A DC-DC converter

Abstract

A DC-DC converter comprises: a DC input; a DC output; a pair of EE or EI magnetic cores, the magnetic core having a middle column and two side columns and a first window and a second window, the two side columns respectively having air gaps of the same size, and the middle column having no air gap; three windings; two rectifiers; characterized in that: the first rectifier, the second rectifier and the positive end of the DC output are respectively located on both sides of the magnetic core; the first winding is wound on the middle column of the magnetic core; the second winding passes through the first window from the positive end of the DC output and is connected to the drain of the first rectifier; the third winding passes through the second window from the positive end of the DC output and is connected to the drain of the second rectifier; the source of the first rectifier and the source of the second rectifier are connected together on the same side of the magnetic core, and are connected to the negative end of the DC output through a conductor; a switch switching circuit is connected across the positive and negative ends of the DC input; and an output capacitor is connected across the positive and negative ends of the DC output. The present invention can significantly reduce the conductivity loss of the low-voltage and high-current output loop of the DC-DC converter and improve the conversion efficiency of the DC-DC converter.

Description

Technical Field

[0001] The invention relates to electric energy conversion, and belongs to a DC-DC converter in an electric energy converter. Background Art

[0002] As the amount of data processing increases, the requirements for IT equipment such as supercomputers or servers are also getting higher and higher. For IT equipment such as supercomputers or servers, the power supply of the motherboard in the frame is usually 12V, or higher, such as 48V, but the internal processor, memory, etc. require 1.8V, or lower, such as 0.9V low-voltage power supply. How to efficiently achieve voltage conversion and provide the low-voltage and high-current DC-DC converters required by processors and memories is a constant challenge facing the industry. Summary of the invention

[0003] A DC-DC converter, comprising:

[0004] One DC input;

[0005] One DC output;

[0006] A pair of EE or EI magnetic cores 1, wherein the magnetic core 1 has a middle column 11 and two side columns 12 and 13, the two side columns 12 and 13 have air gaps 16 and 17 of the same size, the middle column has no air gap, and a first window 14 and a second window 15 are formed between the middle column and the two side columns;

[0007] three windings, namely a first winding 21, a second winding 22 and a third winding 23;

[0008] Two rectifier tubes, namely the first rectifier tube S R1 And the second rectifier tube S R2 ;

[0009] The first rectifier tube S R1 , the second rectifier tube S R2 The first winding 21 is wound on the middle column 11 of the magnetic core 1; the second winding 22 passes through the first window 14 from the DC output positive end and is connected to the first rectifier tube S R1 The third winding 23 passes through the second window 15 from the DC output positive terminal and is connected to the second rectifier tube S R2 The drain of the first rectifier tube S R1 The source of the second rectifier S R2 The sources are connected together on the same side of the magnetic core and connected to the negative terminal of the DC output through conductor 4;

[0010] A switch circuit 3 is connected across the DC input positive terminal and the negative terminal, and the switch circuit converts the input DC power supply voltage into a periodic AC voltage and applies it to the first winding;

[0011] The periodic AC voltage on the second winding 22 and the third winding 23 is rectified by the first rectifier tube S R1 , the second rectifier tube S R2 The rectifier circuit formed by the rectifier circuit rectifies the DC output.

[0012] The output capacitor Co is connected across the positive and negative terminals of the DC output.

[0013] Preferably, the switching circuit 3 is a half-bridge circuit, including two switching tubes, namely a first switching tube S1 and a second switching tube S2, and two capacitors, a first capacitor C1 and a second capacitor C2; the drain of the first switching tube S1 is connected to the positive end of the DC input; the source of the first switching tube S1 is connected to the drain of the second switching tube S2, and is also connected to one end of the first winding 21; the source of the second switching tube S2 is connected to the negative end of the DC input; one end of the first capacitor C1 is connected to the positive end of the DC input, the other end of the first capacitor C1 is connected to one end of the second capacitor C2, and is also connected to the other end of the first winding 21, and the other end of the second capacitor C2 is connected to the negative end of the DC input.

