Multistage series source driving converter circuit and switching power supply

Abstract

The utility model discloses a multi-stage series source electrode driving converter circuit and a switching power supply, and the circuit comprises a transformer which comprises N primary windings and secondary windings; wherein N is an integer greater than or equal to 2; the output end of each stage of primary side circuit is connected to the first input end of the next stage of primary side circuit through a primary side winding, and the output end of each stage of primary side circuit is connected to the second input end of the next stage of primary side circuit; the first input end of the primary side circuit of the first stage is connected to the second input end of the primary side winding of the first stage through the first primary side winding, the second input end of the primary side winding of the first stage is connected to the positive input end, and the output end of the primary side circuit of the last stage is connected to the grounding end. According to the utility model, when the requirement of ultrahigh voltage input in practical application is met, only multiple stages of same primary circuits are required to be connected in series, so that the universality and reliability of the 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 multi-stage series source drive converter circuit and a switch power supply. 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 voltage that a commonly used switch tube can withstand is limited, so the maximum voltage that a single-stage circuit can withstand is also limited. Most input voltage ranges can be met by a single-stage source drive converter circuit. However, with the increasing application of switching power supplies in the photovoltaic industry, the demand for ultra-high voltage input of switching power supplies and application scenarios are gradually emerging. Since the source drive converter has only a single stage, when the input voltage demand far exceeds the maximum specification of the switch tube, that is, the maximum withstand voltage of the circuit, the single-stage source drive converter circuit can no longer meet the demand. If the specifications of the single-stage switch tube are increased to meet the input voltage conditions, the cost will also increase greatly. Therefore, the feasibility of the single-stage source 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 is needed to greatly increase the tolerable input voltage based on the original source drive. Utility Model Content

[0006] The utility model aims to overcome the problem that the prior art cannot meet the ultra-high voltage input, and provides a multi-stage series source drive converter circuit and a switching power supply, which realizes the series connection of multi-stage source drive converters on the basis of the original technology, broadens the range of input voltage, and thus improves the breadth 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 transformer, comprising N primary windings and a secondary winding; wherein N is an integer greater than or equal to 2;

[0010] N-stage primary circuits, the output end of each stage of the primary circuit is connected to the first input end of the next stage of the primary circuit through a primary winding, the output end of each stage of the primary circuit is connected to the second input end of the next stage of the primary circuit, the first input end of the first stage of the primary circuit is connected to the second input end of the first stage of the primary winding through the first primary winding, the second input end of the first stage of the primary winding is connected to the positive input end, and the output end of the last stage of the primary circuit is connected to the ground end;

[0011] A secondary circuit, the secondary circuit being connected to two ends of the secondary winding;

[0012] Each stage of the primary circuit includes a first switch tube, a second switch tube and a first capacitor. The first end of the first capacitor is connected to the control end of the first switch tube, the first end of the first switch tube serves as the first 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 is connected to the second end of the first capacitor, the control end of the second switch tube is used to input a control signal, the first end of the first capacitor serves as the second input end of the primary circuit, and the second end of the first capacitor serves as the output end of the primary circuit.

[0013] Preferably, the primary circuit further includes a voltage regulator tube, a cathode of the voltage regulator tube is connected to the first end of the first capacitor, and an anode of the voltage regulator tube is connected to the second end of the first capacitor.

[0014] Preferably, the primary circuit further includes a first resistor, a first end of the first resistor is replaced by a second input end of the primary circuit, and a second end of the first resistor is connected to a first end of the first capacitor.

[0015] In a second aspect, the utility model further provides a switching power supply, which includes the multi-stage series source drive converter circuit described in the first aspect.

[0016] The beneficial effects of the utility model are:

[0017] 1. The utility model connects the existing source drive converter circuit in multiple stages in series, and evenly distributes the input voltage to each primary circuit without changing the original switch tube specifications. The input voltage range is greatly increased by common voltage division of multiple identical primary circuits. When facing the demand for ultra-high voltage input in practical applications, there is no need to change the specifications and structure of the original single stage. Only multiple identical circuits need to be connected in series 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.

[0018] 2. The utility model can adjust the number of series-connected source drive converter circuits under different ranges of input voltage conditions by connecting multiple stages of existing source drive converter circuits in series. When the original single-stage circuit remains unchanged, the two-stage series-connected circuit can increase the maximum input voltage to twice that of the original single-stage circuit, and the N-stage series-connected primary circuit can increase the maximum input voltage to N times that of the original single-stage circuit. By connecting the corresponding number of primary circuits in series according to the input voltage conditions, the flexibility of the switching power supply design is improved.

[0019] 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

[0020] Figure 1 A circuit diagram of an existing source drive converter circuit;

[0021] Figure 2 It is a circuit block diagram of a first embodiment of a multi-stage series source drive converter circuit of the utility model;

[0022] Figure 3 The utility model is a circuit block diagram of a second embodiment of a multi-stage series source drive converter circuit. DETAILED DESCRIPTION

[0023] 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.

[0024] 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.

