TW201735517A - High step-down converter achieving elevation of step-down ratio by using the first and second step-down inductors without requirement of making the first and second switch operated under minimum duty conduction ratio - Google Patents

Abstract

A high step-down converter comprises first and second input capacitors, first and second switches, first and second input diodes, first and second converters, first and second rectifier diodes, first and second freewheeling diodes, first and second step-down inductors, first and second output inductors, and a output capacitors. The first and second capacitors connected in series share input voltage so that voltage stress of the first and second switches are half input voltage for being adapted to high voltage input utilization. Elevation of step-down ratio can be achieved by using the first and second step-down inductors without requirement of making the first and second switches operated under minimum duty conduction ratio. The first and second output inductors share output current for being adapted to high power and application of outputting low voltage large current. Interleaved operation with difference of half-cycle time between the first and second switches is configured so that current flowing through first and second output inductors respectively have ripple cancellation property for reducing ripple of output current.

Description

High buck converter

This invention relates to a converter, and more particularly to a high buck converter.

Referring to Figure 1, a conventional buck converter whose buck ratio is determined by the duty ratio of its switch. The parameters V _O , D, and V _in are the output voltage, the conduction duty ratio, and the input voltage, respectively, but have the following disadvantages:

1. The step-down ratio is low and limited by the turn-on duty ratio of the switch. To increase the step-down ratio, the switch needs to operate at a minimum duty-conducting ratio.

2. Switches and diodes are subject to high voltage and high current stress.

Accordingly, it is an object of the present invention to provide a high buck converter.

Thus, the high buck converter of the present invention comprises a first input capacitor, a second input capacitor, a first switch, a second switch, a first input diode, a second input diode, and a first a transformer and a second transformer, a first rectifying diode, a second rectifying diode, a first flywheel diode, a second flywheel diode, a first step-down inductor, and a second Buck inductor, a first output inductor, a second output inductor, and an output capacitor.

The first input capacitor has a first end of the positive pole receiving an input voltage, and a second end.

The second input capacitor has a first end electrically connected to the second end of the first input capacitor, and a second end of the negative terminal receiving the input voltage.

The first switch has a first end electrically connected to the first end of the first input capacitor, and a second end, and the first switch is controlled to switch between a conducting state and a non-conducting state.

The second switch has a first end and a second end electrically connected to the second end of the second input capacitor, and the second switch is controlled to switch between the conductive state and the non-conducting state.

The first input diode has a cathode electrically connected to the second end of the first switch, and an anode electrically connected to the second end of the second input capacitor.

The second input diode has a cathode electrically connected to the first end of the first switch, and an anode electrically connected to the first end of the second switch.

Each transformer has a primary side winding and a secondary side winding, and each side winding has a first end and a second end, wherein the first end of the primary side winding of the first transformer is electrically connected to the a second end of the first switch, a first end of the primary side winding of the second transformer is electrically connected to a second end of the primary side winding of the first transformer, and a second end of the primary side winding of the second transformer is electrically connected At the first end of the second switch.

The first rectifying diode has an anode electrically connected to the first end of the secondary side winding of the first transformer, and a cathode.

The second rectifying diode has an anode electrically connected to the first end of the secondary side winding of the second transformer, and a cathode.

The first flywheel diode has an anode electrically connected to the second end of the secondary side winding of the first transformer, and a cathode.

The second flywheel diode has an anode electrically connected to the second end of the secondary side winding of the second transformer, and a cathode.

The first buck inductor has a first end electrically connected to the cathode of the first rectifying diode, and a second end electrically connected to the cathode of the first flywheel diode.

The second step-down inductor has a first end electrically connected to the cathode of the second rectifying diode, and a second end electrically connected to the cathode of the second flywheel diode.

The first output inductor has a first end electrically connected to the second end of the first buck inductor, and a second end.

The second output inductor has a first end electrically connected to the second end of the second buck inductor, and a second end electrically connected to the second end of the first output inductor.

The output capacitor is electrically connected between the second end of the first output inductor and the second end of the secondary side winding of the first transformer for providing an output voltage.

