CN114189131A - Control method and control circuit of switching power supply and switching power supply - Google Patents
Control method and control circuit of switching power supply and switching power supply Download PDFInfo
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- CN114189131A CN114189131A CN202110929871.1A CN202110929871A CN114189131A CN 114189131 A CN114189131 A CN 114189131A CN 202110929871 A CN202110929871 A CN 202110929871A CN 114189131 A CN114189131 A CN 114189131A
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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
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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
- H02M1/14—Arrangements for reducing ripples from dc input or output
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
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Abstract
The invention discloses a control method and a control circuit of a switching power supply and the switching power supply, wherein a limit value adjusting signal is obtained according to a working mode of the switching power supply and a switching signal of a main power switching tube, a limit value of an inductive current is obtained according to a first compensation signal and the limit value adjusting signal, inductive current information of the switching circuit is sampled to obtain a current sampling signal, and the switching signal is generated according to the limit value of the inductive current and the current sampling signal and is used for controlling the on-off of the main power switching tube. According to the scheme of the invention, the difference value of the upper limit and the lower limit of the inductive current is set to be different under different working modes, so that the output voltage ripple is smaller in the process of switching the load of the switching power supply.
Description
Technical Field
The present invention relates to the field of power electronics technologies, and in particular, to a control method and a control circuit for a switching power supply, and a switching power supply.
Background
In the current circuit control of the switching power supply, the output voltage is controlled by controlling the on and off of a main power switch tube in a switch circuit. The switch circuit comprises a BUCK circuit, a BOOST circuit and other circuit structures. For example, fig. 1 is a schematic circuit structure diagram of a BUCK circuit, and as shown in fig. 1, the BUCK circuit includes a first switch transistor M00, a second switch transistor D00, and an inductor L00, where the first switch transistor M00 is a main power MOS transistor, the second switch transistor D00 is a freewheeling diode, Vin is an input voltage of the BUCK circuit, Vout is an output voltage of the BUCK circuit, a sampled signal is compared with a limit signal of the inductor current by sampling the inductor current to generate a driving signal, and the driving signal performs on-off control on the first switch transistor M00 to adjust the output voltage to a proper voltage value.
Generally, when the load of the switching circuit is heavy load, the switching circuit operates in the continuous operation mode, and when the load of the switching power supply is light load, the switching circuit operates in the discontinuous operation mode.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a control method, a control circuit and a switching power supply for a switching power supply, so as to solve the technical problem of large output voltage ripple caused by load switching in the prior art.
The technical solution of the present invention is to provide a control method of a switching power supply, wherein the switching power supply comprises a main power switch tube and an inductor, and the method comprises the following steps:
obtaining a limit value adjusting signal according to the working mode of the switching power supply and the switching signal of the main power switching tube;
receiving the limit value adjusting signal, obtaining a first compensation signal according to an output voltage feedback signal and a reference voltage signal of the switching power supply, and obtaining a limit value of an inductive current according to the first compensation signal and the limit value adjusting signal;
and sampling the inductive current information of the switching circuit to obtain a current sampling signal, and generating the switching signal according to the limit value of the inductive current and the current sampling signal, wherein the switching signal is used for controlling the on-off of the main power switching tube.
Furthermore, the limit value of the inductor current comprises an upper limit value and a lower limit value, the limit value adjusting signal is the difference value between the upper limit value and the lower limit value, and the upper limit value and/or the lower limit value are/is adjusted according to the limit value adjusting signal.
Further, comprising the steps of: judging the working mode of the switching power supply according to a preset parameter to generate a mode judging signal, wherein the preset parameter is the switching signal or the first compensation signal;
obtaining a first control signal according to a switching signal of the main power switching tube and a preset time signal, wherein the first control signal is used for controlling charging and discharging of a first capacitor so as to obtain a first current signal;
and receiving the first current signal and the mode discrimination signal so as to output the limit value adjusting signal according to the working mode of the switching power supply.
