CN107134910B

CN107134910B - Switch driving unit, DC/DC conversion device and control method thereof

Info

Publication number: CN107134910B
Application number: CN201610104195.3A
Authority: CN
Inventors: 代佳乐; 曹宇; 王可志
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2016-02-25
Filing date: 2016-02-25
Publication date: 2020-07-28
Anticipated expiration: 2036-02-25
Also published as: CN107134910A

Abstract

A switch drive unit (2) of a DCDC conversion device (10) including a DCDC conversion circuit (1) including a resonance circuit and a plurality of power switching elements (Q1-Q6) that charge or discharge and rectify a resonance capacitance (Cr) in the resonance circuit, wherein the switch drive unit (2) outputs control signals (S1-S6) to the plurality of power switching elements (Q1-Q6) to control on or off of the plurality of power switching elements (Q1-Q6), and the switch drive unit (2) couples parasitic capacitances of the plurality of power switching elements (Q1-Q6) to the resonance capacitance (Cr) using a circuit including an inductive device. The switch driving unit of the invention can reduce unnecessary power consumption generated when driving the power switch element in the DCDC conversion device, reduce the number of signals for controlling the power switch element and simplify the circuit.

Description

Switch driving unit, DC/DC conversion device and control method thereof

Technical Field

The present invention relates to a switch driving unit, and more particularly, to a switch driving unit that controls on/off of a power switching element included in a DC/DC converter, a DC/DC converter using the switch driving unit, and a control method thereof.

Background

In the prior art, a switching power supply is a power supply which utilizes modern power electronics technology to control the time ratio of the switch on and off and maintain a stable output voltage, wherein a DC/DC conversion device, i.e. a DC-DC conversion circuit, is a voltage converter which effectively converts a DC input voltage into a fixed DC output voltage. Generally, DC/DC conversion devices are classified into three categories: the boost type DC/DC converter, the buck type DC/DC converter and the boost type DC/DC converter can adopt three types of control according to requirements. Specifically, the high-frequency switching operation is performed by a controllable switch (such as a MOSFET) using the energy storage characteristics of a capacitor and an inductor, and the input electric energy is stored in the capacitor or the inductor and is released to the load to supply energy when the switch is turned off. The power or voltage it outputs is related to the duty cycle, i.e. the ratio of the switch on time to the period of the whole switch.

However, with the rapid development of power electronics technology, switching power supplies are required to have higher frequencies, higher conversion efficiency, higher power density, smaller size, lower noise, and the like.

Fig. 9 shows a conventional DC/DC conversion device 100 using an LL C full bridge circuit, and as shown in fig. 9, the DC/DC conversion device 100 includes a L C resonant circuit including an inductor L r and a capacitor Cr, and a transformer including inductors Tr1 and Tr2, and the DC/DC conversion device 100 further includes 4 switching elements Q1 to Q4 constituting a LL C full bridge circuit, and energy transmitted from a primary inductor Tr1 to a secondary inductor Tr2 of the transformer can be controlled by controlling on and off of the respective switching elements Q1 to Q4.

In the DC/DC conversion apparatus 100 shown in fig. 9, the switching elements Q1 to Q4 are turned on and off by a driving unit, and the driving unit switches on/off by controlling the switching elements Q1 to Q4 at appropriate times to change the direction in which the power supply voltage is applied to the L C resonant tank, thereby realizing DC/DC voltage conversion.

Since the driving unit also needs a power supply (e.g. 50V) to form a high level signal (e.g. 10V), i.e. a voltage corresponding to the high level needs to be formed by transforming the dc power supply. As shown in fig. 9, the most common simple method is to directly connect a resistor R1 in series with the gate of the switching element Q1, so that the resistor shares a part of the voltage, and the source-gate voltage Vgs of the switching element Q1 becomes high.

However, the resistor R1 as a power consumption element shares most of the voltage, and the energy is not converted into the output power of the DC/DC converter, so that the efficiency is low.

