CN116317482A - Switch circuit control method, switch circuit control chip and switch circuit - Google Patents

Switch circuit control method, switch circuit control chip and switch circuit Download PDF

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Publication number
CN116317482A
CN116317482A CN202310530980.5A CN202310530980A CN116317482A CN 116317482 A CN116317482 A CN 116317482A CN 202310530980 A CN202310530980 A CN 202310530980A CN 116317482 A CN116317482 A CN 116317482A
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signal
current
unit
switching circuit
mode
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CN116317482B (en
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林思聪
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Fanta Semiconductor Technology Hangzhou Co ltd
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Fanta Semiconductor Technology Hangzhou Co ltd
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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
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/04—Measuring peak values or amplitude or envelope of ac or of pulses
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/175—Indicating the instants of passage of current or voltage through a given value, e.g. passage through zero
    • 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
    • H02M1/0009—Devices or circuits for detecting current in a converter
    • 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dc-Dc Converters (AREA)
  • Rectifiers (AREA)

Abstract

The embodiment of the invention provides a switching circuit control method, a switching circuit control chip and a switching circuit, wherein the switching circuit control method is used for controlling the switching circuit and comprises the following steps of: acquiring a reference current signal of an inductance of the switching circuit, wherein the reference current signal represents an input current value of the switching circuit; correcting the reference current signal to obtain a peak value reference signal; acquiring an inductor current sampling signal representing the inductor current; when the inductance current sampling signal reaches the peak value reference signal, a switching tube of the switching circuit is controlled to be disconnected; and calculating a timing time length, and controlling the switching tube to be closed at least according to the timing time length. The control method is a peak control method, and can realize control of the switch circuit.

Description

Switch circuit control method, switch circuit control chip and switch circuit
Technical Field
The present invention relates to the field of circuit control, and in particular, to a switching circuit control method, a switching circuit control chip, and a switching circuit.
Background
Because of the wide use of switching power supplies, harmonic current pollution and reactive power increase of the power grid are caused in order to reduce non-sinusoidal current waveform distortion generated by the switching power supplies; the industry establishes standards, and requires capacitive load electric equipment with power more than 75W, and a correction circuit for correcting the load characteristic of the capacitive load electric equipment is added, so that the alternating current circuit current is forced to track the instantaneous change track of the alternating current voltage waveform, the current and the voltage are kept in the same phase, and the system is in a pure resistive technology, namely a Power Factor Correction (PFC), namely a circuit current waveform correction technology. Besides the correction of the current waveform, the PFC technology also solves the in-phase problem of voltage and current.
The PFC controller has many control methods including an average current type, a peak control type, a single cycle control type, and the like, and various methods have advantages and disadvantages. Generally, different control strategies and working modes are selected according to the output power. For example, for >250W applications, CCM (Continuous Conduction Mode: inductor current continuous mode: simply continuous mode) operation mode is typically employed, which typically employs average current control. The CCM has the advantages that THD is small in heavy load and current stress is small; disadvantages include high THD at light load, low efficiency, etc., especially low efficiency at high pressure inputs. For <250W applications, CRM (critical-conduction mode: critical mode for short) or DCM (Discontinuous Conduction Mode: inductor current interrupt mode: interrupt mode for short) modes are generally used, and CRM and DCM operation modes generally use peak control or fixed Ton control. The CRM has the advantages of simple control, convenient design, no conduction loss of a switch and non-decisive choice of a boost diode; the disadvantage is that there are potential EMI problems due to frequency variations, a precisely designed input filter is required, and there are problems of poor efficiency under light load.
Disclosure of Invention
In view of the above, the embodiment of the invention provides a switching circuit control method, a switching circuit control chip and a switching circuit, wherein the control method is a novel peak control mode to realize the control of the switching circuit.
In order to solve the technical problems, the application adopts the following technical scheme:
a switching circuit control method for peak control of a switching circuit, the control method comprising the steps of: acquiring a reference current signal of an inductance of the switching circuit, wherein the reference current signal represents an input current value of the switching circuit; correcting the reference current signal to obtain a peak value reference signal; acquiring an inductor current sampling signal representing the inductor current; when the inductance current sampling signal reaches the peak value reference signal, a switching tube of the switching circuit is controlled to be disconnected; and calculating a timing time length T, and controlling the switching tube to be closed at least according to the timing time length. The control method comprises the steps of firstly obtaining a reference current signal, correcting the reference current signal to obtain a peak value reference signal of the inductive current, and controlling a switching tube to be disconnected according to the peak value reference signal and an inductive current sampling signal; and the switching tube is controlled to be closed in a timing mode, so that the control of the switching circuit is realized.
Furthermore, the invention can select different working modes according to the electric signals (such as the first electric signal, the second electric signal and the input alternating voltage) related to the input current value, thereby realizing that the inductance current of the switching circuit works in CCM/CRM/DCM by adopting the brand new control method.
The switching circuit control chip is suitable for carrying out peak control on a switching circuit and comprises a reference current generating unit, a current signal correcting unit, an inductance current acquiring unit and a switching-on signal control unit; the reference current generating unit is electrically connected with the current signal correcting unit, the current signal correcting unit is electrically connected with the opening signal control unit, and the inductance current obtaining unit is electrically connected with the opening signal control unit; the reference current generation unit is used for generating a reference current signal of the inductance of the switching circuit, and the reference current signal represents the input current value of the switching circuit; the current signal correction unit is used for correcting the reference current signal to obtain a peak value reference signal; the induction current acquisition unit is used for acquiring induction current sampling signals representing the induction current; the turn-on signal control unit is used for generating a first control signal for enabling a switching tube of the switching circuit to be disconnected when the inductance current sampling signal reaches the peak value reference signal. The switch circuit control chip is provided with a current signal correction unit, can correct the reference current signal generated by the reference current generation unit to obtain a peak value reference signal, and can control the peak value current by using the corrected peak value reference signal, thereby realizing the control of the switch circuit.
A switching circuit comprises a switching unit, an output voltage sampling unit, an input voltage sampling unit, a current sampling unit, an inductance current zero-crossing sampling unit and the switching circuit control chip; the output voltage sampling unit is electrically connected with the output end of the switch unit and is used for sampling an output voltage sampling signal; the input voltage sampling unit is electrically connected with the input end of the switch unit and is used for sampling an input voltage sampling signal; the output voltage sampling unit and the input voltage sampling unit are also electrically connected with a reference current generating unit of the switch circuit control chip; the current sampling unit is electrically connected with the switch unit and is used for sampling an inductance current sampling signal of the switch unit; the inductance current zero-crossing sampling unit is electrically connected with the switching unit and is used for acquiring an inductance current zero-crossing signal of the inductance of the switching unit; the current sampling unit is electrically connected with the inductance current acquisition unit of the switch circuit control chip; the inductance current zero-crossing sampling unit is electrically connected with the turn-off signal control unit of the switch circuit control chip; the switch circuit control chip is at least used for controlling the switch unit to work according to the output voltage sampling signal, the input voltage sampling signal, the inductance current sampling signal and the inductance current zero crossing signal. The switching circuit can work under the control of the switching circuit control chip.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art, but shall fall within the scope of protection of the present application.
