CN114200992B - Feedback voltage sampling method and circuit, output voltage control method and circuit - Google Patents

Feedback voltage sampling method and circuit, output voltage control method and circuit Download PDF

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CN114200992B
CN114200992B CN202111461964.2A CN202111461964A CN114200992B CN 114200992 B CN114200992 B CN 114200992B CN 202111461964 A CN202111461964 A CN 202111461964A CN 114200992 B CN114200992 B CN 114200992B
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signal
voltage
module
period
circuit
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CN114200992A (en
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文鹏
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Shenzhen Biyi Microelectronics Co ltd
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Shenzhen Biyi Microelectronics Co ltd
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current
    • G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
    • G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
    • 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
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • 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)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The application relates to a feedback voltage sampling method and circuit, and an output voltage control method and circuit.

Description

Feedback voltage sampling method and circuit, output voltage control method and circuit
Technical Field
The present application relates to the field of voltage detection, and in particular, to a feedback voltage sampling method and circuit, and an output voltage control method and circuit.
Background
As the urban development level is continuously improved and the electricity demand is continuously enriched, the requirements on power conversion equipment are also higher and higher. Flyback converters are an indispensable component in electronic devices and are widely used in various forms of alternating current/direct current (AC/DC) and direct current/direct current (DC/DC) conversion applications. Compared with a secondary side feedback control flyback circuit, the primary side feedback control flyback circuit has the advantages of simple structure and good economy, and is widely applied to medium and small power chargers and adapters. Wherein the constant control of the output voltage determines the constant of the output voltage, and the constant control of the output voltage depends on ensuring the constant of the feedback voltage. The constant feedback voltage sampling is therefore critical to ensure a stable output of the flyback circuit.
The existing feedback voltage proportion sampling technology needs to ensure that the primary current peak value cannot be suddenly changed, and the problem that the feedback voltage obtained by sampling cannot accurately reflect the output voltage after the primary current peak value is suddenly reduced exists, so that stable output of a flyback circuit cannot be ensured.
Disclosure of Invention
Accordingly, it is desirable to provide a feedback voltage sampling method and circuit, and an output voltage control method and circuit for solving the above-mentioned problems.
A feedback voltage sampling method, comprising:
acquiring a primary current signal of a flyback circuit, a voltage feedback signal of a current period and a driving signal of a previous period;
generating a control signal according to the voltage feedback signal, the primary side current signal and the driving signal of the previous period;
and carrying out sampling and holding on the voltage feedback signal according to the control signal so as to output a sampling and holding signal of the current period, wherein the sampling and holding signal is used for reflecting the voltage information of the voltage feedback signal.
In one embodiment, the primary current signal includes a current period primary current signal and a previous period primary current signal; the generating a control signal according to the voltage feedback signal, the primary current signal and the driving signal of the previous period includes:
acquiring the demagnetization time of the flyback circuit in the previous period according to the voltage feedback signal and the driving signal;
acquiring a pulse time point of the control signal according to the current period primary side current signal, the last period primary side current signal and the demagnetizing time;
the control signal is generated at the pulse time point.
In one embodiment, the step of obtaining the demagnetization time of the flyback circuit in the previous period according to the voltage feedback signal and the driving signal includes:
acquiring a first time point corresponding to the falling edge of the driving signal according to the driving signal;
acquiring a second time point when the voltage feedback signal first drops to zero after the driving signal arrives;
and acquiring the demagnetizing time according to the first time point and the second time point.
In one embodiment, the time length value between the first time point and the pulse time point is a first time length value; the first time length value of the current period is in direct proportion to the demagnetizing time of the previous period, in direct proportion to the current peak value of the current period primary side current signal, and in inverse proportion to the current peak value of the previous period primary side current signal.
In one embodiment, the method further comprises:
and generating a driving signal of the current period according to the sampling and holding signal of the current period, wherein the driving signal is also used for controlling the output voltage of the flyback circuit.
A method of controlling an output voltage, comprising:
acquiring a driving signal of a corresponding period according to the sampling hold signal of the corresponding period acquired by the method;
and controlling the output voltage of the flyback circuit according to the driving signal of the corresponding period.
A feedback voltage sampling circuit, comprising:
the signal acquisition module is used for being connected with the flyback circuit to acquire a primary side current signal of the flyback circuit, a voltage feedback signal of the current period and a driving signal of the previous period;
the signal generation module is connected with the signal acquisition module and is used for generating a control signal according to the voltage feedback signal, the primary side current signal and the driving signal of the previous period;
the sampling and holding module is used for respectively connecting with the flyback circuit and the signal generating module, sampling and holding the voltage feedback signal according to the control signal so as to output a sampling and holding signal of the current period, and the sampling and holding signal is used for reflecting the voltage information of the voltage feedback signal.
