CN104600992B - DC-DC conversion circuit - Google Patents
DC-DC conversion circuit Download PDFInfo
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- CN104600992B CN104600992B CN201410775455.0A CN201410775455A CN104600992B CN 104600992 B CN104600992 B CN 104600992B CN 201410775455 A CN201410775455 A CN 201410775455A CN 104600992 B CN104600992 B CN 104600992B
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 57
- 238000004804 winding Methods 0.000 claims abstract description 9
- 239000003990 capacitor Substances 0.000 claims description 21
- 230000009466 transformation Effects 0.000 claims description 5
- 230000001131 transforming effect Effects 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 11
- 238000011217 control strategy Methods 0.000 description 10
- 238000000034 method Methods 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 3
- 230000005669 field effect Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M7/2176—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only comprising a passive stage to generate a rectified sinusoidal voltage and a controlled switching element in series between such stage and the output
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
- Rectifiers (AREA)
Abstract
The present invention provides a kind of DC DC conversion circuit, including：Sequentially connected bridge circuit, transforming circuit and secondary commutation circuit；In secondary commutation circuit, one end of the anode of the cathode of first rectification unit and the second rectification unit and the secondary side winding of transforming circuit is connected, and the cathode of the 3rd rectification unit is connected with the anode, the other end of secondary side winding and one end of controllable switch of the 4th rectification unit；One end of first capacitance and one end of the second capacitance are connected with the other end of controllable switch, the other end of first capacitance connects the anode of the first rectification unit and the 3rd rectification unit, and the other end of the second capacitance connects the cathode of the second rectification unit and the 4th rectification unit.By scheme provided by the invention, based on different scenes, by controlling being switched off and on for controllable switch, switch secondary commutation form, realize the auxiliary adjustment to output voltage, input even in wide scope change, under the scene of output voltage, ensure transfer efficiency.
Description
Technical Field
The invention relates to the field of circuits, in particular to a direct current-direct current conversion circuit.
Background
In a switching power supply, a bridge topology is generally used to perform Direct Current (DC) to direct current conversion. Specifically, the PWM bridge topology can adjust the dc gain of the topology by adjusting the duty ratio of the driving signal of the power switch, and the resonant bridge topology can adjust the dc gain of the topology by adjusting the frequency of the driving signal of the power switch, thereby realizing stable output voltage when different voltages are input, or realizing adjustment of the output voltage within a certain range. It can be seen that, in the conventional switching power supply using the bridge topology, the dc gain is adjusted by adjusting the driving signal of the power switch.
However, based on the above dc-dc conversion scheme, when the input voltage and/or the output voltage needs to be adjusted in a large range, the adjustment range of the driving signal of the power switch is correspondingly large. Both the PWM-type bridge topology and the resonant bridge topology have a relatively high-efficiency operating state, and particularly, when the input and output voltages are changed, the operating state may deviate from an ideal operating state seriously, which results in a reduction in the conversion efficiency. Therefore, the existing dc-dc conversion scheme cannot be applied to the scenes of widely varying input and output voltages.
Disclosure of Invention
The invention provides a direct current-direct current conversion circuit which is used for solving the problem that the existing direct current-direct current conversion scheme cannot be suitable for input and output voltage scenes with wide variation.
A first aspect of the present invention provides a dc-dc conversion circuit, including: the bridge circuit, the voltage transformation circuit and the secondary rectification circuit are connected in sequence; the secondary rectification circuit includes: the first rectifying unit, the second rectifying unit, the third rectifying unit, the fourth rectifying unit, the controllable switch, the first capacitor and the second capacitor; the positive electrode of the first rectifying unit is connected with the negative electrode of the second rectifying unit and one end of a secondary winding of the voltage transformation circuit, and the positive electrode of the third rectifying unit is connected with the negative electrode of the fourth rectifying unit, the other end of the secondary winding and one end of the controllable switch; one end of the first capacitor and one end of the second capacitor are both connected with the other end of the controllable switch, the other end of the first capacitor is connected to the cathodes of the first rectifying unit and the third rectifying unit, and the other end of the second capacitor is connected to the anodes of the second rectifying unit and the fourth rectifying unit.