FIG. 1 is a schematic diagram of a boost-PFC circuit according to the prior art;
fig. 2 is a schematic diagram of a switching tube control flow in a switching circuit control method according to an embodiment of the present invention;
FIG. 3 is a schematic flow chart of mode selection in a switching circuit control method according to an embodiment of the present invention;
FIG. 4 is a schematic waveform diagram of a first mode selection according to an embodiment of the present invention;
FIG. 5 is a schematic waveform diagram illustrating a second mode selection according to an embodiment of the present invention;
FIG. 6 is a schematic waveform diagram illustrating a third mode selection according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of current reference signals in various operation modes according to an embodiment of the present invention;
FIG. 8 is a schematic waveform diagram of a driving signal of a switching tube in each working mode according to an embodiment of the present invention;
FIG. 9 is a schematic block diagram of a control chip for a switch circuit according to an embodiment of the present invention;
FIG. 10 is a schematic block diagram of a switch circuit control chip according to another embodiment of the present invention;
FIG. 11 is a schematic block diagram of a switch circuit control chip according to another embodiment of the present invention;
FIG. 12 is a schematic block diagram of a switch circuit control chip according to another embodiment of the present invention;
fig. 13 is a schematic diagram of a first mode control unit according to an embodiment of the present invention
Fig. 14 is a schematic diagram of a second mode control unit according to an embodiment of the present invention;
fig. 15 is a schematic diagram of an on signal control unit according to an embodiment of the present invention;
fig. 16 is a schematic diagram of a shutdown signal control unit according to an embodiment of the present disclosure;
fig. 17 is a schematic diagram of a switching circuit according to an embodiment of the present invention.
Detailed Description
For a better understanding of the technical solution of the present invention, the following detailed description of the embodiments of the present invention refers to the accompanying drawings.
It should be understood that the described embodiments are merely some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Electrical connections include direct electrical connections and indirect electrical connections.
It should be understood that the term "and/or" as used herein is merely one way of describing an association of associated objects, meaning that there may be three relationships, e.g., a and/or b, which may represent: the first and second cases exist separately, and the first and second cases exist separately. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.
The topology of the switch circuit is a BOOST circuit, a totem pole bridgeless BOOST PFC circuit, a flyback circuit and the like. The switching circuit at least comprises a switching tube and an inductor, and a common single-phase boost circuit is shown in fig. 1, and a power conversion function or a power factor correction function is realized by controlling the switching tube Q.
In a first aspect, an embodiment of the present application provides a switching circuit control method for controlling a switching circuit, where the control method is a peak control method, as shown in fig. 2, and the control method includes the following steps:
s21, acquiring a reference current signal: that is, the reference current signal I of the inductance of the switching circuit is obtained ref-ac Reference current signal I ref-ac Input current value I characterizing a switching circuit in 。
S22, correcting the reference current signal, namely, the reference current signal I ref-ac And correcting to obtain a peak reference signal so as to perform peak control.
S23, an inductor current sampling signal, i.e., an inductor current sampling signal Vcs characterizing the inductor current, is obtained.
S24, controlling the switching tube to be disconnected, and particularly, controlling the switching tube of the switching circuit to be disconnected when the inductance current sampling signal reaches the peak value reference signal. That is, the peak control method is adopted for control.
S25, controlling the switch tube to be closed. Specifically, a timing time length T is calculated, and the switching tube is controlled to be closed at least according to the timing time length.
The control method described above is applicable to both continuous mode and discontinuous mode. The peak reference signal in discontinuous mode is referred to as the first peak reference signal and is denoted as I CSPK-DCM The method comprises the steps of carrying out a first treatment on the surface of the The peak reference signal in continuous mode is referred to as the third peak reference signal and is denoted as I CSPK - CCM 。
When the switching circuit operates in the discontinuous mode, the first peak reference signal I CSPK-DCM Greater than the reference current signal I ref-ac Twice as many as that of I CSPK-DCM ＞2*I ref-ac ；
In the intermittent mode, step S25: calculating a timing time length, and controlling the switching tube to be closed at least according to the timing time length comprises the following steps:
when the inductor current zero crossing signal is detected, the timing is started, when the first time length (T off-dcm ) When the switching tube is in the open state, an opening signal of the next switching period is generated, and the switching tube is controlled to be closed; wherein the first time length T off-dcm =0.5*I CSPK-DCM *T zcd /I ref-ac -T zcd The method comprises the steps of carrying out a first treatment on the surface of the Wherein I is CSPK-DCM For the first peak reference signal, T zcd In the intermittent mode, the switching tube is turned on until the time length from the first detection of the zero crossing signal of the inductance current in the period; i ref-ac Is the reference current signal.
When the switching circuit is operated in the continuous mode, the third peak reference signal I CSPK-CCM For reference current signal I ref-ac Double the difference between the inductor valley current Irv in continuous mode, i.e.) CSPK-CCM =2*I ref-ac -Irv；
In the continuous mode, step S25: calculating a timing time length, and controlling the switching tube to be closed at least according to the timing time length comprises the following steps:
when the inductor current sampling signal reaches the third peak reference signal, the switch is opened and begins to time, when reaching the second time period T off-ccm When the switching tube is in the open state, an opening signal of the next switching period is generated, and the switching tube is controlled to be closed; wherein the second time period T off-ccm =vin Ts/Vo; wherein Ts is a fixed value set; vin is an input voltage sampling signal of the switching circuit; vo is the output voltage sampling signal of the switching circuit.
When the switch circuit is operating in the critical mode, the peak control method of the critical mode in the prior art can be referred to, and the peak reference signal in the critical mode is referred to as the second peak reference signal and is denoted as I CSPK - CRM The method comprises the steps of carrying out a first treatment on the surface of the When the inductance current sampling signal reaches a second peak value reference signal in the critical mode, the switching tube is controlled to be disconnected; when the zero-crossing signal of the inductance current is detected, the switching tube is controlled to be closed.
In a second aspect, embodiments of the present application provide a method for selecting a continuous mode, a critical mode, and an intermittent mode, for controlling a switching tube to operate a switching circuit in a suitable operation mode to improve efficiency, as shown in fig. 3, the method includes the following steps:
s11, acquiring a first electric signal: obtaining input current I characterizing a switching circuit in A first electrical signal of average value; the switch circuit can be at least a BOOST-PFC circuit and a flyback circuit, wherein the BOOST-PFC circuit comprises a single-channel BOOST-PFC circuit, a totem pole bridgeless BOOST-PFC circuit or a Dual BOOST bridgeless PFC circuit And a PFC circuit. The average value of the input current is generally determined by the input power and the input voltage of the switching circuit, and the input current can be controlled to follow the change of the input voltage through the switching tube of the switching circuit so as to improve the PF value of the circuit. The first electrical signal may be an input current average value, an input current peak value, or the like, or may be a signal related to the input current average value, the input current peak value, or the like. Since the input current is related to the switching frequency, the first electrical signal may be a frequency-related electrical signal.
S12, comparing: the first electrical signal is compared with a first reference signal CCMref and a second reference signal CRMref. Wherein the first reference signal CCMref is greater than the second reference signal CRMref; the signal may be preset by software and/or hardware.
S13, selecting an operating mode: the switching circuit is controlled to operate in a critical mode (CRM), continuous mode (CCM), or discontinuous mode (DCM) according to the comparison result of step S12.
The embodiment adopts a brand new control method to realize that the inductance current of the switching circuit works in three modes of CCM/CRM/DCM, and the method can lead the switching circuit to truly work in the CRM mode instead of working as an intermediate state when the modes are switched, thereby being capable of selecting different working modes according to the magnitude of the input current and realizing the best performance.
In one embodiment, the first electrical signal is positively correlated, e.g., proportional, to the average value of the input current, in this embodiment, the first electrical signal is e.g., I in-ac As shown. As shown in FIG. 4, in one power frequency period, when the first electric signal I in-ac When the reference signal CCMref is larger than the first reference signal CCMref, the control switch circuit works in a continuous mode; when the first electric signal I in-ac When the first reference signal CCMref is smaller than the second reference signal CRMref and larger than the first reference signal CRMref, the control switch circuit works in a critical mode; when the first electric signal I in-ac And when the voltage is smaller than the second reference signal CRMref, the control switch circuit works in a discontinuous mode.