The invention has the effect of using the first and second step-down inductors to increase the step-down ratio without operating the first and second switches to a minimum duty-conducting ratio.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to FIG. 2, an embodiment of the high buck converter of the present invention includes a first input capacitor C1, a second input capacitor C2, a first switch Q1, a second switch Q2, and a first input diode. Dr1, a second input diode Dr2, a first transformer T1 and a second transformer T2, a first rectifying diode D1, a second rectifying diode D2, and a first flywheel diode Df1. a second flywheel diode Df2, a first buck inductor Lb1, a second buck inductor Lb2, a first output inductor L1, a second output inductor L2, an output capacitor C _O, and a control unit 2 .

A capacitor C1 having a first input receiving a first end and a second end of the input voltage V _in a positive electrode. The second capacitor C2 has an input electrically connected to the first input terminal of a first capacitor C1, a second end, and an input voltage V _in receiving the second end of the negative electrode.

The first switch Q1 has a first end electrically connected to the first end of the first input capacitor C1, and a second end, and the first switch Q1 is controlled to switch between the conducting state and the non-conducting state. The second switch Q2 has a first end, and a second end electrically connected to the second end of the second input capacitor C2, and the second switch Q2 is controlled to switch between the conductive state and the non-conducting state. The first switch Q1 is an N-type power semiconductor transistor, and the first end of the first switch Q1 is a drain, and the second end of the first switch Q1 is a source. The second switch Q2 is an N-type power semiconductor transistor, and the first end of the second switch Q2 is a drain, and the second end of the second switch Q2 is a source.

The first input diode Dr1 has a cathode electrically connected to the second end of the first switch Q1, and an anode electrically connected to the second end of the second input capacitor C2. The second input diode Dr2 has a cathode electrically connected to the first end of the first switch Q1, and an anode electrically connected to the first end of the second switch Q2.

The first transformer T1 has a primary side winding NP1 and a secondary side winding NS1, and the second transformer T2 has a primary side winding NP2 and a secondary side winding NS2, and each side winding NP1, NP2, NS1, NS2 has a first end and a second end, wherein a first end of the primary side winding NP1 of the first transformer T1 is electrically connected to a second end of the first switch Q1, and a primary side winding NP2 of the second transformer T2 The first end is electrically connected to the second end of the primary side winding NP1 of the first transformer T1, and the second end of the primary side winding NP2 of the second transformer T2 is electrically connected to the first end of the second switch Q2. The turns ratios of the first and second transformers T1, T2 are equal. The first end of each of the secondary side windings NS1, NS2 is a polarity point end, and the second end of each of the secondary side windings NS1, NS2 is a non-polar point end. The first end of each of the primary side windings NP1, NP2 is a polarity point end, and the second end of each of the primary side windings NP1, NP2 is a non-polar point end.

The first rectifying diode Dr1 has an anode electrically connected to the first end of the secondary side winding NS1 of the first transformer T1, and a cathode. The second rectifying diode Dr2 has an anode electrically connected to the first end of the secondary side winding NS2 of the second transformer T2, and a cathode.

The first flywheel diode Df1 has an anode electrically connected to the second end of the secondary side winding NS1 of the first transformer T1, and a cathode. The second flywheel diode Df2 has an anode electrically connected to the second end of the secondary side winding NS2 of the second transformer T2, and a cathode.

The first step-down inductor Lb1 has a first end electrically connected to the cathode of the first rectifying diode D1, and a second end electrically connected to the cathode of the first flywheel diode Df1. The second step-down inductor Lb2 has a first end electrically connected to the cathode of the second rectifying diode D2, and a second end electrically connected to the cathode of the second flywheel diode Df2.

The first output inductor L1 has a first end electrically connected to the second end of the first buck inductor Lb1, and a second end. The second output inductor L2 has a first end electrically connected to the second end of the second step-down inductor Lb2, and a second end electrically connected to the second end of the first output inductor L2.

Between the second end of the secondary winding NS1 output capacitance C _O is electrically connected to the first output inductor L1 and the second end of the first transformer T1 for providing an output voltage V _O.

The control unit 2 generates a first pulse modulation signal for switching the first switch Q1 and a second pulse modulation signal for switching the second switch Q2, the first pulse modulation signal and the second pulse Wave modulation signals have the same cycle time. The phase difference between the first and second pulse modulation signals is one-half of the cycle time. The switching timing diagram of the switches Q1 and Q2 will be further explained in the following ten stages.

