CN107425719B - Power converter - Google Patents
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- CN107425719B CN107425719B CN201710839577.5A CN201710839577A CN107425719B CN 107425719 B CN107425719 B CN 107425719B CN 201710839577 A CN201710839577 A CN 201710839577A CN 107425719 B CN107425719 B CN 107425719B
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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
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac 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
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac 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
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac 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 with automatic control of output voltage or current, e.g. switching regulators
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0025—Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/0045—Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode
-
- 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
- H02M1/00—Details of apparatus for conversion
- H02M1/0048—Circuits or arrangements for reducing losses
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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
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac 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
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac 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
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac 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 with automatic control of output voltage or current, e.g. switching regulators
- H02M3/1566—Conversion of dc power input into dc power output without intermediate conversion into ac 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 with automatic control of output voltage or current, e.g. switching regulators with means for compensating against rapid load changes, e.g. with auxiliary current source, with dual mode control or with inductance variation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Abstract
The invention discloses a power converter, which is formed by cascading a front-stage DC-DC converter and a rear-stage linear voltage stabilizer, wherein the DC-DC converter receives a current sampling signal for representing the magnitude of load current, superposes the current sampling signal with a preset first reference voltage to obtain a reference signal, and generates an intermediate voltage according to the reference signal; the linear regulator receives the intermediate voltage such that a difference between an input voltage and an output voltage of the linear regulator is not less than a voltage difference requirement of the linear regulator. The change of load current is fed back to the DC-DC converter through the current sampling circuit, and then the intermediate voltage is adjusted, and finally the voltage difference of the linear voltage stabilizer and the load current are in a linear relation, so that the waste of extra power consumption during light load is reduced, and the high-efficiency conversion of the linear voltage stabilizer in a full load range is realized.
Description
Technical Field
The invention relates to the technical field of power management, in particular to a power converter.
Background
In order to meet the increasingly complex power supply requirements of electronic products and achieve more efficient power conversion, as shown in fig. 1, a low dropout regulator (LDO) is usually cascaded behind a DC-DC converter, and the advantages of high stability, good reliability, low cost, and the like are fully utilized to provide power output in the product, thereby greatly prolonging the service life of the battery.
In the LDO circuit, the Dropout voltage is the minimum input/output voltage difference that can stabilize the output of the LDO voltage, and usually a certain Dropout voltage is needed to ensure that the regulating transistor operates in the high-gain amplification region when the LDO is operating normally, as shown in fig. 2, the Dropout voltage is usually set to be greater than the maximum load voltage difference VdropmaxWhile this pressure difference is more than sufficient when the load is small, it causes additional power consumption resulting in a reduction in overall efficiency.
Disclosure of Invention
In view of the above, the present invention provides a power converter to solve the problem of efficiency reduction caused by extra power consumption of a fixed Dropout voltage during light load in the prior art.
The application provides a power converter, which is formed by cascading a front-stage DC-DC converter and a rear-stage linear voltage regulator;
the reference signal of the DC-DC converter is obtained by superposing a preset first reference voltage and a current sampling signal, the current sampling signal is used for representing the magnitude of load current, and the DC-DC converter generates an intermediate voltage according to the reference signal;
the linear regulator receives the intermediate voltage such that a difference between an input voltage and an output voltage of the linear regulator is not less than a voltage difference requirement of the linear regulator.
Preferably, the linear regulator includes an adjusting transistor and a current sampling circuit, the current sampling circuit obtains the current sampling signal by sampling a current flowing through the adjusting transistor, and one end of the adjusting transistor is connected to an output end of the power converter.
Preferably, the linear regulator further comprises a second error amplifier, one input end of the second error amplifier receives a feedback signal of the output voltage of the power converter, and the other input end of the second error amplifier receives a second reference voltage and generates a second error amplification signal to drive the adjusting transistor.
Preferably, the DC-DC converter includes a power stage circuit, a first error amplifier, and a feedback gain circuit, wherein one input terminal of the first error amplifier receives the reference signal, and the other input terminal receives a feedback signal of the intermediate voltage output by the DC-DC converter.
Preferably, the feedback gain circuit receives the intermediate voltage, and obtains a feedback signal of the intermediate voltage by multiplying the intermediate voltage by a predetermined first gain.
Preferably, the predetermined first gain is configured to satisfy a requirement that a difference between the intermediate voltage and the output voltage is not less than a voltage difference of the linear regulator.
Preferably, a difference between the input voltage and the output voltage of the linear regulator has a positive correlation with the magnitude of the load current.
