Novel voltage detection circuit and switching power supply

Abstract

The utility model discloses a novel voltage detection circuit and a switching power supply. The circuit comprises a detection voltage input end, a first voltage division circuit, a switching circuit, a filter circuit and a control chip. The first voltage division circuit is used for dividing the detection voltage V1 input by the detection voltage input end; the switching circuit is used for switching the on-off state of the switching circuit according to a voltage signal sent by a first pin Port1 of the control chip; and when the switching circuit is in a conducting state, the detection voltage V1 after voltage division enters the second pin Port2 of the control chip through the filter circuit, so that voltage detection is carried out. The voltage detection of the second pin Port2 of the control chip is realized by accessing the first pin Port1 of the control chip and switching the on-off state of the switching circuit according to the voltage signal sent by the first pin Port1, so that the voltage detection and judgment are carried out as required, the voltage detection can be flexibly carried out in the most required time of a user, and the user experience is improved. Misjudgment caused by interference signals is avoided, and the precision is higher and more accurate.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of power supply circuit especially a novel voltage detection circuit and switching power supply. BACKGROUND

[0002] At present, voltage detection circuit is commonly provided in switching power supply, and common voltage detection circuit uses the voltage division of pull-up resistor and pull-down resistor to detect the voltage to be monitored. Figure 1 As shown in the circuit diagram of voltage detection circuit in prior art, Figure 1 Resistance R4 and resistance R5 are used as first-stage voltage dividing resistors, and when the voltage at V1 end increases, the voltage between resistance R4 and resistance R5 also increases; in order to reduce the false action caused by voltage mutation, the RC filter composed of resistance R3 and high-frequency capacitor C1 is led out between resistance R4 and resistance R5, and the wire between resistance R3 and high-frequency capacitor C1 is connected to Port2 pin of control chip, so that when Port2 pin receives a large voltage, the internal output is stopped, thereby protecting the circuit from being damaged due to high voltage.

[0003] The above voltage detection circuit has simple structure, but since the detection loop is directly connected to Port2 pin of control chip, false action is easily caused if the detection voltage V1 is disturbed, and there is certain limitation in high-precision circuit, for example, voltage detection at the time when it is most needed cannot be realized. SUMMARY

[0004] Therefore, the utility model provides a novel voltage detection circuit and switching power supply.

[0005] In the first aspect, the utility model provides a novel voltage detection circuit, which comprises a detection voltage input end, a first voltage dividing circuit, a switching circuit, a filter circuit and a control chip.

[0006] The first voltage dividing circuit is used for voltage dividing the detection voltage V1 input by the detection voltage input end.

[0007] The switching circuit is used for switching the on-off state of the switching circuit according to the voltage signal sent by the first pin Port1 of the control chip.

[0008] When the switching circuit is in the on state, the divided detection voltage V1 enters the second pin Port2 of the control chip through the filter circuit, so as to perform voltage detection.

[0009] As a preferred embodiment of the utility model, the first voltage dividing circuit comprises resistance R4 and resistance R5.

[0010] The detection voltage input end is connected with the resistor R4 and the resistor R5 in sequence and grounded.

[0011] As a preferred embodiment of the utility model, the switch circuit comprises a MOS tube Q1, the MOS tube Q1 is used to control its on-off state according to the input voltage of the gate, thereby realizing the on-off state switching of the switch circuit.

[0012] As a preferred embodiment of the utility model, the MOS tube Q1 is N-MOS type.

[0013] As a preferred embodiment of the utility model, the drain of the MOS tube Q1 is connected between the resistor R4 and the resistor R5.

[0014] The source of the MOS tube Q1 is connected to the filter circuit.

[0015] The gate of the MOS tube Q1 is connected to the first pin Port1.

[0016] As a preferred embodiment of the utility model, the switch circuit further comprises a second voltage dividing circuit.

[0017] The second voltage dividing circuit is connected with the first pin Port1 and the gate of the MOS tube Q1, and is used to realize the on-off state switching of the switch circuit by dividing the voltage signal emitted by the first pin Port1.

[0018] As a preferred embodiment of the utility model, the second voltage dividing circuit comprises a resistor R1 and a resistor R2.

[0019] The first pin Port1 is connected with the resistor R1 and the resistor R2 in sequence and grounded.

[0020] The gate of the MOS tube Q1 is connected between the resistor R1 and the resistor R2.

[0021] As a preferred embodiment of the utility model, the filter circuit comprises a resistor R3 and a capacitor C1.

[0022] The source of the MOS tube Q1 is connected with the resistor R3 and the capacitor C1 in sequence and grounded.

[0023] The second pin Port2 is connected between the resistor R3 and the capacitor C1.

[0024] As a preferred embodiment of the utility model, the capacitor C1 is high-frequency capacitor.

[0025] In the second aspect, the utility model further provides a switching power supply, which comprises the novel voltage detection circuit in any embodiment of the utility model.

