Multistage parallel source driving converter circuit and switching power supply

Abstract

The utility model discloses a multistage parallel source electrode driving converter circuit and a switching power supply, comprising a first capacitor, the first end of the first capacitor is connected to a positive input end, and the second end of the first capacitor is connected to a grounding end; the transformer comprises N primary windings and secondary windings; wherein N is an integer greater than or equal to 2; the first input end of each primary side circuit is connected to a positive input end through a primary side winding, the second input end of each primary side circuit is connected to the first end of the first capacitor, and the output end of each primary side circuit is connected to the second end of the first capacitor; and the secondary circuit is connected to the two ends of the secondary winding. According to the utility model, when the requirement of super power in practical application is met, the requirement can be met only by connecting multiple stages of same primary circuits in parallel, so that the universality and reliability of the source driving converter circuit technology under different application requirement conditions are improved.

Description

Technical Field

[0001] The utility model relates to the field of switch power supply design, in particular to a circuit and a switch power supply in the field of a multi-stage parallel source drive converter. Background Art

[0002] Source drive is widely used in switching power supplies due to its small size, low cost and high efficiency. Its main principle is to fix the gate voltage of the main power switch tube at a certain value, and change its source voltage through the source drive circuit to control the switching state of the main power switch tube.

[0003] Figure 1 The invention discloses an existing source drive converter, wherein the primary circuit mainly comprises a main power switch tube Q1 and a source drive circuit. Specifically, the source drive circuit comprises: a drive switch tube Q2, which is used to raise or lower the source voltage of the main power switch tube Q1; a power supply capacitor C1, which is used to supply power to the gate of the main power switch tube Q1; a voltage regulator tube Z1, which is used to fix the gate voltage of the main power switch tube Q1 at a certain value; and a start-up resistor R1, which is used to charge the power supply capacitor C1 through the start-up resistor R1 when the converter is started, so as to establish the gate supply voltage of the main power switch tube Q1.

[0004] When the converter starts, the power supply capacitor C1 is charged through the starting resistor R1, and the voltage regulator Z1 fixes the gate voltage of the main power switch tube Q1 at a certain value. When the driving switch tube Q2 is turned on, the source voltage of the main power switch tube Q1 is pulled down, and the voltage between the gate and the source increases, causing the main power switch tube Q1 to be turned on, and the primary circuit starts to work; when the driving switch tube Q2 is turned off, the source voltage of the main power switch tube Q1 is raised, and the voltage between the gate and the source drops, causing the main power switch tube Q1 to be turned off, and the primary circuit stops working.

[0005] The maximum current that a commonly used switch tube can withstand is limited, and the maximum power when working is limited. Therefore, the maximum power of a single-stage circuit is also limited. Most output power requirements can be met by a single-stage source-level drive converter circuit. However, with the increasing application of switching power supplies in the photovoltaic industry, the demand for ultra-high power switching power supplies and application scenarios are gradually emerging. Since the source drive converter has only a single stage, when the output power demand far exceeds the maximum working power of the switch tube, the switch tube heats up seriously and the temperature rise is unqualified. The single-stage source-level drive converter circuit can no longer meet the demand. If the maximum working power specification of the single-stage switch tube is increased to meet the conditions for the high-power output of the product, the cost will also increase greatly. Therefore, the feasibility of the single-stage source-level drive solution is greatly reduced, and it is also not conducive to the extensive application and reliability of the switching power supply. Therefore, a technology to increase the power based on the original source-level drive is needed. Utility Model Content

[0006] The utility model aims to overcome the problem that the prior art cannot meet the requirements of higher output power, and provides a multi-stage parallel source drive converter circuit and a switching power supply, which realizes the parallel connection of multi-stage source drive converters on the basis of the original technology, improves the circuit working power, and thus enhances the extensiveness and reliability of the application of the switching power supply.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] In a first aspect, the utility model provides a multi-stage series source drive converter circuit, comprising:

[0009] A first capacitor, wherein a first terminal of the first capacitor is connected to the positive input terminal, and a second terminal of the first capacitor is connected to the ground terminal;

[0010] A transformer, comprising N primary windings and a secondary winding; wherein N is an integer greater than or equal to 2;

[0011] N-level primary circuits, wherein a first input terminal of each primary circuit is connected to a positive input terminal through a primary winding, a second input terminal of each primary circuit is connected to a first terminal of the first capacitor, and an output terminal of each primary circuit is connected to a second terminal of the first capacitor;

[0012] A secondary circuit, the secondary circuit being connected to two ends of the secondary winding;

[0013] Each of the primary circuits includes a first switch tube and a second switch tube, wherein the first end of the first switch tube serves as the first input end of the primary circuit, the control end of the first switch tube serves as the second input end of the primary circuit, the second end of the first switch tube is connected to the first end of the second switch tube, the second end of the second switch tube serves as the output end of the primary circuit, and the control end of the second switch tube is used to input a control signal.

