Figure 1 The principle block diagram of the overcurrent protection sampling circuit of the first embodiment of the utility model, please see Figure 1 Wherein, overcurrent protection sampling circuit includes:
[0030] First comparison circuit, second comparison circuit and third comparison circuit;
[0031] The first input end of the first comparison circuit is the first input end of the overcurrent protection sampling circuit, used for inputting a first voltage signal representing the size of the first-phase input current of the three-phase circuit device; the first input end of the second comparison circuit is the second input end of the overcurrent protection sampling circuit, used for inputting a second voltage signal representing the size of the second-phase input current of the three-phase circuit device; the first input end of the third comparison circuit is the second input end of the overcurrent protection sampling circuit, used for inputting a third voltage signal representing the size of the third-phase input current of the three-phase circuit device; the second input end of the first comparison circuit, the second input end of the second comparison circuit and the second input end of the third comparison circuit are connected together as the fourth input end of the overcurrent protection sampling circuit, used for inputting a first threshold voltage signal; the third input end of the first comparison circuit, the third input end of the second comparison circuit and the third input end of the third comparison circuit are connected together as the fifth input end of the overcurrent protection sampling circuit, used for inputting a second threshold voltage signal, the first threshold voltage signal being greater than the second threshold voltage signal; the output end of the first comparison circuit, the output end of the second comparison circuit and the output end of the third comparison circuit are connected together as the output end of the overcurrent protection sampling circuit, used for outputting an overcurrent protection signal required by the three-phase circuit device to perform an overcurrent protection action.
[0032] When the voltage signal of the first input end of any one of the first comparison circuit, the second comparison circuit and the third comparison circuit is greater than the voltage signal of the second input end thereof during the operation of the three-phase circuit device, the signal output by the comparison circuit represents that the current input into the corresponding phase of the three-phase circuit device is too large.
[0033] The output end of the first comparison circuit, the output end of the second comparison circuit and the output end of the third comparison circuit in the overcurrent protection sampling circuit of the embodiment are connected together as the output end of the overcurrent protection sampling circuit, so that the output end of the overcurrent protection sampling circuit outputs the overcurrent protection signal required by the three-phase circuit device to perform an overcurrent protection action when the output current of any phase of the three-phase circuit device is too large.
[0034] Figure 2 A single-chip microcomputer is connected to a specific circuit diagram of the utility model Figure 1 , please see Figure 2 , wherein
[0035] The first comparison circuit comprises a first current-limiting device, a first comparator U1 and a second comparator U2, one end of the first current-limiting device is a first input end of the first comparison circuit, the other end of the first current-limiting device is connected to the inverting input end of the first comparator U1 and the non-inverting input end of the second comparator U2 at the same time, the non-inverting input end of the first comparator U1 inputs a first threshold voltage signal VREFH as a second input end of the first comparison circuit, the inverting input end of the second comparator U2 inputs a second threshold voltage signal VREFL as a third input end of the first comparison circuit, and the output end of the first comparator U1 and the output end of the second comparator U2 are connected together as an output end of the first comparison circuit. Specifically, the first current-limiting device is a resistor R1.
[0036] The second comparison circuit comprises a second current-limiting device, a third comparator U3 and a fourth comparator U4, one end of the second current-limiting device is a first input end of the second comparison circuit, the other end of the second current-limiting device is connected to the inverting input end of the third comparator U3 and the non-inverting input end of the fourth comparator U4 at the same time, the non-inverting input end of the third comparator U3 inputs a first threshold voltage signal VREFH as a second input end of the second comparison circuit, the inverting input end of the fourth comparator U4 inputs a second threshold voltage signal VREFL as a third input end of the second comparison circuit, and the output end of the third comparator U3 and the output end of the fourth comparator U4 are connected together as an output end of the second comparison circuit. Specifically, the second current-limiting device is a resistor R2.
[0037] The third comparison circuit comprises a third current-limiting device, a fifth comparator U5 and a sixth comparator U6, one end of the third current-limiting device is a first input end of the third comparison circuit, the other end of the third current-limiting device is connected to the inverting input end of the fifth comparator U5 and the non-inverting input end of the sixth comparator U6 at the same time, the non-inverting input end of the fifth comparator U5 inputs a first threshold voltage signal VREFH as a second input end of the third comparison circuit, the inverting input end of the sixth comparator U6 inputs a second threshold voltage signal VREFL as a third input end of the third comparison circuit, and the output end of the fifth comparator U5 and the output end of the sixth comparator U6 are connected together as an output end of the third comparison circuit. Specifically, the third current-limiting device is a resistor R3.