[0026] The utility model discloses relative to prior art has the following beneficial effects:

[0027] The utility model discloses embodiment through the first pin Port1 of access control chip, and according to the voltage signal that it sends out switch circuit's on-off state to realize the voltage detection of the second pin Port2 of control chip, for example: when the voltage signal is high level, make the switch circuit be in the on state, and then make detection voltage V1 through the voltage detection after the division, filtering and enter the second pin Port2 of control chip, to carry out voltage detection, on the contrary, when the voltage is low level, then the switch circuit is in the off state, and the voltage detection will not be carried out at the second pin Port2, thereby realizing the monitoring and judgment of voltage after sending out voltage signal according to the need, avoiding the false recognition and misjudgment of the interference signal of detection foot, and the precision is higher, and the detection is more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained according to the structure shown in these drawings without creative labor.

[0029] Figure 1 It is the circuit diagram of voltage detection circuit in prior art;

[0030] Figure 2 It is the circuit module schematic diagram of novel voltage detection of the utility model embodiment;

[0031] Figure 3 It is the circuit diagram of novel voltage detection of the utility model embodiment. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantage of the utility model embodiment more clear, the technical scheme in the utility model embodiment will be clearly and completely described below in conjunction with the drawings in the utility model embodiment, obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiment, based on the embodiment in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

[0033] Embodiment:

[0034] The first aspect, such as Figure 2The utility model discloses an embodiment provides a novel voltage detection circuit, comprising: detection voltage input end 10, first voltage dividing circuit 20, switch circuit 30, filter circuit 40 and control chip 50,

[0035] The first voltage dividing circuit 20 is used for voltage dividing the detection voltage V1 input by the detection voltage input end 10.

[0036] The switch circuit 30 is used for switching the on-off state of the switch circuit 30 according to the voltage signal emitted by the first pin Port1 of the control chip 50.

[0037] When the switch circuit 30 is in the on state, the detection voltage V1 after voltage division will enter the second pin Port2 of the control chip 50 through the filter circuit 40, so as to perform voltage detection.

[0038] In the utility model embodiment, when the voltage signal is high level at a certain time, the switch circuit is in the on state, and then the detection voltage V1 enters the second pin Port2 of the control chip after voltage division and filtering, so as to perform voltage detection. Conversely, when the voltage is low level, the switch circuit is in the off state, and the second pin Port2 will not perform voltage detection, so as to realize voltage monitoring and judgment after emitting the voltage signal as required, avoid the false recognition and misjudgment caused by the interference signal of the detection pin, and higher precision and more accurate detection.

[0039] As a preferred embodiment of the utility model, referring to Figure 3 The first voltage dividing circuit comprises a resistor R4 and a resistor R5.

[0040] The detection voltage input end is connected to the resistor R4 and the resistor R5 in sequence and then grounded.

[0041] The first voltage dividing circuit is used for voltage dividing the input detection voltage V1, and the resistance values of the resistor R4 and the resistor R5 can be matched according to the parameters of other elements in the circuit and the set threshold value of the second pin Port2.

[0042] As a preferred embodiment of the utility model, referring to Figure 3The switch circuit comprises a MOS tube Q1, and the MOS tube Q1 is used for controlling the on-off state thereof according to the input voltage of the gate, so as to realize the on-off state switching of the switch circuit.

[0043] In the embodiment of the utility model, when the voltage signal is high level, the switch circuit can be in the on state, and then the detection voltage V1 is filtered and enters the second pin Port2 of the control chip, so as to carry out voltage detection, on the contrary, when the voltage is low level, the switch circuit is in the off state, and the second pin Port2 will not carry out voltage detection, so that the voltage monitoring and judgment after the voltage signal is sent according to the need are realized. The specific value or parameter of the voltage signal and the MOS tube Q1 can be flexibly set.

[0044] As a preferred embodiment of the utility model, reference Figure 3 The MOS tube Q1 is N-MOS type.

[0045] As a preferred embodiment of the utility model, reference Figure 3 The drain of the MOS tube Q1 is connected between the resistor R4 and the resistor R5.

[0046] The source of the MOS tube Q1 is connected to the filter circuit.

[0047] The gate of the MOS tube Q1 is connected to the first pin Port1.

[0048] As a preferred embodiment of the utility model, reference Figure 3 The switch circuit further comprises a second voltage dividing circuit.

[0049] The second voltage dividing circuit is connected to the first pin Port1 and the gate of the MOS tube Q1, and is used for realizing the on-off state switching of the switch circuit after the voltage signal sent by the first pin Port1 is divided.

[0050] As a preferred embodiment of the utility model, reference Figure 3 The second voltage dividing circuit comprises a resistor R1 and a resistor R2.

[0051] The first pin Port1 is connected to the resistor R1 and the resistor R2 in sequence and then grounded.

[0052] The gate of the MOS tube Q1 is connected between the resistor R1 and the resistor R2.

[0053] In the embodiment of the utility model, the resistor R1 and the resistor R2 play the voltage dividing role of the circuit, and the setting of the resistor R2 also plays the role of preventing the MOS tube Q1 from being mis-conducted.