[0014] Preferably, the multi-stage parallel source drive converter circuit further includes a Zener diode, a cathode of the Zener diode is connected to the first end of the first capacitor, and an anode of the Zener diode is connected to the second end of the first capacitor.

[0015] Preferably, the multi-stage parallel source drive converter circuit further includes a first resistor, and the first resistor is connected between the first end of the first capacitor and the positive input end.

[0016] In a second aspect, the utility model further provides a switching power supply, which includes the multi-stage parallel source drive converter circuit described in the first aspect.

[0017] Compared with the prior art, the embodiments of the present invention have at least the following beneficial effects:

[0018] 1. The utility model connects the existing source drive converter circuit in parallel in multiple stages. Under the condition that the original switch tube specifications are not changed, the power of each primary circuit remains unchanged. By connecting multiple identical primary circuits in parallel, the total current is increased, and the output power is greatly increased. When facing the demand for ultra-high power in practical applications, there is no need to change the specifications and structure of the original single stage. Only multiple identical primary circuits can be connected in parallel to meet the demand, which not only saves costs, but also improves the breadth and reliability of this source drive converter circuit technology under different application requirements.

[0019] 2. The utility model can adjust the number of parallel source drive converter circuits according to different power requirements by paralleling the existing source drive converter circuits, thereby achieving a high power effect. When the original single-stage circuit remains unchanged, the parallel connection of two-stage primary circuits can increase the output power to twice that of the original single-stage circuit, and the parallel connection of N-stage primary circuits can increase the output power to n times that of the original single-stage circuit. By paralleling the corresponding number of primary circuits according to the circuit output power conditions, the flexibility of the switching power supply design is improved.

[0020] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by practicing the utility model. The purpose and other advantages of the utility model can be realized and obtained by the structures specifically pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A circuit schematic diagram of an existing source drive converter circuit;

[0022] Figure 2 It is a circuit block diagram of a first embodiment of a multi-stage parallel source drive converter circuit of the utility model;

[0023] Figure 3 This is a circuit block diagram of a second embodiment of a multi-stage parallel source drive converter circuit of the utility model. DETAILED DESCRIPTION

[0024] The present invention and its beneficial effects will be further described in detail below in conjunction with specific implementation methods and drawings of the specification; however, the specific implementation methods of the present invention are not limited thereto.

[0025] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0026] It should be noted that the terms "including" and "having" and any variations thereof described in the specification and claims of the present application are intended to cover non-exclusive inclusions. For example, the inclusion of a series of components, unit circuits or control timings is not necessarily limited to those components, unit circuits or control timings clearly listed, but may include components, unit circuits or control timings that are not clearly listed or inherent to these circuits.

[0027] In addition, the embodiments and features of the embodiments in this application may be combined with each other if there is no conflict.

[0028] It should be understood that, in the specification and the claims, when it is described that an element is “connected” to another element, the element may be “directly connected” to the other element or “connected” to the other element through a third element.

[0029] refer to Figure 2 and Figure 3 The embodiment of the utility model provides a multi-stage series source drive converter circuit, comprising:

[0030] A first capacitor C1, a first end of the first capacitor C1 is connected to the positive input end, and a second end of the first capacitor C1 is connected to the ground end;

[0031] A transformer, comprising N primary windings P1 and a secondary winding; wherein N is an integer greater than or equal to 2;

[0032] N-level primary circuits, the first input end of each primary circuit is connected to the positive input end through a primary winding P1, the second input end of each primary circuit is connected to the first end of the first capacitor C1, and the output end of each primary circuit is connected to the second end of the first capacitor C1;

[0033] A secondary circuit, wherein the secondary circuit is connected to two ends of the secondary winding;

[0034] Each primary circuit includes a first switch tube Q1 and a second switch tube Q2, the first end of the first switch tube Q1 serves as the first input end of the primary circuit, the control end of the first switch tube Q1 serves as the second input end of the primary circuit, the second end of the first switch tube Q1 is connected to the first end of the second switch tube Q2, the second end of the second switch tube Q2 serves as the output end of the primary circuit, and the control end of the second switch tube Q2 is used to input a control signal.

