Auxiliary power supply circuit based on switch node power taking

Abstract

The invention provides an auxiliary power supply circuit based on switching node power taking, and belongs to the technical field of power supply circuits. The auxiliary power supply circuit comprises a first circuit which comprises an energy storage capacitor and a half-bridge arm composed of two switching devices, and the first end of the half-bridge arm and the first end of the energy storage capacitor are connected to a voltage input end; the second end of the half-bridge arm and the second end of the energy storage capacitor are grounded; the first end of the second circuit is connected with a switching node between the two switching devices of the half-bridge arm; the second end of the second circuit is connected with the power supply end of the control circuit, and the third end of the second circuit is grounded. Compared with the existing auxiliary power supply circuit, the circuit provided by the invention has the advantages of simple structure, small size, simple process route and high reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply circuits, and in particular to an auxiliary power supply circuit based on taking power from a switch node. Background Art

[0002] For electronic systems, the startup sequence used by the industry is: the linear power supply first draws power from the input power supply and converts the input power supply level to the level required by the control circuit. After the control circuit is powered, a pulse is generated, and then the main circuit starts working. After the main circuit works, the linear power supply is turned off by using an auxiliary winding solution to reduce energy consumption. The auxiliary winding solution used to turn off the linear power supply includes:

[0003] Solution 1: Auxiliary power supply module.

[0004] The linear power supply for starting up and the switching power supply for shutting down the linear power supply are all packaged together.

[0005] Advantages of the solution: simple periphery, mature circuit and high reliability.

[0006] Disadvantages of the solution: high cost, large size, and occupies a large area of ​​PCB.

[0007] Solution 2: Linear power supply + auxiliary winding.

[0008] A solution combining a linear power supply and an auxiliary winding is adopted. During startup, the linear power supply is used for power supply. After the main circuit works, the auxiliary winding is used for power supply and the linear power supply is turned off synchronously.

[0009] Solution advantages: simple circuit structure and low cost.

[0010] Disadvantages of the solution: A winding is added to the transformer or filter inductor, and the winding process is complicated. Summary of the invention

[0011] In order to solve the technical problems of the current auxiliary power supply circuit structure having large volume, complex circuit structure, high cost and complex process, the present invention proposes an auxiliary power supply circuit based on power supply from a switch node.

[0012] In a first aspect, an embodiment of the present invention provides an auxiliary power supply circuit based on taking power from a switch node, including:

[0013] The first circuit includes a half-bridge arm composed of an energy storage capacitor Cin and two switch devices VT1 and VT2, wherein the first end of the half-bridge arm and the first end of the energy storage capacitor Cin are both connected to a voltage input terminal VIN; the second end of the half-bridge arm and the second end of the energy storage capacitor Cin are both grounded GND;

[0014] The second circuit, the first end of the second circuit is connected to the switch node SW between the two switch devices VT1 and VT2 of the half-bridge arm; the second end of the second circuit is connected to the power supply terminal VCC of the control circuit, the third end of the second circuit is grounded GND, the second circuit is used to convert the level of the input voltage connected through the voltage input terminal VIN to the level required by the control circuit when the first circuit generates a rising edge, and provide it to the control circuit through the power supply terminal VCC; it is also used to reset the state of the electronic components on the second circuit when the first circuit generates a falling edge.

[0015] In some implementations, the second circuit includes a control device V6, a resistor R1, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a first diode V1, a second diode V2, a third diode V3, a fourth diode V4 and a fifth diode V5; the control device V6 is a current control device or a voltage control device;

[0016] The first end of the first capacitor C1 is connected to the switch node SW between the two switch devices VT1 and VT2 of the half-bridge arm, and the second end of the first capacitor C1 is connected to the positive terminal of the first diode V1, the negative terminal of the third diode V3, the first end of the resistor R1 and the first end of the fourth capacitor C4;

[0017] The output end of the control device V6 is connected to the positive terminal of the third diode V3 and the second end of the second capacitor C2; the control end of the control device V6 is connected to the second end of the resistor R1 and the second end of the fourth capacitor C4;

[0018] A first end of the second capacitor C2 is connected to a cathode end of the fifth diode V5 and a cathode end of the second diode V2;

[0019] The input end of the control device V6, the positive terminal of the fifth diode V5, the second end of the third capacitor C3, and the positive terminal of the fourth diode V4 are grounded GND;

[0020] The cathode terminal of the first diode V1, the cathode terminal of the second diode V2, the first terminal of the third capacitor C3, and the cathode terminal of the fourth diode V4 are connected to the power supply terminal VCC of the control circuit.