Referring to FIG. 3, it is an operation timing diagram of the embodiment, wherein the parameters V _gs1 and V _gs2 respectively represent voltages of the first and second pulse modulation signals that control whether the first and second switches Q1 and Q2 are turned on. The parameters V _Q1 and V _Q2 respectively represent the two-terminal voltage across the first and second switches Q1 and Q2, and the parameter T _S is the cycle time of the first pulse modulation signal, wherein the parameters i _Dr1 to i _Dr2 respectively represent the flow. The currents of the first to second input diodes Dr1 to Dr2, the parameters i _Dr1 to i _Dr2 respectively represent the currents flowing through the first to second input diodes Dr1 to Dr2, and the parameters i _Lb1 to i _Lb2 represent the flows respectively. The currents of the first to second step-down inductors Lb1, Lb2, the parameters i _L1 - i _L2 represent the current flowing through the first to second output inductors L1, L2, respectively, and the parameter i _Lo represents the flow through the first to the second outputs The sum of the currents of the inductors L1, L2, the parameter i _o represents the output current provided by the output capacitor C _O .

The following is a circuit diagram of the ten stages of the present embodiment, wherein the conductive elements are indicated by solid lines, the non-conducting elements are indicated by broken lines, and the non-ideal of the primary side windings NP1, NP2 of the two transformers T1 and T2 are further illustrated. The magnetizing inductances Lm1, Lm2 in the equivalent circuit, the parameters i _Lm1 to i _Lm2 represent the currents flowing through the magnetizing inductances Lm1, Lm2, respectively, and the parameters V _p1 , V _s1 represent the primary side winding NP1 and the secondary of the first transformer T1, respectively. The two ends of the side winding NS1 are voltage-crossed, and the parameters v _p2 and v _s2 respectively represent the two-terminal voltage across the primary winding NP2 and the secondary winding NS2 of the second transformer T2, and the parameters V _Lb1 and V _Lb2 respectively represent the first And the two-terminal voltage across the second step-down inductors Lb1 and Lb2, and the parameters V _L1 and V _L2 respectively represent the two-terminal voltage across the first and second output inductors L1 and L2, which will be described below for each stage.

The first stage (time:):

Referring to FIG. 3 and FIG. 4, the first switch Q1 is turned on, the second switch Q2 is not turned on, the first input diode Dr1 is not turned on, the second input diode Dr2 is turned on, and the first rectifying diode D1 is turned on, first The flywheel diode Df1 is turned on, the second rectifying diode D2 is not turned on, and the second flywheel diode Df2 is turned on.

The voltage of the first input capacitor C1 Across the primary side winding NP1 of the first transformer T1, ie Current flowing through the magnetizing inductance Lm1 Slope Linear rise, and the voltage of the secondary side winding NS1 of the first transformer T1 The parameter n ₁ is the turns ratio of the first transformer T1, and the first rectifying diode D1 and the first flywheel diode Df1 are simultaneously turned on, and the current flowing through the first step-down inductor Lb1 Slope from 0 Linear rise, and the voltage across the first output inductor L1 is Therefore, the current flowing through the first output inductor Slope Linear decline. The voltage across the primary side winding of the second transformer T2 is Current flowing through the magnetizing inductance Lm2 Slope The linear drop causes the second rectifying diode D2 to be non-conducting, and the second flywheel diode Df2 is turned on, and the voltage of the second output inductor L2 Therefore, the current flowing through the second output inductor L2 Slope Linear decline. when Current flowing through the magnetizing inductance Lm2 It drops to 0, that is, the second transformer T2 completes the magnetic flux reset, and the second input diode Dr2 becomes non-conductive, and the first phase ends.

Second stage (time: ):

Referring to FIG. 3 and FIG. 5, the first switch Q1 is turned on, the second switch Q2 is not turned on, the first input diode Dr1 is not turned on, the second input diode Dr2 is not turned on, and the first rectifying diode D1 is turned on. A flywheel diode Df1 is turned on, the second rectifying diode D2 is not turned on, and the second flywheel diode Df2 is turned on.