According to a first aspect, in a first implementation manner of the first aspect, the dc-dc conversion circuit further includes: a controller connected to the controllable switch, the controller comprising: the acquisition unit is used for acquiring the current input voltage and the current output voltage of the direct current-direct current conversion circuit; the processing unit is connected with the acquisition unit and used for determining a current required rectification mode according to the input voltage and the output voltage; and the control unit is connected with the processing unit and used for controlling the controllable switch to be switched on if the current rectifying mode required to be adopted is voltage-multiplying rectification, and controlling the controllable switch to be switched off if the current rectifying mode required to be adopted is bridge-type rectification.
According to a first implementation form of the first aspect, in a second implementation form of the first aspect, the processing unit comprises: the first calculating subunit is used for calculating the ratio of the input voltage to the output voltage; the first processing subunit is used for determining that the current rectification mode required to be adopted is voltage-multiplying rectification if the ratio is smaller than a first threshold value, and otherwise, determining that the current rectification mode required to be adopted is bridge rectification; or, the first calculating subunit is configured to calculate a ratio of the output voltage to the input voltage; and the first processing subunit is configured to determine that the current rectification mode required to be adopted is voltage-doubling rectification if the ratio is greater than the reciprocal of the first threshold, and otherwise determine that the current rectification mode required to be adopted is bridge rectification.
According to the first implementation manner of the first aspect, in a third implementation manner of the first aspect, the acquisition unit is connected to the control unit, and is further configured to acquire a current output current of the dc-dc conversion circuit, so that the control unit controls the controllable switch according to the output current.
According to a third implementation manner of the first aspect, in a fourth implementation manner of the first aspect, the control unit is further configured to control the controllable switch to be turned on if it is determined that a currently required rectification manner is voltage-doubling rectification and the output current is greater than a third threshold value according to the input voltage and the output voltage, and otherwise, control the controllable switch to be turned off.
According to a second implementation manner of the first aspect, in a fifth implementation manner of the first aspect, the first threshold value is a preset value.
According to a sixth implementation form of the first aspect according to any of the second to fourth implementation forms of the first aspect, the controller further comprises: and the first adjusting unit is connected with the acquisition unit and the control unit and used for adjusting the first threshold value according to the output current so that the control unit controls the controllable switch according to the current first threshold value.
According to a seventh implementation form of the first aspect, the acquiring unit is further configured to acquire the current temperature; the controller further includes: and the second adjusting unit is connected with the acquisition unit and the control unit and used for adjusting the first threshold value according to the temperature so that the control unit controls the controllable switch according to the current first threshold value.
According to any implementation manner of the first aspect, in an eighth implementation manner of the first aspect, the first rectifying unit, the second rectifying unit, the third rectifying unit and the fourth rectifying unit include: one rectifying device, or a plurality of rectifying devices connected in parallel and/or series.
According to an eighth implementation form of the first aspect, in the ninth implementation form of the first aspect, the rectifying device is a rectifying diode or a MOSFET.
According to any of the embodiments of the first aspect, in a tenth embodiment of the first aspect, the controllable switch comprises a MOSFET, an IGBT, a BJT or a relay.
