Efficient peak absorption circuit and switching power supply device using same

Abstract

The invention relates to the technical field of switching power supplies, in particular to a high-efficiency peak absorption circuit and a switching power supply device applying the circuit, the circuit comprises a receiving module, a threshold voltage comparison module and a voltage reduction module, a first receiving end X of the receiving module is used for being connected with a drain electrode of an MOS tube Q1, and a second receiving end X of the receiving module is used for being connected with a drain electrode of an MOS tube Q2; a second receiving end Y of the receiving module is used for being connected with a drain electrode of the MOS tube Q2, an output end of the receiving module is connected to the threshold voltage comparison module, an output end of the threshold voltage comparison module is connected to the voltage reduction module, and an output end of the voltage reduction module is connected to a positive electrode of the power supply B. According to the invention, the absorption effect of the peak voltage is improved.

Description

Technical Field

[0001] The present application relates to the technical field of switching power supplies, and in particular to a high-efficiency peak absorption circuit and a switching power supply device using the circuit. Background Art

[0002] With the development of electronic technology, a push-pull circuit is set in the switching power supply. In the process of controlling the closing and closing of the push-pull circuit, a spike voltage will be generated. The spike voltage will damage the components in the circuit due to its excessive voltage value.

[0003] In order to avoid damage to components due to spike voltage, in the related art, an RC absorption circuit or an RCD absorption circuit is generally set at the push-pull circuit to absorb the spike voltage. However, the RC absorption circuit or the RCD absorption circuit used in the related art has limited absorption effect and low efficiency. Summary of the invention

[0004] In order to improve the absorption effect of peak voltage, the present application provides a high-efficiency peak absorption circuit and a switching power supply device using the circuit.

[0005] In the first aspect, the present application provides a high-efficiency peak absorption circuit using the following technical solutions: A high-efficiency spike absorption circuit is applied to a power supply B converter circuit, wherein the power supply B converter circuit comprises a power supply B and a push-pull circuit, wherein the push-pull circuit comprises a MOS tube Q1 and a MOS tube Q2, and comprises a receiving module, a threshold voltage comparison module, and a step-down module, wherein a first receiving end X of the receiving module is used to connect to the drain of the MOS tube Q1, a second receiving end Y of the receiving module is used to connect to the drain of the MOS tube Q2, an output end of the receiving module is connected to the threshold voltage comparison module, an output end of the threshold voltage comparison module is connected to a control end of the step-down module, a power supply end of the step-down module is connected to an output end of the receiving module, and an output end of the step-down module is connected to a positive electrode of the power supply B.

[0006] By adopting the above technical solution, the peak voltage generated at the push-pull circuit is absorbed by the receiving module, and the voltage is compared by the threshold voltage comparison module. When the preset value is met, that is, the voltage is greater than the reference voltage of the threshold voltage comparison module, the threshold voltage comparison module outputs a signal to control the step-down module to enable, so that the energy of the peak voltage absorbed by the receiving module is recovered through the step-down module, that is, the receiving module outputs the electric energy to the power supply circuit through the power supply end of the step-down module. Compared with the related technology, it can better absorb and suppress the peak voltage, limit the peak voltage to a lower level, reduce the possibility of component damage, improve the reliability and stability of the circuit, and can recover the electric energy of the absorbed peak voltage, reducing the waste of electric energy.

[0007] Optionally, the receiving module includes a diode D1, a diode D2, a capacitor C1 and a capacitor C2, the anode end of the diode D1 is connected to the first receiving end X, the cathode end of the diode D1 is connected to the threshold voltage comparison module, one end of the capacitor C1 is connected to the cathode end of the diode D1, the other end of the capacitor C1 is connected to the ground end, the anode end of the diode D2 is connected to the second receiving end Y, the cathode end of the diode D2 is connected to the threshold voltage comparison module, one end of the capacitor C2 is connected to the cathode end of the diode D2, and the other end of the capacitor C2 is connected to the ground end.

[0008] By adopting the above technical solution, when a peak voltage is generated, the capacitor C1 and the capacitor C2 can absorb the electric energy of the peak voltage, that is, charge the capacitor C1 and the capacitor C2.

[0009] Optionally, the receiving module includes a diode D11, a diode D21, a capacitor C11 and a capacitor C21, the anode end of the diode D11 is connected to the first receiving end X, the cathode end of the diode D11 is connected to the threshold voltage comparison module, one end of the capacitor C11 is connected to the cathode end of the diode D11, and the other end of the capacitor C11 is used to connect to the positive electrode of the power supply B, the anode end of the diode D21 is connected to the second receiving end Y, the cathode end of the diode D21 is connected to the threshold voltage comparison module, one end of the capacitor C21 is connected to the cathode end of the diode D21, and the other end of the capacitor C21 is used to connect to the positive electrode of the power supply B.