In view of such a problem, as shown in fig. 10, patent document 1 proposes a low-loss switching element drive circuit that supplies a gate control signal to two switching elements Q1 and Q2 by using one resonant gate drive circuit, in the resonant gate drive circuit used for this, an inductor L1 is added so that the inductor L1 is connected to parasitic capacitances of Q1 and Q2 to form a resonant tank, and then by appropriately controlling the switching elements S1 to S4 in the resonant gate drive circuit, a current in the resonant tank can be charged to the parasitic capacitances of Q1 and Q2 at a desired time to turn them on.

Documents of the prior art

Patent document

Patent document 1: U.S. Pat. No. 7598792

Disclosure of Invention

Problems to be solved by the invention

However, in the above case, the control circuit of the switching element becomes complicated. As can be seen from fig. 10, in order to control the two switching elements Q1 and Q2, 4 additional switching elements S1 to S4 are required, which also means that four additional control signals are required to control the 4 switching elements.

Means for solving the problems

The present invention has been made to solve the above-mentioned problems, and a first object of the present invention is to provide a switch driving unit of a DC/DC converter, which can reduce unnecessary power consumption generated when driving a switching element in a DCDC converter.

A second object of the present invention is to provide a switch driving unit of a DC/DC converter, which can reduce the number of signals for controlling switching elements and simplify a circuit.

A switch driving unit of a DCDC converter according to a first aspect of the present invention includes a DCDC conversion circuit including a resonance circuit and a plurality of power switching elements that charge or discharge and rectify a resonance capacitance in the resonance circuit, wherein the switch driving unit outputs a control signal to the plurality of power switching elements to control on or off of the plurality of power switching elements, and the switch driving unit couples a parasitic capacitance of the plurality of power switching elements to the resonance capacitance by a circuit including an inductive device.

A switch drive unit of a DC/DC converter according to a second aspect of the present invention includes: a transformer primary side circuit connected in parallel with the resonance capacitor and having a transformer primary side inductance; and a secondary side circuit of the transformer with a driving module.

A switch driving unit of a DC/DC converter according to a third aspect of the present invention, wherein the driving module includes: a secondary inductor of the transformer inductively coupled with the primary inductor of the transformer; and a driving switching element connected in series with the secondary side inductor of the transformer, wherein a series connection circuit formed by the secondary side inductor of the transformer and the driving switching element is also connected in series with a parasitic capacitance between a gate and a source of the power switching element, and the resonant capacitance charges and discharges the parasitic capacitance by the conduction and the disconnection of the driving switching element so as to conduct and disconnect the power switching element.

A switch driving unit of a DC/DC converter according to a fourth aspect of the present invention includes a driving module connected in parallel to a resonant inductor in the resonant circuit, the driving module including a driving switching element connected in series to a parasitic capacitor between a gate and a source of the power switching element, the driving switching element being turned on and off to charge and discharge the parasitic capacitor, thereby turning on and off the power switching element.

In the switch driving unit of the DC/DC converter according to the fifth aspect of the present invention, the plurality of driving modules turn on and off the plurality of power switching elements, respectively.

In the switch driving unit of the DC/DC conversion device according to the sixth aspect of the present invention, the primary side circuit of the transformer further includes an energy storage inductor and an energy storage capacitor connected in series with the primary side inductor of the transformer.

In the switch driving unit of a DC/DC converter according to the seventh aspect of the present invention, the DCDC converter circuit is an LL C full-bridge converter circuit.

In the switch driving unit of the DC/DC converter according to the eighth aspect of the present invention, the DCDC converter circuit is an LL C half-bridge converter circuit.

In the switch driving unit of the DC/DC converter according to the ninth aspect of the present invention, the driving switching element is formed by connecting one N-channel MOS field effect transistor and one P-channel MOS field effect transistor in series.

A DCDC converter according to a tenth aspect of the present invention includes: a DCDC conversion circuit including a resonance circuit and a plurality of power switching elements that charge or discharge a resonance capacitance in the resonance circuit; the switch driving unit of any one of the first to ninth aspects, which turns on and off the plurality of power switching elements; and a controller outputting a control signal to the switch driving unit to turn on and off the driving switching element.