Further, comprising the steps of: and receiving the mode judging signal, taking the first current signal as a limit value adjusting signal with a first current value when the switching power supply is judged to be in a first working mode, and reducing the limit value adjusting signal with the first current value to obtain a limit value adjusting signal with a second current value when the switching power supply is judged to be in a second working mode.
Further, comprising the steps of: receiving the mode discrimination signal to obtain a first coefficient associated with the mode discrimination signal,
and multiplying the first coefficient and the first current signal to obtain the limit value adjusting signal.
Further, comprising the steps of:
and receiving the mode discrimination signal, wherein when the switching power supply works in a continuous working mode, the value of the first coefficient is a first threshold value, and when the switching power supply enters an intermittent working mode, the value of the first coefficient monotonically decreases from the first threshold value along with the load size of the switching power supply until the value decreases to a second threshold value.
Further, comprising the steps of: receiving a sampled signal representative of the switching power supply input voltage and/or output voltage to obtain a second coefficient proportional to the sampled signal,
and multiplying the second coefficient by the limit adjusting signal to obtain a second limit adjusting signal, and outputting the second limit adjusting signal as a final limit adjusting signal.
Further, a switching period corresponding time is obtained according to a switching signal of the main power switching tube, and the switching period corresponding time is compared with a preset time signal to obtain a first control signal;
the first control signal is used for controlling charging and discharging of the first capacitor to obtain a first voltage signal; the first voltage signal is subjected to voltage-current conversion to obtain the first current signal.
In a second aspect, a control circuit for a switching power supply is provided, the switching power supply including a main power switch tube and an inductor, including:
the limit value adjusting circuit is used for obtaining a limit value adjusting signal according to the working mode of the switching power supply and the switching signal of the main power switching tube;
the inductive current limit circuit receives the limit adjusting signal, obtains a first compensation signal according to an output voltage feedback signal and a reference voltage signal of the switching power supply, and obtains a limit of an inductive current according to the first compensation signal and the limit adjusting signal;
and the driving control circuit is used for sampling the inductive current information of the switching circuit to obtain a current sampling signal, and generating the switching signal according to the limit value of the inductive current and the current sampling signal, wherein the switching signal is used for controlling the on-off of the main power switching tube.
Further, the limit value adjusting circuit comprises a timing circuit and an adjusting circuit, the timing circuit receives the switching signal and the preset time signal, the timing circuit obtains a switching period according to the switching signal, and generates a first control signal according to a difference value between the time of the switching period and the preset time signal;
the adjusting circuit receives the first control signal and a mode discrimination signal representing the working mode of the switching power supply to generate the limit adjusting signal.
Further, the adjusting circuit comprises a mode judging circuit, a charging and discharging circuit and a current adjusting circuit, the mode judging circuit receives a predetermined parameter of the switching power supply, so as to judge the working mode of the switching power supply according to the predetermined parameter and generate the mode judging signal, and the predetermined parameter is the switching signal or the first compensation signal;
the charging and discharging circuit receives the first control signal, and the first control signal is used for controlling charging and discharging of a first capacitor to obtain a first current signal;
the current adjusting circuit receives the first current signal and the mode judging signal to output the limit adjusting signal according to the working mode of the switching power supply.
Further, the current adjusting circuit receives the mode judging signal, when the switching power supply is judged to be in the first working mode, the first current signal is used as a limit adjusting signal with a first current value, and when the switching power supply is judged to be in the second working mode, the limit adjusting signal with the first current value is reduced to obtain a limit adjusting signal with a second current value.
Further, the current adjusting circuit receives the mode discrimination signal to obtain a first coefficient associated with the mode discrimination signal, and the current adjusting circuit multiplies the first coefficient by the first current signal to obtain the limit value adjusting signal, wherein when the switching power supply operates in a continuous operation mode, the value of the first coefficient is a first threshold value, and when the switching power supply enters an intermittent operation mode, the value of the first coefficient monotonically decreases from the first threshold value along with the load size of the switching power supply until the value decreases to a second threshold value.