[0010] By adopting the above technical solution, when a peak voltage is generated, the capacitor C11 and the capacitor C21 can absorb the electric energy of the peak voltage, that is, charge the capacitor C11 and the capacitor C21.

[0011] Optionally, the threshold voltage comparison module includes a comparator U1, a resistor R1, a capacitor C5 and a reference voltage submodule, one end of the resistor R1 is used to connect the receiving module, the other end of the resistor R1 is connected to the non-inverting input terminal of the comparator U1, one end of the capacitor C5 is connected to the non-inverting input terminal of the comparator U1, the other end of the capacitor C5 is connected to the ground terminal, the reference voltage submodule is connected to the inverting input terminal of the comparator U1, and the output terminal of the comparator U1 is connected to the output terminal of the threshold voltage comparison module.

[0012] Optionally, the step-down module includes a power chip U2, a capacitor C6, a capacitor C7, a capacitor C8, a resistor R5, a resistor R6, a resistor R7, a diode D5 and an inductor L2, the enable end EN of the power chip U2 is connected to the control end of the step-down module, the 6th pin of the power chip U2 is connected to the capacitor C7, the other end of the capacitor C7 is connected to the 7th pin of the power chip U2, the 8th pin of the power chip U2 is connected to the resistor R5, the other end of the resistor R5 is connected to the 7th pin of the power chip U2, the 7th pin of the power chip U2 is connected to the inductor L2, and the other end of the inductor L2 connected to the output end of the step-down module, pin 7 of the power chip U2 is connected to the cathode end of the diode D5, the anode end of the diode D5 is connected to the ground end, one end of the capacitor C8 is connected to the output end of the step-down module, the other end of the capacitor C8 is connected to the ground end, one end of the resistor R6 is connected to the output end of the step-down module, the other end of the resistor R6 is connected to the resistor R7, the other end of the resistor R7 is connected to the ground end, pin 5 of the power chip U2 is connected to the connection point of the resistor R6 and the resistor R7, and pin 1 of the power chip U2 is connected to the power supply end of the step-down module.

[0013] By adopting the above technical solution, after the power chip U2 is enabled, the peak voltage electric energy absorbed by the receiving module can be output to the positive electrode of the power supply, thereby realizing electric energy recovery and reducing electric energy waste.

[0014] In a second aspect, a switching power supply device provided by the present application adopts the following technical solution: A switching power supply device comprises a high-efficiency peak absorption circuit as described in the first aspect.

[0015] In summary, the present application includes at least one of the following beneficial technical effects: 1. The receiving module is used to absorb the peak voltage generated at the push-pull circuit, and the threshold voltage comparison module is used to compare the voltage. When the preset value is met, that is, the voltage is greater than the reference voltage of the threshold voltage comparison module, the threshold voltage comparison module outputs a signal to control the buck module to enable, so that the energy of the peak voltage absorbed by the receiving module is recovered through the buck module, that is, the receiving module outputs the electric energy to the power supply circuit through the power supply end of the buck module. Compared with the related technology, it can better absorb and suppress the peak voltage, limit the peak voltage to a lower level, reduce the possibility of component damage, improve the reliability and stability of the circuit, and can recover the electric energy of the absorbed peak voltage, reducing the waste of electric energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a frame body connected as a whole in the embodiment of the present application.

[0017] Figure 2 This is the circuit schematic diagram of Example 1 of the present application.

[0018] Figure 3 This is the circuit schematic diagram of Example 2 of the present application.

[0019] Figure 4 It is a circuit schematic diagram of the threshold comparison module of the embodiment of the present application.

[0020] Figure 5 It is a circuit schematic diagram of the step-down module of the embodiment of the present application.

[0021] Figure 6 It is a waveform diagram of the peak voltage in the related art.

[0022] Figure 7 It is a waveform diagram of the peak voltage after applying the circuit of this application.

[0023] Explanation of the accompanying drawings: 1. Receiving module; 2. Threshold voltage comparison module; 3. Step-down module. DETAILED DESCRIPTION

[0024] The following is combined with Figure 1-7 This application is described in further detail.