The DC-DC conversion circuit provided by the invention can correspondingly switch the form of the secondary rectification circuit of the DC-DC conversion circuit in bridge rectification and voltage-multiplying rectification by controlling the cut-off and the conduction of the controllable switch under different scenes. Under the same condition, the output voltage of the voltage-doubling rectification is usually higher than that of the bridge rectification, so that the voltage-doubling rectification circuit can be applied to the scenes of lower input voltage and higher output voltage, and on the contrary, the bridge rectification circuit can be applied to the scenes of higher input voltage and lower output voltage, so that the auxiliary regulation of the output voltage is realized by switching the secondary rectification mode, and the conversion efficiency can be still effectively ensured even under the scenes of widely-changed input and output voltages.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a dc-dc conversion circuit according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an equivalent circuit of a dc-dc conversion circuit according to an embodiment of the present invention;
fig. 3 is an equivalent circuit diagram of a dc-dc conversion circuit according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a dc-dc conversion circuit according to a second embodiment of the present invention;
fig. 5 is a schematic structural diagram of the controller according to the second embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a schematic structural diagram of a dc-dc conversion circuit according to an embodiment of the present invention, as shown in fig. 1, the circuit includes: a bridge circuit 10, a voltage transformation circuit 20 and a secondary rectification circuit 30 which are connected in sequence; the secondary rectification circuit 30 includes:
a first rectifying unit 31, a second rectifying unit 32, a third rectifying unit 33, a fourth rectifying unit 34, a controllable switch 35, a first capacitor 36, and a second capacitor 37; wherein,
the positive pole of the first rectifying unit 31 is connected with the negative pole of the second rectifying unit 32 and one end of the secondary winding 21 of the transforming circuit 20, and the positive pole of the third rectifying unit 33 is connected with the negative pole of the fourth rectifying unit 34, the other end of the secondary winding 21 and one end of the controllable switch 35;
one end of the first capacitor 36 and one end of the second capacitor 37 are both connected to the other end of the controllable switch 35, the other end of the first capacitor 36 is connected to the cathodes of the first rectifying unit 31 and the third rectifying unit 33, and the other end of the second capacitor 37 is connected to the anodes of the second rectifying unit 32 and the fourth rectifying unit 34.
Specifically, in the dc-dc conversion circuit, the bridge circuit 10 converts an input dc power into an ac power, the ac power adjusted by the transformer circuit 20 is input to the secondary rectifier circuit 30, and the ac power is converted into a dc power by the secondary rectifier circuit 30 and output.
In this embodiment, the bridge circuit 10 may specifically adopt any bridge topology capable of converting input direct current into alternating current, for example, an LLC circuit, a current-mode full bridge circuit, and the like, and the circuit form of this embodiment is not limited herein.
The controllable switch 35 may be specifically any controllable switch device capable of switching between on and off states of current in any direction, for example, the controllable switch 35 may include a Semiconductor device, such as a Metal-Oxide-Semiconductor Field effect Transistor (Metal-Oxide-Semiconductor Field-effect Transistor, abbreviated as MOSFET), an Insulated Gate Bipolar Transistor (IGBT), a Bipolar Junction Transistor (BJT), and the like, for example, the controllable switch 35 may include two MOSFETs connected in series in reverse, and specifically, since the MOSFET itself has a parasitic diode connected in parallel between a source and a drain, when the MOSFET itself is in an off state, current may still pass in one direction, and thus, two MOSFETs connected in series in reverse are used, and in the off state, preventing current in any direction from passing through; alternatively, the controllable switch 35 may also be a controllable mechanical switch, for example, a relay, or the controllable switch 35 may also be a circuit structure capable of implementing two operation states of turning on and off, and the embodiment is not limited herein.
Specifically, as shown in fig. 1, in the present embodiment, the basic structure of the secondary rectification circuit employs bridge rectification, and the intermediate connection point between one end of the secondary winding 21 of the transformer circuit 20 and the output filter capacitor, i.e., the first capacitor 36 and the second capacitor 37, is skillfully connected through the controllable switch 35, so that the secondary rectification form can be switched between bridge rectification and voltage-doubling rectification by changing the operating state of the controllable switch 35.
For better understanding of the present solution, fig. 2 and fig. 3 are schematic equivalent circuit diagrams of the dc-dc conversion circuit according to an embodiment of the present invention. Specifically, fig. 2 is an equivalent circuit diagram of the controllable switch 35 in the off state, and it can be understood that, in the case that the controllable switch 35 is off, the rectification mode of the secondary rectification circuit is bridge rectification. More specifically, fig. 3 is a schematic diagram of an equivalent circuit when the controllable switch 35 is in a conducting state, and it can be understood that, when the controllable switch 35 is in a conducting state, the rectification mode of the secondary rectification circuit is voltage-doubling rectification.
Theoretically, under the same conditions, the voltage-doubler rectified output voltage is twice the bridge rectified output voltage. Therefore, when the input voltage of the topology is high or a low output voltage is required, the secondary rectification mode can adopt bridge rectification; when the input voltage is low or a high output voltage is required, the secondary rectification mode can adopt voltage-doubling rectification. Based on the circuit provided by the embodiment, based on different scenes, the secondary rectification mode can be switched by changing the working state of the controllable switch 35, so as to realize auxiliary regulation of the output voltage, thereby adapting to the scenes of input and output voltages with wide variation.