Under different input voltages and output loads, the input current will also change, the first electrical signal I in-ac Also, as shown in fig. 4, the first electrical signal is proportional to the input current, and if the output load is unchanged, the higher the input voltage, the smaller the input current; in a power frequency period, the input current is sine wave, and the first electric signal I in-ac Also sinusoidal. In this embodiment, in the power frequency period, if the first electrical signal I in-ac When the voltage is larger than the first reference signal CCMref, the switching circuit is controlled to work in a CCM mode, so that ripple waves are reduced, and current stress is reduced; if the first electric signal I in-ac The switching circuit is controlled to work in a CRM mode when the switching circuit is smaller than a first reference signal CCMref and larger than a second reference signal CRMref, so that the switching loss of a switching tube of the switching circuit is reduced; if the first electric signal Iin-ac is smaller than the second reference signal CRMref, the switching circuit is controlled to work in a DCM mode, and the switching frequency is reduced to reduce the switching loss. In this embodiment, in one power frequency period, the switching circuit may select different working modes according to the magnitude of the first electrical signal, and the switching circuit may actually work in the CRM mode, instead of working the CRM mode only as an intermediate state, so as to achieve an optimal efficiency design.
In one embodiment, as shown in FIG. 5, the first electrical signal may be set to be positively correlated with the peak value of the input current average, e.g., I in-ac-pk Shown; the steps S12 and S13 are specifically as follows:
when the first electric signal I in-ac-pk When the voltage is larger than a first reference signal CCMref, controlling the switching circuit to work in a continuous mode in the power frequency period, so that ripple waves are reduced, and current stress is reduced;
when the first electric signal I in-ac-pk When the voltage is smaller than the first reference signal CCMref and larger than the second reference signal CRMref, the switching circuit is controlled to work in a critical mode in the power frequency period so as to reduce the switching loss of a switching tube of the switching circuit;
When the first electric signal I in-ac-pk And when the frequency is smaller than the second reference signal CRMref, controlling the switching circuit to work in an intermittent mode in the power frequency period so as to reduce the switching frequency and the switching loss.
In this embodiment, in one power frequency period, the operation modes of the whole power frequency period are selected according to the peak value of the average value of the input current, that is, the three operation modes of CCM/CRM/DCM only include one operation mode of CCM, CRM and DCM in one power frequency period, and the three operation modes are freely switched according to the peak value of the average value of the input current. Compared with the single control mode in the prior art, the efficiency is higher. However, because the working mode is unchanged in one power frequency period, compared with a control method with multiple working modes in one power frequency period, the control method has the advantages of slightly lower efficiency and simpler control mode.
In one embodiment, as shown in FIG. 6, the first electrical signal is still set to be positively correlated with the peak value of the input current average, e.g., I in-ac-pk Shown; steps S12 and S13 are specifically as follows;
when the first electric signal I in-ac-pk When the voltage is larger than a first reference signal CCMref, controlling the switching circuit to work in a continuous mode in the power frequency period, so that ripple waves are reduced, and current stress is reduced;
When the first electric signal I in-ac-pk When the frequency is smaller than the second reference signal CRMref, the switching circuit is controlled to work in an intermittent mode in the power frequency period, so that the switching frequency is reduced, and the switching loss is reduced;
and when the first electric signal I in-ac-pk When the input current average value is smaller than the first reference signal CCMref but larger than the second reference signal CRMref, further judging the magnitude of the input current average value and the magnitude of the second reference signal CRMref in a power frequency period; when the average value of the input current is larger than the second reference signal CRMref, the switching circuit is controlled to work in a critical mode, and when the average value of the input current is smaller than the second reference signal CRMref, the switching circuit is controlled to work in an intermittent mode. That is, when the peak value of the average value of the input current is at the intermediate value, the working mode in the power frequency period is further determined according to the average value of the input current, and when the average value of the input current is greater than the second reference signal CRMref, the switching circuit is controlled to work in the critical mode so as to reduce the switching loss of the switching tube of the switching circuit; when the average value of the input current is smaller than the second reference signal CRMref, the switch circuit is controlled to operate in the discontinuous mode to reduceLow switching frequency, reduced switching losses.
In this embodiment, the three modes of operation CCM/CRM/DCM include the conditions of CCM, CRM/DCM combination and DCM in one power frequency cycle. The three modes of operation are freely switched according to the peak magnitude of the input average current. Compared with the control modes of the embodiment shown in fig. 4 and 5, the control method provided by the embodiment balances the advantages and disadvantages of the two, has slightly higher efficiency than the embodiment shown in fig. 5, and is slightly complicated to control; compared to fig. 4, the control is simple but the efficiency is slightly lower.
In another embodiment, the operating mode of the switching circuit may also be selected by inputting the magnitude of the ac voltage. Specifically, when the input ac voltage is set to Highline, the switching circuit is controlled to operate in a critical mode or an intermittent mode, so as to reduce switching loss and improve efficiency and EMI. When the input alternating voltage is set as Lowline, the switching circuit is controlled to work in a continuous mode, a critical mode or an intermittent mode at the moment so as to reduce current stress and improve efficiency. In general, highline represents an effective value of the input ac voltage of 175V or more, and lowline represents an effective value of the input ac voltage of less than 175V.
Further, in the above embodiment, the different first electric signal selections may correspond to different first reference signals and second reference signals, and the first and second reference signals may be freely set. In addition, the continuous mode, the critical mode and the discontinuous mode can all adopt a peak current type control mode to control the switching circuit, and the specific control mode can refer to the switching circuit control method provided in the first aspect of the application. Specifically, the switching circuit control method further comprises the steps of:
Obtaining a reference current signal I of the inductance of the switching circuit ref-ac The reference current signal is proportional to the input current average; the reference current signal is determined by the input voltage value and the input power, which in turn is related to the output voltage value, so in one embodiment, as shown in FIG. 10, the reference current signal I can be obtained by taking the input voltage sample Vin and the output voltage sample Vo ref-ac 。
Obtaining an inductor current sampling signal V representing the inductor current cs The method comprises the steps of carrying out a first treatment on the surface of the Specifically, the inductor current sampling signal V can be obtained by sampling the inductor current or the switching tube current cs 。
Referring to FIG. 8, the first peak reference signal Icspk-CCM in discontinuous mode is greater than the reference current signal I ref-ac Is twice and less than or equal to the second reference signal I CRM-DCM The method comprises the steps of carrying out a first treatment on the surface of the Wherein the second reference signal is a preset threshold value and is positively correlated with the second reference signal CRMref;
the second peak reference signal Icspk-CRM in critical mode is the reference current signal I ref-ac Twice as many as (2);
the third peak reference signal Icspk-CCM in continuous mode is the reference current signal I ref-ac Is twice the difference between the inductive valley current Irv in continuous mode; wherein Irv may sample V by a sample/hold circuit cs Obtained by the current valley of (a).
Referring to the Vrst signal of fig. 8, in the discontinuous mode, when the inductor current sampling signal reaches the first peak reference signal, a turn-off signal Vrst is generated to control a switching transistor of the switching circuit to be turned off;
in a critical mode, when the inductance current sampling signal reaches the second peak value reference signal, the switching-off signal is generated, and the switching tube is controlled to be switched off;
and in a continuous mode, when the inductance current sampling signal reaches the third peak value reference signal, the turn-off signal is generated, and the switch tube is controlled to be turned off.