The second switch is located across the pressure clamp , the cross-voltage of the primary side winding NS2 of the second transformer T2 Clamp at 0. Current flowing through the first step-down inductor Lb1 Continued to slope Linear rise. when Current flowing through the first step-down inductor Lb1 Rising to the current flowing through the first output inductor L1 When flowing, the current flowing through the first flywheel diode Df1 When it is 0, when the first flywheel diode Df1 is switched to be non-conducting, the second phase ends.

The third stage (time:):

Referring to FIG. 3 and FIG. 6, the first switch Q1 is turned on, the second switch Q2 is not turned on, the first input diode Dr1 is not turned on, the second input diode Dr2 is not turned on, and the first rectifying diode D1 is turned on. A flywheel diode Df1 is non-conducting, a second rectifying diode D2 is non-conducting, and a second flywheel diode Df2 is conducting.

Since the first step-down inductor Lb1 is equivalent to the first output inductor L1 in series as one inductor, the voltage across the two inductors Lb1 and L1 connected in series is , the current flowing through the two inductors Lb1, L1 connected in series simultaneously with the slope Linear rise. when At the same time, the first switch Q1 switches to non-conduction, and the third phase ends.

The fourth stage (time:):

Referring to FIG. 3 and FIG. 7, the first switch Q1 is not turned on, the second switch Q2 is not turned on, the first input diode Dr1 is turned on, the second input diode Dr2 is not turned on, and the first rectifying diode D1 is turned on. A flywheel diode Df1 is turned on, the second rectifying diode D2 is not turned on, and the second flywheel diode Df2 is turned on.

At this time, the voltage of the primary side winding NP1 of the first transformer T1 Current flowing through the magnetizing inductance Lm1 Slope Linearly decreasing, the primary side winding NP1 of the first transformer T1 starts the magnetic flux reset by the path of the first input pole body Dr1 and the second input capacitor C2. At this time, the secondary side of the first transformer T1 crosses the pressure When the first rectifying diode D1 and the first flywheel diode Df1 are simultaneously turned on, the current flowing through the first step-down inductor Lb1 Start by its maximum value with a slope Linearly falling, while the current flowing through the first output inductor L1 Slope Linear decline. when Current flowing through the first step-down inductor Lb1 Drop to 0, that is, the current flowing through the first rectifying diode D1 When the first rectifying diode D1 is non-conducting, the fourth stage ends.

The fifth stage (time:):

Referring to FIG. 3 and FIG. 8 , the first switch Q1 is not turned on, the second switch Q2 is not turned on, the first input diode Dr1 is turned on, the second input diode Dr2 is not turned on, and the first rectifying diode D1 is not turned on. The first flywheel diode Df1 is turned on, the second rectifying diode D2 is not turned on, and the second flywheel diode Df2 is turned on.

a current flowing through the magnetizing inductance Lm1, the first output inductor L1, and the second output inductor L1 , and Continuous linear decline. when At the same time, the second switch Q2 is turned on, and the fifth stage ends.

The sixth stage (time:):

Referring to FIG. 3 and FIG. 9, the first switch Q1 is not turned on, the second switch Q2 is turned on, the first input diode Dr1 is turned on, the second input diode Dr2 is not turned on, and the first rectifying diode D1 is not turned on. A flywheel diode Df1 is turned on, the second rectifying diode D2 is turned on, and the second flywheel diode Df2 is turned on.

The voltage of the second input capacitor C2 Across the primary side winding NP2 of the second transformer T2, ie Current flowing through the magnetizing inductance Lm2 Slope Linear rise, and the voltage of the secondary side winding NS2 of the second transformer T2 , the second rectifying diode D2 and the second flywheel diode Df2 are simultaneously turned on, and the current flowing through the second step-down inductor Lb2 Slope from 0 Linear rise, and the second output inductor L2 crosses the pressure Therefore, the current flowing through the second output inductor L2 Slope Linear decline. The primary side winding NP1 of the first transformer T1 is transposed Current flowing through the magnetizing inductance Lm1 Slope The linearity decreases, the first rectifying diode D1 continues to be non-conducting, and the first flywheel diode Df1 is turned on, and the voltage of the first output inductor L1 Therefore, the current flowing through the first output inductor L1 Slope Linear decline. when Current flowing through the magnetizing inductance Lm1 It drops to 0, that is, the first transformer T1 completes the magnetic flux reset, the first input pole body Dr1 becomes non-conductive, and the sixth stage ends.