[0035] In one embodiment, the multi-stage parallel source drive converter circuit further includes a Zener diode, wherein the cathode of the Zener diode Z1 is connected to the first end of the first capacitor C1, and the anode of the Zener diode Z1 is connected to the second end of the first capacitor C1.

[0036] In one embodiment, the multi-stage parallel source drive converter circuit further includes a first resistor R1 , and the first resistor R1 is connected between the first end of the first capacitor C1 and the positive input end.

[0037] First embodiment

[0038] Please refer to Figure 2 , is a circuit block diagram of a first embodiment of a multi-stage parallel source drive converter circuit of the utility model. In this embodiment, there is a two-stage parallel source drive converter circuit, which includes:

[0039] transformer;

[0040] The primary circuit at least includes the first switch tubes Q1 and Q12, the second switch tubes Q2 and Q22, and the power supply capacitor C1; one end of the primary winding P1 of the transformer is simultaneously connected to the positive input end of the source drive converter circuit, the first end of the power supply capacitor C1, the control end of the first switch tube Q1, and the primary winding P2 of the transformer of the second-level source drive converter circuit, and the other end is connected to the first end of the first switch tube Q1, the control end of the first switch tube Q1 is connected to the control end of the first switch tube Q12 of the second-level source drive converter circuit, and the second end is connected to the second end of the second switch tube Q2. One end, the control end of the second switch tube Q2 is used to input a control signal, the second end is connected to the input ground end of the source drive converter circuit, the first end of the first switch tube Q12 of the second-level source drive converter circuit is connected to the other end of the primary winding P2 of the second-level source drive converter circuit transformer, the second end is connected to the first end of the second switch tube Q22 of the second-level source drive converter circuit, the control end of the second switch tube Q22 of the second-level source drive converter circuit is connected to the second switch tube Q2, and the second end is connected to the input ground end of the source drive converter circuit.

[0041] The secondary circuit is connected to two ends of the secondary winding of the transformer.

[0042] It should be noted that Figure 2The power supply capacitor C1 can be a specially set capacitor or a parasitic capacitor of an auxiliary device, for example, it can be a parasitic junction capacitor at both ends of the voltage regulator tube Z1. The setting scheme of the power supply capacitor can be freely selected and implemented by technicians in this field, and this embodiment does not limit this.

[0043] in, Figure 2 The circuit shown also includes: a voltage regulator tube Z1, which is used to fix the gate voltage of the first switch tubes Q1 to Q12 at a certain value; a starting resistor R1, which is used to charge the power supply capacitor C1 through the starting resistor R1 when the converter is started, so as to establish the gate power supply voltage of the first switch tubes Q1 to Q12; these auxiliary devices are not the innovative points of the present utility model, and technicians in this field can independently choose whether to set these auxiliary devices according to circuit requirements, or use other components or unit circuits with the same functions to replace these components. Technicians in this field can freely choose to implement, and this embodiment does not limit this.

[0044] in, Figure 2 The secondary circuit of the circuit shown is Figure 1 The existing source drive converter circuit shown is the same as that shown in the figure, including a rectifier diode D1 and an output filter capacitor C2. The secondary circuit is used to rectify and filter the energy transmitted from the transformer before outputting it. Figure 2 In addition to the specific circuit shown, a secondary circuit using a synchronous rectifier tube for rectification may also be used to obtain higher efficiency. This embodiment does not limit the specific rectification circuit used.

[0045] The first switch tubes Q1 and Q12, and the second switch tubes Q2 and Q22 can be Figure 2 The metal oxide semiconductor transistor (MOSFET) shown in the figure may also use other types of electrically controlled switching devices, such as bipolar junction transistors (BJT) and insulated gate transistors (IGBT) and other switching tubes. This embodiment does not limit the type of switching tube used.

[0046] The control signal input to the control terminal of the second switch tubes Q2 and Q22 can be Figure 2 The control signal output by the PWM IC shown in the figure may also be a control signal output by a single-chip microcomputer (MCU), a digital signal processing (DSP) or other hardware device or software device with logic processing execution functions. The technicians in this field can freely choose which method to use to obtain the control signal, and this embodiment does not limit this.