Further, the current regulation circuit receives a sampling signal representing the input voltage and/or the output voltage of the switching power supply to obtain a second coefficient proportional to the input sampling signal,
and the current adjusting circuit multiplies the second coefficient by the limit adjusting signal to obtain a second limit adjusting signal, and the second limit adjusting signal is used as a final output signal of the current adjusting circuit and is transmitted to the inductance circuit limit circuit.
In a third aspect, a switching power supply is provided, where the switching power supply includes a main power switch tube and an inductor, the switching circuit adjusts an input voltage to a desired output voltage through the on and off of the main power switch tube, and the switching power supply includes the above control circuit, and the control circuit generates a switching signal to control the on and off of the main power switch tube.
By adopting the switching power supply circuit structure, the limit value of the inductive current is adjusted by judging the working mode of the switching power supply, so that the difference value of the upper limit value and the lower limit value of the inductive current is different in different working modes, and the output voltage ripple is reduced in the process of switching the load of the switching power supply from heavy load to light load.
Drawings
FIG. 1 is a circuit block diagram of a BUCK circuit in the prior art;
fig. 2 is a schematic circuit diagram of a control circuit of a switching circuit according to a first embodiment of the present invention;
FIG. 3 is a schematic circuit diagram of a limit adjusting circuit according to a first embodiment of the present invention;
FIG. 4 is a diagram of operating waveforms according to FIGS. 2 and 3;
FIG. 5 is a schematic circuit diagram of a limit adjusting circuit according to a second embodiment of the present invention;
fig. 6 is a schematic circuit diagram of a limit adjusting circuit according to a third embodiment of the invention.
Detailed Description
Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to only these embodiments. The invention is intended to cover alternatives, modifications, equivalents and alternatives which may be included within the spirit and scope of the invention.
In the following description of the preferred embodiments of the present invention, specific details are set forth in order to provide a thorough understanding of the present invention, and it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.
The invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. It should be noted that the drawings are in simplified form and are not to precise scale, which is only used for convenience and clarity to assist in describing the embodiments of the present invention.
Fig. 2 is a schematic circuit diagram of a control circuit of a switch circuit according to a first embodiment of the present invention, and fig. 3 is a schematic specific structure diagram of a limit adjusting circuit according to the present invention. The power stage circuit in fig. 2 is exemplified by a Buck topology, the power stage circuit includes a main power switch transistor, for example, M00 in fig. 2 is a main power switch transistor, the Buck switching power supply includes a main power switch transistor M00, a second switch transistor D00 and an inductor L00, an input voltage is denoted as Vin, an output voltage is denoted as Vout, and a control circuit includes a limit value adjusting circuit 10, an inductor current limit value circuit 20 and a driving control circuit 30, the control circuit generates a switching signal for controlling the on and off of the main power switch transistor M00, and the Buck switching power supply adjusts the input voltage to a desired output voltage by the on and off of the main power switch transistor.
Referring to fig. 3, in an embodiment, the limit adjusting circuit 10 receives the switching signal T and a mode decision signal indicating an operation mode of the switching power supply to obtain a limit adjusting signal Δ I. In particular, the limit adjustment circuit includes a timing circuit receiving the switching signal T and a predetermined time signal, and an adjustment circuit obtaining a switching period corresponding time from the switching signal T and generating a first control signal (e.g., VK1, VK2) from a difference between the switching period corresponding time and the predetermined time signal, the predetermined time signal representing a desired switching period time.