[0021] In some implementations, the second circuit includes: a resistor R1, a first capacitor C1, a third capacitor C3, a first diode V1, a third diode V3, and a fourth diode V4;

[0022] The first end of the first capacitor C1 is connected to the switch node SW between the two switch devices VT1 and VT2 of the half-bridge arm, and the second end of the first capacitor C1 is connected to the positive terminal of the first diode V1 and the negative terminal of the third diode V3;

[0023] The positive terminal of the third diode V3 is connected to the first end of the resistor R1;

[0024] The cathode terminal of the first diode V1, the first terminal of the third capacitor C3, and the cathode terminal of the fourth diode V4 are connected to the power supply terminal VCC of the control circuit;

[0025] The second end of the resistor R1 , the second end of the third capacitor C3 , and the positive terminal of the fourth diode V4 are grounded GND.

[0026] In some implementations, the current-controlled device V6 is a triode.

[0027] In some implementations, the voltage-controlled device V6 is a MOSFET.

[0028] In some implementations, the first capacitor C1 is a high-voltage coupling capacitor, and the fourth capacitor C4 is a filter capacitor.

[0029] In some implementations, the second capacitor C2 is a reset capacitor.

[0030] In some implementations, the fourth diode V4 is a Zener diode.

[0031] In some implementations, the third capacitor C3 is an energy storage capacitor.

[0032] In a first aspect, an embodiment of the present invention provides a linear power supply, including the auxiliary power supply circuit based on taking power from a switch node as described above.

[0033] One or more embodiments of the present invention bring at least the following beneficial effects:

[0034] The circuit provided by the present invention can convert the level of the input voltage into the level required by the control circuit and provide it to the control circuit when the switching action of the two switching devices in the first circuit generates a rising edge; and reset the state of the electronic components on the second circuit when a falling edge is generated. Compared with the existing auxiliary power supply circuit, the circuit provided by the present invention has the advantages of simple structure, small size, simple process route and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope.

[0036] Figure 1 A self-power supply principle block diagram of an auxiliary power supply circuit based on powering from a switch node provided in the first embodiment of the present invention;

[0037] Figure 2 Another self-power supply principle block diagram of an auxiliary power supply circuit based on powering from a switch node provided in the first embodiment of the present invention;

[0038] Figure 3 A block diagram of the self-power supply principle of an auxiliary power supply circuit based on taking power from a switch node provided in the second embodiment of the present invention. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0040] Embodiment 1

[0041] This embodiment provides an auxiliary power supply circuit based on taking power from a switch node, including a first circuit and a second circuit.

[0042] The first circuit includes a half-bridge arm composed of an energy storage capacitor Cin and two switch devices VT1 and VT2. The two switch devices VT1 and VT2 are respectively an upper switch device VT1 and a lower switch device VT2. The first end of the half-bridge arm and the first end of the energy storage capacitor Cin are both connected to a voltage input terminal VIN. The second end of the half-bridge arm and the second end of the energy storage capacitor Cin are both grounded GND.

[0043] The first end of the second circuit is connected to the switch node SW between the two switch devices VT1 and VT2 of the half bridge; the second end of the second circuit is connected to the power input terminal VCC of the control circuit, and the third end of the second circuit is grounded GND. The second circuit is used to convert the level of the input voltage connected through the voltage input terminal VIN to the level required by the control circuit when the first circuit generates a rising edge, and provide it to the control circuit through the power terminal VCC; and is also used to reset the state of the electronic components on the second circuit when the first circuit generates a falling edge.

[0044] like Figure 1 or Figure 2 As shown, the second circuit includes a control type device V6, a resistor R1, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a first diode V1, a second diode V2, a third diode V3, a fourth diode V4 and a fifth diode V5. The control type device V6 includes a current type control device or a voltage type control device.