The peak current type control provided by the embodiment can realize the turn-off of the switching tube. Further, the embodiment of the application further provides a control method for switching on a switching tube, that is, the control method for a switching circuit further includes the following steps to generate a switching-on signal Vset of the switching tube, so as to realize the control of the switching tube on: refer to the Vset signal of fig. 8.
Detecting an inductance current zero crossing signal Vzcd;
under a critical mode, when the zero crossing signal of the inductance current is detected, an opening signal is generated, and the switching tube is controlled to be closed;
in the intermittent mode, when the zero-crossing signal of the inductance current is detected, the timing is started, and when the first time length T is reached off-dcm When the switching tube is in a closed state, the switching tube is controlled to be in a closed state; wherein the first time length T off-dcm =0.5*I CSPK-DCM *T zcd /I ref-ac -T zcd The method comprises the steps of carrying out a first treatment on the surface of the Wherein I is CSPK-DCM Is the first peak reference signal; t (T) zcd In the intermittent mode, the time from switching on the switching tube to detecting the zero-crossing signal of the inductance current for the first time by the switching circuit can be obtained through timing; i ref-ac Is the reference current signal;
in the continuous mode, when the inductor current reaches the third peak reference signal, starting timing, and when reaching the second time period T off-ccm When the switching tube is in a closed state, the switching tube is controlled to be in a closed state; wherein the second time period T off-ccm =vin Ts/Vo; wherein Ts is a fixed value set; vin is an input voltage sampling signal of the switching circuit; vo is the output voltage sampling signal of the switching circuit.
The switch circuit control method provided in any of the above embodiments has at least one or more of the following advantages:
1. and the peak current type control is realized based on digital reconstruction, and the control is simple and reliable.
2. When the power factor correction circuit is applied to a boost-PFC circuit, the PFC inductance current can be conveniently controlled to work in CCM, CRM and DCM working states respectively according to the magnitude of the input average value current through the design of simple PFC inductance parameters, so that the optimal efficiency design is realized. The concrete steps are as follows: the PFC conversion circuit realizes optimal efficiency in a period of inputting alternating current, and when the input current is relatively large, PFC inductance current works in a CCM state; when the input current is smaller, the PFC inductor current works in a CRM or DCM state, so that the switching frequency is reduced, and the efficiency is improved. In addition, when the input alternating voltage is Highline, the PFC converter works in a CRM/DCM working state, so that the switching loss is reduced, and the efficiency and the EMI are improved; when the input alternating voltage is Lowline, the PFC converter works in a CCM/CRM/DCM working state, so that the current stress is reduced, the efficiency is improved, and the like.
3. A high PF, low iTHD can be achieved.
4. Except for the BOOST-PFC circuit shown in fig. 1. In order to improve efficiency, the current market starts to prevail a totem pole bridgeless PFC topology, and as shown in fig. 17, the control method can also be used for the totem pole bridgeless PFC topology.
5. The method for sampling the digital-analog mixture can realize loop control by adopting digital PI, reduces external components of a voltage loop, does not need an additional current loop, reduces the number and cost of components and simplifies the design of a system.
In order to realize the control of the switching circuit or cooperatively execute the above-mentioned switching circuit control method, the embodiment of the present application provides a switching circuit control chip IC, as shown in fig. 9, suitable for the control of the switching circuit, where the IC includes a reference current generating unit 11, a current signal correcting unit 12, an inductor current acquiring unit 13, and an on signal controlling unit 14; the reference current generating unit 11 is electrically connected with the current signal correcting unit 12, the current signal correcting unit 12 is electrically connected with the turn-on signal control unit 14, and the inductance current obtaining unit 13 is electrically connected with the turn-on signal control unit 14;
a reference current generating unit 11 for generating a reference current signal I of the inductance of the switching circuit ref-ac The reference current signal characterizes an input current value of the switching circuit. In one embodiment, as shown in fig. 10, the reference current generating unit 11 is capable of receiving an input voltage sampling signal Vin and an output voltage sampling signal Vo of the switching circuit and generating a reference current signal I according to the input voltage sampling signal and the output voltage sampling signal ref-ac The method comprises the steps of carrying out a first treatment on the surface of the The input voltage sampling signal Vin may be sampled by the input voltage sampling unit 21, and the output voltage sampling signal Vo may be sampled by the output voltage sampling unit 22. Fig. 1 shows a specific circuit manner for acquiring Vin and Vo, which is not limited in this application. The switch circuit control chip IC provided by the application can replace the CCM PFC controller in the figure 1 to obtain higher efficiency, andlow iTHD.
A current signal correction unit 12, configured to correct the reference current signal to obtain a peak reference signal;
an inductor current acquisition unit 13 for acquiring an inductor current sampling signal Vcs characterizing said inductor current. The inductor current obtaining unit 13 may be a signal port, and is connected with the current sampling unit to obtain an inductor current sampling signal Vcs; other forms are possible, such as an integrated current sampling unit.
The on signal control unit 14 is configured to generate a first control signal for turning off a switching tube of the switching circuit when the inductor current signal reaches the peak reference signal.
In one embodiment, as shown in FIG. 10, the current signal correction unit 12 includes a waveform processing unit 121, the waveform processing unit 121 being electrically connected to the reference current generation unit 11 and capable of receiving the reference current signal I ref-ac For the reference current signal I ref-ac Performing clamping or shaping to generate a current reference signal in discontinuous mode, i.e. a first peak reference signal I CSPK-DCM ；
In one embodiment, as shown in fig. 10, the current signal correction unit 12 includes a valley current obtaining unit 1221 and a calculating unit 1222, where the valley current obtaining unit 1221 is electrically connected to the inductor current obtaining unit 13, and is capable of receiving an inductor current sampling signal Vcs characterizing an inductor current, and is configured to output an inductor valley current Irv at least according to the inductor current sampling signal Vcs; the inductor current sampling signal Vcs may be implemented by the current sampling unit 23, such as Rs in fig. 1, and of course, the current sampling unit 23 may also be disposed between the switching tube Q and ground, and the inductor current may be obtained by sampling the current of the switching tube and performing calculation or processing.
The calculating unit 1222 is electrically connected to the valley current obtaining unit 1221 and the reference current generating unit 11, and is configured to generate a current reference signal in continuous mode, i.e. a third peak reference signal I, based on at least the inductive valley current Irv and the reference current signal Iref-ac CSPK-CCM The method comprises the steps of carrying out a first treatment on the surface of the Wherein the computing unit comprises a subtracter which is used for receiving the reference current signalAnd (3) carrying out difference between the double of the number Iref-ac and the valley current Irv of the inductor to obtain a current reference signal in a continuous mode.
Further, as shown in fig. 11, the switch circuit control chip further includes a turn-off signal control unit 15; the turn-off signal control unit is capable of receiving the reference current signal Iref-ac, an inductor current zero crossing signal Vzcd, and the current reference signal I in the discontinuous mode CSPK-DCM And based at least on the reference current signal Iref-ac, the inductor current zero crossing signal Vzcd and the current reference signal I in the discontinuous mode CSPK-DCM Generating a second control signal for closing a switching tube of the switching circuit in an intermittent mode;
the turn-off signal control unit is capable of receiving the input voltage sampling signal Vin and the output voltage sampling signal Vo and generating a second control signal for closing a switching tube of the switching circuit in a continuous mode at least according to the input voltage sampling signal Vin and the output voltage sampling signal Vo.
As shown in fig. 12, the above-mentioned switch circuit control chip further includes a mode control unit 16, wherein the mode control unit 16 is electrically connected to the reference current generating unit, is capable of receiving the reference current signal, and is used for determining the operation mode of the switch circuit at least according to the reference current signal Iref-ac, and the reference current signal I ref-ac Correlation, such as a positive/proportional correlation, with the input current value of the switching circuit; the operating modes include discontinuous mode, critical mode, and/or continuous mode.