Specifically, in an embodiment, the adjusting circuit includes a mode determining circuit, a charging/discharging circuit, and a current adjusting circuit, the mode determining circuit receives a predetermined parameter of the switching power supply, so as to determine an operating mode of the switching power supply according to the predetermined parameter, and generates the mode determining signal VM, where the predetermined parameter is the switching signal T or the first compensating signal VC, where, according to an operating principle of the switching power supply, when the system operates in different operating modes, a duty ratio of the switching signal T or a magnitude of the first compensating signal VC is different, for example, when the system operates in a continuous operating mode, a duty ratio of the switching signal is larger, and when the system operates in an intermittent operating mode, a duty ratio of the switching signal is smaller, or, when the system operates in a continuous operating mode, the first compensating signal of the switching signal is larger, when the system works in the discontinuous working mode, the first compensation signal of the switching signal is smaller, so that the working mode of the current switching power supply can be correspondingly obtained by analyzing the duty ratio of the switching signal T or the magnitude of the first compensation signal VC. The charging and discharging circuit receives the first control signal VK1 or VK2, and the first control signal is used for controlling charging and discharging of a first capacitor to obtain a first current signal; as shown in fig. 3, the charging and discharging circuit obtains a first capacitor voltage signal V3 by charging and discharging the first capacitor C40 through two current sources, and then obtains a first current signal Δ I through the second voltage-to-current circuit U03. And the current adjusting circuit receives the first current signal delta I and the mode judging signal VM to output the limit adjusting signal according to the working mode of the switching power supply. In the embodiment shown in fig. 3, the current adjusting circuit receives the mode determination signal, and when the switching power supply is in a first operation mode, such as a continuous operation mode, the current adjusting circuit uses the first current signal as the limit adjusting signal Δ I of the first current value, and when the switching power supply is in a second operation mode, such as an intermittent operation mode, the current adjusting circuit reduces the limit adjusting signal Δ I of the first current value to obtain the limit adjusting signal Δ I of the second current value, for example, the limit adjusting signal Δ I of the second current value is reduced to 1/2 × Δ I.
In one embodiment, the inductor current limit circuit 20 includes an error compensation circuit and a current limit circuit, the error compensation circuit obtains a first compensation signal Vc based on an output voltage feedback signal FB and a reference voltage signal Vref1 that characterize the output voltage information; the current limit circuit obtains a limit value of an inductor current according to the first compensation signal Vc and a limit value adjustment signal, where the limit value of the inductor current includes an upper limit value and a lower limit value, such as an upper limit value IM and a lower limit value IL, the limit value adjustment signal Δ I is a difference between the upper limit value and the lower limit value, and the inductor current limit circuit adjusts the upper limit value and/or the lower limit value according to the limit value adjustment signal Δ I to adjust a switching time of a main power switching tube, as shown in fig. 2, the first compensation signal Vc may be obtained through a comparator U00 and a first voltage-to-current circuit U01. In the present embodiment, the limit signal is described by taking a current signal as an example, but the present invention is not limited thereto, and may be represented by a voltage signal.
The driving control circuit 30 comprises an inductive current control circuit U04 and a driving circuit U05, the inductive current control circuit U04 samples inductive current information of the switching circuit to obtain a current sampling signal, the switching signal T is generated according to the limit value of the inductive current and the current sampling signal, and the switching signal is driven by the driving circuit U05 to control the on and off of the main power switching tube. Here, the inductor current control circuit may be implemented as a comparison circuit, but is not limited thereto.
Referring to fig. 4, which is a waveform diagram of the operation according to fig. 2 and 3, according to the above control scheme, ILm is an inductor current, Δ I is a difference between an upper limit value and a lower limit value, and a shaded portion is a charge of an output capacitor by a difference between the inductor current and the output current in one switching period, so that the shaded portion can represent a fluctuation condition of an output voltage. By setting different difference values of the upper limit value and the lower limit value under different working modes, for example, under a continuous working mode CCM, the difference value between the upper limit value and the lower limit value is delta I, and under an intermittent working mode DCM, the difference value between the upper limit value and the lower limit value is 1/2 delta I, so that under the CCM and DCM, the area difference of shadow departments is not large, and in the process of load switching, the fluctuation of output voltage is small.
