CN218449866U - Switching power supply and working mode control circuit thereof - Google Patents
Switching power supply and working mode control circuit thereof Download PDFInfo
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- CN218449866U CN218449866U CN202222696482.1U CN202222696482U CN218449866U CN 218449866 U CN218449866 U CN 218449866U CN 202222696482 U CN202222696482 U CN 202222696482U CN 218449866 U CN218449866 U CN 218449866U
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- 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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Abstract
The utility model discloses a switching power supply's mode of operation control circuit and switching power supply relates to switching power supply control field, according to switching power supply's output voltage, load and input line voltage integrated control switching power supply entering different modes of operation. The mode control module generates a first clock signal when the output voltage is smaller than a first preset voltage threshold and the load is a heavy load so as to control the switching power supply to work in a CCM or DCM mode through the power switch control module, and the problems that the working frequency of the switching power supply is low and the switching power supply is easy to damage due to the limitation of a QR mode when the switching power supply has a low output voltage are solved. When the output voltage is not less than the first preset voltage threshold and the load is a heavy load, the mode control module generates a second clock signal according to the input line voltage so as to control the switching power supply to work in one mode of CCM, DCM or QR through the power switch control module, and the working efficiency of the switching power supply is ensured.
Description
Technical Field
The utility model relates to a switching power supply control field especially relates to a switching power supply's of wide output range mode control circuit and switching power supply.
Background
The switching power supply is widely applied due to the characteristics of simple circuit structure and capability of efficiently providing multi-path direct current output. The operation modes of the switching power supply include CCM (continuous Conduction Mode), DCM (discontinuous Conduction Mode), and QR (Quasi-Resonant Mode). In the prior art, when a load connected to the rear end of the switching power supply is heavy and the input line voltage is high, the switching power supply is controlled to work in a QR mode. However, when the switching power supply has a wider output voltage requirement, for example, a lower output voltage requirement, the operating frequency of the switching power supply is limited due to the characteristics of the QR mode, so that the stress of the transformer in the switching power supply is increased, and the problems of saturation of the magnetic element and damage to the switching power supply are easily caused.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a switching power supply's mode of operation control circuit and switching power supply can get into different modes of operation according to switching power supply's output voltage, load and switching power supply's input line voltage integrated control switching power supply.
In order to solve the technical problem, the utility model provides a switching power supply's mode of operation control circuit, include:
the mode control module is used for generating a first clock signal when the output voltage of the switching power supply is smaller than a first preset voltage threshold and the load of the switching power supply meets a preset overloading condition, and generating a second clock signal according to the input line voltage of the switching power supply when the output voltage is not smaller than the first preset voltage threshold and the load meets the preset overloading condition;
and the power switch control module is used for controlling the state of a power switch in the switching power supply according to the first clock signal so as to control the switching power supply to enter a CCM or DCM working mode, and controlling the state of the power switch according to the second clock signal so as to control the switching power supply to enter the CCM or DCM or QR working mode.
Preferably, the mode control module comprises a clock output selector, a first clock module and a second clock module;
the output end of the first clock module and the output end of the second clock module are respectively connected with the first clock input end and the second clock input end of the clock output selector, and the output end of the clock output selector is used as the output end of the mode control module;
the first clock module is used for generating the first clock signal, and the frequency of the first clock signal is positively correlated with the size of the load;
the second clock module is used for generating a second clock signal based on the primary side resonance waveform when the valley number of the primary side resonance waveform of the switching power supply is not more than a preset valley number threshold value, and generating a second clock signal with the frequency positively correlated with the load size when the valley number of the primary side resonance waveform is more than the preset valley number threshold value;
the clock output selector is used for outputting a first clock signal generated by the first clock module when the output voltage is smaller than the first preset voltage threshold and the load meets the preset heavy load condition, and outputting a second clock signal output by the second clock output selector when the output voltage is not smaller than the first preset voltage threshold and the load meets the preset heavy load condition.
Preferably, the second clock module comprises a second clock submodule, a valley locking module and a second clock output selector;
the output end of the second clock submodule and the output end of the valley bottom locking module are respectively connected with the first input end and the second input end of the second clock output selector, and the output end of the second clock output selector is connected with the second clock input end of the clock output selector;
the second clock submodule is used for generating a second clock sub-signal when the valley number of the primary side resonance waveform of the switching power supply is larger than a preset valley number threshold value, the frequency of the second clock sub-signal is in negative correlation with the valley number of the primary side resonance waveform, and the valley number of the primary side resonance waveform is in negative correlation with the size of the load;
the valley bottom locking module is used for controlling the primary side resonance waveform to be opened at a plurality of valley bottoms when the number of valley bottoms of the primary side resonance waveform is not more than the preset valley bottom threshold value, and taking the primary side resonance waveform opened at the valley bottoms as a second clock valley bottom signal;
the second clock output selector is configured to output a second clock valley signal generated by the valley bottom locking module to the clock output selector as the second clock signal when the number of valleys of the primary-side resonant waveform is greater than the preset valley bottom threshold value, and output a second clock sub-signal generated by the second clock sub-module to the clock output selector as the second clock signal when the number of valleys of the primary-side resonant waveform is not greater than the preset valley bottom threshold value.