Fig. 7 shows the input signal Vin, vo and the output signal I of the reference current generating unit ref-ac Corresponding relation of (3). The PFC converter ensures that the output voltage Vout is regulated at a fixed value in a steady state, namely Vout and Vout are kept stable and unchanged in a power frequency alternating current period. Corresponding I ref-ac Is the value of a sine wave that completely follows the Vin signal. Reference current signal I ref-ac Following the variation of the input voltage, iin-ac follows I ref-ac In a certain proportional relationship, i.e. Iin-ac= Kcs ×i ref-ac . FIG. 7 simultaneously illustrates that the three modes CCM/CRM/DCM are based on the reference current signal I ref-ac To make a cutAnd (3) exchanging. When I ref-ac >I CRM-CCM When working in CCM mode, the open signal control unit selects I cspk-CCM As a threshold for peak comparison; when I CRM-DCM <I ref-ac <I CRM-CCM When working in CRM mode, the control unit of the turn-on signal selects I CSPK-CRM As a threshold for peak comparison; when I ref-ac <I CRM-DCM When working in DCM mode, the turn-on signal control unit selects I CSPK-DCM As a threshold for peak comparison; i CRM-CCM And I CRM-DCM Is a programmable threshold that can be changed.
In DCM, I CSPK-DCM The signal is the signal I ref-ac Is embedded in 2*I ref-ac Or ratio 2*I ref-ac An arbitrary value having a larger value; at CRM, I CSPK-CRM I.e. 2 x Iref-ac, in CCM, I CSPK-CCM Is made of 2*I ref-ac Subtracting Irv, which is the sample V by the sample/hold circuit cs Obtained by the current valley of (2), referring to Irv (n-1) and Irv (n) in fig. 8.
Fig. 8 is a waveform diagram illustrating a process of implementing on and off of a switching tube and related signals in three working modes of DCM, CRM and CCM respectively according to the control method of the present invention. Wherein, the Vgda is a driving signal of the switching tube, the Vgda is a positive level, the switching tube is turned on, and the Vgda is a zero level, and the switching tube is turned off. The Vset signal pulse is a second control signal, triggers and controls the VGda to turn from zero level to positive level, and controls the switching tube to be closed; and the Vrst signal pulse is a first control signal, triggers the control of the Vgda to turn from a positive level to a zero level, and controls the switching tube to be disconnected.
Further, in one embodiment, to implement mode selection, as shown in fig. 13, the mode control unit 16 is configured to include a first comparator 161, a second comparator 162, and a control logic generation module 163;
The signal terminals of the first and second comparators are electrically connected with the reference current generating unit 11, and receive the reference current signal Iref-ac, and the reference terminal of the first comparator is provided with a first reference signal I CRM-CCM The method comprises the steps of carrying out a first treatment on the surface of the The reference end of the second comparator is provided withWith the second reference signal I CRM-DCM The method comprises the steps of carrying out a first treatment on the surface of the The output ends of the first comparator and the second comparator are electrically connected with the control logic generation module, and the control logic generation module generates a working mode of the switching circuit according to comparison results output by the first comparator and the second comparator; the first reference signal is greater than the second reference signal;
when the reference current signal Iref-ac is greater than or equal to the first reference signal I CRM-CCM The control logic generation module generates a first mode signal that causes the switching circuit to operate in a continuous mode.
When the reference current signal Iref-ac is greater than the second reference signal I CRM-DCM And is smaller than the first reference signal I CRM-CCM When the control logic generating module generates a second mode signal for enabling the switch circuit to work in a critical mode;
when the reference current signal Iref-ac is smaller than the second reference signal I CRM-DCM When the control logic generation module generates a third mode signal that causes the switching circuit to operate in an intermittent mode.
In order to achieve mode selection, as shown in fig. 14, the mode control unit 16 is provided in another embodiment to include a first comparator 161, a second comparator 162, a control logic generation module 163, and a peak acquisition unit 164;
the peak value acquisition unit 164 is electrically connected to the reference current generation unit 11 and receives the reference current signal I ref-ac And generates a reference current signal peak value I ref-ac-pk ；
The signal terminals of the first comparator and the second comparator are electrically connected with the peak value acquisition unit 164, and receive the reference current signal peak value I ref-ac-pk The method comprises the steps of carrying out a first treatment on the surface of the The reference end of the first comparator is provided with a first reference signal I CRM-CCM The method comprises the steps of carrying out a first treatment on the surface of the The reference end of the second comparator is provided with a second reference signal I CRM-DCM The method comprises the steps of carrying out a first treatment on the surface of the The output ends of the first comparator and the second comparator are electrically connected with the control logic generation module, and the control logic generation module outputs according to the first comparator and the second comparatorThe output comparison result generates the working mode of the switching circuit; the first reference signal is greater than the second reference signal;
when the reference current signal peak value I ref-ac-pk Greater than or equal to the first reference signal I CRM-CCM The control logic generation module generates a first mode signal that causes the switching circuit to operate in a continuous mode.
When the reference current signal peak value I ref-ac-pk Is greater than the second reference signal I CRM-DCM And is smaller than the first reference signal I CRM-CCM When the control logic generating module generates a second mode signal for enabling the switch circuit to work in a critical mode;
when the reference current signal peak value I ref-ac-pk Less than the second reference signal I CRM-DCM When the control logic generation module generates a third mode signal that causes the switching circuit to operate in an intermittent mode.
After the mode control unit determines the corresponding mode, the mode control unit sends the corresponding mode signal to the on signal control unit and the off signal control unit, so that different control modes are executed according to different modes.
In one embodiment, the turn-on signal control unit 14 includes, as shown in fig. 15, a third comparator 141, a switching tube K1, a first reference terminal, a second reference terminal, a third reference terminal, and a sampling terminal; the first reference terminal is electrically connected to the waveform processing unit 121 for receiving the current reference signal in the intermittent mode, i.e. the first peak reference signal I CSPK-DCM The method comprises the steps of carrying out a first treatment on the surface of the The second reference end is electrically connected with the reference current generating unit and is used for receiving the reference current signal I ref-ac Twice, i.e. the second peak reference signal I CSPK-CRM The method comprises the steps of carrying out a first treatment on the surface of the The third reference terminal is electrically connected with the computing unit and is used for receiving the current reference signal in the continuous mode, namely, the third peak value reference signal I CSPK-CCM ；
The control end of the switch tube K1 is electrically connected with the mode control unit 16 and controls the first reference end or the first reference end according to the working mode of the switch circuitThe second reference end or the third reference end is electrically connected with the comparison end of the third comparator; the sampling end of the third comparator is electrically connected with the inductor current obtaining unit 13 and is capable of receiving an inductor current sampling signal Vcs, the third comparator compares the inductor current sampling signal with the current reference signal, and when the inductor current sampling signal reaches the current reference signal, a first pulse signal Vrst is output, and the first pulse signal is the first control signal. In this embodiment, vcs and I are respectively associated with the three different modes of CCM, CRM and DCM CSPK-CCM , I CSPK-CRM And I CSPK-DCM When Vcs is larger than the reference value, vrst generates a signal pulse, triggers the driving signal Vdga to jump from a high level to a low level, enables the switching tube to be disconnected, and controls the Ton signal in a peak current mode.