[0045] The first end of the first capacitor C1 is connected to the switch node SW between the two switch devices VT1 and VT2 of the half-bridge arm, and the second end of the first capacitor C1 is connected to the positive terminal of the first diode V1, the negative terminal of the third diode V3, the first end of the resistor R1 and the first end of the fourth capacitor C4.

[0046] The output end of the control device V6 is connected to the positive terminal of the third diode V3 and the second end of the second capacitor C2; the control end of the control device V6 is connected to the second end of the resistor R1 and the second end of the fourth capacitor C4.

[0047] A first end of the second capacitor C2 is connected to a cathode end of the fifth diode V5 and an anode end of the second diode V2.

[0048] The input end of the control device V6, the positive terminal of the fifth diode V5, the second end of the third capacitor C3, and the positive terminal of the fourth diode V4 are grounded GND.

[0049] The cathode terminal of the first diode V1, the cathode terminal of the second diode V2, the first end of the third capacitor C3, and the cathode terminal of the fourth diode V4 are connected to the power input terminal VCC of the control circuit.

[0050] In some implementations, such as Figure 1 As shown, the current-controlled device V6 is a triode.

[0051] In some implementations, such as Figure 2As shown, the voltage-controlled device V6 may also be a metal oxide semiconductor field effect transistor (MOSFET for short).

[0052] In some implementations, the first capacitor C1 is a high-voltage coupling capacitor.

[0053] In some implementations, the second capacitor C2 is a reset capacitor.

[0054] In some implementations, the third capacitor C3 is an energy storage capacitor. The fourth capacitor C4 is a filter capacitor.

[0055] In some implementations, the fourth diode V4 is a voltage-stabilizing diode, which is used to protect the control circuit from being broken down by overvoltage.

[0056] The working principle of the auxiliary power supply circuit based on the switch node power supply provided in this embodiment is described in detail below:

[0057] The first type of working state: When the upper switch tube device VT1 is turned on, the auxiliary power supply circuit based on the switch node power supply provided in this embodiment has two main functions. The first function is to supply power to the control circuit (load), and the current flows in the following direction: flowing out from the first end of the energy storage capacitor Cin, passing through the upper switch tube device VT1, the first capacitor C1, the first diode V1 and the third capacitor C3 in sequence, and then returning to the second end of the energy storage capacitor Cin. During this period, the first capacitor C1 is charged. The second function is to discharge the second capacitor C2. The current flows in the following direction: flowing out from the first end of the second capacitor C2, passing through the second diode V2, the third capacitor C3, the control-type device V6, and then returning to the second end of the second capacitor C2.

[0058] The second working state: the lower switch tube device VT2 is turned on. The auxiliary power supply circuit based on the switch node provided in this embodiment has a main function, that is, to reset the first capacitor C1. The current flows from the first end of the first capacitor C1, passes through the lower switch tube device VT2, the fifth diode V5, the second capacitor C2, the third diode V3, and then returns to the second end of the first capacitor C1. During this period, the first capacitor C1 is discharged and the second capacitor C2 is charged.

[0059] In summary, the auxiliary power supply circuit based on switch node power supply provided in this embodiment, when the upper switch tube device VT1 is turned on, the switch node SW point is a rising edge, and the input voltage connected to the voltage input terminal VIN is divided by the first capacitor C1 and the third capacitor C3, thereby obtaining the level required by the control circuit, and providing it to the control circuit through the power supply terminal VCC. During this period, the first capacitor C1 is charged and the second capacitor C2 is discharged. When the lower switch tube device VT2 is turned on, the switch node SW point is a falling edge, the first capacitor C1 is discharged, and the energy is stored in the second capacitor C2, thereby resetting the first capacitor C1.

[0060] Embodiment 2

[0061] This embodiment provides an auxiliary power supply circuit based on taking power from a switch node, including a first circuit and a second circuit.