The power converter provided by the invention is formed by cascading a front-stage DC-DC converter and a rear-stage linear voltage regulator, wherein the DC-DC converter receives a current sampling signal for representing the magnitude of load current, superposes the current sampling signal with a preset first reference voltage to obtain a reference signal, and generates an intermediate voltage according to the reference signal; the linear regulator receives the intermediate voltage such that a difference between an input voltage and an output voltage of the linear regulator is not less than a voltage difference requirement of the linear regulator. The change of load current is fed back to the DC-DC converter through the current sampling circuit, and then the intermediate voltage is adjusted, and finally the voltage difference of the linear voltage stabilizer and the load current are in a linear relation, so that the waste of extra power consumption during light load is reduced, and the high-efficiency conversion of the linear voltage stabilizer in a full load range is realized.
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 described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a circuit diagram of a power converter in the prior art;
FIG. 2 shows Dropout voltage and load current I in a power converter of the prior artOGraph of the relationship of (1);
fig. 3 is a circuit block diagram of a power converter according to a first embodiment of the invention;
fig. 4 is a specific circuit structure diagram of a power converter according to a second embodiment of the invention;
FIG. 5 shows an intermediate voltage V of the power converter according to the second embodiment of the present inventionPREDependent on the load current IOA graph of the variation;
FIG. 6 shows a voltage difference Vd and a load current I of a linear regulator in a power converter according to the prior art and the present inventionOThe relationship of (c) is compared to the graph.
Detailed Description
The present invention will be described below based on examples, but the present invention is not limited to only these examples. In the following detailed description of the present invention, certain specific details are set forth. It will be apparent to one skilled in the art that the present invention may be practiced without these specific details. Well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention.
Further, those of ordinary skill in the art will appreciate that the drawings provided herein are for illustrative purposes and are not necessarily drawn to scale.
Meanwhile, it should be understood that, in the following description, a "circuit" refers to a conductive loop constituted by at least one element or sub-circuit through electrical or electromagnetic connection. When an element or circuit is referred to as being "connected to" another element or element/circuit is referred to as being "connected between" two nodes, it may be directly coupled or connected to the other element or intervening elements may be present, and the connection between the elements may be physical, logical, or a combination thereof. In contrast, when an element is referred to as being "directly coupled" or "directly connected" to another element, it is intended that there are no intervening elements present.
Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is, what is meant is "including, but not limited to".
In the description of the present invention, it is to be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.
The invention is further illustrated by the following figures and examples.
Referring to fig. 3, a circuit block diagram of a power converter according to a first embodiment of the present invention is shown, the power converter is composed of a two-stage power conversion circuit, and includes a DC-DC converter 31 at a front stage and a linear regulator 32 at a rear stage, and the DC-DC converter 31 is connected to the linear regulator 32 in cascade. The reference signal of the DC-DC converter 31 is composed of a predetermined first reference voltage and a current sampling signal VloadObtained by superposition, wherein the current sampling signal VloadFor characterizing the load current IOThe DC-DC converter 31 receives a direct voltage signal VINAccording to the reference signal, converting it into an intermediate voltage VPRESaid linear voltage regulator32 receive the intermediate voltage VPREConvert it into a stable output voltage VOThe intermediate voltage V is regulated by the DC-DC converter 31PRESuch that the difference between the input voltage and the output voltage of the linear regulator 32 is no less than the voltage differential requirement of the linear regulator.
According to the embodiment of the present invention, the DC-DC converter 31 may select any one of boost, buck and buck-boost topologies, and is not limited to the buck converter disclosed in the embodiment as long as the DC-DC converter can utilize inductive energy storage to achieve the highest power conversion efficiency.