In one embodiment, the sample-hold module is further configured to control a switching tube inside the sample-hold module to conduct a path between the sample-hold module and the flyback circuit according to the control signal, so as to obtain a voltage feedback signal of the flyback circuit, and perform sample-hold to output a sample-hold signal.
In one embodiment, the circuit further comprises:
the voltage loop module is connected with the sample and hold module and is used for generating a driving signal of the current period according to the sample and hold signal of the current period, and the driving signal is also used for controlling the output voltage of the flyback circuit.
In one embodiment, the sample-and-hold module includes:
a first switching tube and a first capacitor; one end of the first switching tube is connected with one end of the flyback circuit, the other end of the first switching tube, one end of the first capacitor and one end of the voltage loop module are connected together, and the other end of the first capacitor is grounded.
In one embodiment, the circuit further comprises:
and the primary side current module is used for being respectively connected with the flyback circuit and the signal acquisition module to acquire the primary side current signal of the flyback circuit.
In one embodiment, the primary side current module comprises:
the second switch tube and the second capacitor; one end of the second switching tube is connected with one end of the flyback circuit, the other end of the second switching tube, one end of the second capacitor and the other end of the signal generating module are connected together, and the other end of the second capacitor is grounded.
An output voltage control circuit comprising:
the driving control module is used for acquiring a driving signal of a corresponding period according to the sampling hold signal of the corresponding period acquired by the circuit;
and the voltage control module is used for controlling the output voltage of the flyback circuit according to the driving signal of the corresponding period.
According to the feedback voltage sampling method and circuit, the output voltage control method and circuit, the primary side current signal of the flyback circuit, the voltage feedback signal of the current period and the driving signal of the previous period are obtained, the control signal is generated according to the voltage feedback signal, the primary side current signal and the driving signal of the previous period, the voltage feedback signal is sampled and held according to the control signal to output the sampling and holding signal of the current period, the sampling and holding signal is used for reflecting the voltage information of the voltage feedback signal, the accuracy of feedback voltage sampling under abrupt change of the primary side current signal is achieved, and therefore stable output of the flyback circuit is guaranteed, and stability of power supply conversion is guaranteed.
Drawings
In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a feedback voltage sampling method in one embodiment;
FIG. 2 is a schematic diagram of a sample-and-hold process in one embodiment;
FIG. 3 is a diagram showing current-voltage waveforms through a feedback voltage sampling method and a circuit in one embodiment;
FIG. 4 is a flowchart showing step 104 in one embodiment;
FIG. 5 is a flowchart showing step 402 in one embodiment;
FIG. 6 is a flow chart of a method of controlling output voltage in one embodiment;
FIG. 7 is a block diagram of a feedback voltage sampling circuit in one embodiment;
FIG. 8 is a block diagram of a feedback voltage sampling circuit in one embodiment;
FIG. 9 is a block diagram of a feedback voltage sampling circuit in one embodiment;
FIG. 10 is a block diagram of a feedback voltage sampling circuit in one embodiment;
FIG. 11 is a block diagram of a feedback voltage sampling circuit in one embodiment;
FIG. 12 is a block diagram of a feedback voltage sampling circuit in one embodiment;
FIG. 13 is a block diagram of an output voltage control circuit in one embodiment;
FIG. 14 is a block diagram of an output voltage control circuit in one embodiment;
FIG. 15 is a schematic diagram of a rectifier module according to one embodiment;
FIG. 16 is a schematic diagram of the structure of an absorber module in one embodiment;
FIG. 17 is a schematic diagram of a secondary rectifying and filtering module in one embodiment;
FIG. 18 is a schematic diagram of a power module in one embodiment;
fig. 19 is a schematic structural diagram of a detection module in one embodiment.
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
It will be understood that the terms first, second, etc. as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first client may be referred to as a second client, and similarly, a second client may be referred to as a first client, without departing from the scope of the application. Both the first client and the second client are clients, but they are not the same client.
Referring to fig. 1, a flow chart of a feedback voltage sampling method in one embodiment is shown.
In this embodiment, as shown in fig. 1, the feedback voltage sampling method includes steps 102 to 106.
Step 102, obtaining a primary current signal of the flyback circuit, a voltage feedback signal of a current period and a driving signal of a previous period.
The flyback circuit is a primary side circuit of a transformer of the flyback power supply; and flyback power supply means that when the primary coil of the transformer is excited by the direct current pulse voltage, the secondary coil of the transformer does not provide power output to the load, but only provides power output to the load after the excitation voltage of the primary coil of the transformer is turned off, and the transformer switching power supply is called flyback switching power supply or flyback transformer switching power supply. The transformer is composed of a primary winding Np, a secondary winding Ns and an auxiliary winding Na, and the three windings are in mutual coupling relation.