[0025] In the related art, the power supply B converter circuit includes a power supply B, a push-pull circuit and a transformer T1, the positive electrode of the power supply B is connected to the second input terminal of the transformer T1, the drain of the MOS tube Q1 is connected to the first input terminal of the transformer T1, the gate of the MOS tube Q1 is connected to the push-pull control module, the drain of the MOS tube Q2 is connected to the third input terminal of the transformer T1, and the gate of the MOS tube Q2 is connected to the push-pull control module. Pin 1 of the transformer T1 is connected to the first input terminal, pin 2 of the transformer T1 is connected to the second input terminal, and pin 3 of the transformer T1 is connected to the third input terminal.

[0026] Example 1 The present application embodiment discloses a high-efficiency peak absorption circuit. Figure 1 A high-efficiency spike absorption circuit comprises a receiving module 1, a threshold voltage comparison module 2, and a step-down module 3. The first receiving end X of the receiving module 1 is used to connect the drain of the MOS tube Q1, and the second receiving end Y of the receiving module 1 is used to connect the drain of the MOS tube Q2. The output end of the receiving module 1 is connected to the threshold voltage comparison module 2, and the output end of the threshold voltage comparison module 2 is connected to the control end of the step-down module 3. The power supply end of the step-down module (3) is connected to the output end of the receiving module (1), and the output end of the step-down module 3 is connected to the positive electrode of the power supply B.

[0027] Reference Figure 2 The receiving module 1 includes a diode D1, a diode D2, a capacitor C1 and a capacitor C2, the anode end of the diode D1 is connected to the first receiving end X, the cathode end of the diode D1 is connected to the output end of the receiving module 1, that is, the cathode end of the diode D1 is connected to the threshold voltage comparison module 2, one end of the capacitor C1 is connected to the cathode end of the diode D1, the other end of the capacitor C1 is connected to the ground end, the anode end of the diode D2 is connected to the second receiving end Y, the cathode end of the diode D2 is connected to the output end of the receiving module 1, that is, the cathode end of the diode D2 is connected to the threshold voltage comparison module 2, one end of the capacitor C2 is connected to the cathode end of the diode D2, and the other end of the capacitor C2 is connected to the ground end.

[0028] Reference Figure 4 The threshold voltage comparison module 2 includes a comparator U1, a resistor R1, a capacitor C5 and a reference voltage submodule, one end of the resistor R1 is used to connect to the receiving module 1, the other end of the resistor R1 is connected to the non-inverting input terminal of the comparator U1, one end of the capacitor C5 is connected to the non-inverting input terminal of the comparator U1, the other end of the capacitor C5 is connected to the ground terminal, the reference voltage submodule is connected to the inverting input terminal of the comparator U1, and the output terminal of the comparator U1 is connected to the output terminal of the threshold voltage comparison module 2.

[0029] Reference Figure 5The step-down module 3 includes a power chip U2, a capacitor C6, a capacitor C7, a capacitor C8, a resistor R5, a resistor R6, a resistor R7, a diode D5 and an inductor L2. The enable end EN of the power chip U2 is connected to the control end of the step-down module, that is, the enable end EN of the power chip U2 is connected to the output end of the comparator U1. The 3rd pin of the power chip U2 is the enable end EN. The 6th pin of the power chip U2 is connected to the capacitor C7. The other end of the capacitor C7 is connected to the 7th pin of the power chip U2. The 8th pin of the power chip U2 is connected to the resistor R5. The other end of the resistor R5 is connected to the 7th pin of the power chip U2. The 7th pin of the power chip U2 is connected to the inductor L2. The other end of the inductor L2 is connected to the inductor L2. One end is connected to the output end of the step-down module 3, that is, the other end of the inductor L2 is used to connect to the positive electrode of the power supply B, the 7-pin of the power chip U2 is connected to the cathode end of the diode D5, and the anode end of the diode D5 is connected to the ground end, one end of the capacitor C8 is connected to the output end of the step-down module 3, and the other end of the capacitor C8 is connected to the ground end, one end of the resistor R6 is connected to the output end of the step-down module 3, and the other end of the resistor R6 is connected to the resistor R7, and the other end of the resistor R7 is connected to the ground end, the 5-pin of the power chip U2 is connected to the connection point of the resistor R6 and the resistor R7, and the 1-pin of the power chip U2 is connected to the power supply end of the step-down module, that is, the 1-pin of the power chip U2 is connected to the output end of the receiving module.

[0030] The power chip U2 can be a chip of model EG1192, and in this application, the power chip U2 adopts a constant current mode. The output end of the step-down module 3 is Figure 5 The connection terminal labeled OUT+.