Fig. 5 is a schematic circuit diagram of a limit adjustment circuit according to a second embodiment of the present invention, in which an inductor current limit circuit and a driving control circuit in this embodiment have the same circuit structure as those in the first embodiment, except that the current adjustment circuit includes a first coefficient circuit, the first coefficient circuit receives the mode decision signal to obtain a first coefficient K1 associated with the mode decision signal, preferably, when the switching power supply operates in the continuous operation mode, a value of the first coefficient is a first threshold, and when the switching power supply enters the discontinuous operation mode, a value of the first coefficient monotonically decreases from the first threshold until the value decreases to a second threshold along with a load size of the switching power supply. Here, the first threshold may be set to be normalized 1, and when the switching power supply enters the discontinuous operation mode, the value of the first coefficient monotonically decreases from 1 as the load size of the switching power supply enters the discontinuous operation mode, where, due to the difference in load size, the required power is different, for example, the smaller the load is, the deeper the switching power supply enters the discontinuous operation mode, and at this time, the smaller the first coefficient is, so as to meet the ripple requirement, where the monotonic decrease may be a linear decrease or other monotonic decrease manner. Then, the current adjustment circuit multiplies the first coefficient K1 by the first current signal Δ I to obtain the limit adjustment signal K1 Δ I.
In the embodiment, the change of the limit value adjusting signal is accurately controlled by the switching power supply system along with the gradual switching of the modes through a more accurate gradual change process, and the control precision is high and accurate.
It will be appreciated that in the embodiments of fig. 4 and 5, which take the CCM transition to DCM as an example, the limit adjustment circuit may also switch the magnitude of the limit adjustment signal in reverse according to the current mode during the transition from DCM to CCM, in the same manner as described above.
Fig. 6 is a schematic diagram of a circuit configuration of a control circuit of a switching circuit according to a third embodiment of the present invention, in which an inductor current limit circuit and a driving control circuit are the same as those in the first embodiment, except that the current adjusting circuit includes a second coefficient circuit, the second coefficient circuit receives a sampling signal representing an input voltage and/or an output voltage of the switching power supply to obtain a second coefficient K2 proportional to the sampling signal, such as K2 ═ (Vin-Vo)/Vin, the second coefficient may also be proportional to the input voltage or the output voltage alone, and the current adjusting circuit multiplies the second coefficient by the limit adjusting signal to obtain a second limit adjusting signal as an output signal of the current adjusting circuit to be transmitted to the inductor current limit circuit. Here, the second coefficient K2 may be combined with the first or second embodiment, such as K2 × 1/2 × Δ I or K2 × K1 × Δ I, and the multiplied signal is transmitted to the inductor limit circuit as the final output signal of the current adjusting circuit.
In this embodiment, since there is a process of adjusting the limit value adjustment signal Δ I to be stable when the input voltage Vin or the output voltage Vo jumps, and there is a process of adjusting the operating frequency of the system in this process, the input voltage Vin or the output voltage is associated with the second coefficient according to this embodiment, so that the change of the input voltage can be reflected to the control loop through the limit value adjustment signal Δ I, thereby maintaining the stability of the operating frequency of the system in the adjustment process.
The above-described embodiments do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the above-described embodiments should be included in the protection scope of the technical solution.
Claims (15)
1. A control method of a switching power supply, the switching power supply comprises a main power switch tube and an inductor, and the control method is characterized by comprising the following steps:
obtaining a limit value adjusting signal according to the working mode of the switching power supply and the switching signal of the main power switching tube;
receiving the limit value adjusting signal, obtaining a first compensation signal according to an output voltage feedback signal and a reference voltage signal of the switching power supply, and obtaining a limit value of an inductive current according to the first compensation signal and the limit value adjusting signal;
and sampling the inductive current information of the switching circuit to obtain a current sampling signal, and generating the switching signal according to the limit value of the inductive current and the current sampling signal, wherein the switching signal is used for controlling the on-off of the main power switching tube.
2. The control method of the switching power supply according to claim 1, wherein the limit value of the inductor current includes an upper limit value and a lower limit value,
the limit value adjusting signal is the difference value of the upper limit value and the lower limit value, and the upper limit value and/or the lower limit value are adjusted according to the limit value adjusting signal.