Fig. 4 is a schematic circuit diagram of a power converter according to a second embodiment of the invention. The DC-DC converter 41 specifically includes a first error amplifier EA1, a PWM modulation circuit 411, a power stage circuit 412, and a first feedback gain circuit 413, a first input (e.g., a non-inverting input) of the first error amplifier EA1 receiving a predetermined first reference voltage VREF1And said current sampling signal VloadReference signal V generated after superpositionREFA second input terminal (e.g., an inverting input terminal) receives the feedback signal V of the intermediate voltage output by the first feedback gain circuit 413FB1The output terminal of the first error amplifier EA1 outputs a first error amplified signal VEA1First error amplified signal VEA1The power stage circuit 412 is further controlled by the PWM modulation circuit 411, wherein the first feedback gain circuit 413 receives the output end intermediate voltage V of the DC-DC converter 41PREAnd generates a feedback signal V of the intermediate voltageFB1。
The linear regulator 42 specifically includes a current sampling circuit 421, a regulating transistor Q1, a second error amplifier EA2, a second feedback gain circuit 422, and an output capacitor C2. The current sampling circuit 421 is connected in parallel between a first terminal and a second terminal of the adjusting transistor Q1, a first terminal of the adjusting transistor Q1 is connected to the output terminal of the DC-DC converter 41, a second terminal of the adjusting transistor Q1 is connected to the first terminal of the output capacitor C2, a second terminal of the output capacitor C2 is connected to ground, and the second error amplifierA first input (e.g., an inverting input) of the amplifier EA2 receives a second reference voltage VREF2A second input terminal (e.g., non-inverting input terminal) receives the feedback signal V of the output voltage outputted from the second feedback gain circuit 422FB2And an output terminal connected to the control terminal of the regulating transistor Q1, wherein the second feedback gain circuit 422 receives the output voltage V of the linear regulator 42OAnd generates a feedback signal V of the output voltageFB2。
In the present embodiment, taking the adjusting transistor Q1 as a P-type MOS transistor as an example, the first terminal of the adjusting transistor Q1 is a source S, the second terminal is a drain D, and the control terminal is a gate G. Of course, those skilled in the art may also use other common devices, such as N-type MOS transistor, BJT, etc. to replace P-type MOS transistor, and make some simple adaptive changes to the circuit to achieve the same function.
The operating principle of the DC-DC converter 41 is: when the load current IOWhen the current sampling circuit 421 converts the sampled load current into a current sampling signal VloadAnd is connected to a predetermined first reference voltage VREF1The superimposed signal is inputted to the non-inverting input terminal of the first error amplifier EA1, and the first feedback gain circuit 413 receives the intermediate voltage VPREObtaining a feedback signal V of the intermediate voltage by multiplying it by a predetermined first gain beta 1FB1And the first error signal is input to the inverting input terminal of the first error amplifier EA1, and the first error amplifier EA1 performs error comparison and amplification to output a first error amplified signal VEA1First error amplified signal VEA1The PWM modulation circuit 411 further controls a power switch tube M1 and a power rectifier tube M2 in the power stage circuit 412, the power switch tube M1 and the power rectifier tube M2 are controlled by duty ratio signals to be alternately conducted, continuous inductive current is generated, and stable intermediate voltage V is output after filtering through an output capacitor C1PRE。
In this embodiment, the power rectifier M2 is an N-type MOS transistor for example, but those skilled in the art may also use other common devices, such as a diode, instead of the N-type MOS transistor, and perform some simple adaptive transformations on the circuit to achieve the same function.
The operation principle of the linear regulator 42 is as follows: when the load increases, the output voltage VOFalls, the feedback signal V of the output voltage obtained by the second feedback gain circuit 422FB2Also decreases, at which time the feedback signal V of the output voltageFB2Is less than the second reference voltage VREF2And thus the second error amplified signal V of the output of the second error amplifier EA2EA2Causing the gate voltage of the regulating transistor Q1 to drop, i.e. VGSThe absolute value of (1) is increased (the adjusting transistor is a PMOS tube) because of VIN＝-VDS+VOthen-VDSThe conduction depth of the adjusting transistor Q1 is increased, and a larger current is driven through the adjusting transistor Q1 to ensure the output voltage VOThe gradual recovery is achieved, and the gate voltage of the regulating transistor Q1 will continue to drop until the error reaches zero, and the regulation is finished when the error is zero. On the contrary, when the output voltage V isOWhen the required set value is exceeded, the drive current output from the regulating transistor Q1 is reduced, so that the output voltage V is reducedOAnd decreases.
The working principle of the power converter is as follows: when the load current IOIncrease, the current sampling signal VloadIncreased, then the reference signal V of the DC-DC converter 41REFAnd increases accordingly, if the value of the predetermined first gain β 1 is given, the reference signal VREFAnd a feedback signal V of the intermediate voltageFB1The difference value of (a) is increased, the first error amplifier EA1 passes through the PWM modulation circuit 411 after error amplification, and then the gate-source voltage of the power switch tube M1 is controlled to be increased, and the current flowing through the inductor L is increased, so that the intermediate voltage V output by the DC-DC converter 41 is increasedPREIncrease, i.e. intermediate voltage VPREDependent on the load current IOIs increased, the output voltage V is obtained from the operating principle of the linear regulator 42OWill be maintained at a stable constant voltage value, so the voltage difference Vd of the linear voltage regulator will follow the load current IOIs increased. On the contrary, when the load current IOWhen reduced, the current sampling signal VloadDown of the DC-DC converter 41Reference signal VREFAnd decreases accordingly, if the value of the predetermined first gain β 1 is given, the reference signal VREFAnd a feedback signal V of the intermediate voltageFB1Then the first error amplifier EA1 performs error comparison amplification to generate a first error amplified signal VEA1Reducing, first error amplifying signal VEA1The PWM modulation circuit 411 further controls the gate-source voltage of the power switch M1 in the power stage circuit 412 to decrease, the current flowing through the inductor L decreases, and the intermediate voltage V output by the DC-DC converter 41 decreasesPREReduced, output voltage VOWhen the voltage difference Vd of the linear voltage regulator is kept constant, the voltage difference Vd of the linear voltage regulator is reduced, and the loss of the transistor Q1 is adjusted to be that the product of the voltage difference Vd borne by two ends of the transistor and the current flowing through the transistor is reduced.