[0031] The implementation principle of a high-efficiency peak absorption circuit in the embodiment of the present application is as follows: in the energy absorption stage, at the moment when the two MOS tubes are turned off, the parasitic inductance in the circuit, the parasitic inductance of the MOS tube pins, and the leakage inductance of the transformer T1 will generate a peak voltage at the drain connection line of the MOS tube Q1 and the drain connection line of the MOS tube Q2. At this time, the capacitor C1 and the capacitor C2 in the high-efficiency peak absorption circuit of the present application start to charge through the corresponding diodes D1 and D2, thereby absorbing part of the peak energy. Thus, the MOS tube and other components are protected from the impact of excessively high voltage.

[0032] Furthermore, the threshold voltage comparison module 2 can detect the voltage quickly and accurately, thereby ensuring that the peak voltage does not exceed the withstand voltage of the two MOS tubes, thereby reducing the possibility of circuit damage.

[0033] In the energy release stage, when the capacitor voltage on capacitor C1 and capacitor C2 is greater than the set value of the threshold voltage comparison module 2, the comparator U1 is used to compare the capacitor voltage with the reference voltage provided by the reference voltage submodule. When the capacitor voltage is greater than the reference voltage, the step-down module 3 is turned on, that is, the power chip U2 is enabled, and discharge begins at this time. The electricity stored in capacitor C1 and capacitor C2 is fed back to the second input terminal of transformer T1 through the step-down module 3. This control method not only improves the efficiency of the circuit, but also reduces the waste of electric energy, effectively solves the problems of high peak voltage and electric energy waste in related technologies, and also improves the reliability and stability of the circuit.

[0034] Because in the related art, the method of eliminating the spike voltage by using the RC circuit or the RCD circuit has limitations on the selection of the capacitance of the capacitor therein. If the capacitance is too large, the resistance will be too heated and the loss will be too large. In the present application, the capacitance of the capacitor in the receiving module is very limited, and the capacitance can be much larger than the capacitance in the related art, so that better absorption of the spike voltage can be achieved, and the effect of eliminating the spike voltage can be achieved. At the same time, based on the characteristic that the capacitor voltage cannot change suddenly, the capacitor C1 and the capacitor C2 in this embodiment can be avoided from being overcharged, and the possibility of damage to the MOS tube can be reduced, because the capacitor is easy to select with high withstand voltage and the cost is relatively low, while the MOS tube uses a high withstand voltage model, which will lead to high cost, and the on-resistance of the high withstand voltage MOS tube will increase accordingly, and the high on-resistance MOS tube has high power consumption, so as to affect stability, high heat and low efficiency. Therefore, by using the funny spike absorption circuit disclosed in this embodiment, a low withstand voltage MOS tube can be selected while ensuring that the MOS tube is not broken.

[0035] For the peak voltage, the peak voltage in the related art refers to Figure 6 , where VDS1 is the peak voltage at the drain of MOS tube Q1, and VDS2 is the peak voltage at the drain of MOS tube Q2. The peak voltage after applying the high-efficiency peak absorption circuit of the present application is referenced to Figure 7 , VDS1 is the peak voltage at the drain of MOS tube Q1, and VDS2 is the peak voltage at the drain of MOS tube Q2. By comparing the two figures, it can be seen that the peak voltage absorption effect is better after applying the high-efficiency peak absorption circuit of the present application.

[0036] Example 2 The present application also discloses a highly efficient peak absorption circuit. Figure 3Different from the receiving module 1 in Example 1, the receiving module 1 in this embodiment includes a diode D11, a diode D21, a capacitor C11 and a capacitor C21, the anode end of the diode D11 is connected to the first receiving end X, the cathode end of the diode D11 is connected to the threshold voltage comparison module 2, one end of the capacitor C11 is connected to the cathode end of the diode D11, and the other end of the capacitor C11 is used to connect to the positive electrode of the power supply B, the anode end of the diode D21 is connected to the second receiving end Y, the cathode end of the diode D21 is connected to the threshold voltage comparison module 2, one end of the capacitor C21 is connected to the cathode end of the diode D21, and the other end of the capacitor C21 is used to connect to the positive electrode of the power supply B.

[0037] The implementation principle of a high-efficiency peak absorption circuit in an embodiment of the present application is as follows: the circuit principle in this embodiment is the same as the implementation principle in Example 1, except that there are certain differences in the connection method.

[0038] The present application also discloses a switching power supply device, including a high-efficiency peak absorption circuit as disclosed in Example 1 or Example 2.

[0039] By applying a high-efficiency peak absorption circuit, better absorption of peak voltage can be achieved, thereby reducing the possibility of damage to the switching power supply device and improving the stability and reliability of the switching power supply device.