[0014] Preferably, the switch switching circuit 3 is a full-bridge circuit, including four switch tubes, namely a first switch tube S1, a second switch tube S2, a third switch tube S3 and a fourth switch tube S4; the drain of the first switch tube S1 is connected to the positive end of the DC input; the source of the first switch tube S1 is connected to the drain of the second switch tube S2, and is also connected to one end of the first winding 21; the source of the second switch tube S2 is connected to the negative end of the DC input; the drain of the third switch tube S3 is connected to the positive end of the DC input; the source of the third switch tube S3 is connected to the drain of the fourth switch tube S4, and is also connected to the other end of the first winding 21; the source of the fourth switch tube S4 is connected to the negative end of the DC input.

[0015] Preferably, the conductor 4 passes through the lower side of the magnetic core 1 and is connected to the first rectifier tube S R1 , the second rectifier tube S R2 The source terminal and negative terminal of DC output.

[0016] Preferably, the conductor 4 is divided into two paths 41 and 42, which respectively pass through the outer sides of the two side columns 12 and 13 of the magnetic core 1 and connect to the first rectifier tube S R1 , the second rectifier tube S R2 The source terminal and negative terminal of DC output.

[0017] Preferably, the output current flows through the conductor 4 to generate a voltage drop, and the voltage drop signal is amplified by the differential amplifier circuit to output a current signal representing the output current. The current signal of the differential amplifier circuit includes but is not limited to being used to implement overcurrent protection, output short-circuit protection, output current equalization and other functions.

[0018] Preferably, the conductor 4 is made of copper, and when PCB is used as the substrate, it can be copper foil on the PCB.

[0019] Preferably, the conductor 4 may be made of an alloy with a low temperature coefficient, such as constantan or manganese copper.

[0020] The present invention can significantly reduce the conductivity loss of the low-voltage and high-current output loop of the DC-DC converter and improve the conversion efficiency of the DC-DC converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of Example 1 of the present invention.

[0022] Figure 2 is a schematic diagram of the magnetic core and air gap of the present invention, wherein Figure 2 (A) is EE type core, Figure 2 (B) is an EI type core.

[0023] Figure 3 It is a schematic diagram of the conductor 4 of the present invention connecting the source of the first rectifier tube SR1 and the second rectifier tube SR2 and the negative terminal of the DC output through the lower side of the magnetic core.

[0024] Figure 4 The switch circuit of the present invention is a schematic diagram of a full-bridge circuit.

[0025] Figure 5 yes Figure 1 The schematic diagram of the waveforms of the voltage of the first winding 21 and the current between some nodes in Example 1 is shown. DETAILED DESCRIPTION

[0026] Preferred embodiments are given below and described in detail with reference to the accompanying drawings.

[0027] Figure 1 It is a schematic diagram of Example 1 of the present invention, referring to Figure 1 :

[0028] The switch switching circuit is a half-bridge circuit, including two switch tubes, namely a first switch tube S1 and a second switch tube S2, and two capacitors, namely a first capacitor C1 and a second capacitor C2; the drain of the first switch tube S1 is connected to the DC input positive terminal (Vin+); the source of the first switch tube S1 is connected to the drain of the second switch tube S2, and is also connected to one end of the first winding 21 (node ​​a); the source of the second switch tube S2 is connected to the DC input negative terminal (Vin-); one end of the first capacitor C1 is connected to the DC input positive terminal (Vin+), the other end of the first capacitor C1 is connected to one end of the second capacitor C2, and is also connected to the other end of the first winding 21 (node ​​b), and the other end of the second capacitor C2 is connected to the DC input negative terminal (Vin-).

[0029] The magnetic core 1 has a middle column 11 and two side columns 12 and 13. The two side columns 12 and 13 have air gaps 16 and 17 of the same size respectively. The middle column has no air gap. Figure 2 (A) or Figure 2 (B) A first window 14 and a second window 15 are formed between the middle column and the two side columns.

[0030] There are three windings, namely a first winding 21 , a second winding 22 and a third winding 23 .

[0031] Two rectifier tubes, namely the first rectifier tube S R1 And the second rectifier tube S R2 .