A method for controlling a DCDC converter device according to an eleventh aspect of the present invention includes: a DCDC conversion circuit including a resonance circuit and a plurality of power switching elements that charge or discharge and rectify a resonance capacitance in the resonance circuit; and a switch driving unit that outputs a control signal to the plurality of power switching elements and controls on or off of the plurality of power switching elements, the control method being characterized by: the switch driving unit inductively couples the parasitic capacitances of the plurality of power switching elements with the resonance capacitance; the parasitic capacitance is charged or discharged; the power switching element is turned on or off; and the turning on or off of the power switching element causes a change in direction of the voltage applied to the resonant circuit, thereby causing the resonant capacitor to be charged or discharged.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, when charging and discharging between the gate and the source of the switching element in the DCDC conversion circuit, there is no resistance-type device in the circuit through which the charge and discharge current flows, and the loss is not caused by the resistance, and therefore, the loss is low.

Further, according to the present invention, since the driving switching elements are turned on and off simultaneously, only one control signal is required to control any one of the power switching elements, and thus the number of control signals can be reduced and the circuit configuration can be simplified as compared with the technical solution proposed in patent document 1.

Drawings

Fig. 1 is a schematic block diagram showing a DC/DC converter according to the present invention.

Fig. 2 is a block diagram showing a circuit configuration of a DC/DC converter according to a first embodiment of the present invention.

Fig. 3 is a circuit diagram showing the switch driving unit according to the first embodiment of the present invention in further detail.

Fig. 4 is a schematic diagram showing an equivalent circuit of the drive module according to the first embodiment of the present invention.

Fig. 5 is a signal waveform diagram showing an operation principle of the switch driving unit according to the first embodiment of the present invention.

Fig. 6 is a block diagram showing a circuit configuration of a DC/DC converter according to a second embodiment of the present invention.

Fig. 7 is a circuit diagram showing the switch driving unit according to the second embodiment of the present invention in further detail.

Fig. 8 is a flowchart showing a control method of the DC/DC converter of the present invention.

Fig. 9 is a schematic diagram of a DC/DC conversion device of the related art.

Fig. 10 is a schematic diagram of a DC/DC conversion device of the related art.

Detailed Description

Fig. 1 is a schematic block diagram showing a DC/DC converter according to the present invention. The DCDC converter 10 of the present invention is provided with a switch drive unit 2 for controlling switching operations of the power switching elements in the DCDC converter circuit 1. By controlling these power switching elements to switch between on and off states at appropriate timings, the DCDC converter circuit 1 converts the dc voltage from the dc power supply 4 into a dc voltage of a desired magnitude and outputs the dc voltage.

As an important distinguishing feature of the present invention, the present invention also utilizes a circuit comprising an inductive device to couple the parasitic capacitance of the power switching element to the resonant capacitance of the DCDC conversion circuit 1. With this arrangement, the resonance capacitance of the DCDC converter circuit 1 can charge and discharge the parasitic capacitance of the power switching element via the switch driving unit 2. Since energy is reciprocated between the resonance capacitance of the DCDC conversion circuit 1 and the parasitic capacitance of the power switching element, wasteful loss due to the provision of an extra resistor is not lost, and hence wasteful loss can be reduced.

(embodiment I)

Next, a DC/DC converter according to a first embodiment of the present invention will be described with reference to fig. 2.

Fig. 2 is a block diagram showing a circuit configuration of a DC/DC converter according to a first embodiment of the present invention, and as shown in fig. 2, a DC/DC converter 10 includes an LL C full-bridge converter circuit 1, a switch drive unit 2, and a controller 3.

The LL C full-bridge converter circuit 1 includes a series resonant circuit including a resonant inductor L r and a resonant capacitor Cr, and is electrically connected to a dc voltage source (not shown) via a plurality of power switching elements Q1 to Q4, a primary inductor Tr1 of a transformer is connected in series to the series resonant circuit including the inductor L r and the capacitor Cr by switching on and off of the plurality of power switching elements Q1 to Q4, a converting unit of the LL C full-bridge converter circuit 1 is configured by switching on and off of the power switching elements Q5 and Q6 and an output capacitor, and the secondary inductor Tr 865 4 of the transformer is connected in series to the series resonant circuit including the inductor L r and the capacitor Cr, and an ac power output from the secondary inductor Tr2 of the transformer is rectified into a dc power in synchronization by switching on and off of the Q5 and Q6.