[0062] The first circuit includes a half-bridge arm composed of an energy storage capacitor Cin and two switch devices VT1 and VT2. The two switch devices VT1 and VT2 are respectively an upper switch device VT1 and a lower switch device VT2. The first end of the half-bridge arm and the first end of the energy storage capacitor Cin are both connected to a voltage input terminal VIN. The second end of the half-bridge arm and the second end of the energy storage capacitor Cin are both grounded GND.

[0063] The first end of the second circuit is connected to the switch node SW between the two switch devices VT1 and VT2 of the half bridge; the second end of the second circuit is connected to the power input terminal VCC of the control circuit, and the third end of the second circuit is grounded GND. The second circuit is used to convert the level of the input voltage connected through the voltage input terminal VIN to the level required by the control circuit when the first circuit generates a rising edge, and provide it to the control circuit through the power terminal VCC; and is also used to reset the state of the electronic components on the second circuit when the first circuit generates a falling edge.

[0064] like Figure 3 As shown, the second circuit includes a resistor R1, a first capacitor C1, a third capacitor C3, a first diode V1, a third diode V3 and a fourth diode V4.

[0065] The first end of the first capacitor C1 is connected to the switch node SW between the two switch devices VT1 and VT2 of the half-bridge arm, and the second end of the first capacitor C1 is connected to the positive terminal of the first diode V1 and the negative terminal of the third diode V3.

[0066] An anode terminal of the third diode V3 is connected to the first end of the resistor R1 .

[0067] The cathode terminal of the first diode V1 , the first terminal of the third capacitor C3 , and the cathode terminal of the fourth diode V4 are connected to the power supply terminal VCC of the control circuit.

[0068] The second end of the resistor R1 , the second end of the third capacitor C3 , and the positive terminal of the fourth diode V4 are grounded GND.

[0069] In some implementations, the first capacitor C1 is a high-voltage coupling capacitor.

[0070] In some implementations, the third capacitor C3 is an energy storage capacitor.

[0071] In some implementations, the fourth diode V4 is a voltage-stabilizing diode, which is used to protect the control circuit from being broken down by overvoltage.

[0072] The working principle of the auxiliary power supply circuit based on the switch node power supply provided in this embodiment is described in detail below:

[0073] The first working state: when the upper switch tube device VT1 is turned on, the auxiliary power supply circuit based on the switch node provided in this embodiment has a main function, that is, to supply power to the control circuit (load), and the current flows as follows: flows out from the first end of the energy storage capacitor Cin, passes through the upper switch tube device VT1, the first capacitor C1, the first diode V1 and the third capacitor C3 in sequence, and then returns to the second end of the energy storage capacitor Cin. During this period, the first capacitor C1 is charged.

[0074] The second working state: the lower switch tube device VT2 is turned on. The auxiliary power supply circuit based on the switch node provided in this embodiment has a main function, that is, to reset the first capacitor C1. The current flows from the first end of the first capacitor C1, passes through the lower switch tube device VT2, the resistor R1, the third diode V3, and then returns to the second end of the first capacitor C1. During this period, the first capacitor C1 is discharged.

[0075] In summary, the auxiliary power supply circuit based on switch node power supply provided in this embodiment, when the upper switch tube device VT1 is turned on, the switch node SW point is a rising edge, and the input voltage connected to the voltage input terminal VIN is divided by the first capacitor C1 and the third capacitor C3, thereby obtaining the level required by the control circuit, and providing it to the control circuit through the power supply terminal VCC. During this period, the first capacitor C1 is charged; when the lower switch tube device VT2 is turned on, the switch node SW point is a falling edge, and the first capacitor C1 is discharged, thereby resetting the first capacitor C1.

[0076] Embodiment 3

[0077] This embodiment provides a linear power supply, which includes the auxiliary power supply circuit based on switching node power supply as described in the first or second embodiment.