[0025] 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.

[0026] In addition, the embodiments and features of the embodiments in this application may be combined with each other if there is no conflict.

[0027] 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.

[0028] refer to Figure 2 and Figure 3 The embodiment of the utility model provides a multi-stage series source drive converter circuit, comprising:

[0029] A transformer, comprising N primary windings P1 and a secondary winding; wherein N is an integer greater than or equal to 2;

[0030] N-stage primary circuits, the output end of each stage of the primary circuit is connected to the first input end of the next stage of the primary circuit through a primary winding P1, the output end of each stage of the primary circuit is connected to the second input end of the next stage of the primary circuit, the first input end of the first stage of the primary circuit is connected to the second input end of the first stage of the primary winding P1 through the first primary winding P1, the second input end of the first stage of the primary winding P1 is connected to the positive input end, and the output end of the last stage of the primary circuit is connected to the ground end;

[0031] A secondary circuit, wherein the secondary circuit is connected to two ends of the secondary winding;

[0032] Each stage of the primary circuit includes a first switch tube Q1, a second switch tube Q2 and a first capacitor C1. The first end of the first capacitor C1 is connected to the control end of the first switch tube Q1. The first end of the first switch tube Q1 serves as the first 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 is connected to the second end of the first capacitor C1. The control end of the second switch tube Q2 is used to input a control signal. The first end of the first capacitor C1 serves as the second input end of the primary circuit. The second end of the first capacitor C1 serves as the output end of the primary circuit.

[0033] In one embodiment, the primary circuit further includes a voltage regulator tube, a cathode of the voltage regulator tube is connected to the first end of the first capacitor C1, and an anode of the voltage regulator tube is connected to the second end of the first capacitor C1.

[0034] In one embodiment, the primary circuit further includes a first resistor, a first end of the first resistor is replaced by a second input end of the primary circuit, and a second end of the first resistor is connected to a first end of the first capacitor C1.

[0035] First embodiment

[0036] Please refer to Figure 2 , is a circuit block diagram of a first embodiment of a multi-stage series source drive converter circuit of the utility model. In this embodiment, a two-stage series source drive converter circuit includes:

[0037] transformer;

[0038] The primary circuit at least includes the first switch tubes Q1 and Q12, the second switch tubes Q2 and Q22, and the first capacitors C1 and C12; the first end of the first capacitor C1 is simultaneously connected to one end of the primary winding P1 of the transformer 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 primary winding P1 of the transformer, and the second end is connected to the first end of the second switch tube Q2, the control end of the second switch tube Q2 is used to input the control signal, the second end and the second end of the first capacitor C1, the primary winding of the transformer of the second-stage source drive converter circuit One end of P2, the first end of the first capacitor C12 of the second-level source drive converter circuit, and the control end of the first switch tube Q12 of the second-level source drive converter circuit are connected. 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, and the second end is connected to the first end of the second switch tube Q22. The control end of the second switch tube Q22 is used to input a control signal, and the second end is connected to the second end of the first capacitor C12 and the input ground end of the source drive converter circuit.

[0039] The secondary circuit is connected at both ends of the secondary winding of the transformer.

[0040] It should be noted that Figure 2The first capacitors C1 and C12 may be specially configured capacitors or parasitic capacitors of auxiliary devices, such as parasitic junction capacitors at both ends of the voltage regulator tube Z1. The configuration scheme of the first capacitors may be freely selected and implemented by technicians in this field, and this embodiment does not impose any restrictions on this.

[0041] in, Figure 2 The circuit shown also includes: voltage regulator tubes Z1 and Z2, which are used to fix the gate voltage of the first switch tubes Q1 and Q12 at a certain value; first resistors R1 and R2, which are used to charge the first capacitors C1 and C12 through the first resistors R1 and R2 when the converter is started, so as to establish the gate supply voltage of the first switch tubes Q1 and 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.

[0042] 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.

[0043] 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.

[0044] The control signal input to the control terminal of the second switch tubes Q2 and Q22 can be Figure 2 The control signals output by PWM1 IC to PWM2 IC shown in the figure may also be control signals output by a single chip microcomputer (MCU), a digital signal processing (DSP) or other hardware devices or software devices 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.

[0045] against Figure 2 The two-stage series source drive converter circuit shown in the figure has its working principle analyzed as follows:

[0046] The source drive converter circuit starts up and powers on, and charges the first capacitors C1 and C12 through the first resistors R1 and R2. The voltage regulators Z1 and Z2 fix the gate voltages of the first switch tubes Q1 and Q12 at a certain value, so that the gate potentials of the first switch tubes Q1 and Q12 remain unchanged.

[0047] When the control signal from PWM1 IC to PWM2 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;

[0048] When the control signal given by PWM1 IC to PWM2 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 and 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 switch tubes Q1 and Q12 is lower than the turn-off threshold voltage, and the switch tubes Q1 and Q12 begin to be turned off.

[0049] This embodiment connects two stages of the existing source drive converter circuit in series, thereby widening the input voltage range to twice the original range and improving the reliability of the switching power supply.