3. The control method of the switching power supply according to claim 1, further comprising the steps of:
judging the working mode of the switching power supply according to a preset parameter to generate a mode judging signal, wherein the preset parameter is the switching signal or the first compensation signal;
obtaining a first control signal according to a switching signal of the main power switching tube and a preset time signal, wherein the first control signal is used for controlling charging and discharging of a first capacitor so as to obtain a first current signal;
and receiving the first current signal and the mode discrimination signal so as to output the limit value adjusting signal according to the working mode of the switching power supply.
4. The control method of the switching power supply according to claim 3, further comprising the steps of:
and receiving the mode judging signal, taking the first current signal as a limit value adjusting signal with a first current value when the switching power supply is judged to be in a first working mode, and reducing the limit value adjusting signal with the first current value to obtain a limit value adjusting signal with a second current value when the switching power supply is judged to be in a second working mode.
5. The control method of the switching power supply according to claim 3, further comprising the steps of:
receiving the mode discrimination signal to obtain a first coefficient associated with the mode discrimination signal,
and multiplying the first coefficient and the first current signal to obtain the limit value adjusting signal.
6. The control method of the switching power supply according to claim 5, further comprising the steps of:
and receiving the mode discrimination signal, wherein when the switching power supply works in a continuous working mode, the value of the first coefficient is a first threshold value, and when the switching power supply enters an intermittent working mode, the value of the first coefficient monotonically decreases from the first threshold value along with the load size of the switching power supply until the value decreases to a second threshold value.
7. The control method of the switching power supply according to claim 3, 4 or 5, characterized by further comprising the steps of:
receiving a sampled signal representative of the switching power supply input voltage and/or output voltage to obtain a second coefficient proportional to the sampled signal,
and multiplying the second coefficient by the limit adjusting signal to obtain a second limit adjusting signal, and outputting the second limit adjusting signal as a final limit adjusting signal.
8. The control method of the switching power supply according to claim 3,
obtaining a switching period corresponding time according to a switching signal of the main power switching tube, and comparing the switching period corresponding time with a preset time signal to obtain a first control signal;
the first control signal is used for controlling charging and discharging of the first capacitor to obtain a first voltage signal; the first voltage signal is subjected to voltage-current conversion to obtain the first current signal.
9. A control circuit for a switching power supply, the switching power supply including a main power switch transistor and an inductor, comprising:
the limit value adjusting circuit is used for obtaining a limit value adjusting signal according to the working mode of the switching power supply and the switching signal of the main power switching tube;
the inductive current limit circuit receives the limit adjusting signal, obtains a first compensation signal according to an output voltage feedback signal and a reference voltage signal of the switching power supply, and obtains a limit of an inductive current according to the first compensation signal and the limit adjusting signal;
and the driving control circuit is used for sampling the inductive current information of the switching circuit to obtain a current sampling signal, and generating the switching signal according to the limit value of the inductive current and the current sampling signal, wherein the switching signal is used for controlling the on-off of the main power switching tube.
10. The control circuit of the switching power supply according to claim 9, wherein the limit value adjusting circuit includes a timing circuit and an adjusting circuit,
the timing circuit receives the switching signal and the preset time signal, obtains a switching period according to the switching signal, and generates a first control signal according to the difference value between the time of the switching period and the preset time signal;
the adjusting circuit receives the first control signal and a mode discrimination signal representing the working mode of the switching power supply to generate the limit adjusting signal.
11. The control circuit of the switching power supply according to claim 10, wherein the adjusting circuit comprises a mode discriminating circuit, a charging/discharging circuit, and a current adjusting circuit,
the mode discrimination circuit receives a preset parameter of the switching power supply, so as to judge the working mode of the switching power supply according to the preset parameter and generate the mode discrimination signal, wherein the preset parameter is the switching signal or the first compensation signal;
the charging and discharging circuit receives the first control signal, and the first control signal is used for controlling charging and discharging of a first capacitor to obtain a first current signal;
the current adjusting circuit receives the first current signal and the mode judging signal to output the limit adjusting signal according to the working mode of the switching power supply.