In one embodiment, as shown in fig. 16, the off signal control unit 15 includes a first timer 151, a second timer 152, and a signal selector 153;
the first timer 151 is used for receiving the reference current signal I ref-ac An inductor current zero crossing signal Vzcd and a current reference signal I in said discontinuous mode CSPK-DCM When the zero-crossing signal of the inductance current is detected, starting timing, when the first time length T is reached off-dcm Generating a first timing signal; wherein the first time length T off-dcm =0.5*I CSPK-DCM *T zcd /I ref-ac -T zcd The method comprises the steps of carrying out a first treatment on the surface of the Wherein I is CSPK-DCM For the first peak reference signal, T zcd In the intermittent mode, the time period from the switching tube is switched on to the first detection of the zero-crossing signal of the inductive current by the switching circuit.
The second timer 152 is capable of receiving the input voltage sampling signal Vin and the output voltage sampling signal Vo and presetting a fixed value Ts, starting to count when the inductor current reaches the third peak reference signal, and reaching a second time period T off-ccm Generating a second timing signal; wherein the second time period T off-ccm =vin Ts/Vo; wherein Ts is a fixed value set; vin is the input voltage of the switching circuitA sample signal; vo is an output voltage sampling signal of the switching circuit;
the signal selector 153 receives the first timing signal, the second timing signal, the inductor current zero crossing signal Vzcd, and the operation mode of the switching circuit; and is used for: when the working mode is an intermittent mode, generating the second control signal according to the first timing signal; when the working mode is a continuous mode, generating the second control signal according to the second timing signal; when the working mode is a critical mode, generating the second control signal according to the inductance current zero crossing signal Vzcd; the second control signal is a pulse signal. Referring to fig. 8, that is, the present embodiment generates the Vset signal when the inductor current zero crossing signal Vzcd is detected in the critical mode; in the intermittent mode, when the zero crossing signal Vzcd of the inductance current reaching the peak current is detected, the timing is started to reach the first time length T off-dcm Generating a Vset signal; in the continuous mode, the timing is started after the peak current is reached, and the second time length T is reached off-ccm Generating a Vset signal; the Vset signal triggers the driving signal Vdga to transition from a low level to a high level, turning on the switching tube.
Further, in one embodiment, as shown in fig. 12, the on signal control unit 14 is electrically connected to the mode control unit 16; the turn-on signal control unit 14 is capable of acquiring a working mode of the switching circuit, and is used for determining a current reference signal in a corresponding mode at least according to the working mode, and generating a first control signal when the inductance current sampling signal reaches the current reference signal;
the switch circuit control chip IC further comprises a switch drive output unit 17, wherein the switch drive output unit 17 is electrically connected with the on signal control unit 14 and the off signal control unit 15, receives a first control signal Vrst and a second control signal Vset, and is used for generating a control signal for controlling the switching tube of the switch circuit to be opened according to the first control signal and also used for generating a control signal for controlling the switching tube of the switch circuit to be closed according to the second control signal; the two control signals constitute a drive signal Vgda for driving the switching tube.
The above-mentioned switch circuit control chip can be connected with a small number of external circuits (such as the input voltage sampling unit 21, the output voltage sampling unit 22, the current sampling unit 23 and the inductor current zero-crossing sampling unit 24) to realize that different working modes can be selected according to the magnitude of the input current, so that the switch circuit using the IC has the advantages of high PF value, high efficiency and low THD value, and the advantages thereof can be described with reference to the advantages of the switch circuit control method in the foregoing embodiments, and are not repeated herein.
Based on the above-mentioned switch circuit control chip and control method, the embodiment of the present application further provides a switch circuit, and as shown in fig. 1 and 17, the switch circuit includes a switch unit 20, an output voltage sampling unit 22, an input voltage sampling unit 21, a current sampling unit 23, an inductance current zero-crossing sampling unit 24, and the above-mentioned switch circuit control chip IC; the switching unit may be a flyback converter, a BOOST converter (as shown in fig. 1), or a single-phase totem-pole bridgeless BOOST PFC converter (as shown in fig. 17) including a single-channel BOOST-PFC circuit, a totem-pole bridgeless BOOST-PFC circuit, or a Dual BOOST bridgeless PFC circuit. The switch circuit control chip is used for controlling a switch tube in the switch unit to enable the switch circuit to work in a proper working mode.
The output voltage sampling unit 21 is electrically connected with the output end of the switch unit 20 and samples an output voltage sampling signal Vo; the input voltage sampling unit 21 is electrically connected with the input end of the switch unit 20 and samples an input voltage sampling signal Vin; the output voltage sampling unit 22 and the input voltage sampling unit 21 are also electrically connected with the reference current generating unit 11 of the switching circuit control chip IC; the current sampling unit 23 is electrically connected with the switching unit 20, and samples an inductance current sampling signal Vcs of the switching unit; the inductor current zero-crossing sampling unit 24 is electrically connected with the switch unit 20, and is used for acquiring an inductor current zero-crossing signal Vzcd of an inductor of the switch unit; the current sampling unit 23 is electrically connected with the inductance current acquisition unit 13 of the switch circuit control chip IC; the inductance current zero-crossing sampling unit 24 is electrically connected with the turn-off signal control unit 15 of the switch circuit control chip IC; the switch circuit control chip IC is at least configured to control the switch unit to work according to the output voltage sampling signal Vo, the input voltage sampling signal Vin, the inductor current sampling signal Vcs, and the inductor current zero crossing signal Vzcd, and the specific control manner is as described in the foregoing embodiments of the switch circuit control method and the switch circuit control chip, which are not described herein in detail.
The control method and the control chip of the switch circuit provided by the embodiment of the application are not only suitable for the traditional single-phase BOOST-PFC converter, but also can be used for the single-phase totem pole bridgeless BOOST PFC converter. As shown in FIG. 17, the single-phase totem-pole bridgeless BOOST PFC converter has slightly different requirements on a control chip from the traditional BOOST PFC converter (shown in FIG. 1), and because of different reference grounds, the output of the control chip is different from the output of the VGda, and a Vdgb needs to be generated, a dead time is needed to be inserted between the VGdb and the VGda to ensure the working safety, and the VGda and the VGdb need to exchange the master-slave relationship in the positive half cycle and the negative half cycle of the power frequency period.
The foregoing disclosure is directed to the preferred embodiment of the present application and is not intended to limit the scope of the claims, but rather to cover any and all modifications, equivalents, alternatives, and improvements within the spirit and principles of the present application.

Claims (18)

1. A switching circuit control method for peak control of a switching circuit, the control method comprising the steps of:
acquiring a reference current signal of an inductance of the switching circuit, wherein the reference current signal represents an input current value of the switching circuit;
Correcting the reference current signal to obtain a peak value reference signal;
acquiring an inductor current sampling signal representing the inductor current;
when the inductance current sampling signal reaches the peak value reference signal, a switching tube of the switching circuit is controlled to be disconnected;
and calculating a timing time length, and controlling the switching tube to be closed at least according to the timing time length.
2. The method of claim 1, wherein the peak reference signal is a first peak reference signal when the switching circuit is operating in an intermittent mode, the first peak reference signal being greater than twice the reference current signal;
the calculating the timing time length and controlling the switching tube to be closed at least according to the timing time length comprises the following steps:
when the zero-crossing signal of the inductance current is detected, starting timing, and when the first duration is reached, generating an opening signal of the next switching period to control the switching tube to be closed; wherein the first time length T off-dcm =0.5*I CSPK-DCM *T zcd /I ref-ac -T zcd The method comprises the steps of carrying out a first treatment on the surface of the Wherein I is CSPK-DCM For the first peak reference signal, T zcd In the intermittent mode, the switching tube is switched on until the time when the zero-crossing signal of the inductance current is detected for the first time in the period; i ref-ac Is the reference current signal.