[0032] The first rectifier tube S R1 , the second rectifier tube S R2 The first winding 21 is wound on the middle column 11 of the magnetic core 1; the second winding 22 passes through the first window 14 from the DC output positive end and is connected to the first rectifier tube S R1 The drain (node ​​i); the third winding 23 passes through the second window 15 from the DC output positive end and is connected to the second rectifier tube S R2 The drain of the first rectifier tube S R1 The source of the second rectifier S R2 The sources of the second winding 22 and the third winding 23 are connected together on the same side of the magnetic core. It is easy to understand that when the second winding 22 and the third winding 23 are implemented on a planar transformer, there may be a common path, that is, from the node k to the DC output positive terminal (node ​​c).

[0033] The first rectifier tube S R1 The source (node ​​g) of the second rectifier tube S R2 The sources (nodes h) of the two electrodes are connected together on the same side of the magnetic core. The impedance between nodes g and h is very low, and they can actually be regarded as the same node f.

[0034] Node f is connected to the negative DC output terminal (node ​​d) through conductor 4; conductor 4 is divided into two paths 41 and 42, passing through the outside of the two side columns 12 and 13 of the magnetic core 1 respectively. It is also easy to understand that the actual junction point of conductor 4 (node ​​e) may be some distance away from the negative DC output terminal (node ​​d), depending on the design of the product. The impedance between nodes e and d is very low, and they can actually be regarded as the same node d.

[0035] The periodic AC voltage on the second winding 22 and the third winding 23 is rectified by the rectifier circuit formed by the first rectifier tube SR1 and the second rectifier tube SR2 to become a DC output.

[0036] The output capacitor Co is connected across the positive and negative terminals of the DC output.

[0037] Reference Figure 5 , Figure 5 yes Figure 1 The waveform diagram of the voltage of the first winding 21 and the current waveform between some nodes in the embodiment shown. Vab is the voltage applied to both ends of the first winding 21 after the DC input passes through the switch switching circuit. It can be seen that the current Iik flowing through the second winding 22 and the current Ijk of the third winding 23 have very large current pulsations. After being rectified by the first rectifier SR1 and the second rectifier SR2 rectifier circuit, the pulsation of the current Idf flowing through the conductor 4 (the sum of the currents flowing through the paths 41 and 42) is very small.

[0038] The PCB is used as the substrate, the conductor 4 is the copper foil on the PCB, and the conductor 4 is used as a current sampling resistor, which can save a dedicated current sampling resistor and further improve the efficiency of the DC-DC converter.

[0039] The voltage signal Vdf on the conductor 4 is connected to a differential amplifier circuit 5 composed of IC01, resistors R01, R02, R04 and other devices. The amplifier circuit outputs a Vcs signal representing the output current. The Vcs signal of the current is used to implement overcurrent protection, output short-circuit protection, output current sharing and other functions.

[0040] It must be noted that copper is a metal with a positive temperature coefficient, and appropriate temperature compensation needs to be performed on the voltage signal Vdf or the current signal Vcs.

[0041] In addition, the conductor 4 may also directly use an alloy with a low temperature coefficient, such as constantan or manganese copper, etc. The resistivity of alloy materials such as constantan or manganese copper changes very little with temperature.

[0042] Figure 3 1 is another embodiment of the connection method of the conductor 4 of the present invention. The conductor 4 is connected to the first rectifier tube S through the lower side of the magnetic core 1. R1 , the second rectifier tube S R2The source electrode and the DC output negative terminal, the remaining principles and methods are the same as those in Example 1.

[0043] Figure 4 This is another embodiment schematic diagram of the switch switching circuit of the present invention being a full-bridge circuit. The full-bridge circuit has four switch tubes, namely the first switch tube S1, the second switch tube S2, the third switch tube S3 and the fourth switch tube S2; the drain of the first switch tube S1 is connected to the positive end of the DC input; the source of the first switch tube S1 is connected to the drain of the second switch tube S2, and is also connected to one end of the first winding 21; the source of the second switch tube S2 is connected to the negative end of the DC input; the drain of the third switch tube S3 is connected to the positive end of the DC input; the source of the third switch tube S3 is connected to the drain of the fourth switch tube S4, and is also connected to the other end of the first winding 21; the source of the fourth switch tube S4 is connected to the negative end of the DC input. The remaining principles and methods are the same as those in Example 1.