Regarding the specific circuit configuration of the LL C full-bridge switching circuit 1, the present invention is not different from the prior art, and is not described herein again.

The switch driving unit 2 includes driving modules 21 to 26 that respectively output gate driving signals S1 to S6 to gates of the plurality of power switching elements Q1 to Q6 to control on/off of the power switching elements Q1 to Q6. Of course, it can be understood by those skilled in the art that although the present invention is described by taking the case where each driving module outputs one gate driving signal correspondingly, a scheme may be adopted in which one driving module outputs a plurality of gate driving signals correspondingly, or even a scheme may be adopted in which all gate driving signals are output correspondingly without providing any driving module. That is, the number of the drive modules in the present invention may be arbitrary, and is not limited to 6 as exemplified in the present embodiment, or the drive modules may not be provided exclusively.

As an important inventive point of the present invention, referring to fig. 2, the switch driving unit 2 is also connected in parallel with the capacitance Cr in the series resonant circuit at points a and B. Thus, the switch driving unit 2 of the present invention also inductively couples the parasitic capacitances of the plurality of power switching elements Q1 to Q6 to the capacitance Cr in the series resonant circuit. In this regard, it will be described in detail hereinafter.

Next, a circuit configuration of the switch driving unit according to the first embodiment of the present invention will be further described with reference to fig. 3.

The switch driving unit 2 comprises an energy storage inductor L, an energy storage capacitor C, a transformer primary side inductor Tdr1 and driving modules 21-26, wherein a series circuit of the energy storage inductor L, the energy storage capacitor C and the transformer primary side inductor Tdr1 forms a primary side circuit of the transformer Tdr, the primary side circuit is connected to a resonance capacitor Cr. of the series resonance circuit in parallel at a point A and a point B, and the driving modules 21-26 form a secondary side circuit of the transformer Tdr.

Since the structures of the drive modules 21 to 26 are the same, the following description will be given only by taking the drive module 21 as an example. The driving module 21 includes a transformer secondary inductor Tdr21 connected in series to the gate-source (G-S) of the power switching element Q1, and driving switching elements Qa1 and Qb 1. The inductor Tdr21 and the driving switching elements Qa1 and Qb1 are also connected in series with each other. Wherein Qa1 is composed of P-channel MOS field effect transistor, and Qb1 is composed of N-channel MOS field effect transistor. In addition, the driving switching elements Qa1 to Qa6 or Qb1 to Qb6 of the driving modules 21 to 26 may be collectively referred to as Qa and Qb unless otherwise specified in the following and drawings.

Referring to fig. 4, the parasitic capacitance Ciss1 represents the gate-source parasitic capacitance of Q1. Therefore, although fig. 2 and the following drawings show that the parasitic capacitor Ciss1 is connected in series with the inductor Tdr21 and the driving switching elements Qa1 and Qb1, in the actual connection state, the inductor Tdr21 and the driving switching elements Qa1 and Qb1 are connected in series with the gate-source (G-S) of the power switching element Q1. Hereinafter, the parasitic capacitances Ciss1 to Ciss6 of the power switching elements Q1 to Q6 may be collectively referred to as Ciss if they are not to be distinguished from each other. In addition, the secondary side inductances Tdr21 through Tdr26 of the driving modules 21 through 26 may be collectively referred to as Tdr2 if they are not necessary to be distinguished hereinafter and in the drawings.

The gates of the driving switching elements Qa1, Qb1 are connected to the controller 3. The on/off of Qa1 and Qb1 are controlled by gate drive signals C11 and C21 output from the controller 3, respectively. The gate driving signals C11 and C21 herein correspond to the gate driving signal C1 shown in fig. 1.

The inductor Tdr21 acts as one of the secondary sides of the transformer Tdr and is inductively coupled to the primary inductor Tdr 1. The secondary side inductors Tdr 22-26 in the driving modules 22-26 are also inductively coupled with the primary side inductor Tdr 1.

In summary, the gate-source (or parasitic capacitance Ciss) of the 6 power switching elements Q1-Q6 are coupled to the resonant capacitor Cr of the series resonant circuit through a transformer Tdr by the secondary inductors Tdr 21-26 of the driving modules 21-26. That is, the parasitic capacitance Ciss is coupled to the resonant capacitance Cr on the series resonant tank via a circuit including an inductive device.