3. The method according to claim 1, wherein when the switching circuit is operated in a continuous mode, the peak reference signal is a third peak reference signal, the third peak reference signal being a difference between twice the reference current signal and an inductance valley current in the continuous mode;
the calculating the timing time length and controlling the switching tube to be closed at least according to the timing time length comprises the following steps:
when the inductance current sampling signal reaches the third peak value reference signal, starting timing, and when the second duration is reached, generating an opening signal of the next switching period to control the switching tube to be closed; wherein the second time period T off-ccm =vin Ts/Vo; wherein Ts is a fixed value set; vin is an input voltage sampling signal of the switching circuit; vo is the output voltage sampling signal of the switching circuit.
4. A switching circuit control method according to any one of claims 1 to 3, further comprising the steps of:
obtaining a first electrical signal representative of an average value of an input current of the switching circuit;
comparing the first electrical signal with a first reference signal and a second reference signal; the first reference signal is greater than the second reference signal;
The first electrical signal is positively correlated with the input current average; in a power frequency period, when the first electric signal is larger than the first reference signal, controlling the switching circuit to work in a continuous mode; when the first electric signal is smaller than the first reference signal but larger than the second reference signal, controlling the switching circuit to work in a critical mode; when the first electric signal is smaller than the second reference signal, the switching circuit is controlled to work in an intermittent mode; the peak reference signal in discontinuous mode is less than or equal to the second reference signal.
5. A switching circuit control method according to any one of claims 1 to 3, further comprising the steps of:
obtaining a second electrical signal representative of an input current peak of the switching circuit;
comparing the second electrical signal with a first reference signal and a second reference signal; the first reference signal is greater than the second reference signal;
when the second electric signal is larger than the first reference signal, the switching circuit is controlled to work in a continuous mode in a power frequency period;
when the second electric signal is smaller than the first reference signal but larger than the second reference signal, controlling the switching circuit to work in a critical mode in a power frequency period;
And when the second electric signal is smaller than the second reference signal, controlling the switching circuit to work in an intermittent mode in a power frequency period.
6. A switching circuit control method according to any one of claims 1 to 3, further comprising the step of:
detecting an input alternating voltage of the switching circuit;
when the effective value of the input alternating voltage is more than or equal to 175V, controlling the switching circuit to work in a critical mode or an intermittent mode;
and when the effective value of the input alternating voltage is smaller than 175V, controlling the switching circuit to work in a continuous mode, a critical mode or an intermittent mode.
7. The switching circuit control chip is suitable for carrying out peak control on a switching circuit and is characterized by comprising a reference current generating unit, a current signal correcting unit, an inductance current acquiring unit and a turn-on signal control unit; the reference current generating unit is electrically connected with the current signal correcting unit, the current signal correcting unit is electrically connected with the opening signal control unit, and the inductance current obtaining unit is electrically connected with the opening signal control unit;
the reference current generation unit is used for generating a reference current signal of the inductance of the switching circuit, and the reference current signal represents the input current value of the switching circuit;
The current signal correction unit is used for correcting the reference current signal to obtain a peak value reference signal;
the induction current acquisition unit is used for acquiring induction current sampling signals representing the induction current;
the turn-on signal control unit is used for generating a first control signal for enabling a switching tube of the switching circuit to be disconnected when the inductance current sampling signal reaches the peak value reference signal.
8. The switch circuit control chip of claim 7, wherein the current signal correction unit comprises a waveform processing unit, the waveform processing unit is electrically connected with the reference current generation unit, and is capable of receiving the reference current signal and performing clamping or shaping on the reference current signal to obtain a first peak value reference signal; the first peak reference signal is a peak reference signal of an inductance current of the switching circuit working in an intermittent mode; the first peak reference signal is greater than twice the reference current signal.
9. The switching circuit control chip of claim 7, wherein the current signal correction unit comprises a valley current acquisition unit and a calculation unit, the valley current acquisition unit being capable of receiving an inductor current sampling signal representative of an inductor current and for outputting an inductor valley current in dependence upon at least the inductor current sampling signal;
The calculation unit is electrically connected with the valley current acquisition unit and the reference current generation unit, and performs difference between twice of the reference current signal and the inductance valley current to obtain a third peak value reference signal; the third peak reference signal is a peak reference signal of an inductor current of the switching circuit operating in a continuous mode.
10. The switching circuit control chip according to any one of claims 7 to 9, further comprising a turn-off signal control unit;
the turn-off signal control unit can receive the reference current signal, the inductance current zero-crossing signal and the current reference signal in the intermittent mode, and generate a second control signal for closing a switching tube of the switching circuit in the intermittent mode at least according to the reference current signal, the inductance current zero-crossing signal and the peak value reference signal in the intermittent mode;
or alternatively, the process may be performed,
the turn-off signal control unit is capable of receiving the input voltage sampling signal and the output voltage sampling signal and generating a second control signal for closing a switching tube of the switching circuit in a continuous mode at least according to the input voltage sampling signal and the output voltage sampling signal.
11. The switching circuit control chip according to claim 10, further comprising a mode control unit; the mode control unit is electrically connected with the reference current generation unit, can receive the reference current signal and is used for determining the working mode of the switching circuit at least according to the reference current signal; the operating modes include discontinuous mode, critical mode, and/or continuous mode.
12. The switching circuit control chip of claim 11, wherein the mode control unit comprises a first comparator, a second comparator, and a control logic generation module;
the signal ends of the first comparator and the second comparator are electrically connected with the reference current generating unit and are used for receiving the reference current signal, and the reference end of the first comparator is provided with a first reference signal; the reference end of the second comparator is provided with a second reference signal; the output ends of the first comparator and the second comparator are electrically connected with the control logic generation module, and the control logic generation module generates a working mode of the switching circuit according to comparison results output by the first comparator and the second comparator; the first reference signal is greater than the second reference signal;
When the reference current signal is greater than or equal to the first reference signal, the control logic generation module generates a first mode signal that causes the switching circuit to operate in a continuous mode;
when the reference current signal is larger than the second reference signal and smaller than the first reference signal, the control logic generation module generates a second mode signal for enabling the switch circuit to work in a critical mode;
when the reference current signal is smaller than the second reference signal, the control logic generation module generates a third mode signal that causes the switching circuit to operate in a discontinuous mode.
13. The switching circuit control chip according to claim 11, wherein the mode control unit includes a first comparator, a second comparator, a control logic generation module, and a peak acquisition unit;
the peak value acquisition unit is electrically connected with the reference current generation unit, receives the reference current signal and generates a reference current signal peak value;
the signal ends of the first comparator and the second comparator are electrically connected with the peak value acquisition unit and are used for receiving the reference current signal peak value; the reference end of the first comparator is provided with a first reference signal; the reference end of the second comparator is provided with a second reference signal; the output ends of the first comparator and the second comparator are electrically connected with the control logic generation module, and the control logic generation module generates a working mode of the switching circuit according to comparison results output by the first comparator and the second comparator; the first reference signal is greater than the second reference signal;
When the peak value of the reference current signal is greater than or equal to the first reference signal, the control logic generation module generates a first mode signal for enabling the switching circuit to work in a continuous mode;
when the peak value of the reference current signal is larger than the second reference signal and smaller than the first reference signal, the control logic generation module generates a second mode signal for enabling the switch circuit to work in a critical mode;
when the reference current signal peak value is smaller than the second reference signal, the control logic generation module generates a third mode signal for enabling the switch circuit to work in a discontinuous mode.