The seventh stage (time:):

Referring to FIG. 3 and FIG. 10, the first switch Q1 is not turned on, the second switch Q2 is turned on, the first input diode Dr1 is not turned on, the second input diode Dr2 is not turned on, and the first rectifying diode D1 is not turned on. The first flywheel diode Df1 is turned on, the second rectifying diode D2 is turned on, and the second flywheel diode Df2 is turned on.

First switch Cross clamp is located , the cross-voltage of the primary side winding NP1 of the first transformer T1 Clamp at 0. Current flowing through the second step-down inductor Lb2 Continued to slope Linear rise. when Current flowing through the second step-down inductor Lb2 Rising to the current flowing through the second output inductor L2 When flowing, the current flowing through the second flywheel diode Df2 When it is 0, when the second flywheel diode Df2 is switched to be non-conducting, the seventh stage ends.

The eighth stage (time:):

Referring to FIG. 3 and FIG. 11, the first switch Q1 is not turned on, the second switch Q2 is turned on, the first input diode Dr1 is not turned on, the second input diode Dr2 is not turned on, and the first rectifying diode D1 is not turned on. The first flywheel diode Df1 is turned on, the second rectifying diode D2 is turned on, and the second flywheel diode Df2 is not turned on.

Since the second step-down inductor Lb2 and the second output inductor L2 are equivalent in series to one inductor, the two inductors Lb2 and L2 are across the voltage. , the current flowing through the two inductors Lb2, L2 simultaneously with the slope Linear rise. when Second switch Switch to non-conduction and the eighth phase ends.

The ninth stage (time:):

Referring to FIG. 3 and FIG. 12, the first switch Q1 is not turned on, the second switch Q2 is not turned on, the first input diode Dr1 is not turned on, the second input diode Dr2 is turned on, and the first rectifying diode D1 is not turned on. The first flywheel diode Df1 is turned on, the second rectifying diode D2 is turned on, and the second flywheel diode Df2 is turned on.

At this time, the voltage of the primary side winding NP2 of the second transformer T2 Current flowing through the magnetizing inductance Lm2 Slope Linearly falling, the primary side winding NP2 of the second transformer T2 starts the magnetic flux reset by the path of the second input pole body Dr2 and the first input capacitor C1. At this time, the cross-voltage of the secondary side winding NS2 of the second transformer T2 When the second rectifying diode D2 and the second flywheel diode Df2 are simultaneously turned on, the current flowing through the second step-down inductor Lb2 Slope from its maximum value Linearly falling while flowing through the second output inductor L2 Slope Linear decline. when Current flowing through the second step-down inductor Lb2 Drop to 0, that is, the current flowing through the second rectifying diode D2 And when the second rectifying diode D2 is non-conducting, the ninth stage ends.

The tenth stage (time:):

Referring to FIG. 3 and FIG. 13, the first switch Q1 is not turned on, the second switch Q2 is not turned on, the first input diode Dr1 is not turned on, the second input diode Dr2 is turned on, and the first rectifying diode D1 is not turned on. The first flywheel diode Df1 is turned on, the second rectifying diode D2 is not turned on, and the second flywheel diode Df2 is turned on.

The current flowing through the magnetizing inductance Lm2, the first output inductor L1, and the second output inductor L2 in this stage , and Continuous linear decline, when When the first switch Q1 is turned from non-conducting to conducting, it returns to the first stage.

Experimental simulation:

Referring to Figure 14, the two-pulse modulation signal, the input voltage V _in and the output voltage Waveform diagram, when the first and second switches Q1, Q2 are responsible for the conduction ratio Output voltage 48V, according to the voltage conversion ratio formula of the conventional buck converter ,in , When the output voltage of a conventional buck converter At 74 V, it is obviously impossible to reduce the output voltage reached in this case. It is 48V.