Specifically, the operating state of the controllable switch 35 can be decision-making controlled by the operating state of the circuit, such as the input voltage, the output voltage, the current, and the like, so as to adapt to the scenes of widely varying input and output voltages. For example, when the input voltage of the topology is high and the output voltage is low, the controllable switch 35 may be controlled to be in an off state, and accordingly, the currently adopted secondary rectification manner is bridge rectification. On the contrary, when the input voltage of the topology is low and the output voltage is high, the controllable switch 35 may be controlled to be in a conducting state, and accordingly, the currently adopted secondary rectification mode is voltage-doubling rectification.
In practical applications, the controllable switch 35 may be controlled based on different scenarios in a variety of ways, for example, it may be implemented by an analog circuit, or may be implemented by a mixture of an analog circuit and a Digital circuit, or may be implemented by a programming program including a Micro Control Unit (MCU) of a peripheral circuit, a single chip, a Digital Signal Processing (DSP) chip, and the like.
In different scenes, the dc-dc conversion circuit provided by this embodiment controls the on and off of the controllable switch, so that the form of the secondary rectification circuit of the dc-dc conversion circuit can be switched between bridge rectification and voltage-doubling rectification. Under the same condition, the output voltage of the voltage-doubling rectification is usually higher than that of the bridge rectification, so that the voltage-doubling rectification circuit can be applied to the scenes of lower input voltage and higher output voltage, and on the contrary, the bridge rectification circuit can be applied to the scenes of higher input voltage and lower output voltage, so that the auxiliary regulation of the output voltage is realized by switching the secondary rectification mode, and the conversion efficiency can be still effectively ensured even under the scenes of widely-changed input and output voltages.
In order to control the operating state of the controllable switch based on different scenarios to adapt to a scenario of widely varying input and output voltages, fig. 4 is a schematic structural diagram of a dc-dc conversion circuit provided in a second embodiment of the present invention, and as shown in fig. 4, the dc-dc conversion circuit further includes:
and a controller 40 connected to the controllable switch 35 for controlling the operating state of the controllable switch 35.
Optionally, the controller 40 may determine what rectification manner needs to be adopted currently according to the input voltage and the output voltage of the dc-dc conversion circuit, and further control the working state of the controllable switch 35 according to the rectification manner that needs to be adopted currently, and accordingly, fig. 5 is a schematic structural diagram of the controller in the second embodiment of the present invention, as shown in fig. 5, the controller includes:
the acquisition unit 41 is configured to acquire a current input voltage and an output voltage of the dc-dc conversion circuit;
the processing unit 42 is connected with the acquisition unit 41 and is used for determining a current required rectification mode according to the input voltage and the output voltage;
and the control unit 43 is connected to the processing unit 42, and is configured to control the controllable switch 35 to be turned on if the currently required rectification manner is voltage-doubling rectification, and control the controllable switch 35 to be turned off if the currently required rectification manner is bridge rectification.
Specifically, the controller 40 may perform decision control on the controllable switch 35 according to a ratio of the input voltage Vin to the output voltage Vo of the dc-dc conversion circuit or a ratio of the output voltage Vo to the input voltage Vin, that is, Vin/Vo or Vo/Vin. More specifically, when Vin/Vo is larger or Vo/Vin is smaller, that is, when the input voltage of the topology is higher and the output voltage is lower, the controllable switch 35 is controlled to be in the off state, and accordingly, the currently adopted secondary rectification mode is bridge rectification. On the contrary, when Vin/Vo is smaller or Vo/Vin is larger, that is, when the input voltage of the topology is lower and the output voltage is higher, the controllable switch 35 is controlled to be in the on state, and accordingly, the currently adopted secondary rectification mode is voltage-doubling rectification. Accordingly, the processing unit 42 may specifically include:
the first calculating subunit is used for calculating the ratio of the input voltage to the output voltage; the first processing subunit is used for determining that the current rectification mode required to be adopted is voltage-multiplying rectification if the ratio is smaller than a first threshold value, and otherwise, determining that the current rectification mode required to be adopted is bridge rectification; or,
the first calculating subunit is configured to calculate a ratio of the output voltage to the input voltage; and the first processing subunit is configured to determine that the current rectification mode required to be adopted is voltage-doubling rectification if the ratio is greater than the reciprocal of the first threshold, and otherwise determine that the current rectification mode required to be adopted is bridge rectification.