The primary current signal of the flyback circuit refers to a current signal flowing through a primary winding Np of the flyback transformer switching power supply, and may be a primary current peak signal Ipk, that is, a current flowing through a primary winding switching tube. The primary side current peak signal obtaining method may be that the primary side current peak signal Ipk is represented by measuring a reference current signal ipk_ref generated by the voltage control module, or that the primary side current peak signal Ipk is represented by measuring a current sampling signal vcs_sample generated when the primary side current signal flows through the sampling resistor.
Wherein, the voltage feedback signal V of the current period FB For characterizing the dc pulse in the current period to provide the power output Vout to the load. The method for obtaining the voltage feedback signal of the current period can be to obtain the feedback signal of the output voltage of the current period through non-optocoupler transmission modes such as an auxiliary winding Na and the like.
The driving signal PWM is a pulse width adjusting signal output by the primary side feedback controller, and is used to control the on and off of a primary side winding switching tube of the flyback power supply, so as to adjust the output voltage Vout provided to the load.
Step 104, generating a control signal according to the voltage feedback signal, the primary current signal and the driving signal of the previous period.
The method for generating the control signal according to the voltage feedback signal, the primary current signal and the driving signal of the previous period may be to use a circuit unit with signal generation function in the primary feedback controller to generate the voltage feedback signal V FB And analyzing and processing the primary current signal Ipk and the driving signal of the previous period, and generating a driving signal of the current period for controlling the primary winding switching tube.
And step 106, according to the control signal, sampling and holding the voltage feedback signal to output a sampling and holding signal of the current period, wherein the sampling and holding signal is used for reflecting the voltage information of the voltage feedback signal.
The sampling and holding process means that under ideal conditions, when the sampling state is in, the output signal of the sampling and holding module changes along with the change of the input signal; while in the hold state, the output signal of the sample-and-hold module is held at the instantaneous input signal level value that received the hold command. Optionally, as shown in fig. 2, when the circuit is in a sampling state, the switch is turned on, and the holding capacitor is charged, if the capacitance value is small, the holding capacitor can be charged and discharged in a short time, and then the output signal of the output terminal changes along with the change of the input signal; when the circuit is in a hold state, the switch is opened, the input end of the integrated operational amplifier is in a high-resistance state, the capacitor discharges slowly, and the output signal is basically kept at a signal level value at the moment of opening because one end of the capacitor is connected with a signal following circuit formed by the integrated operational amplifier. The switch in the sampling hold module is a semiconductor switch tube.
Optionally, referring to fig. 3, a current-voltage waveform diagram of the feedback voltage sampling method and the circuit in one embodiment is shown. As shown in fig. 3, when the current flowing through the primary winding switching tube, that is, the primary current peak value Ipk, is suddenly changed, the demagnetization time Tdem of the flyback circuit is used as a time starting point, and the first falling zero of the voltage after the PWM of the driving signal is turned off is a time ending point; the method for marking the feedback voltage sampling position P in the current period uses the falling edge of the PWM driving signal as the time start point and the rising edge of the pulse of the current sampling signal vcs_sample as the time end point. Thus, the principle of capacitive charge balance is available:
P(n)≈k*Tdem(n)
therefore, when the primary current peak signal Ipk suddenly decreases, the sampling pulse signal, i.e. the control signal cv_sample, occurs before the demagnetization of the flyback power transformer is finished, so that the sample-and-hold signal of the current period output according to the control signal cv_sample can accurately reflect the voltage information of the voltage feedback signal.
According to the feedback voltage sampling method provided by the embodiment, the primary side current signal of the flyback circuit, the voltage feedback signal of the current period and the driving signal of the previous period are obtained, the control signal is generated according to the voltage feedback signal, the primary side current signal and the driving signal of the previous period, the voltage feedback signal is sampled and held according to the control signal to output the sampling and holding signal of the current period, and the sampling and holding signal can accurately reflect the voltage information of the voltage feedback signal due to the fact that the control signal is generated before demagnetization of the flyback power transformer is finished, and accuracy of feedback voltage sampling under abrupt change of the primary side current signal is achieved.
Referring to FIG. 4, a flowchart is shown illustrating step 104 in one embodiment.
In this embodiment, the primary current signal includes a current period primary current signal and a previous period primary current signal, and as shown in fig. 4, the step 104 includes sub-steps 402 to 406.
Step 402, obtaining the demagnetization time of the flyback circuit of the previous period according to the voltage feedback signal and the driving signal.
Wherein the demagnetizing time Tdem of the flyback circuit includes a time starting point and a time ending point, wherein the time starting point may be a time point corresponding to a falling edge of the driving signal PWM, and the time ending point may be a voltage feedback signal V of a current period after the driving signal PWM is turned off FB The time point of the zero crossing is first dropped.
Step 404, obtaining the pulse time point of the control signal according to the current period primary side current signal, the previous period primary side current signal and the demagnetizing time.
The primary current signal may be a reference current signal ipk_ref generated by a current reference generation module in the primary feedback controller, or may be a primary current peak signal obtained by sampling and holding, and a voltage signal generated by the primary current through a sampling resistor, and vcs_sample is obtained by sampling and holding.