[0054] As a preferred embodiment of the utility model, refer to Figure 3 , the filter circuit includes resistance R3 and capacitor C1;

[0055] The source of the MOS tube Q1 is connected to the resistance R3 and the capacitor C1 in turn and then grounded.

[0056] The second pin Port2 is connected between the resistance R3 and the capacitor C1.

[0057] Among them, the filter circuit eliminates the voltage of the frequency not interested, so that the voltage entering the second pin Port2 is more pure, improves the detection precision and accuracy.

[0058] As a preferred embodiment of the utility model, refer to Figure 3 , the capacitor C1 is a high-frequency capacitor. The frequency response of the circuit can be improved.

[0059] The working principle of the novel voltage detection circuit in the embodiment of the utility model is as follows:

[0060] As Figure 3 , the detection voltage input end inputs the detection voltage V1, and the detection voltage V1 is the voltage to be detected. When detection is needed, the control chip can send a detection signal, and the first pin Port1 can output a high level according to the signal of the control chip. When the first pin Port1 outputs a high level, the MOS tube Q1 is turned on, the detection voltage V1 is divided by the resistance R4 and the resistance R5, and then enters the second pin Port2 through the MOS tube Q1, the resistance R3 and the capacitor C1, so that voltage detection can be performed through the control chip. Conversely, when detection is not needed, the first pin Port1 outputs a low level, and the MOS tube Q1 is disconnected, so that the detection voltage V1 cannot enter the second pin Port2. At this time, voltage detection is not performed, so that voltage detection and judgment can be performed according to needs, voltage detection can be flexibly performed at the time when the user needs it most, false judgment caused by the existence of interference signals is avoided, and the precision is higher and more accurate.

[0061] It should be noted that the novel voltage detection circuit in the embodiment of the utility model can be flexibly applied to the circuit structure of the main and secondary two-stage circuit voltage detection judgment working state.

[0062] In a second aspect, the utility model also provides a switching power supply, which comprises the novel voltage detection circuit in any embodiment of the utility model.

[0063] The above merely describes preferred embodiments of the present utility model patent, but the protection scope of the present utility model patent is not limited thereto, and any person skilled in the art, within the scope disclosed by the present utility model patent, can make equivalent replacements or changes to the technical scheme and the utility model concept of the present utility model patent, and all of them belong to the protection scope of the present utility model patent.

Claims

1. A novel voltage detection circuit, characterized by, The novel voltage detection circuit comprises a detection voltage input end, a first voltage dividing circuit, a switch circuit, a filter circuit and a control chip. The first voltage dividing circuit is used for dividing the detection voltage V1 input by the detection voltage input end. The switch circuit is used for switching the on-off state of the switch circuit according to the voltage signal sent by the first pin Port1 of the control chip. When the switch circuit is in the on state, the divided detection voltage V1 will enter the second pin Port2 of the control chip through the filter circuit, so as to perform voltage detection. The first voltage dividing circuit comprises a resistor R4 and a resistor R5.

2. The novel voltage detection circuit according to claim 1, characterized in that, The detection voltage input end is connected to the resistor R4 and the resistor R5 in sequence and then grounded. The switch circuit comprises a MOS tube Q1, which is used for controlling the on-off state of the MOS tube Q1 according to the input voltage of the gate, so as to realize the switching of the on-off state of the switch circuit.

3. The novel voltage detection circuit according to claim 2, characterized in that, The MOS tube Q1 is N-MOS type.

4. The novel voltage detection circuit according to claim 3, characterized in that, 5. The novel voltage detection circuit according to claim 4, wherein The drain of the MOS tube Q1 is connected between the resistor R4 and the resistor R5. The source of the MOS tube Q1 is connected to the filter circuit. The gate of the MOS tube Q1 is connected to the first pin Port1. The switch circuit further comprises a second voltage dividing circuit.

6. The novel voltage detection circuit according to claim 5, characterized in that, The second voltage dividing circuit is connected to the first pin Port1 and the gate of the MOS tube Q1, and is used for dividing the voltage signal sent by the first pin Port1 to realize the switching of the on-off state of the switch circuit. The second voltage dividing circuit comprises a resistor R1 and a resistor R2.

7. The novel voltage detection circuit according to claim 6, characterized in that, The first pin Port1 is connected to the resistor R1 and the resistor R2 in sequence and then grounded. The gate of the MOS tube Q1 is connected between the resistor R1 and the resistor R2. The filter circuit comprises a resistor R3 and a capacitor C1.

8. The novel voltage detection circuit according to claim 5, characterized in that, The source of the MOS tube Q1 is connected to the resistor R3 and the capacitor C1 in sequence and then grounded. The second pin Port2 is connected between the resistor R3 and the capacitor C1. The capacitor C1 is a high-frequency capacitor.

9. The novel voltage detection circuit according to claim 8, characterized in that, The novel voltage detection circuit comprises a detection voltage input end, a first voltage dividing circuit, a switch circuit, a filter circuit and a control chip.

10. A switching power supply, characterized by comprising: The novel voltage detection circuit comprises a detection voltage input end, a first voltage dividing circuit, a switch circuit, a filter circuit and a control chip.

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