12. The control circuit of the switching power supply according to claim 11, wherein the current adjusting circuit receives the mode discrimination signal, and when the switching power supply is determined to be in the first operation mode, the current adjusting circuit takes the first current signal as a limit adjusting signal having a first current value, and when the switching power supply is determined to be in the second operation mode, the current adjusting circuit reduces the limit adjusting signal having the first current value to obtain a limit adjusting signal having a second current value.
13. The control circuit of the switching power supply according to claim 11, wherein the current adjusting circuit receives the mode discrimination signal to obtain a first coefficient associated with the mode discrimination signal,
the current adjustment circuit multiplies the first coefficient by the first current signal to obtain the limit adjustment signal,
when the switching power supply works in a continuous working mode, the value of the first coefficient is a first threshold value, and when the switching power supply enters an intermittent working mode, the value of the first coefficient monotonically decreases from the first threshold value to a second threshold value along with the load of the switching power supply.
14. The control circuit of the switching power supply according to claim 11, 12 or 13, wherein the current adjusting circuit receives a sampling signal representing the input voltage and/or the output voltage of the switching power supply to obtain a second coefficient proportional to the input sampling signal,
and the current adjusting circuit multiplies the second coefficient by the limit adjusting signal to obtain a second limit adjusting signal, and the second limit adjusting signal is used as a final output signal of the current adjusting circuit and is transmitted to the inductance circuit limit circuit.
15. A switching power supply comprising a main power switch tube and an inductor, said switching circuit regulating an input voltage to a desired output voltage by switching said main power switch tube on and off,
the switching power supply comprises the control circuit of any one of claims 9-14, the control circuit generating a switching signal to control the switching on and off of the main power switching tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110929871.1A CN114189131B (en) | 2021-08-13 | 2021-08-13 | Control method and control circuit of switching power supply and switching power supply |
Applications Claiming Priority (1)
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116436293A (en) * | 2023-06-07 | 2023-07-14 | 杰华特微电子股份有限公司 | Hybrid control circuit and control method of switching power supply and switching power supply |
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| CN106130321A (en) * | 2016-08-31 | 2016-11-16 | 杰华特微电子（张家港）有限公司 | The control method of a kind of on-off circuit, control circuit and switch circuit devices |
| CN106300972A (en) * | 2016-08-31 | 2017-01-04 | 杰华特微电子（张家港）有限公司 | The control method of a kind of on-off circuit, control circuit and switch circuit devices |
| US20200091815A1 (en) * | 2018-09-18 | 2020-03-19 | Astec International Limited | Control Circuits With Peak Current Limit Protection For Switched Mode Power Supplies |
| CN112187024A (en) * | 2020-09-27 | 2021-01-05 | 上海新进芯微电子有限公司 | Switching power supply and output power regulation and control circuit and method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106130321A (en) * | 2016-08-31 | 2016-11-16 | 杰华特微电子（张家港）有限公司 | The control method of a kind of on-off circuit, control circuit and switch circuit devices |
| CN106300972A (en) * | 2016-08-31 | 2017-01-04 | 杰华特微电子（张家港）有限公司 | The control method of a kind of on-off circuit, control circuit and switch circuit devices |
| US20200091815A1 (en) * | 2018-09-18 | 2020-03-19 | Astec International Limited | Control Circuits With Peak Current Limit Protection For Switched Mode Power Supplies |
| CN112187024A (en) * | 2020-09-27 | 2021-01-05 | 上海新进芯微电子有限公司 | Switching power supply and output power regulation and control circuit and method thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116436293A (en) * | 2023-06-07 | 2023-07-14 | 杰华特微电子股份有限公司 | Hybrid control circuit and control method of switching power supply and switching power supply |
| CN116436293B (en) * | 2023-06-07 | 2023-09-22 | 杰华特微电子股份有限公司 | Hybrid control circuit and control method of switching power supply and switching power supply |
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| CN114189131B (en) | 2024-06-25 |
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