Referring to Figure 15, the current waveform flowing through the first and second output inductors L1, L2, when At the time and time, due to the circuit output parallel structure, the output current is distributed by the first and second output inductors L1, L2, and the current flowing through the first and second output inductors L1, L2 is about 4.2A on average. And the first and second switches Q1 and Q2 are interleaved to make the current flowing through the first and second output inductors L1 and L2 , Wave wave difference Does make the output current Chopper Lower many .

Referring to Figures 16 and 17, respectively, the current waveform flowing through the first step-down inductor Lb1 and the first output inductor L1, the current waveform flowing through the second step-down inductor Lb2 and the second output inductor L2, and the first and second drops are added. The voltage inductors Lb1 and Lb2 can achieve a high step-down because the current flowing through the first step-down inductor Lb1 when the first switch Q1 is switched to be turned on Start to rise, wait for the current flowing through the first step-down inductor Lb1 When the diode current is commutated, energy can be transferred to the load.

Buck ratio analysis:

Referring to FIG. 18, a voltage and current analysis diagram of each stage in this embodiment is performed. According to the duty conduction ratio D of the first and second switches Q1 and Q2, the first and second output inductors L1 and L2 can be derived. The current is as in Equation 1, where the parameters For the minimum current value flowing through the first output inductor L1, the parameter T _{X is} defined as the time sum of the first and second phases, and the parameter For the amount of change of the current flowing through the first output inductor L1 over time T _X , the parameter L ₁ is the inductance value of the first output inductor L1, and the parameter L _b1 is the inductance value of the first step-down inductor Lb1, in this embodiment The inductance value of the first step-down inductor Lb1 is equal to the inductance value of the second step-down inductor Lb2.

, Formula 1

Formula 2

Put the first and second generations into Push .

by ...three

by The design conditions of the first output inductor can be derived.

Three generations of The available output voltage V _O is a functional relationship ...four

From the fourth equation, a step-down ratio graph as shown in FIG. 19 can be derived. Compared with the conventional buck converter, the step-down ratio of the adjustment switch is used to obtain a step-down ratio. This embodiment utilizes the first and second drops. The inductors Lb1, Lb2 are pressed to achieve a high step-down ratio. As shown in FIG. 19, when the input voltage is 400 V, it can be seen from the curve of the step-down ratio in the figure that the step-down ratio of this embodiment is much better than the existing buck converter, and the adjustment can be adjusted. The inductance values of the first and second step-down inductors Lb1, Lb2 are used to achieve a better step-down ratio.

In summary, the above embodiment has the following advantages:

1. With high step-down ratio, the first and second step-down inductors Lb1 and Lb2 can be used to increase the step-down ratio without reducing the first and second switches Q1 and Q2 to a minimum duty-conducting ratio. The turns ratio of the first and second transformers T1, T2 can reduce the parasitic components of the first and second transformers T1, T2 to reduce the glitch.

2. With low voltage stress, since the first and second capacitors C1 and C2 connected in series share the input voltage, the voltage stress of the first and second switches Q1 and Q2 is only one-half of the input voltage V _in , and can be used. Low-rated piezoelectric crystals with low on-resistance are also suitable for high voltage input applications.

3. With low current stress, the first output inductor L1, the second output inductor L2, the first buck inductor Lb1, and the second buck inductor can be reduced by sharing the output current by parallelizing the first and second output inductors L1 and L2. Lb2 and power loss of the first transformer T1 and the second transformer T2, and conduction losses of the first rectifying diode D1, the second rectifying diode D2, the first flywheel diode Df1 and the second flywheel diode Df2 Suitable for high power and output low voltage and high current applications.

4. Reduce the chopping of the output current, the first and second switches Q1, Q2 are separated by 1/2 cycle time, so that the current flowing through the first and second output inductors L1, 2 respectively is chopped Performance, reducing the chopping of the output current, thus reducing the output capacitor value and its size, you can choose a smaller output capacitor C _O , to reduce the overall circuit volume and increase power density.

In summary, the apparatus of the present invention can indeed achieve the object of the present invention.

However, the above is only the embodiment of the present invention, and the scope of the invention is not limited thereto, and all the equivalent equivalent changes and modifications according to the scope of the patent application and the patent specification of the present invention are still The scope of the invention is covered.