[0047] against Figure 2 The two-stage parallel source drive converter circuit shown in the figure has its working principle analyzed as follows:

[0048] The source drive converter circuit starts up and powers on, charging the power supply capacitor C1 through the start-up resistor R1, and the voltage regulator Z1 fixes the gate voltage of the first switch tubes Q1 to Q12 at a certain value, so that the gate potential of the first switch tubes Q1 to Q12 remains unchanged;

[0049] When the control signal given by the PWM IC is at a high level, the second switch tubes Q2 and Q22 are turned on, the source voltage of the first switch tubes Q1 and Q12 is pulled down, and the gate potential of the first switch tubes Q1 and Q12 remains unchanged, so the gate-source voltage Vgs of the first switch tubes Q1 and Q12 increases. When the turn-on threshold voltage Vth of the first switch tubes Q1 and Q12 is reached, the first switch tubes Q1 and Q12 are passively turned on;

[0050] When the control signal given by the PWM IC is at a low level, the second switch tubes Q2 and Q22 are turned off, and the drain potential of the second switch tubes Q2 and Q22 rises, that is, the source potential of the first switch tubes Q1 and Q12 gradually rises, while the gate potential of the first switch tubes Q1 to Q12 remains unchanged, that is, the gate-source voltage Vgs of the first switch tubes Q1 and Q12 gradually decreases, until the threshold voltage of the first switch tubes Q1 and Q12 is lower than the turn-off threshold voltage, and the first switch tubes Q1 and Q12 begin to be turned off.

[0051] This embodiment increases the output power of the circuit to two times on the original basis by connecting two stages of the existing source drive converter circuit in parallel, thereby improving the reliability of the switching power supply.

[0052] Second embodiment

[0053] Please refer to Figure 3 , is a circuit block diagram of a second embodiment of a multi-stage parallel source drive converter circuit of the utility model. This embodiment is an N-stage parallel source drive converter circuit, comprising:

[0054] transformer;

[0055] The primary circuit at least includes first switch tubes Q1 to Q1n, second switch tubes Q2 to Q2n (n≥2), and a power supply capacitor C1;

[0056] One end of the transformer primary winding P1 is simultaneously connected to the positive input end of the source drive converter circuit, the first end of the power supply capacitor C1, the control end of the first switch tube Q1, and the primary winding P2 of the transformer of the next source drive converter circuit, and the other end is connected to the first end of the first switch tube Q1. The first end of the power supply capacitor C1 is simultaneously connected to one end of the transformer primary winding P1 and the control end of the first switch tube Q1. The first end of the first switch tube Q1 is connected to the other end of the transformer primary winding P1, and the second end is connected to the first end of the second switch tube Q2. The control end is connected to the first switch tube of the next source drive converter circuit. The control end of the second switch tube Q2 is used to input a control signal and communicate with the next source drive converter circuit. The second switch tube control end is connected, and the second end is connected to the second end of the power supply capacitor C1 and the input ground end of the source drive converter circuit, and so on, until the primary winding is connected to one end of the primary winding Pn of the transformer of the n-th source drive converter circuit, the first switch tube control end is connected to the control end of the first switch tube Q1n of the n-th source drive converter circuit, the second switch tube control end is connected to the control end of the second switch tube Q2n of the n-th source drive converter circuit, the first end of the second switch tube Q1n is connected to the other end of the primary winding Pn of the transformer, the second end is connected to the first end of the second switch tube Q2n, and the second end of the second switch tube Q2n is connected to the input ground end of the source drive converter circuit.

[0057] The secondary circuit is connected to two ends of the secondary winding of the transformer.

[0058] It should be noted that Figure 2 The power supply capacitor C1 can be a specially set capacitor or a parasitic capacitor of an auxiliary device, for example, it can be a parasitic junction capacitor at both ends of the voltage regulator tube Z1. The setting scheme of the power supply capacitor can be freely selected and implemented by technicians in this field, and this embodiment does not limit this.

[0059] in, Figure 2 The circuit shown also includes: a voltage regulator tube Z1, which is used to fix the gate voltage of the first switch tubes Q1 to Q1n at a certain value; a starting resistor R1, which is used to charge the power supply capacitor C1 through the starting resistor R1 when the converter is started, so as to establish the gate power supply voltage of the first switch tubes Q1 to Q1n; these auxiliary devices are not the innovative points of the present utility model, and technicians in this field can independently choose whether to set these auxiliary devices according to circuit requirements, or use other components or unit circuits with the same functions to replace these components. Technicians in this field can freely choose to implement, and this embodiment does not limit this.

[0060] in, Figure 2 The secondary circuit of the circuit shown is Figure 1The existing source drive converter circuit shown is the same as that shown in the figure, including a rectifier diode D1 and an output filter capacitor C2. The secondary circuit is used to rectify and filter the energy transmitted from the transformer before outputting it. Figure 2 In addition to the specific circuit shown, a secondary circuit using a synchronous rectifier tube for rectification may also be used to obtain higher efficiency. This embodiment does not limit the specific rectification circuit used.