Optionally, the first threshold may be a preset value, that is, the first threshold may be a fixed value. Specifically, the first threshold may be determined according to an actual application scenario and experience.
Specifically, the acquisition unit 41 may specifically acquire the current input voltage and the current output voltage of the dc-dc conversion circuit through a voltage sensor, so as to acquire the current input voltage and the current output voltage of the dc-dc conversion circuit.
In practical application, when the expected input voltage or output voltage of the dc-dc conversion circuit has a narrow variation range, the voltage with the narrow variation range may be regarded as a certain constant value, and the corresponding comparison value K is calculated according to the relationship between the preset Vin/Vo and the first threshold value R, or between the Vo/Vin and the reciprocal 1/R of the first threshold value, so that the operating state of the controllable switch 35 can be controlled only by referring to the variation condition of another voltage.
Taking the relationship between Vin/Vo and the first threshold R as an example, assuming that a power source is to adapt to a wide range of output voltages and the stable input voltage is not changed, the input voltage Vin is considered to be constant. Since the division needs to be calculated for calculating Vin/Vo, and the calculation for realizing the division by the analog circuit is complex, it is complex to determine the relationship between Vin/Vo and the first threshold R, and it is relatively simple to determine the relationship between Vo and Vin/R, specifically, since Vin is constant, the comparison value K can be calculated in advance, and at this time, K is Vin/R, and accordingly, the operating state of the controllable switch 35 can be controlled only according to the comparison result of the changed Vo and K. That is, the control strategy of the controllable switch 35 is equivalent to that only the magnitude relation between Vo and K needs to be judged: when Vo is larger than K, voltage doubling rectification is adopted to control the controllable switch 35 to be switched on, otherwise, bridge rectification is adopted to control the controllable switch 35 to be switched off.
For another example, if a power supply is to adapt to a wide range of input voltages and the output voltage is stable and constant, the output voltage Vo may be regarded as constant, so the contrast value K may be calculated in advance, and at this time, K is Vo × R, and the operating state of the controllable switch 35 may be controlled only according to the comparison result of the changed Vin and K. That is, the control strategy of the controllable switch 35 is equivalent to that only the magnitude relationship between Vin and K needs to be determined: when Vin is larger than K, bridge rectification is adopted to control the controllable switch 35 to be turned off, otherwise, voltage-doubling rectification is adopted to control the controllable switch 35 to be turned on.
It should be noted that, with reference to the above method, in the scheme of determining the rectification manner according to the relation between Vo/Vin and the reciprocal 1/R of the first threshold, the operating state of the controllable switch 35 can be controlled by referring to the variation of one of the voltages.
Optionally, in order to better adapt to the scenes of input and output voltages with wide variation, the output current of the dc-dc conversion circuit may also be used as an additional parameter in the control strategy of the controllable switch 35, and accordingly, the acquisition unit 41 is connected to the control unit 42 and is further configured to obtain the current output current of the dc-dc conversion circuit, so that the control unit 43 controls the controllable switch 35 according to the output current.
As an alternative, the output current may be directly used to participate in a control strategy for the controllable switch 35, and in particular, on the basis of the control strategy described above, further, bridge rectification is preferred when the output current is low, and voltage-doubling rectification is preferred when the output current is high. Correspondingly, the control unit 43 is specifically configured to determine, according to the input voltage and the output voltage, that the currently required rectification manner is voltage-doubling rectification, and if the output current is greater than a third threshold value, control the controllable switch to be turned on, otherwise, control the controllable switch to be turned off. The third threshold may also be a preset value, that is, the third threshold may be a fixed value. Specifically, the third threshold may be determined according to an actual application scenario and experience.