The method for obtaining the pulse time point P (n+1) of the control signal of the current period may be that the signal processing module in the primary side feedback controller processes the primary side current signal Ipk (n+1) of the current period, the primary side current signal Ipk (n) of the previous period and the demagnetization time Tdem of the flyback circuit according to a mapping relationship.
Step 406, generating a control signal at a pulse time point.
The control signal cv_sample is output according to the pulse time point P (n+1) information.
Referring to FIG. 5, a flowchart is shown illustrating step 402 in one embodiment.
In this embodiment, as shown in FIG. 3, the step 402 includes sub-steps 502 through 506.
Step 502, obtaining a first time point corresponding to a falling edge of the driving signal according to the driving signal.
Alternatively, the first time point is a time point corresponding to a falling edge of the driving signal, and may be a time starting point of the demagnetization time of the flyback circuit.
Step 504, a second point in time is obtained at which the voltage feedback signal first falls zero crossing after the arrival of the drive signal.
Alternatively, the second point in time may be the time end point of the demagnetization time of the flyback circuit.
Step 506, obtaining the demagnetizing time according to the first time point and the second time point.
And determining the demagnetization time length of the flyback circuit according to the time interval between the time starting point and the time ending point of the demagnetization time of the flyback circuit.
In one embodiment, the time length value between the first time point and the pulse time point is a first time length value; the first time length value of the current period is in direct proportion to the demagnetizing time of the previous period, in direct proportion to the current peak value of the current signal of the primary side of the current period, and in inverse proportion to the current peak value of the current signal of the primary side of the previous period.
The first time length value of the current period may be a time interval length P (n+1) between a time starting point of the demagnetization time of the flyback circuit and a pulse time marking point of the control signal, where the time interval length P (n+1) is in direct proportion to a demagnetization time Tdem (n) of a previous period of the flyback circuit; the time interval length P (n+1) between the time starting point of the demagnetizing time of the flyback circuit and the pulse time marking point of the control signal is in direct proportion to the current peak value Ipk (n+1) of the primary current signal of the current period; the time interval length P (n+1) between the time starting point of the demagnetizing time of the flyback circuit and the pulse time mark point of the control signal is inversely proportional to the current peak value Ipk (n) of the primary current signal of the previous period. The specific relational expression:
P(n+1)＝k*Ipk(n+1)/Ipk(n)*Tdem(n)
in a similar way to that described above,
Tdem(n+1)≈Ipk(n+1)/Ipk(n)*Tdem(n)
then
P(n+1)≈k*Tdem(n+1)
Namely, approximately, can be obtained: the sampling position of the feedback voltage in the current period is in direct proportion to the demagnetizing time of the transformer in the current period. Where k is a scaling factor.
In one embodiment, the drive signal of the current period is generated from the sample-and-hold signal of the current period, the drive signal also being used to control the output voltage of the flyback circuit.
Outputting a control signal CV_sample according to the information of the pulse time point P (n+1) of the control signal; the control signal CV_sample is used for controlling the on-off of a switching tube in the sample hold module to realize the voltage feedback signal V FB Sample and hold is performed to generate a sample and hold signal vfb_hold and further generate a driving signal of the current period, thereby controlling the output voltage Vout of the flyback circuit.
Referring to fig. 6, a flowchart of a method for controlling an output voltage in one embodiment is shown.
In this embodiment, as shown in fig. 6, the control method of the output voltage includes steps 602 to 604.
Step 602, obtaining a driving signal of a corresponding period according to the sample-and-hold signal of a corresponding period obtained by the method as described above.
Step 604, controlling the output voltage of the flyback circuit according to the driving signal of the corresponding period.
According to the current period primary current signal Ipk (n+1), the previous period primary current signal Ipk (n) and the demagnetizing time Tdem (n)) Acquiring a pulse time point P (n+1) of the control signal; outputting a control signal CV_sample according to the information of the pulse time point P (n+1) of the control signal; the control signal CV_sample is used for controlling the on-off of a switching tube in the sample hold module to realize the voltage feedback signal V FB Sample and hold is performed to generate a sample and hold signal vfb_hold and further generate a driving signal of the current period, thereby controlling the output voltage Vout of the flyback circuit.
It should be understood that, although the steps in the flowcharts of fig. 1 and 4 to 6 are sequentially shown as indicated by arrows, these steps are not necessarily sequentially performed in the order indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in fig. 1 and 4-6 may include multiple sub-steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of execution of the sub-steps or stages is not necessarily sequential, but may be performed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps. It should be noted that the above-described different embodiments may be combined with each other.
Referring to fig. 7, a block diagram of a feedback voltage sampling circuit in one embodiment is shown.
In this embodiment, the feedback voltage sampling circuit includes a signal acquisition module 702, a signal generation module 704, and a sample-and-hold module 706.