[0038] Wherein, the first voltage signal IU, the second voltage signal IV and the third voltage signal IW can be obtained by a Hall current sensor; the first voltage signal IU is compared with the first threshold voltage signal VREFH by the first comparator U1, when the first voltage signal IU is greater than the first threshold voltage signal VREFH, the output end 1 pin of the first comparator U1 outputs low level, the first voltage signal IU is compared with the second threshold voltage signal VREFL by the second comparator U2, when the first voltage signal IU is less than the second threshold voltage signal VREFL, the output end 1 pin of the second comparator U2 outputs low level; the second voltage signal IV is compared with the first threshold voltage signal VREFH by the third comparator U3, when the second voltage signal IV is greater than the first threshold voltage signal VREFH, the output end 1 pin of the third comparator U3 outputs low level, the second voltage signal IV is compared with the second threshold voltage signal VREFL by the fourth comparator U4, when the second voltage signal IV is less than the second threshold voltage signal VREFL, the output end 1 pin of the fourth comparator U4 outputs low level; the third voltage signal IW is compared with the first threshold voltage signal VREFH by the fifth comparator U5, when the third voltage signal IW is greater than the first threshold voltage signal VREFH, the output end 1 pin of the fifth comparator U5 outputs low level, the third voltage signal IW is compared with the second threshold voltage signal VREFL by the sixth comparator U6, when the third voltage signal IW is less than the second threshold voltage signal VREFL, the output end 1 pin of the sixth comparator U6 outputs low level.
[0039] Wherein, the single-chip microcomputer only shows the pins closely related to the utility model, which are respectively:
[0040] The I_FAIL pin is an overcurrent protection pin, which is connected with the output end of the overcurrent protection sampling circuit, and the single-chip microcomputer judges whether the overcurrent protection action needs to be performed according to the level signal output by the output end of the overcurrent protection sampling circuit, if yes, the overcurrent protection function is triggered;
[0041] The VCC pin is a power supply pin, which is connected with the +3.3V power signal;
[0042] The AGND pin is a ground pin, which is connected with the ground signal GND;
[0043] The DC_EN pin is an enable pin, which is connected with the DC power control enable signal, and the single-chip microcomputer works only when the pin receives the DC power control enable signal;
[0044] Wherein, the resistance R4 is further included, one end of the resistance R4 is connected with the I_FAIL pin of the single-chip microcomputer U7, and the other end of the resistance R4 is connected with the +3.3V power signal, and the purpose of connecting the resistance is to provide a bias current to ensure the stability of the signal.
[0045] Figure 2Since the output ends of the comparators are connected together, when the level outputted by any one of the comparators U1, U3 and U5 is a low level, it indicates that the output current of the corresponding phase of the three-phase circuit device is too large, and the single-chip microcomputer controls the three-phase circuit device to perform an overcurrent protection action.
[0046] Second embodiment
[0047] The three-phase circuit device provided by the embodiment comprises any one of the overcurrent protection sampling circuits in the first embodiment, so that the overcurrent protection of the three-phase input can be realized by using one ADC sampling port of the single-chip microcomputer, the three-phase circuit device is effectively prevented from being disabled due to the excessive input current, and the overcurrent protection circuit is similar to an AND gate circuit, so that the shortage of the port resources of the single-chip microcomputer is relieved.
[0048] Further, the three-phase circuit device is a switching power supply.
[0049] The above is only the implementation manner of the present application, and it should be particularly pointed out that the above implementation manner should not be regarded as the limitation of the present application, and for the ordinary skilled in the art, some improvements and decorations can be made without departing from the spirit and scope of the present application, and these improvements and decorations should also be regarded as the protection scope of the present application.
Claims
1. An overcurrent protection sampling circuit applied to a three-phase circuit device, characterized by, The overcurrent protection sampling circuit comprises: a first comparison circuit, a second comparison circuit and a third comparison circuit; a first input terminal of the first comparison circuit is a first input terminal of the overcurrent protection sampling circuit, configured to input a first voltage signal representing a size of a first-phase input current of the three-phase circuit device; a first input terminal of the second comparison circuit is a second input terminal of the overcurrent protection sampling circuit, configured to input a second voltage signal representing a size of a second-phase input current of the three-phase circuit device; a first input terminal of the third comparison circuit is a third input terminal of the overcurrent protection sampling circuit, configured to input a third voltage signal representing a size of a third-phase input current of the three-phase circuit device; a second input terminal of the first comparison circuit, a second input terminal of the second comparison circuit and a second input terminal of the third comparison circuit are connected together to be a fourth input terminal of the overcurrent protection sampling circuit, configured to input a first threshold voltage signal; a third input terminal of the first comparison circuit, a third input terminal of the second comparison circuit and a third input terminal of the third comparison circuit are connected together to be a fifth input terminal of the overcurrent protection sampling circuit, configured to input a second threshold voltage signal, the first threshold voltage signal being greater than the second threshold voltage signal; and an output terminal of the first comparison circuit, an output terminal of the second comparison circuit and an output terminal of the third comparison circuit are connected together to be an output terminal of the overcurrent protection sampling circuit, configured to output an overcurrent protection signal indicating that the three-phase circuit device needs to perform an overcurrent protection action; when the three-phase circuit device is working, if a voltage signal at the first input terminal of any one of the first comparison circuit, the second comparison circuit and the third comparison circuit is greater than a voltage signal at its second input terminal, a signal output by the comparison circuit represents that a current input to a corresponding phase of the three-phase circuit device is too large.