As another possible implementation, the output current may also be used to adjust the first threshold value in real time, so as to indirectly participate in the control strategy of the controllable switch 35. Accordingly, the controller 40 may further include:
and the first adjusting unit is connected with the acquisition unit 41 and the control unit 43, and is configured to adjust the first threshold value according to the output current, so that the control unit 43 controls the controllable switch 35 according to the current first threshold value.
It is understood that, in the present embodiment, the first threshold value is not a fixed constant value, but a value updated in real time according to the output current. Specifically, the strategy for adjusting the first threshold according to the output current may be implemented by a mathematical algorithm, and the embodiment does not limit the specific adjustment strategy.
Through the two implementation modes, the current working state of the controllable switch can be comprehensively considered by combining the factor of the output current on the basis of controlling the working state of the controllable switch according to the input voltage and the output voltage, so that the direct current-direct current conversion circuit can be better suitable for the scenes of input and output voltages with wide variation.
It should be noted that the foregoing embodiments may be implemented individually or in combination, for example, the output current may directly participate in the control strategy of the controllable switch, or may be used to indirectly participate in the control strategy of the controllable switch, and the present embodiment is not limited thereto.
Optionally, in order to better adapt to the scenarios of widely varying input and output voltages, more condition factors, such as temperature, etc., may be introduced to participate in the decision control of the controllable switch. Correspondingly, the collecting unit 41 is also used for collecting the current temperature; the controller 40 may further include:
and the second adjusting unit is connected with the acquisition unit 41 and the control unit 43, and is configured to adjust the first threshold value according to the temperature, so that the control unit 43 controls the controllable switch according to the current first threshold value.
According to the embodiment, the current working state of the controllable switch can be comprehensively considered by combining other influence factors on the basis of controlling the working state of the controllable switch according to the ratio of the input voltage to the output voltage, so that the direct current-direct current conversion circuit can be better suitable for the scenes of input and output voltages with wide variation.
Optionally, in order to avoid repeated switching of the working state of the controllable switch, when detecting that the working state of the controllable switch needs to be switched, the controller 40 may not perform switching control first, but detect whether the working state of the controllable switch still needs to be switched again after a certain time period, and if still needed, switch the working state of the controllable switch.
Optionally, an upper limit value and a lower limit value may be introduced into the first threshold value, so as to improve a problem that the operating state of the controllable switch is repeatedly switched due to the influence of noise. Specifically, still taking the relationship between Vin/Vo and the first threshold R, for example, if the first threshold is 10, that is, 10 is a dividing point for switching two working states of the controllable switch 35, the method for improving the noise problem may include: the first threshold value comprises a lower limit value 9 and an upper limit value 11, when Vin/Vo is smaller than 9, the controllable switch is controlled to work in a conducting state, when Vin/Vo is larger than 11, the controllable switch is controlled to work in a cut-off state, and when Vin/Vo is between 9 and 11, the working state of the current controllable switch is maintained unchanged. As a result, when the ratio continuously rises from very small to over 11, the state is switched from the on state to the off state; when noise occurs at this time, and Vin/Vo fluctuates between 10 and 12, the current working state of the controllable switch is kept unchanged. That is, as long as the amplitude of the noise does not exceed 2, the operating state of the controllable switch is not affected.
In the dc-dc conversion circuit provided by this embodiment, in different scenarios, the controller is combined with a corresponding control strategy to control the on and off of the controllable switch, so that the form of the secondary rectification circuit of the dc-dc conversion circuit can be switched between the bridge rectification and the voltage-doubler rectification, and the auxiliary regulation of the output voltage is realized by switching the form of the secondary rectification, so that the conversion efficiency can be effectively ensured even in the scenario of widely varying input and output voltages.
It should be noted that, in this embodiment, each rectifying unit may specifically be a single rectifying device, and accordingly, the positive electrode and the negative electrode of the rectifying unit, that is, the positive electrode and the negative electrode of the rectifying device, are respectively. In addition, each rectifying unit may be specifically a circuit in which a plurality of rectifying devices are connected in parallel and/or in series and then still equivalent to one rectifying device, and the rectifying unit may realize the function realized by a single rectifying diode, that is, the rectifying unit is equivalent to a single rectifying diode. That is, the first rectifying unit, the second rectifying unit, the third rectifying unit, and the fourth rectifying unit may specifically include: one rectifying device, or a plurality of rectifying devices connected in parallel and/or series, respectively, the positive and negative poles of the rectifying unit are the positive and negative poles of a single rectifying diode corresponding to the rectifying unit. Wherein the rectifying device may include, but is not limited to: rectifier diodes, MOSFETs, etc.