The signal obtaining module 702 is configured to be connected to the flyback circuit, and obtain a primary current signal of the flyback circuit, a voltage feedback signal of a current period, and a driving signal of a previous period.
The signal generating module 704 is connected to the signal obtaining module 702, and is configured to generate a control signal according to the voltage feedback signal, the primary current signal, and the driving signal of the previous period.
The sample-hold module 706 is configured to be connected to the flyback circuit and the signal generating module 704, and sample-hold the voltage feedback signal according to the control signal to output a sample-hold signal of a current period, where the sample-hold signal is used to reflect voltage information of the voltage feedback signal.
In this embodiment, each module is configured to execute each step in the corresponding embodiment in fig. 1, and specifically refer to fig. 1 and the related description in the corresponding embodiment in fig. 1, which are not repeated herein.
In the feedback voltage sampling circuit provided in this embodiment, the signal acquisition module 702 acquires the primary current signal of the flyback circuit, the voltage feedback signal of the current period and the driving signal of the previous period, the signal generation module 704 generates a control signal according to the voltage feedback signal, the primary current signal and the driving signal of the previous period, the sample-hold module 706 samples and holds the voltage feedback signal according to the control signal to output a sample-hold signal of the current period, and the sample-hold signal is used for reflecting the voltage information of the voltage feedback signal, so as to realize the accuracy of feedback voltage sampling under abrupt change of the primary current signal, thereby ensuring stable output of the flyback circuit and further ensuring the stability of power conversion.
In one embodiment, the sample-hold module is further configured to control a switching tube inside the sample-hold module to conduct a path between the sample-hold module and the flyback circuit according to the control signal, so as to obtain a voltage feedback signal of the flyback circuit, and perform sample-hold to output a sample-hold signal.
The control signal CV_sample is used for controlling the on and off of a switching tube in the feedback voltage sampling and holding module, namely, a channel between the sampling and holding module and the voltage feedback module in the flyback circuit is conducted, so that a voltage feedback signal of the flyback circuit is obtained, and sampling and holding are carried out to output a sampling and holding signal VFB_hold.
Referring to fig. 8, a block diagram of a feedback voltage sampling circuit in one embodiment is shown.
In this embodiment, the feedback voltage sampling circuit includes a signal acquisition module 802, a signal generation module 804, a sample-and-hold module 806, and a voltage loop module 808.
The voltage loop module 808 is connected to the sample-and-hold module 806, and is configured to generate a driving signal of a current period according to the sample-and-hold signal of the current period, where the driving signal is further configured to control an output voltage of the flyback circuit.
The voltage loop module 808 receives the sample-hold signal vfb_hold of the current period output by the sample-hold module 806 to generate a driving signal of the current period, thereby controlling the output voltage Vout of the flyback circuit.
Referring to fig. 9, a block diagram of a feedback voltage sampling circuit in one embodiment is shown.
As shown in fig. 9, in this embodiment, the feedback voltage sampling circuit includes a signal acquisition module, a signal generation module, a sample-and-hold module, and a voltage loop module.
The signal generation module generates a control signal, namely a sampling pulse signal CV_sample, according to the voltage feedback signal, the primary current signal and the driving signal of the previous period; the sampling pulse signal CV_sample is used for controlling the on and off of a switching tube in the feedback voltage sampling and holding module, namely, a passage between the sampling and holding module and a voltage feedback module in the flyback circuit is conducted, so that a voltage feedback signal of the flyback circuit is obtained, and sampling and holding are carried out to output a sampling and holding signal VFB_hold; and the voltage loop module receives the sampling hold signal VFB_hold of the current period output by the sampling hold module to generate a driving signal of the current period, so as to control the output voltage Vout of the flyback circuit.
In one embodiment, as shown in fig. 9, the sample-and-hold module includes a first switching tube S1, a first capacitor C1; one end of the first switching tube S1 is connected with one end of the flyback circuit, the other end of the first switching tube S1, one end of the first capacitor C1 and one end of the voltage loop module are connected together, and the other end of the first capacitor C1 is grounded.
Referring to fig. 10, a block diagram of a feedback voltage sampling circuit in one embodiment is shown.
In this embodiment, the feedback voltage sampling circuit includes a signal acquisition module 1002, a signal generation module 1004, a sample-and-hold module 1006, a voltage loop module 1008, and a primary current module 1010.
The primary side current module 1010 is configured to be connected to the flyback circuit and the signal acquisition module 1002, respectively, to acquire a primary side current signal of the flyback circuit.
The primary current module 1010 may be configured to obtain a primary current signal of the flyback circuit by measuring a reference current signal ipk_ref generated by the voltage control module to represent a primary current peak signal Ipk, or by measuring a current sampling signal vcs_sample generated when the primary current signal flows through the sampling resistor to represent the primary current peak signal Ipk.