C1‧‧‧first input capacitor
C2‧‧‧second input capacitor
Q1‧‧‧First switch
Q2‧‧‧Second switch
Dr1‧‧‧First Input Dipole
Dr2‧‧‧Second input diode
T1‧‧‧ first transformer
T2‧‧‧second transformer
D1‧‧‧First Rectifier Diode
D2‧‧‧Secondary rectifier diode
Df1‧‧‧First flywheel diode
Df2‧‧‧Second flywheel diode
Lb1‧‧‧ first step-down inductor
Lb2‧‧‧Second step-down inductor
L1‧‧‧first output inductor
L2‧‧‧second output inductor
C _O ‧‧‧ output capacitor
2‧‧‧Control unit
Lm1‧‧‧ Magnetized Inductance
Lm2‧‧‧ Magnetized Inductance
V _in ‧‧‧ input voltage
V _O ‧‧‧Output voltage
i _{Dr1 ‧‧‧current} flowing through the first input diode
i _{Dr2 ‧‧‧current} flowing through the second input diode
i _D1 ‧‧‧current flowing through the first rectifying diode
i _D2 ‧‧‧current flowing through the second rectifying diode
i _Df1 ‧‧‧current flowing through the first flywheel diode
i _{Df2 ‧‧‧current} flowing through the second flywheel diode
i _Lb1 ‧‧‧current flowing through the first buck inductor
i _Lb2 ‧‧‧current flowing through the second buck inductor
i _L1 ‧‧‧current flowing through the first output inductor
i _L2 ‧‧‧current flowing through the second output inductor
i _Lm1 ‧‧‧current flowing through the magnetizing inductance of the first transformer
i _Lm2 ‧‧‧current flowing through the magnetizing inductance of the second transformer
i _Lo ‧‧‧The sum of the currents flowing through the first to second output inductors
i _o ‧‧‧Output current
v _p1 ‧‧‧cross-voltage of the primary side winding of the first transformer
v _s1 ‧‧‧cross-voltage of the secondary winding of the first transformer
v _p2 ‧‧‧cross-voltage of the primary side winding of the second transformer
v _s2 ‧‧‧The voltage across the secondary winding of the second transformer
v _C1 ‧‧‧cross pressure of the first capacitor
v _C2 ‧‧‧cross-voltage of the second capacitor
V _Lb1 ‧‧‧Two-terminal cross-voltage of the first step-down inductor
V _Lb2 ‧‧‧Two-terminal voltage across the second step-down inductor
V _L1 ‧‧‧Two-terminal cross-voltage of the first output inductor
V _L2 ‧‧‧Two-terminal cross-voltage of the second output inductor
V _Q1 ‧‧‧Two-terminal cross-over of the first switch
V _Q2 ‧‧‧Two-terminal cross-pressure of the second switch

Other features and effects of the present invention will be apparent from the following description of the drawings, wherein: Figure 1 is a circuit diagram of a conventional buck converter; Figure 2 is a high buck converter of the present invention. FIG. 3 is a circuit diagram of the operation of the embodiment; FIG. 4 is a circuit diagram of the operation of the embodiment in the first stage; FIG. 5 is a circuit diagram of the second stage of the embodiment; Figure 7 is a circuit diagram of the operation of the embodiment in the fourth stage; Figure 8 is a circuit diagram of the operation of the embodiment in the fifth stage; Figure 9 is a circuit diagram of the operation of the embodiment in the fifth stage; FIG. 10 is a circuit diagram of the embodiment operating in the seventh stage; FIG. 11 is a circuit diagram of the embodiment operating in the eighth stage; FIG. 12 is a circuit diagram of the embodiment operating in the ninth stage. Figure 13 is a circuit diagram of the operation of the embodiment in the tenth stage; Figure 14 is a waveform diagram of the two-pulse modulation signal, the input voltage and the output voltage; Figure 15 is a flow through the first and second output inductors Current waveform Figure 16 is a current waveform diagram of the first step-down inductor and the first output inductor; Figure 17 is a current waveform diagram of the second step-down inductor and the second output inductor; Figure 18 is a stage of the present embodiment The voltage and current analysis diagrams; and FIG. 19 is a step-down ratio graph of the present embodiment and the conventional buck converter.