Specifically, in the case that the rectifying device is a rectifying diode, the positive and negative electrodes of the rectifying device are respectively the positive and negative electrodes of the rectifying diode, and in the case that the rectifying device is an MOSFET, the positive and negative electrodes of the rectifying device can be determined according to a body diode of the MOSFET. -
In addition, in the dc-dc conversion circuit, a circuit structure including at least one secondary rectification circuit as the secondary rectification circuit described in the embodiments of the present invention is all within the scope of the present patent.
In practical applications, for a wide range of input and output voltage scenarios, the existing secondary rectifier circuit can also be implemented by some non-bridge topology or multi-stage topology, for example, a combination of some basic topology and bridge circuit. However, the circuits of the above solutions are generally complex. Compared with the above scheme, in the dc-dc conversion circuit provided in this embodiment, in different scenes, the controller is combined with corresponding control strategies to control the turn-off and turn-on of the controllable switch, so that the form of the secondary rectification circuit of the dc-dc conversion circuit can be correspondingly switched between bridge rectification and voltage-doubling rectification, and the auxiliary regulation of the output voltage is realized by switching the form of the secondary rectification, so that the conversion efficiency can be effectively ensured even in the scenes of widely varying input and output voltages, and the circuit is simple and easy to implement.
Those of ordinary skill in the art will understand that: all or a portion of the steps of implementing the above-described method embodiments may be performed by hardware associated with program instructions. The program may be stored in a computer-readable storage medium. When executed, the program performs steps comprising the method embodiments described above; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (8)
1. A dc-dc conversion circuit, comprising: the bridge circuit, the voltage transformation circuit and the secondary rectification circuit are connected in sequence; the secondary rectification circuit includes:
the first rectifying unit, the second rectifying unit, the third rectifying unit, the fourth rectifying unit, the controllable switch, the first capacitor and the second capacitor; wherein,
the positive electrode of the first rectifying unit is connected with the negative electrode of the second rectifying unit and one end of a secondary winding of the voltage transformation circuit, and the positive electrode of the third rectifying unit is connected with the negative electrode of the fourth rectifying unit, the other end of the secondary winding and one end of the controllable switch;
one end of the first capacitor and one end of the second capacitor are both connected with the other end of the controllable switch, the other end of the first capacitor is connected to the cathodes of the first rectifying unit and the third rectifying unit, and the other end of the second capacitor is connected to the anodes of the second rectifying unit and the fourth rectifying unit;
the dc-dc conversion circuit further includes: a controller connected to the controllable switch, the controller comprising:
the acquisition unit is used for acquiring the current input voltage and the current output voltage of the direct current-direct current conversion circuit;
the processing unit is connected with the acquisition unit and used for determining a current required rectification mode according to the input voltage and the output voltage;
the control unit is connected with the processing unit and used for controlling the controllable switch to be switched on if the current rectifying mode required to be adopted is voltage-multiplying rectification, and controlling the controllable switch to be switched off if the current rectifying mode required to be adopted is bridge rectification;
the first adjusting unit is connected with the acquisition unit and the control unit and used for adjusting a first threshold value according to the current output current of the direct current-direct current conversion circuit acquired by the acquisition unit so that the control unit controls the controllable switch according to the current first threshold value;
the processing unit includes:
the first calculating subunit is used for calculating the ratio of the input voltage to the output voltage; the first processing subunit is configured to determine that the current rectification mode required to be adopted is voltage-multiplying rectification if the ratio is smaller than the first threshold, and otherwise, determine that the current rectification mode required to be adopted is bridge rectification; or,
the first calculating subunit is configured to calculate a ratio of the output voltage to the input voltage; and the first processing subunit is configured to determine that the current rectification mode required to be adopted is voltage-doubling rectification if the ratio is greater than the reciprocal of the first threshold, and otherwise determine that the current rectification mode required to be adopted is bridge rectification.