Referring to fig. 11, a block diagram of a feedback voltage sampling circuit in one embodiment is shown.
As shown in fig. 11, in this embodiment, the feedback voltage sampling circuit includes a signal acquisition module, a signal generation module, a sample-and-hold module, a voltage loop module, and a primary current module; the primary side current module is respectively connected with the voltage loop module and the signal acquisition module.
The signal acquisition module acquires a primary side current signal of the flyback circuit, a voltage feedback signal of a current period and a driving signal of a previous period, and the signal generation module generates a control signal, namely a sampling pulse signal CV_sample, according to the voltage feedback signal, the primary side current signal and the driving signal of the previous period; the sampling pulse signal CV_sample is used for controlling the on and off of a switching tube in the feedback voltage sampling and holding module, namely, a passage between the sampling and holding module and a voltage feedback module in the flyback circuit is conducted, so that a voltage feedback signal of the flyback circuit is obtained, and sampling and holding are carried out to output a sampling and holding signal VFB_hold; and the voltage loop module receives the sampling hold signal VFB_hold of the current period output by the sampling hold module to generate a driving signal of the current period, so as to control the output voltage Vout of the flyback circuit.
Referring to fig. 12, a block diagram of a feedback voltage sampling circuit in one embodiment is shown.
As shown in fig. 12, in this embodiment, the feedback voltage sampling circuit includes a signal acquisition module, a signal generation module, a sample-and-hold module, a voltage loop module, and a primary current module; the primary side current module is connected with the signal acquisition module.
The current sampling signal Vcs_sample generated when a primary current signal flows through a sampling resistor is measured through a primary current module, the primary current peak signal Ipk is characterized by the primary current signal of the flyback circuit, the signal acquisition module acquires the primary current signal of the flyback circuit, a voltage feedback signal of the current period and a driving signal of the previous period, and the signal generation module generates a control signal, namely a sampling pulse signal CV_sample, according to the voltage feedback signal, the primary current signal and the driving signal of the previous period; the sampling pulse signal CV_sample is used for controlling the on and off of a switching tube in the feedback voltage sampling and holding module, namely, a passage between the sampling and holding module and a voltage feedback module in the flyback circuit is conducted, so that a voltage feedback signal of the flyback circuit is obtained, and sampling and holding are carried out to output a sampling and holding signal VFB_hold; and the voltage loop module receives the sampling hold signal VFB_hold of the current period output by the sampling hold module to generate a driving signal of the current period, so as to control the output voltage Vout of the flyback circuit.
In one embodiment, as shown in fig. 12, the primary current module includes a second switching tube S2 and a second capacitor C2; one end of the second switching tube S2 is connected with one end of the flyback circuit, the other end of the second switching tube S2, one end of the second capacitor C2 and the other end of the signal generating module are connected together, and the other end of the second capacitor C2 is grounded.
Referring to fig. 13, a block diagram of an output voltage control circuit in one embodiment is shown.
In this embodiment, the output voltage control circuit includes a driving control module 1302 and a voltage control module 1304.
The driving control module 1302 is configured to obtain a driving signal of a corresponding period according to the sample-and-hold signal of the corresponding period obtained by the circuit.
The voltage control module 1304 is configured to control an output voltage of the flyback circuit according to the driving signal of the corresponding period.
In this embodiment, each module is configured to execute each step in the corresponding embodiment in fig. 6, and specifically refer to fig. 6 and related descriptions in the corresponding embodiment in fig. 6, which are not repeated herein.
According to the output voltage control circuit provided by the embodiment, the driving control module 1302 obtains the driving signal with the corresponding period according to the sampling and holding signal with the corresponding period obtained by the circuit, and the voltage control module 1304 controls the output voltage of the flyback circuit according to the driving signal with the corresponding period, so that the accuracy of feedback voltage sampling under abrupt change of the primary current signal is realized, and the stable output of the flyback circuit is ensured, and the stability of power supply conversion is further ensured.
Referring to fig. 14, a block diagram of an output voltage control circuit in one embodiment is shown.
In this embodiment, as shown in fig. 14, the voltage control module may also be used in an output voltage control circuit, where the output voltage control circuit includes a rectifying module 1410, a starting module 1420, an absorbing module 1430, a secondary rectifying and filtering module 1440, a power supply module 1450, a detecting module 1460, a voltage control module 1470, and a voltage converting module 1480.
The rectification module 1410 is connected to the ac power source, and is configured to convert an ac signal output by the ac power source into a dc signal.
The starting module 1420 is connected to the rectifying and filtering module 1410 and is used for starting the voltage control module 1470 through an external power source.
The absorption module 1430 is connected to the voltage conversion module 1480 for suppressing voltage surges.
The secondary rectifying and filtering module 1440 is connected to the voltage converting module 1480, and is configured to convert an output signal in an ac form output through the secondary winding in the voltage converting module into an output voltage in a dc form.