From the above analysis, the current sampling signal VloadAnd the load current IOIn proportion, the predetermined first gain β 1 is configured to satisfy such that the intermediate voltage V isPREAnd said output voltage VOIs not less than the voltage difference requirement of the linear regulator 42, so that the current sampling signal VloadComprises the following steps:
Vload＝k*IO*RON*β1 (1)
wherein R isONK is the gain of the current sampling circuit in order to adjust the on-resistance of the transistor Q1 when the driving voltage is maximum;
in the DC-DC converter 41, the intermediate voltage V is generated due to the presence of negative feedbackPREComprises the following steps:
VPRE＝(Vload+VREF1)/β1＝k*IO*RON+VREF1/β1 (2)
similarly, in the linear regulator 42, the output voltage VOComprises the following steps:
VO＝VREF2/β2 (3)
where β 2 is the second gain of the second feedback gain circuit 422;
ideal minimum input-output pressure difference VdropV is provided to ensure that the regulating transistor Q1 operates in the critical saturation regiondrop＝VGS-VTHThe current flowing through the regulating transistor Q1 is:
IO＝1/2*μ*Cox*W/L*(VGS-VTH)2 (4)
wherein W/L is the width-to-length ratio of the channel of the adjusting transistor Q1, CoxTo adjust the capacitance per unit area of the gate oxide of transistor Q1, μ is the mobility of the holes, VTHTo adjust the threshold voltage of transistor Q1. From equation (4), it can be seen that the ideal VdropAnd the load current IONot a linear relationship, so it is necessary to set a minimum value V of the input-output pressure differencedropminHere, the first gain β 1 is set such that VREF1/β1＝VO+VdropminCombining equation (2) can obtain:
Vdrop＝VPRE-VO＝Vdropmin+k*IO*RON (5)
now assume the load current IOAt maximum, one V is requireddropIs a VdropmaxFrom equations (2) (3), we can obtain:
Vdropmax＝k*IOmax*RON+VREF1/β1-VO (6)
at the same time, Vdropmin＝VREF1/β1-VO (7)
K ═ V can be obtained by combining formulae (6) and (7)dropmax-Vdropmin)/(IOmax*RON) It can be seen that k is constant, and the input-output differential pressure V isdropAnd the load current IOIn a linear relationship, and k RONIs the slope of a linear curve, and the intersection point of the linear curve and the y axis is VdropminAdjusting VdropminThe value of (A) is such that the voltage difference Vd of the linear regulator is greater than the ideal Vd over the entire load rangedropVoltage, i.e. adjusting said predetermined first gain β 1 such that said intermediate voltage V isPREAnd said output voltage VOIs not less than the linear voltage stabilizationDifferential pressure requirements of the vessel.
Referring to FIG. 5, an intermediate voltage V of the power converter according to the embodiment of the invention is shownPREDependent on the load current IOGraph of the variation. When the load is changed from light load to heavy load, the output voltage VORemains stable and has an intermediate voltage VPRELinearly increasing to ensure the voltage difference Vd of the linear voltage regulator to follow the load current IOThe increase in (c) increases linearly.