[0050] Second embodiment

[0051] Please refer to Figure 3 , is a circuit block diagram of a second embodiment of a multi-stage series source drive converter circuit of the utility model. The multi-stage series source drive converter circuit of this embodiment includes:

[0052] transformer;

[0053] The primary circuit at least includes first switch tubes Q1 to Q1n, second switch tubes Q2 to Q2n, and first capacitors C1 to C1n (n≥2); the first end of the first capacitor C1 is simultaneously connected to one end of the primary winding P1 of the transformer 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 primary winding P1 of the transformer, the second end is connected to the first end of the second switch tube Q2, the control end of the second switch tube Q2 is used to input a control signal, the second end and the second end of the first capacitor C1, one end of the primary winding of the transformer of the next stage source drive converter circuit, and the first end of the next stage source drive converter circuit are connected to the first end of the second switch tube Q2. The first end of the first capacitor C1n is connected, and so on, until it is connected to one end of the primary winding Pn of the transformer of the N-th source drive converter circuit and the first end of the first capacitor C1n of the N-th source drive converter circuit. The first end of the first capacitor C1n is simultaneously connected to one end of the primary winding Pn of the transformer and the control end of the first switch tube Q1n. The first end of the first switch tube Q1n is connected to the other end of the primary winding Pn of the transformer, and the second end is connected to the first end of the second switch tube Q2n. The control end of the second switch tube Q2n is used to input a control signal, and the second end is connected to the second end of the first capacitor C1n and the input ground end of the source drive converter circuit.

[0054] The secondary circuit is connected at both ends of the secondary winding of the transformer.

[0055] It should be noted that Figure 2 The first capacitors C1 to C1n may be specially configured capacitors or parasitic capacitors of auxiliary devices, such as parasitic junction capacitors at both ends of the voltage regulator tube Z1. The configuration scheme of the first capacitors may be freely selected and implemented by technicians in this field, and this embodiment does not impose any restrictions on this.

[0056] in, Figure 2 The circuit shown also includes: voltage regulator tubes Z1 to Z1n, which are used to fix the gate voltage of the first switch tubes Q1 to Q1n at a certain value; first resistors R1 to Rn, which are used to charge the first capacitors C1 to C1n through the first resistors R1 to Rn when the converter is started, so as to establish the gate 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.

[0057] 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 2In 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.

[0058] 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.

[0059] The control signal input to the control terminal of the second switch tubes Q2 to Q2n can be Figure 2 The control signals output by PWM1 IC to PWMn IC shown in the figure may also be control signals output by a single chip microcomputer (MCU), a digital signal processing (DSP) or other hardware devices or software devices 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.

[0060] against Figure 2 The working principle of the multi-stage series source drive converter circuit shown is analyzed as follows:

[0061] The source drive converter circuit starts up and powers on, and charges the first capacitors C1 to C1n through the first resistors R1 to Rn. The voltage regulators Z1 to Zn fix the gate voltages of the first switch tubes Q1 to Q1n at a certain value, so that the gate potentials of the first switch tubes Q1 to Q1n remain unchanged;

[0062] When the control signal given by PWM1 IC to PWMn 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;

[0063] When the control signal given by PWM1 IC to PWMn 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.

[0064] This embodiment expands the input voltage range and improves the reliability of the switching power supply by connecting the existing source drive converter circuit in multiple stages in series.

[0065] In addition, an embodiment of the utility model further provides a switching power supply, which includes the multi-stage series source drive converter circuit described in the above embodiment.

[0066] The specific circuit principle of this embodiment is consistent with the above embodiment and will not be described in detail here.

[0067] 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 series source drive converter circuit, characterized in that: The multi-stage series source drive converter circuit comprises: A transformer, comprising N primary windings and a secondary winding; wherein N is an integer greater than or equal to 2; N-stage primary circuits, the output end of each stage of the primary circuit is connected to the first input end of the next stage of the primary circuit through a primary winding, the output end of each stage of the primary circuit is connected to the second input end of the next stage of the primary circuit, the first input end of the first stage of the primary circuit is connected to the second input end of the first stage of the primary winding through the first primary winding, the second input end of the first stage of the primary winding is connected to the positive input end, and the output end of the last stage of the primary circuit is connected to the ground end; A secondary circuit, the secondary circuit being connected to two ends of the secondary winding; Each stage of the primary circuit includes a first switch tube, a second switch tube and a first capacitor. The first end of the first capacitor is connected to the control end of the first switch tube, the first end of the first switch tube serves as the first 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 is connected to the second end of the first capacitor, the control end of the second switch tube is used to input a control signal, the first end of the first capacitor serves as the second input end of the primary circuit, and the second end of the first capacitor serves as the output end of the primary circuit.

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

3. The multi-stage series source drive converter circuit according to claim 1 or 2, characterized in that: The primary circuit further includes a first resistor, a first end of the first resistor is replaced by a second input end of the primary circuit, and a second end of the first resistor is connected to a first end of the first capacitor.

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

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