2. The DC-DC conversion circuit according to claim 1,
the acquisition unit is connected with the control unit and is also used for acquiring the current output current of the direct current-direct current conversion circuit so that the control unit controls the controllable switch according to the output current.
3. The DC-DC conversion circuit according to claim 2,
the control unit is specifically configured to control the controllable switch to be turned on if it is determined that a current rectification mode required to be adopted is voltage-doubling rectification and the output current is greater than a third threshold value according to the input voltage and the output voltage, and otherwise, control the controllable switch to be turned off.
4. The dc-dc conversion circuit according to claim 1, wherein the first threshold value is a preset value.
5. The dc-dc conversion circuit according to any of claims 1-3, wherein the collecting unit is further configured to collect a current temperature; the controller further includes:
and the second adjusting unit is connected with the acquisition unit and the control unit and used for adjusting the first threshold value according to the temperature so that the control unit controls the controllable switch according to the current first threshold value.
6. The dc-dc conversion circuit according to any one of claims 1 to 3, wherein the first rectifying unit, the second rectifying unit, the third rectifying unit, and the fourth rectifying unit include: one rectifying device, or a plurality of rectifying devices connected in parallel and/or series.
7. The dc-dc conversion circuit of claim 6, wherein the rectifying device is a rectifying diode or a MOSFET.
8. A dc-dc converter circuit according to any of claims 1-3, wherein the controllable switch comprises a MOSFET, an IGBT, a BJT or a relay.
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| CN201410775455.0A CN104600992B (en) | 2014-12-15 | 2014-12-15 | DC-DC conversion circuit |
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| CN201410775455.0A CN104600992B (en) | 2014-12-15 | 2014-12-15 | DC-DC conversion circuit |
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| CN108964474B (en) * | 2018-08-13 | 2020-02-11 | 三峡大学 | Three-mode rectification topological structure based on LLC resonant converter |
| CN110719031A (en) * | 2019-08-30 | 2020-01-21 | 上海瞻芯电子科技有限公司 | Constant frequency oscillation DC/DC power conversion device and power supply equipment |
| CN111446872B (en) * | 2020-04-01 | 2021-08-31 | 石家庄通合电子科技股份有限公司 | Transformer transformation ratio adjustable wide-range constant power output switching circuit |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3851182A (en) * | 1973-09-04 | 1974-11-26 | North Electric Co | Bias transformer for dual voltage input off-line converters |
| US4937731A (en) * | 1989-09-21 | 1990-06-26 | Zenith Electronics Corporation | Power supply with automatic input voltage doubling |
| CN1277487A (en) * | 1999-06-03 | 2000-12-20 | 索尼公司 | Electric source device, method and electronic apparatus |
| JP2004064813A (en) * | 2002-07-25 | 2004-02-26 | Toshiba Corp | Power circuit |
| CN101414193A (en) * | 2007-10-16 | 2009-04-22 | 鸿富锦精密工业（深圳）有限公司 | Power supply automatic switchover circuit |
| CN103780105A (en) * | 2014-01-23 | 2014-05-07 | 上海沪工焊接集团股份有限公司 | Method and system for double-voltage automatic switching control |
-
2014
- 2014-12-15 CN CN201410775455.0A patent/CN104600992B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3851182A (en) * | 1973-09-04 | 1974-11-26 | North Electric Co | Bias transformer for dual voltage input off-line converters |
| US4937731A (en) * | 1989-09-21 | 1990-06-26 | Zenith Electronics Corporation | Power supply with automatic input voltage doubling |
| CN1277487A (en) * | 1999-06-03 | 2000-12-20 | 索尼公司 | Electric source device, method and electronic apparatus |
| JP2004064813A (en) * | 2002-07-25 | 2004-02-26 | Toshiba Corp | Power circuit |
| CN101414193A (en) * | 2007-10-16 | 2009-04-22 | 鸿富锦精密工业（深圳）有限公司 | Power supply automatic switchover circuit |
| CN103780105A (en) * | 2014-01-23 | 2014-05-07 | 上海沪工焊接集团股份有限公司 | Method and system for double-voltage automatic switching control |
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