Hereinafter, the operation of the driving module according to the embodiment of the present invention will be described in detail with reference to fig. 5, mainly taking the driving module 21 as an example.

Both of the two drive switching elements Qa1 and Qb1 of the drive module 21 are controlled by a single small-sized controller 3, and perform on/off operations in synchronization with each other. Qa1 and Qb1 remain in the off state for a long period of time and are turned on synchronously for a short period of time only at the instant when Q1 needs to be turned on or off. See times t0, t1, t4, and t5 of fig. 5.

Specifically, when the resonant capacitor Cr is discharged (t0 and t4), the controller 3 instructs the driving switching elements Qa1 and Qb1 to be instantaneously turned on at the same time and then immediately turned off. At the moment of conduction, the discharge current of the resonant capacitor Cr flows through the primary side Tdr1 and the secondary side Tdr21 of the transformer, flows between the gate and the source of the Q1 (i.e., the parasitic capacitor Ciss1 of the Q1), and charges the parasitic capacitor Ciss 1. After the parasitic capacitor Ciss1 is charged, the switching elements Qa1 and Qb1 are driven to be turned off, and the charge is always kept on the parasitic capacitor Ciss1, so that the Q1 is turned on and is in a high state.

While the resonant capacitor Cr is charged (t1 and t5), the controller 3 instructs the driving switching elements Qa1 and Qb1 to be instantaneously turned on at the same time and then immediately turned off. At the moment of conduction, the resonant capacitor Cr will draw the charges of Ciss1 away through the secondary side Tdr21 and the primary side Tdr1 of the transformer, and discharge the charges to the parasitic capacitor Ciss 1. After the parasitic capacitor Ciss1 discharges, the switching elements Qa1 and Qb1 are driven to be turned off, no charging current flows into the parasitic capacitor Ciss1, the parasitic capacitor Ciss1 keeps a low charge state, so that the Q1 is turned off, and the Q1 returns to a low level state.

Although described above with reference to the driving module 21, the driving modules 22 to 26 control the on/off of the Q2 to Q6 in the same operation manner, and are not described herein again.

(second embodiment)

Although the LL C full-bridge converter circuit is described as the DCDC converter circuit according to the first embodiment, the present invention is not limited to this.

Next, a description will be given of a case where the present invention is applied to an LL C half-bridge switching circuit with reference to fig. 6 and 7, and in the following description, only a description will be given of a place different from the first embodiment.

As shown in fig. 6, in the DCDC converter 10 ' of the present invention, the conversion circuit employs a LL C half-bridge conversion circuit 1 ' formed by omitting Q3 and Q4 in fig. 2. furthermore, the connection points a and B between the switch driving units 2 ' and LL C half-bridge conversion circuits are not both ends of the resonant capacitor Cr, but are both ends of the resonant inductor L r, that is, in this embodiment, when LL C half-bridge conversion circuit 1 ' is used as the DCDC conversion circuit, the resonant inductor L r provided in the resonant circuit itself of the LL C half-bridge conversion circuit 1 ' is used as an inductive device in the present invention to couple the parasitic capacitors Ciss of the power switching elements Q1 to Q6 to the resonant capacitor Cr.

Next, a circuit configuration of a switch driving unit according to a second embodiment of the present invention will be further described with reference to fig. 7.

The difference between the present embodiment and the first embodiment is that the switch driving unit 2 'does not include the primary side circuit of the transformer Tdr, which is formed by a series circuit of the energy storage inductor L, the energy storage capacitor C, and the primary side inductor Tdr1 of the transformer, the driving modules 21 to 26 do not include the secondary side inductors Tdr21 to Tdr26 of the transformer, that is, the energy storage inductor L, the energy storage capacitor C, and the transformer Tdr are omitted in the second embodiment, and the switch driving unit 2' is directly connected to the resonant inductor L r in parallel at the point a and the point B.