The power supply module 1450 is connected to the voltage control module 1470 and the voltage conversion module 1480, respectively, and is configured to convert the electric energy output through the voltage conversion module 1480 into the voltage control module 1470.
The detection module 1460 is connected to the power supply module 1450, the voltage control module 1470, and the voltage conversion module 1480, and is used for detecting whether the voltage conversion module 1480 is demagnetized and whether the output voltage control circuit is over-voltage.
The voltage control module 1470 is respectively connected to the start module 1420, the absorption module 1430, the power supply module 1450, and the detection module 1460, and is used for controlling the stability of the dc voltage output of the flyback circuit.
The voltage conversion module 1480, which may be a transformer, includes a primary winding Np, a secondary winding Ns, and an auxiliary winding Na.
Referring to fig. 15, a schematic structural diagram of a rectifying module according to an embodiment is shown.
In this embodiment, as shown in fig. 15, the rectifying module may be a full-bridge rectifying circuit formed by four diodes of the first diode D1, the second diode D2, the third diode D3, and the fourth diode D4, and configured to rectify an input voltage into a dc output, where the dc output corresponds to the input voltage, i.e., when the input voltage increases, the dc output increases, and when the input voltage decreases, the dc output decreases.
In one embodiment, the start-up module may be a start-up resistor Rst, which is connected to the power supply terminal VDD of the voltage control module. The starting resistor charges the power supply module when the voltage control module is started.
Referring to fig. 16, a schematic diagram of an absorber module in one embodiment is shown.
In this embodiment, as shown in fig. 16, the absorption module includes a fifth diode D5, a second capacitor C2, and a first resistor R1; the cathode of the fifth diode D5, one end of the second capacitor C2, and one end of the first resistor R1 are commonly connected, the other end of the second capacitor C2, the other end of the first resistor R1, and one end of the primary winding Np are commonly connected, and the anode of the fifth diode D5 is connected with the other end of the primary winding Np.
Referring to fig. 17, a schematic diagram of a secondary rectifying and filtering module in one embodiment is shown.
In this embodiment, as shown in fig. 17, the secondary rectifying and filtering module includes a sixth diode D6, a third capacitor C3, and a first resistor R2; the cathode of the sixth diode D6, one end of the third capacitor C3, and one end of the second resistor R2 are commonly connected to each other, the other end of the third capacitor C3, the other end of the second resistor R2, and one end of the secondary winding Ns are commonly connected to the ground, and the anode of the sixth diode D6 is connected to the other end of the secondary winding Ns.
Referring to fig. 18, a schematic structural diagram of a power supply module in one embodiment is shown.
In this embodiment, as shown in fig. 12, the power supply module includes a seventh diode D7 and a fourth capacitor C4; the cathode of the seventh diode D7, one end of the fourth capacitor C4, and the power supply end VDD of the voltage control module are commonly connected, and the anode of the seventh diode D7 is connected to one end of the auxiliary winding Na.
Referring to fig. 19, a schematic structural diagram of a detection module in one embodiment is shown.
In this embodiment, as shown in fig. 19, the detection module includes a third resistor R3 and a fourth resistor R4; one end of the third resistor R3, one end of the fourth resistor R4 and the feedback end FB of the voltage control module are commonly connected, the other end of the third resistor R3 is grounded, and the other end of the fourth resistor R4 is connected with one end of the auxiliary winding Na.
Referring to fig. 18, a current-voltage waveform diagram of a circuit and a feedback voltage sampling method in one embodiment is shown. As shown in fig. 18, even when the primary current peak signal Ipk suddenly decreases, the sample-and-hold pulse signal cv_sample occurs before the end of demagnetization of the flyback power transformer, that is, the sample-and-hold pulse signal can accurately reflect the voltage information of the voltage feedback signal.
The division of each module in the feedback voltage sampling circuit and the output voltage control circuit is only used for illustration, and in other embodiments, the feedback voltage sampling circuit and the output voltage control circuit may be divided into different modules according to the needs, so as to complete all or part of the functions of the feedback voltage sampling circuit and the output voltage control circuit.
For specific limitations of the feedback voltage sampling circuit and the output voltage control circuit, reference may be made to the above limitations of the feedback voltage sampling method and the output voltage control method, and no further description is given here. The feedback voltage sampling circuit and the output voltage control circuit may be all or partially implemented by software, hardware, or a combination thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.
The embodiment of the application also provides a computer device, which comprises a memory and a processor, wherein the memory stores a computer program, and the computer program when executed by the processor causes the processor to execute the steps of the method in the embodiment.
A computer-readable storage medium is also provided in an embodiment of the present application. One or more non-transitory computer-readable storage media containing computer-executable instructions that, when executed by one or more processors, cause the processors to perform the steps of a feedback voltage sampling method, an output voltage control method.