[0044] It can be seen that the path through which the output large pulsating current flows in the present invention is very short, so the conductivity loss of the low-voltage and large-current output circuit of the DC-DC converter can be greatly reduced, and the conversion efficiency of the DC-DC converter can be improved. In addition, the path through which the large pulsating current flows is very short, which can also improve or reduce electromagnetic interference.

Claims

1. A DC-DC converter, comprising: One DC input; One DC output; A pair of EE or EI magnetic cores, wherein the magnetic core has a middle column and two side columns, the two side columns have air gaps of the same size, the middle column has no air gap, and a first window and a second window are formed between the middle column and the two side columns respectively; three windings, namely a first winding, a second winding and a third winding; two rectifier tubes, namely a first rectifier tube and a second rectifier tube; The invention is characterized in that: the first rectifier tube, the second rectifier tube and the positive end of the DC output are respectively located on both sides of the magnetic core; the first winding is wound on the middle column of the magnetic core; the second winding passes through the first window from the positive end of the DC output and is connected to the drain of the first rectifier tube; the third winding passes through the second window from the positive end of the DC output and is connected to the drain of the second rectifier tube; the source of the first rectifier tube and the source of the second rectifier tube are connected together on the same side of the magnetic core, and are connected to the negative end of the DC output through a conductor, and the conductor is divided into two paths, passing through the outside of the two side columns of the magnetic core respectively, or the conductor passes through the bottom side of the magnetic core; a switch circuit connected across the DC input positive terminal and the negative terminal, the switch circuit converts the input DC power supply voltage into a periodic AC voltage and applies it to the first winding, the switch circuit is a half-bridge circuit or a full-bridge circuit; The half-bridge circuit comprises two switch tubes, namely a first switch tube and a second switch tube, and two capacitors, namely a first capacitor and a second capacitor; the drain of the first switch tube is connected to the positive end of the DC input; the source of the first switch tube is connected to the drain of the second switch tube, and is also connected to one end of the first winding; the source of the second switch tube is connected to the negative end of the DC input; one end of the first capacitor is connected to the positive end of the DC input, the other end of the first capacitor is connected to one end of the second capacitor, and is also connected to the other end of the first winding, and the other end of the second capacitor is connected to the negative end of the DC input; The full-bridge circuit includes four switch tubes, namely, a first switch tube, a second switch tube, a third switch tube and a fourth switch tube; the drain of the first switch tube is connected to the positive end of the DC input; the source of the first switch tube is connected to the drain of the second switch tube, and is also connected to one end of the first winding; the source of the second switch tube is connected to the negative end of the DC input; the drain of the third switch tube is connected to the positive end of the DC input; the source of the third switch tube is connected to the drain of the fourth switch tube, and is also connected to the other end of the first winding; the source of the fourth switch tube is connected to the negative end of the DC input; The output capacitor is connected across the positive and negative terminals of the DC output.

2. The DC-DC converter according to claim 1, characterized in that: The DC-DC converter has a differential amplifier circuit, and the voltage signal on the conductor connecting the source of the first rectifier tube, the source of the second rectifier tube and the negative end of the DC output is connected to the differential amplifier circuit, and the differential amplifier circuit outputs a current signal Vcs representing the output current.

3. The DC-DC converter according to claim 1, characterized in that: The material of the conductor connecting the source of the first rectifier tube, the source of the second rectifier tube and the negative end of the DC output is copper.

4. The DC-DC converter according to claim 1 or 3, characterized in that: The material of the conductor connecting the source of the first rectifier tube, the source of the second rectifier tube and the negative end of the DC output is copper foil on the PCB.

5. The DC-DC converter according to claim 1, characterized in that: The material of the conductor connecting the source of the first rectifier tube, the source of the second rectifier tube and the negative end of the DC output is an alloy with a low temperature coefficient.

6. The DC-DC converter according to claim 2, characterized in that: The current signal Vcs includes but is not limited to being used to implement overcurrent protection, output short circuit protection, and output current sharing functions.

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