2. The overcurrent protection sampling circuit of claim 1, wherein: The first comparison circuit comprises a first current-limiting device, a first comparator and a second comparator, one end of the first current-limiting device is a first input terminal of the first comparison circuit, the other end of the first current-limiting device is connected to an inverting input terminal of the first comparator and a non-inverting input terminal of the second comparator at the same time, a non-inverting input terminal of the first comparator is a second input terminal of the first comparison circuit, an inverting input terminal of the second comparator is a third input terminal of the first comparison circuit, and an output terminal of the first comparator and an output terminal of the second comparator are connected together to be an output terminal of the first comparison circuit.
3. The overcurrent protection sampling circuit of claim 2, wherein: The first current-limiting device is a resistor.
4. The overcurrent protection sampling circuit of claim 1, wherein: The second comparison circuit comprises a second current-limiting device, a third comparator and a fourth comparator, one end of the second current-limiting device is a first input end of the second comparison circuit, the other end of the second current-limiting device is connected to the inverting input end of the third comparator and the non-inverting input end of the fourth comparator at the same time, the non-inverting input end of the third comparator is a second input end of the second comparison circuit, the inverting input end of the fourth comparator is a third input end of the second comparison circuit, and the output end of the third comparator and the output end of the fourth comparator are connected together to be an output end of the second comparison circuit.
5. The overcurrent protection sampling circuit of claim 4, wherein: The second current-limiting device is a resistor.
6. The overcurrent protection sampling circuit of claim 1, wherein: The third comparison circuit comprises a third current-limiting device, a fifth comparator and a sixth comparator, one end of the third current-limiting device is a first input end of the third comparison circuit, the other end of the third current-limiting device is connected to the inverting input end of the fifth comparator and the non-inverting input end of the sixth comparator at the same time, the non-inverting input end of the fifth comparator is a second input end of the third comparison circuit, the inverting input end of the sixth comparator is a third input end of the third comparison circuit, and the output end of the fifth comparator and the output end of the sixth comparator are connected together to be an output end of the third comparison circuit.
7. The overcurrent protection sampling circuit of claim 6, wherein: The third current-limiting device is a resistor.
8. The overcurrent protection sampling circuit according to claim 1, characterized in that: The first comparison circuit comprises a first current-limiting device, a first comparator and a second comparator, one end of the first current-limiting device is a first input end of the first comparison circuit, the other end of the first current-limiting device is connected to the inverting input end of the first comparator and the non-inverting input end of the second comparator at the same time, the non-inverting input end of the first comparator is a second input end of the first comparison circuit, the inverting input end of the second comparator is a third input end of the first comparison circuit, and the output end of the first comparator and the output end of the second comparator are connected together to be an output end of the first comparison circuit; The second comparison circuit comprises a second current-limiting device, a third comparator and a fourth comparator, one end of the second current-limiting device is a first input end of the second comparison circuit, the other end of the second current-limiting device is connected to the inverting input end of the third comparator and the non-inverting input end of the fourth comparator at the same time, the non-inverting input end of the third comparator is a second input end of the second comparison circuit, the inverting input end of the fourth comparator is a third input end of the second comparison circuit, and the output end of the third comparator and the output end of the fourth comparator are connected together to be an output end of the second comparison circuit; The third comparison circuit comprises a third current-limiting device, a fifth comparator and a sixth comparator, one end of the third current-limiting device is a first input end of the third comparison circuit, the other end of the third current-limiting device is connected to the inverting input end of the fifth comparator and the non-inverting input end of the sixth comparator at the same time, the non-inverting input end of the fifth comparator is a second input end of the third comparison circuit, the inverting input end of the sixth comparator is a third input end of the third comparison circuit, and the output end of the fifth comparator and the output end of the sixth comparator are connected together to be an output end of the third comparison circuit.
9. A three-phase circuit arrangement, characterized by: The overcurrent protection sampling circuit comprises the overcurrent protection sampling circuit according to any one of claims 1 to 8.
10. The three-phase circuit arrangement of claim 9, characterized in that: The three-phase circuit device is a switching power supply.