[0040] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high-efficiency peak absorption circuit is applied to a power supply B converter circuit, wherein the power supply B converter circuit includes a power supply B and a push-pull circuit, wherein the push-pull circuit includes a MOS tube Q1 and a MOS tube Q2, and wherein: It comprises a receiving module, a threshold voltage comparison module (2), and a voltage reduction module (3); the first receiving end X of the receiving module (1) is used to connect the drain of the MOS tube Q1; the second receiving end Y of the receiving module (1) is used to connect the drain of the MOS tube Q2; the output end of the receiving module (1) is connected to the threshold voltage comparison module (2); the output end of the threshold voltage comparison module (2) is connected to the control end of the voltage reduction module (3); the power supply end of the voltage reduction module (3) is connected to the output end of the receiving module (1); and the output end of the voltage reduction module (3) is connected to the positive electrode of the power supply B.

2. The high-efficiency peak absorption circuit according to claim 1, characterized in that: The receiving module (1) comprises a diode D1, a diode D2, a capacitor C1 and a capacitor C2, wherein an anode terminal of the diode D1 is connected to the first receiving terminal X, a cathode terminal of the diode D1 is connected to the threshold voltage comparison module (2), one end of the capacitor C1 is connected to the cathode terminal of the diode D1, the other end of the capacitor C1 is connected to the ground terminal, an anode terminal of the diode D2 is connected to the second receiving terminal Y, a cathode terminal of the diode D2 is connected to the threshold voltage comparison module (2), one end of the capacitor C2 is connected to the cathode terminal of the diode D2, and the other end of the capacitor C2 is connected to the ground terminal.

3. The high-efficiency peak absorption circuit according to claim 1, characterized in that: The receiving module (1) comprises a diode D11, a diode D21, a capacitor C11 and a capacitor C21, wherein an anode end of the diode D11 is connected to the first receiving end X, a cathode end of the diode D11 is connected to the threshold voltage comparison module (2), one end of the capacitor C11 is connected to the cathode end of the diode D11, and the other end of the capacitor C11 is used to connect to the positive electrode of the power supply B, an anode end of the diode D21 is connected to the second receiving end Y, a cathode end of the diode D21 is connected to the threshold voltage comparison module (2), one end of the capacitor C21 is connected to the cathode end of the diode D21, and the other end of the capacitor C21 is used to connect to the positive electrode of the power supply B.

4. The high-efficiency peak absorption circuit according to claim 1, characterized in that: The threshold voltage comparison module (2) comprises a comparator U1, a resistor R1, a capacitor C5 and a reference voltage submodule, one end of the resistor R1 is used to connect to the receiving module (1), the other end of the resistor R1 is connected to the non-inverting input end of the comparator U1, one end of the capacitor C5 is connected to the non-inverting input end of the comparator U1, the other end of the capacitor C5 is connected to the ground end, the reference voltage submodule is connected to the inverting input end of the comparator U1, and the output end of the comparator U1 is connected to the output end of the threshold voltage comparison module (2).

5. A high-efficiency peak absorption circuit according to claim 1 or 4, characterized in that: The step-down module (3) comprises a power chip U2, a capacitor C6, a capacitor C7, a capacitor C8, a resistor R5, a resistor R6, a resistor R7, a diode D5 and an inductor L2, wherein an enable terminal EN of the power chip U2 is connected to a control terminal of the step-down module (3), a pin 6 of the power chip U2 is connected to the capacitor C7, the other end of the capacitor C7 is connected to the pin 7 of the power chip U2, the pin 8 of the power chip U2 is connected to the resistor R5, the other end of the resistor R5 is connected to the pin 7 of the power chip U2, the pin 7 of the power chip U2 is connected to the inductor L2, and the other end of the inductor L2 is connected to the The output end of the step-down module (3), the 7th pin of the power chip U2 is connected to the cathode end of the diode D5, the anode end of the diode D5 is connected to the ground end, one end of the capacitor C8 is connected to the output end of the step-down module (3), the other end of the capacitor C8 is connected to the ground end, one end of the resistor R6 is connected to the output end of the step-down module (3), the other end of the resistor R6 is connected to the resistor R7, the other end of the resistor R7 is connected to the ground end, the 5th pin of the power chip U2 is connected to the connection point of the resistor R6 and the resistor R7, and the 1st pin of the power chip U2 is connected to the power supply end of the step-down module (3).

6. A switching power supply device, characterized in that: The invention comprises a high-efficiency peak absorption circuit as claimed in any one of claims 1 to 5.

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