C1‧‧‧first input capacitor

C2‧‧‧second input capacitor

Q1‧‧‧First switch

Q2‧‧‧Second switch

Dr1‧‧‧First Input Dipole

Dr2‧‧‧Second input diode

T1‧‧‧ first transformer

T2‧‧‧second transformer

D1‧‧‧First Rectifier Diode

D2‧‧‧Secondary rectifier diode

Df1‧‧‧First flywheel diode

Df2‧‧‧Second flywheel diode

Lb1‧‧‧ first step-down inductor

Lb2‧‧‧Second step-down inductor

L1‧‧‧first output inductor

L2‧‧‧second output inductor

C _O ‧‧‧ output capacitor

2‧‧‧Control unit

V _in ‧‧‧ input voltage

V _O ‧‧‧Output voltage

Claims (8)

A high buck converter comprising: a first input capacitor having a first end of a positive terminal receiving an input voltage, and a second end; a second input capacitor having an electrical connection to the first input capacitor a first end of the second end, and a second end of the negative terminal receiving the input voltage; a first switch having a first end electrically connected to the first end of the first input capacitor, and a second end And the first switch is controlled to switch between the conductive state and the non-conductive state; a second switch has a first end, and a second end electrically connected to the second end of the second input capacitor, and the first The second switch is controlled to switch between the conducting state and the non-conducting state; a first input diode having a cathode electrically connected to the second end of the first switch, and a second end electrically connected to the second input capacitor An anode; a second input diode having a cathode electrically connected to the first end of the first switch, and an anode electrically connected to the first end of the second switch; a first transformer and a second transformer, Every transformation The device has a primary side winding and a secondary side winding, and each side winding has a first end and a second end, wherein the first end of the primary side winding of the first transformer is electrically connected to the first a second end of the switch, the first end of the primary side winding of the second transformer is electrically connected to the second end of the primary side winding of the first transformer, and the second end of the primary side winding of the second transformer is electrically connected to the second end a first end of the second switch; a first rectifying diode having an anode electrically connected to the first end of the secondary side winding of the first transformer, and a cathode; a second rectifying diode having a An anode electrically connected to the first end of the secondary side winding of the second transformer, and a cathode; a first flywheel diode having an anode electrically connected to the second end of the secondary side winding of the first transformer, and a cathode; a second flywheel diode having an anode electrically connected to the second end of the secondary side winding of the second transformer, and a cathode; a first step-down inductor having an electrical connection to the first rectifier The cathode of the polar body And a second end of the cathode electrically connected to the first flywheel diode; a second step-down inductor having a first end electrically connected to the cathode of the second rectifying diode, and an electrical connection a second end of the cathode of the second flywheel diode; a first output inductor having a first end electrically connected to the second end of the first buck inductor, and a second end; a second output inductor having a first end electrically connected to the second end of the second buck inductor, and a second end electrically connected to the second end of the first output inductor; and an output capacitor electrically connected to the first output inductor The second end is coupled to the second end of the secondary side winding of the first transformer for providing an output voltage. The high buck converter of claim 1, wherein the first and second transformers have equal turns ratios. The high buck converter of claim 1, wherein the first end of each secondary side winding is a polarity point end and the second end of each secondary side winding is a non-polar point end. The high buck converter of claim 1, wherein the first end of each primary side winding is a polarity point end and the second end of each primary side winding is a non-polar point end. The high buck converter of claim 1, wherein the first switch is an N-type power semiconductor transistor, and the first end of the first switch is a drain, and the second end of the first switch is Source. The high buck converter of claim 1, wherein the second switch is an N-type power semiconductor transistor, and the first end of the second switch is a drain, and the second end of the second switch is Source. The high buck converter according to claim 1, further comprising a control unit, wherein the control unit generates a first pulse modulation signal for switching the first switch and a second pulse modulation for switching the second switch The signal is changed, and the first pulse modulation signal has the same cycle time as the second pulse modulation signal. The high buck converter of claim 7, wherein the phase difference of the first and second pulse modulated signals is one-half of a cycle time.