[0061] The first switch tubes Q1 to Q1n and the second switch tubes Q2 to Q2n can be Figure 2 The metal oxide semiconductor transistor (MOSFET) shown in the figure may also use other types of electrically controlled switching devices, such as bipolar junction transistors (BJT) and insulated gate transistors (IGBT) and other switching tubes. This embodiment does not limit the type of switching tube used.

[0062] The control signal input to the control terminal of the second switch tubes Q2 to Q2n can be Figure 2 The control signal output by the PWM IC shown in the figure may also be a control signal output by a single-chip microcomputer (MCU), a digital signal processing (DSP) or other hardware device or software device with logic processing execution functions. The technicians in this field can freely choose which method to use to obtain the control signal, and this embodiment does not limit this.

[0063] against Figure 3 The working principle of the multi-stage parallel source drive converter circuit shown is analyzed as follows:

[0064] The source drive converter circuit starts up and powers on, charging the power supply capacitor C1 through the start-up resistor R1, and the voltage regulator Z1 fixes the gate voltage of the first switch tubes Q1 to Q1n at a certain value, so that the gate potential of the first switch tubes Q1 to Q1n remains unchanged;

[0065] When the control signal given by the PWM IC is at a high level, the second switch tubes Q2 to Q2n are turned on, the source voltage of the first switch tubes Q1 to Q1n is pulled down, and the gate potential of the first switch tubes Q1 to Q1n remains unchanged, so the gate-source voltage Vgs of the first switch tubes Q1 to Q1n increases. When the turn-on threshold voltage Vth of the first switch tubes Q1 to Q1n is reached, the first switch tubes Q1 to Q1n are passively turned on;

[0066] When the control signal given by the PWM IC is at a low level, the second switch tubes Q2 to Q2n are turned off, and the drain potential of the second switch tubes Q2 to Q2n rises, that is, the source potential of the first switch tubes Q1 to Q1n gradually rises, while the gate potential of the first switch tubes Q1 to Q1n remains unchanged, that is, the gate-source voltage Vgs of the first switch tubes Q1 to Q1n gradually decreases, until the threshold voltage of the switch tubes Q1 to Q1n is lower than the turn-off threshold voltage, and the switch tubes Q1 to Q1n begin to be turned off.

[0067] This embodiment increases the output power that can be achieved by the circuit on the original basis by performing multi-stage parallel connection on the existing source drive converter circuit, thereby improving the reliability of the switching power supply.

[0068] In addition, an embodiment of the utility model further provides a switching power supply, which includes the multi-stage parallel source drive converter circuit described in the above embodiment.

[0069] The specific circuit principle of this embodiment is consistent with the above embodiment and will not be described in detail here.

[0070] The above are only implementation modes of the present invention. It should be pointed out that the above implementation modes should not be regarded as limitations of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A multi-stage parallel source drive converter circuit, characterized in that: The multi-stage parallel source drive converter circuit comprises: A first capacitor, wherein a first terminal of the first capacitor is connected to the positive input terminal, and a second terminal of the first capacitor is connected to the ground terminal; A transformer, comprising N primary windings and a secondary winding; wherein N is an integer greater than or equal to 2; N-level primary circuits, wherein a first input terminal of each primary circuit is connected to a positive input terminal through a primary winding, a second input terminal of each primary circuit is connected to a first terminal of the first capacitor, and an output terminal of each primary circuit is connected to a second terminal of the first capacitor; A secondary circuit, the secondary circuit being connected to two ends of the secondary winding; Each of the primary circuits includes a first switch tube and a second switch tube, wherein the first end of the first switch tube serves as the first input end of the primary circuit, the control end of the first switch tube serves as the second input end of the primary circuit, the second end of the first switch tube is connected to the first end of the second switch tube, the second end of the second switch tube serves as the output end of the primary circuit, and the control end of the second switch tube is used to input a control signal.

2. The multi-stage parallel source drive converter circuit according to claim 1, characterized in that: The multi-stage parallel source drive converter circuit also includes a voltage regulator tube, the cathode of the voltage regulator tube is connected to the first end of the first capacitor, and the anode of the voltage regulator tube is connected to the second end of the first capacitor.

3. The multi-stage parallel source drive converter circuit according to claim 1, characterized in that: The multi-stage parallel source drive converter circuit also includes a first resistor, which is connected between the first end of the first capacitor and the positive input end.

4. A switching power supply, characterized in that: It comprises the multi-stage parallel source drive converter circuit as described in any one of claims 1 to 3.

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