The driving module 21 includes a driving switching element Qa1 and a parasitic capacitance Ciss1 of a power switching element Q1, which are connected in series to a gate-source (G-S) of a power switching element Q1, and coupled to a resonant capacitance Cr at a point A, B via a resonant inductor L r, which is an inductive device, and the controller 3 controls on/off of the driving switching elements Qa1 and Qb1 to control charging/discharging of the parasitic capacitance Ciss1 by the resonant capacitance Cr.

Since the driving modules 21 to 26 are connected in parallel, the parasitic capacitances Ciss1 to Ciss6 are connected in parallel. By controlling the on/off of the driving switching elements Qa and Qb by the controller 3, it is possible to control the resonant capacitor Cr to charge/discharge one or more or all of the parasitic capacitors Ciss1 to Ciss 6.

As for the working mode of the driving module in the second embodiment, the same as the first embodiment is used, and the description thereof is omitted.

Next, a method of controlling the DC/DC converter of the present invention will be described with reference to fig. 8. In step ST1, the switch driving unit 2 inductively couples the parasitic capacitances Ciss of the power switching elements Q1 to Q6 to the resonance capacitance Cr. Specifically, the coupling is realized by the controller 3 outputting the gate drive signals (C1 to C6) to instantaneously turn on and off the drive switching elements Qa and Qb. In step ST2, the parasitic capacitances Ciss of the power switching elements Q1 to Q6 are charged or discharged. In step ST3, the states of the power switching elements Q1 to Q6 become on or off. In step ST4, the turning on or off of the power switching elements Q1 to Q6 causes the direction of the voltage applied to the series resonant circuit to change, thereby causing the resonant capacitor Cr to be charged or discharged. The controller 3 further instructs the driving of the switching elements Qa and Qb in accordance with the charging/discharging state of the resonant capacitor Cr, and repeats the steps ST1 to ST4 to charge/discharge the parasitic capacitors Ciss of Q1 to Q6, thereby forming one cycle.

In the above-described configuration of the present invention, when the gate-source electrodes (parasitic capacitances Ciss) of Q1 to Q6 are charged and discharged, there is no resistance device in the circuit through which the charge and discharge current flows, and the energy is not lost due to the resistance and is temporarily stored in the storage device such as an inductor and a capacitor, so that the loss is low. Since the parasitic capacitance is very small, the current to flow through the two switching elements Qa and Qb is much smaller than the currents flowing through Q1 to Q6, and the size of the switching elements Qa and Qb is much smaller than Q1 to Q6, so that no loss is caused.

On the other hand, although it is shown in fig. 3 and 7 that two gate driving signals are required for each driving module (C11 and C12 of the driving module 21, C21 and C22 of the driving module 22, C31 and C32 of the driving module 23, C41 and C42 of the driving module 24, C51 and C52 of the driving module 25, and C61 and C62 of the driving module 26), since the driving switching elements Qa and Qb are always turned on and off at the same time, only one control signal is actually required to control one of the power switching elements Q1 to Q6, which is simpler than the related art.

In the drive unit 2 according to the first embodiment, the capacitive and inductive components L and C are provided, so that energy flowing between the parasitic capacitance Ciss and the resonant capacitance Cr can be temporarily stored, and the phase of current fluctuation can be adjusted while the drive unit performs a protective function.

In the above description, an LL C full-bridge/half-bridge rectifier circuit including a series resonant circuit was described as an example, but it will be understood by those skilled in the art that the present invention is not limited thereto, and any converter circuit including a resonant circuit and performing voltage conversion and rectification by using periodic change of current can be applied to the present invention.

In the above description, two mosfet transistors having different channel types are used as the driving switching elements Qa and Qb, respectively, so that it is possible to ensure that the current cannot pass in both directions when the driving switching elements Qa and Qb are turned off. It will be understood by those skilled in the art that the present invention is not limited thereto, and the present invention may use the same channel type of mosfet, or other switching elements other than the mosfet, or only one switching element, as long as it can block the current from flowing into or out of the parasitic capacitance Ciss.

The present invention is susceptible to various embodiments and modifications without departing from the broad spirit and scope of the present invention. The above embodiments are merely illustrative of the present invention, and do not limit the scope of the present invention. That is, the scope of the present invention is shown by the scope of claims, not by the above embodiments. Various modifications made within the scope of the claims and within the scope of the equivalent meaning to the claims are also considered to be within the scope of the present invention.