The feedback voltage sampling method and circuit, the output voltage control method and the circuit provided in the embodiments realize the accuracy of feedback voltage sampling under the abrupt change of the primary current signal under the abrupt change of the primary current, thereby ensuring the stable output of the flyback circuit, further ensuring the stability of power supply conversion, further improving the safety and reliability of the power system and equipment, and having important economic value and popularization and practice value.
Any reference to memory, storage, database, or other medium used in the present application may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM), which acts as external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous Link DRAM (SLDRAM), memory bus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims (11)

1. A feedback voltage sampling method, comprising:
acquiring a primary side current signal of a flyback circuit, a voltage feedback signal of a current period and a driving signal of a previous period, wherein the primary side current signal comprises the primary side current signal of the current period and the primary side current signal of the previous period;
acquiring a first time point corresponding to the falling edge of the driving signal according to the driving signal;
acquiring a second time point when the voltage feedback signal first drops to zero after the driving signal arrives;
acquiring demagnetization time according to the first time point and the second time point;
processing the current period primary side current signal, the last period primary side current signal and the demagnetizing time according to a mapping relation to obtain a pulse time point of a control signal;
generating the control signal at the pulse time point;
and carrying out sampling and holding on the voltage feedback signal according to the control signal so as to output a sampling and holding signal of the current period, wherein the sampling and holding signal is used for reflecting the voltage information of the voltage feedback signal.
2. The method of claim 1, wherein the time length value between the first time point and the pulse time point is a first time length value; the first time length value of the current period is in direct proportion to the demagnetizing time of the previous period, in direct proportion to the current peak value of the current period primary side current signal, and in inverse proportion to the current peak value of the previous period primary side current signal.
3. The method as recited in claim 1, further comprising:
and generating a driving signal of the current period according to the sampling and holding signal of the current period, wherein the driving signal is also used for controlling the output voltage of the flyback circuit.
4. A method of controlling an output voltage, comprising:
a method according to any one of claims 1 to 3, wherein the sample-and-hold signal of the corresponding period obtained by the method is used to obtain a drive signal of the corresponding period;
and controlling the output voltage of the flyback circuit according to the driving signal of the corresponding period.
5. A feedback voltage sampling circuit, comprising:
the signal acquisition module is used for being connected with the flyback circuit to acquire a primary side current signal of the flyback circuit, a voltage feedback signal of the current period and a driving signal of the previous period, wherein the primary side current signal comprises the primary side current signal of the current period and the primary side current signal of the previous period;
the signal generation module is used for being connected with the signal acquisition module and acquiring a first time point corresponding to the falling edge of the driving signal according to the driving signal; acquiring a second time point when the voltage feedback signal first drops to zero after the driving signal arrives; acquiring demagnetization time according to the first time point and the second time point; processing the current period primary side current signal, the last period primary side current signal and the demagnetizing time according to a mapping relation to obtain a pulse time point of a control signal; generating the control signal at the pulse time point;
the sampling and holding module is used for respectively connecting with the flyback circuit and the signal generating module, sampling and holding the voltage feedback signal according to the control signal so as to output a sampling and holding signal of the current period, and the sampling and holding signal is used for reflecting the voltage information of the voltage feedback signal.
6. The feedback voltage sampling circuit of claim 5 wherein the sample-and-hold module is further configured to control a switching tube within the sample-and-hold module to turn on a path between the sample-and-hold module and a flyback circuit according to the control signal to obtain a voltage feedback signal of the flyback circuit and to sample-and-hold to output a sample-and-hold signal.
7. The feedback voltage sampling circuit of claim 5, further comprising:
the voltage loop module is connected with the sample and hold module and is used for generating a driving signal of the current period according to the sample and hold signal of the current period, and the driving signal is also used for controlling the output voltage of the flyback circuit.
8. The feedback voltage sampling circuit of claim 7, wherein the sample-and-hold module comprises:
a first switching tube and a first capacitor; one end of the first switching tube is connected with one end of the flyback circuit, the other end of the first switching tube, one end of the first capacitor and one end of the voltage loop module are connected together, and the other end of the first capacitor is grounded.
9. The feedback voltage sampling circuit of claim 5, further comprising:
and the primary side current module is used for being respectively connected with the flyback circuit and the signal acquisition module to acquire the primary side current signal of the flyback circuit.
10. The feedback voltage sampling circuit of claim 9, wherein the primary side current module comprises:
the second switch tube and the second capacitor; one end of the second switching tube is connected with one end of the flyback circuit, the other end of the second switching tube, one end of the second capacitor and the other end of the signal acquisition module are connected together, and the other end of the second capacitor is grounded.
11. An output voltage control circuit, comprising:
a driving control module for obtaining a driving signal of a corresponding period according to the sample-and-hold signal of a corresponding period obtained by the feedback voltage sampling circuit according to any one of claims 5 to 10;
and the voltage control module is used for controlling the output voltage of the flyback circuit according to the driving signal of the corresponding period.
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