[0078] It should be noted that, in this article, the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. The terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0079] Although the embodiments disclosed in the present invention are as above, the above contents are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. An auxiliary power supply circuit based on taking power from a switch node, characterized in that: include: A first circuit comprises a half-bridge arm composed of an energy storage capacitor (Cin) and two switch devices (VT1, VT2), wherein a first end of the half-bridge arm and a first end of the energy storage capacitor (Cin) are both connected to a voltage input terminal (VIN); a second end of the half-bridge arm and a second end of the energy storage capacitor (Cin) are both grounded (GND); The second circuit, the first end of the second circuit is connected to the switch node (SW) between the two switch devices (VT1, VT2) of the half-bridge arm; the second end of the second circuit is connected to the power supply end (VCC) of the control circuit, the third end of the second circuit is grounded (GND), the second circuit is used to convert the level of the input voltage connected through the voltage input end (VIN) to the level required by the control circuit when the first circuit generates a rising edge, and provide it to the control circuit through the power supply end (VCC), and is also used to reset the state of the electronic components on the second circuit when the first circuit generates a falling edge.

2. The auxiliary power supply circuit based on switching node power supply according to claim 1, characterized in that: The second circuit comprises a control type device (V6), a resistor (R1), a first capacitor (C1), a second capacitor (C2), a third capacitor (C3), a fourth capacitor (C4), a first diode (V1), a second diode (V2), a third diode (V3), a fourth diode (V4) and a fifth diode (V5); the control type device (V6) is a current type control device or a voltage type control device; The first end of the first capacitor (C1) is connected to a switch node (SW) between two switch devices (VT1, VT2) of the half-bridge arm, and the second end of the first capacitor (C1) is connected to a positive terminal of the first diode (V1), a negative terminal of the third diode (V3), a first end of the resistor (R1) and a first end of the fourth capacitor (C4); The output end of the control type device (V6) is connected to the positive terminal of the third diode (V3) and the second end of the second capacitor (C2); the control end of the control type device (V6) is connected to the second end of the resistor (R1) and the second end of the fourth capacitor (C4); A first end of the second capacitor (C2) is connected to a negative terminal of the fifth diode (V5) and a positive terminal of the second diode (V2); The input end of the control device (V6), the positive terminal of the fifth diode (V5), the second end of the third capacitor (C3), and the positive terminal of the fourth diode (V4) are grounded (GND); The cathode terminal of the first diode (V1), the cathode terminal of the second diode (V2), the first end of the third capacitor (C3), and the cathode terminal of the fourth diode (V4) are connected to the power supply terminal (VCC) of the control circuit.

3. The auxiliary power supply circuit based on switching node power supply according to claim 1, characterized in that: The second circuit includes: a resistor (R1), a first capacitor (C1), a third capacitor (C3), a first diode (V1), a third diode (V3) and a fourth diode (V4); A first end of the first capacitor (C1) is connected to a switch node (SW) between two switch devices (VT1, VT2) of the half-bridge arm, and a second end of the first capacitor (C1) is connected to a positive terminal of the first diode (V1) and a negative terminal of the third diode (V3); The positive terminal of the third diode (V3) is connected to the first end of the resistor (R1); The cathode terminal of the first diode (V1), the first terminal of the third capacitor (C3), and the cathode terminal of the fourth diode (V4) are connected to the power supply terminal (VCC) of the control circuit; The second end of the resistor (R1), the second end of the third capacitor (C3), and the positive terminal of the fourth diode (V4) are grounded (GND).

4. The auxiliary power supply circuit based on switching node power supply according to claim 2, characterized in that: The current control device (V6) is a triode.

5. The auxiliary power supply circuit based on switching node power supply according to claim 2, characterized in that: The voltage-controlled device (V6) is a MOSFET.

6. The auxiliary power supply circuit based on taking power from a switch node according to claim 2 or 3, characterized in that: The first capacitor (C1) is a high-voltage coupling capacitor.

7. The auxiliary power supply circuit based on switching node power supply according to claim 2, characterized in that: The second capacitor (C2) is a reset capacitor, and the fourth capacitor (C4) is a filter capacitor.

8. The auxiliary power supply circuit based on taking power from a switch node according to claim 2 or 3, characterized in that: The fourth diode (V4) is a voltage stabilizing diode.

9. The auxiliary power supply circuit based on taking power from a switch node according to claim 2 or 3, characterized in that: The third capacitor (C3) is an energy storage capacitor.

10. A linear power supply, characterized in that: It comprises an auxiliary power supply circuit based on taking power from a switch node as described in any one of claims 1 to 9.

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