Description of the reference symbols

1. 1' DCDC conversion circuit

2. 2' switch drive unit

3 controller

10. 10' DC/DC conversion device

21-26 driving module

Cr resonant capacitor

L r resonant inductor

Q1-Q6 power switch element

Qa, Qb drive switching element

Tdr1 transformer primary side inductance

Secondary side inductor of Tdr 21-Tdr 26 transformer

L energy storage inductor

C energy storage capacitor

Gate driving signals of S1 to S6, C1 to C6, C11, C12, C21, C22, C31, C32, C41, C42, C51, C52, C61 and C62.

Claims

1. A switch driving unit of a DCDC conversion device including a DCDC conversion circuit including a resonance circuit having at least one resonance capacitor and one resonance inductor and a plurality of power switching elements that charge or discharge and rectify the resonance capacitor, characterized in that:

the switch driving unit is connected in parallel with the resonant capacitor or the resonant inductor, and outputs a control signal to the plurality of power switching elements to control the plurality of power switching elements to be turned on or off,

the switch driving unit couples a parasitic capacitance formed between the gates and the sources of the plurality of power switching elements to the resonance capacitance using a circuit including an inductive device.

2. The switch drive unit of claim 1, comprising:

a transformer primary side circuit connected in parallel with the resonance capacitor and having a transformer primary side inductance; and

and a secondary side circuit of the transformer with a driving module.

3. The switch drive unit of claim 2, wherein the drive module comprises:

a secondary inductor of the transformer inductively coupled with the primary inductor of the transformer; and

a drive switching element connected in series with the secondary inductor of the transformer,

the series circuit of the secondary side inductance of the transformer and the driving switching element is also connected in series with a parasitic capacitance between the gate and the source of the power switching element,

the resonance capacitor charges and discharges the parasitic capacitor by turning on and off the driving switching element to turn on and off the power switching element.

4. Switch drive unit as claimed in claim 1,

comprising a drive module connected in parallel with a resonant inductance in said resonant circuit,

the driving module includes a driving switching element,

the driving switching element is connected in series with a parasitic capacitance between a gate and a source of the power switching element,

5. Switch drive unit as claimed in claim 4,

the driving modules are connected in parallel and are used for respectively conducting and disconnecting one or more of the power switching elements.

6. Switch drive unit as claimed in claim 2,

the primary side circuit of the transformer further comprises an energy storage inductor and an energy storage capacitor which are connected with the primary side inductor of the transformer in series.

7. Switch drive unit as claimed in claim 1,

the DCDC conversion circuit is an LL C full-bridge conversion circuit.

8. Switch drive unit as claimed in claim 1,

the DCDC conversion circuit is an LL C half-bridge conversion circuit.

9. Switch drive unit as claimed in any one of the claims 2 to 4,

the driving switch element is formed by connecting an N-channel MOS field effect transistor and a P-channel MOS field effect transistor in series.

10. A DCDC conversion apparatus, comprising:

a DCDC conversion circuit including a resonance circuit and a plurality of power switching elements that charge or discharge a resonance capacitance in the resonance circuit;

the switch drive unit according to any one of claims 1 to 9, which turns on and off the plurality of power switching elements; and

a controller outputting a control signal to the switch driving unit to turn on and off the driving switching element.

11. A control method of a DCDC conversion apparatus, the DCDC conversion apparatus comprising:

a DCDC conversion circuit including a resonance circuit having at least one resonance capacitor and one resonance inductor, and a plurality of power switching elements that charge or discharge and rectify the resonance capacitor; and

a switch driving unit connected in parallel to the resonant capacitor or the resonant inductor and outputting a control signal to the plurality of power switching elements to control the plurality of power switching elements to be turned on or off,

the control method is characterized in that:

the switch driving unit inductively couples a parasitic capacitance formed between the gates and the sources of the plurality of power switching elements with the resonance capacitance;

the parasitic capacitance is charged or discharged;

the power switching element is turned on or off; and

the switching on or off of the power switching element causes a change in the direction of the voltage applied to the resonant circuit, which in turn causes the resonant capacitor to be charged or discharged.