14. The switch circuit control chip of claim 11, wherein the turn-on signal control unit comprises a third comparator, a switching tube K1, a first reference terminal, a second reference terminal, a third reference terminal, and a sampling terminal; the first reference end is electrically connected with the waveform processing unit and is used for receiving the current reference signal in the intermittent mode; the second reference end is electrically connected with the reference current generation unit and is used for receiving the reference current signal; the third reference end is electrically connected with the computing unit and is used for receiving the current reference signal in the continuous mode;
The control end of the switching tube K1 is electrically connected with the mode control unit, and controls the first reference end or the second reference end or the third reference end to be electrically connected with the comparison end of the third comparator according to the working mode of the switching circuit; the sampling end of the third comparator can receive an inductance current sampling signal, the third comparator compares the inductance current sampling signal with the current reference signal, and when the inductance current sampling signal reaches the current reference signal, a first pulse signal is output, and the first pulse signal is the first control signal.
15. The switch circuit control chip of claim 11, wherein the off signal control unit includes a first timer, a second timer, and a signal selector;
the first timer is used for receiving the reference current signal, the inductance current zero crossing signal and the current reference signal in the intermittent mode, starting timing when the inductance current zero crossing signal is detected, and generating a first timing signal when a first duration is reached; wherein the first time length T off-dcm =0.5*I CSPK-DCM *T zcd /I ref-ac -T zcd The method comprises the steps of carrying out a first treatment on the surface of the Wherein I is CSPK-DCM For the first peak reference signal, T zcd In the intermittent mode, the switching tube is switched on until the time when the zero-crossing signal of the inductance current is detected for the first time in the period; the second timer can receive the input voltage sampling signal and the output voltage sampling signal, preset a fixed value Ts, start timing when the inductance current reaches a third peak value reference signal, and generate a second timing signal when the inductance current reaches a second duration; wherein the second time period T off-ccm =vin Ts/Vo; wherein Ts is a fixed value set; vin is an input voltage sampling signal of the switching circuit; vo is an output voltage sampling signal of the switching circuit;
the signal selector receives the first timing signal, the second timing signal, the inductance current zero crossing signal and the working mode of the switching circuit; and is used for: when the working mode is an intermittent mode, generating the second control signal according to the first timing signal; when the working mode is a continuous mode, generating the second control signal according to the second timing signal; when the working mode is a critical mode, generating the second control signal according to the inductance current zero crossing signal; the second control signal is a pulse signal.
16. The switch circuit control chip of claim 11, wherein the turn-on signal control unit is electrically connected to the mode control unit; the switching-on signal control unit can acquire the working mode of the switching circuit and is used for determining a current reference signal in a corresponding mode at least according to the working mode, and when the inductance current sampling signal reaches the current reference signal, a first control signal is generated;
The switch circuit control chip further comprises a switch drive output unit, wherein the switch drive output unit is electrically connected with the on signal control unit and the off signal control unit, receives the first control signal and the second control signal, and is used for generating a control signal for controlling the switching tube of the switch circuit to be opened according to the first control signal and also used for generating a control signal for controlling the switching tube of the switch circuit to be closed according to the second control signal.
17. A switching circuit, characterized by comprising a switching unit, an output voltage sampling unit, an input voltage sampling unit, a current sampling unit, an inductor current zero crossing sampling unit and a switching circuit control chip according to any one of claims 7-16; the output voltage sampling unit is electrically connected with the output end of the switch unit and is used for sampling an output voltage sampling signal; the input voltage sampling unit is electrically connected with the input end of the switch unit and is used for sampling an input voltage sampling signal; the output voltage sampling unit and the input voltage sampling unit are also electrically connected with a reference current generating unit of the switch circuit control chip; the current sampling unit is electrically connected with the switch unit and is used for sampling an inductance current sampling signal of the switch unit; the inductance current zero-crossing sampling unit is electrically connected with the switching unit and is used for acquiring an inductance current zero-crossing signal of the inductance of the switching unit; the current sampling unit is electrically connected with the inductance current acquisition unit of the switch circuit control chip; the inductance current zero-crossing sampling unit is electrically connected with the turn-off signal control unit of the switch circuit control chip; the switch circuit control chip is at least used for controlling the switch unit to work according to the output voltage sampling signal, the input voltage sampling signal, the inductance current sampling signal and the inductance current zero crossing signal.
18. The switching circuit of claim 17, wherein the switching unit comprises a boost-PFC converter, the switching circuit control chip to control switching tubes in the boost-PFC converter; the BOOST-PFC converter comprises a single-channel BOOST-PFC circuit, a totem-pole bridgeless BOOST-PFC circuit or a Dual BOOST bridgeless PFC circuit.
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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101743683A (en) * 2007-05-02 2010-06-16 美国思睿逻辑有限公司 Power factor correction (PFC) controller and method using a finite state machine to adjust the duty cycle of a PWM control signal
CN101986542A (en) * 2010-11-02 2011-03-16 华南理工大学 PFC (power factor correction) control method with high input power factor and control circuit thereof
CN102638162A (en) * 2011-02-11 2012-08-15 快捷半导体(苏州)有限公司 Constant off time boost converter
CA2806870A1 (en) * 2012-10-09 2014-04-09 Delta-Q Technologies Corp. Digital controller based detection methods for adaptive mixed conduction mode power factor correction circuit
CN103916004A (en) * 2014-04-22 2014-07-09 成都芯源系统有限公司 Power factor correction circuit and control method thereof
US20170155319A1 (en) * 2015-11-26 2017-06-01 Silergy Semiconductor Technology (Hangzhou) Ltd. Control circuit and control method for power converter
CN107834847A (en) * 2016-08-31 2018-03-23 杰华特微电子（张家港）有限公司 The control circuit and control method of a kind of on-off circuit, switching power circuit
CN110943605A (en) * 2018-09-21 2020-03-31 乐金电子研发中心(上海)有限公司 Control method and device of totem-pole power factor correction circuit
US10720829B1 (en) * 2019-04-10 2020-07-21 Chicony Power Technology Co., Ltd. Totem-pole bridgeless PFC conversion device and method of operating the same
US20200244159A1 (en) * 2019-01-30 2020-07-30 Chengdu Monolithic Power Systems Co., Ltd. Mix-mode pfc circuit and a method thereof

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101743683A (en) * 2007-05-02 2010-06-16 美国思睿逻辑有限公司 Power factor correction (PFC) controller and method using a finite state machine to adjust the duty cycle of a PWM control signal
CN101986542A (en) * 2010-11-02 2011-03-16 华南理工大学 PFC (power factor correction) control method with high input power factor and control circuit thereof
CN102638162A (en) * 2011-02-11 2012-08-15 快捷半导体(苏州)有限公司 Constant off time boost converter
CA2806870A1 (en) * 2012-10-09 2014-04-09 Delta-Q Technologies Corp. Digital controller based detection methods for adaptive mixed conduction mode power factor correction circuit
CN103916004A (en) * 2014-04-22 2014-07-09 成都芯源系统有限公司 Power factor correction circuit and control method thereof
US20170155319A1 (en) * 2015-11-26 2017-06-01 Silergy Semiconductor Technology (Hangzhou) Ltd. Control circuit and control method for power converter
CN107834847A (en) * 2016-08-31 2018-03-23 杰华特微电子（张家港）有限公司 The control circuit and control method of a kind of on-off circuit, switching power circuit
CN110943605A (en) * 2018-09-21 2020-03-31 乐金电子研发中心(上海)有限公司 Control method and device of totem-pole power factor correction circuit
US20200244159A1 (en) * 2019-01-30 2020-07-30 Chengdu Monolithic Power Systems Co., Ltd. Mix-mode pfc circuit and a method thereof
US10720829B1 (en) * 2019-04-10 2020-07-21 Chicony Power Technology Co., Ltd. Totem-pole bridgeless PFC conversion device and method of operating the same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
徐厚建;姚文熙;: "基于开关管电压检测的图腾柱整流器控制方案", 浙江大学学报(工学版), no. 09, pages 146 - 161 *

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