Referring to FIG. 6, a voltage difference Vd and a load current I of a linear regulator in a power converter according to the prior art and the present invention are shownOThe relationship of (c) is compared to the graph. Since the Dropout voltage is a fixed value, it is much higher than the ideal minimum Dropout voltage at light load, and the voltage difference Vd and the load current I of the linear regulator of the embodiment of the invention are substantially equal to each otherOThe voltage is in a linear relation and is very close to an ideal Dropout voltage, so that the waste of extra power consumption in light load is reduced, and the high-efficiency conversion of the linear voltage regulator in a full load range is realized.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. A power converter, the power converter is formed by cascading a front-stage DC-DC converter and a rear-stage linear voltage regulator, and is characterized in that:
the reference signal of the DC-DC converter is obtained by superposing a preset first reference voltage and a current sampling signal, the current sampling signal is used for representing the magnitude of load current, the DC-DC converter generates an intermediate voltage according to the reference signal and a feedback signal, and the feedback signal is obtained by multiplying the intermediate voltage by a preset gain and is used for representing the magnitude of the intermediate voltage;
the linear voltage regulator receives the intermediate voltage, so that the difference between the input voltage and the output voltage of the linear voltage regulator is not less than the voltage difference requirement of the linear voltage regulator, wherein the difference between the input voltage and the output voltage of the linear voltage regulator has a positive correlation with the magnitude of the load current.
2. The power converter according to claim 1, wherein the linear regulator comprises a regulating transistor and a current sampling circuit, the current sampling circuit obtains the current sampling signal by sampling a current flowing through the regulating transistor, and one end of the regulating transistor is connected to the output end of the power converter.
3. The power converter of claim 2, wherein the linear regulator further comprises a second error amplifier having one input terminal receiving a feedback signal of the output voltage of the power converter and another input terminal receiving a second reference voltage and generating a second error amplified signal to drive the regulating transistor.
4. The power converter of claim 1, wherein the DC-DC converter comprises a power stage circuit, a first error amplifier, and a feedback gain circuit, wherein one input of the first error amplifier receives the reference signal, and the other input of the first error amplifier receives a feedback signal of the intermediate voltage output by the DC-DC converter.
5. The power converter according to claim 4, wherein the feedback gain circuit receives the intermediate voltage, and obtains the feedback signal of the intermediate voltage by multiplying the intermediate voltage by a predetermined first gain.
6. The power converter of claim 5, wherein the predetermined first gain is configured to meet a voltage difference requirement such that the difference between the intermediate voltage and the output voltage is not less than the voltage difference requirement of the linear regulator.
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| CN108512282B (en) * | 2018-05-16 | 2020-10-27 | 维沃移动通信有限公司 | Power supply circuit, terminal equipment and power supply control method thereof |
| CN109802562A (en) * | 2019-03-22 | 2019-05-24 | 北京集创北方科技股份有限公司 | Voltage-regulating system |
| CN109802563A (en) * | 2019-03-22 | 2019-05-24 | 北京集创北方科技股份有限公司 | Voltage-regulating system |
| CN110071629A (en) * | 2019-06-05 | 2019-07-30 | 恒信大友（北京）科技有限公司 | A kind of high-precision low noise power supply design method |
| US11194356B2 (en) * | 2019-06-28 | 2021-12-07 | Analog Devices International Unlimited Company | Linear stage efficiency techniques for H-bridge systems |
| CN110941322A (en) * | 2019-12-06 | 2020-03-31 | 苏州浪潮智能科技有限公司 | Method and system for optimizing server power supply |
| CN111769751A (en) * | 2020-05-15 | 2020-10-13 | 海信（山东）空调有限公司 | Direct current power supply circuit and air conditioner |
| CN113035123B (en) * | 2021-02-02 | 2022-08-05 | 深圳精智达技术股份有限公司 | Multi-path homologous independent compensation driving power supply device |
| CN113285589B (en) * | 2021-04-21 | 2022-09-02 | 珠海迈巨微电子有限责任公司 | Voltage conversion circuit and electronic device |
| CN115208183A (en) * | 2022-09-13 | 2022-10-18 | 武汉精能电子技术有限公司 | LDO (Low dropout regulator) differential pressure control circuit and control method based on minimum differential pressure automatic regulation |
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| CN104092375B (en) * | 2014-07-17 | 2016-08-31 | 电子科技大学 | A kind of two-stage series connection DC-DC converter |
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| CN101340148A (en) * | 2008-08-12 | 2009-01-07 | 北京中星微电子有限公司 | Low difference voltage regulator and power source converter |
| CN102075088A (en) * | 2011-01-31 | 2011-05-25 | 复旦大学 | Method for cascade connection of switch voltage converter and linear voltage regulator |
| CN204244074U (en) * | 2014-09-22 | 2015-04-01 | 上海翱翼汽车电子有限公司 | Dc-dc |
| WO2016055240A1 (en) * | 2014-10-06 | 2016-04-14 | Zentrum Mikroelektronik Dresden Ag | Pulsed linear power converter |
| CN105490537A (en) * | 2015-12-29 | 2016-04-13 | 无锡中感微电子股份有限公司 | Power management circuit |
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