Preferably, the power switch control module comprises an and gate, a D flip-flop and a driving circuit;
the first input end of the AND gate and the clock signal input end of the D trigger are both connected with the output end of the mode control module, the positive phase output end of the D trigger is connected with the second input end of the AND gate, the output end of the AND gate is connected with the input end of the driving circuit, and the output end of the driving circuit is used as the output end of the power switch control module and is connected with the control end of the power switch;
the driving circuit is used for amplifying the signal output by the output end of the AND gate so as to control the state of the power switch.
Preferably, the mode control module is further configured to generate a third clock signal when the output voltage of the switching power supply is smaller than the first preset voltage threshold and the load meets a preset light load condition;
the power switch control module is further configured to control a state of the power switch based on the third clock signal so as to control the switching power supply to enter a DCM operation mode.
Preferably, the mode control module is further configured to generate a fourth clock signal when the output voltage of the switching power supply is not less than the first preset voltage threshold and the load meets a preset light load condition;
the power switch control module is further configured to control a state of the power switch based on the fourth clock signal so as to control the switching power supply to enter a DCM operation mode.
Preferably, the mode control module is specifically configured to generate a first clock signal when the output voltage of the switching power supply is less than a first preset voltage threshold and the load of the switching power supply meets a preset heavy load condition; generating a fifth clock signal when the output voltage is not less than the first preset voltage threshold, the load meets the preset overloading condition, and the input line voltage is greater than a second preset voltage threshold; generating a sixth clock signal when the output voltage is not less than the first preset voltage threshold, the load meets the preset overloading condition, and the input line voltage is not greater than a second preset voltage threshold;
the power switch control module is specifically used for controlling the state of a power switch in the switching power supply according to the first clock signal so as to control the switching power supply to enter a CCM or DCM working mode; controlling the state of the power switch according to the fifth clock signal so as to control the switching power supply to enter a QR (quick response) working mode; and controlling the state of the power switch according to the sixth clock signal so as to control the switching power supply to enter a CCM or DCM working mode.
Preferably, the mode control module is specifically configured to generate a first clock signal when an output voltage of the switching power supply is less than a first preset voltage threshold and a load of the switching power supply meets a preset heavy load condition, and generate the second clock signal when the output voltage is not less than the first preset voltage threshold, the load meets the preset heavy load condition and the input line voltage is within a full voltage range;
the power switch control module is specifically configured to control the state of the power switch according to the first clock signal so as to control the switching power supply to enter a CCM or DCM working mode, and control the state of the power switch according to the second clock signal so as to control the switching power supply to enter a QR working mode.
In order to solve the above technical problem, the present application further provides a switching power supply, which includes the above operating mode control circuit of the switching power supply, and further includes:
the rectifier filter module is used for converting input alternating current into direct current and outputting the filtered direct current to the primary side of the transformer;
the transformer;
the output module is arranged between the secondary side of the transformer and a load and used for generating voltage based on the voltage of the secondary side of the transformer, and the voltage values of the output voltages are different from each other;
and the control end of the power switch is connected with the output end of the control device of the switching power supply.
To sum up, the utility model provides a switching power supply's mode of operation control circuit and switching power supply according to switching power supply's output voltage, load and input line voltage integrated control switching power supply entering different modes of operation. The mode control module generates a first clock signal when the output voltage is smaller than a first preset voltage threshold and the load is a heavy load so as to control the switching power supply to work in a CCM or DCM mode through the power switch control module, and the problems that the working frequency of the switching power supply is low and the switching power supply is easy to damage due to the limitation of a QR mode when the switching power supply has a low output voltage are solved. When the output voltage is not less than the first preset voltage threshold and the load is a heavy load, the mode control module generates a second clock signal according to the input line voltage so as to control the switching power supply to work in one mode of CCM, DCM or QR through the power switch control module, so that the working efficiency of the switching power supply is ensured, and the power switch control module is suitable for a switching power supply application system with a wider output voltage/current range.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required in the prior art and the embodiments will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained without creative efforts.
Fig. 1 is a schematic structural diagram of a working mode control circuit of a switching power supply according to the present invention;
fig. 2 is a schematic structural diagram of a mode control module in a working mode control circuit of a switching power supply according to the present invention;
fig. 3 is a schematic diagram of a first control mode of the operating mode control circuit of the switching power supply according to the present invention;
fig. 4 is a schematic diagram of a second control mode of the operating mode control circuit of the switching power supply according to the present invention;
fig. 5 is a schematic diagram of a third control mode of the operating mode control circuit of the switching power supply according to the present invention;
fig. 6 is a circuit diagram of a switching power supply according to the present invention.
Detailed Description
The core of the utility model is to provide a switching power supply's mode of operation control circuit and switching power supply, can get into different modes of operation according to switching power supply's output voltage, load and switching power supply's input line voltage integrated control switching power supply.
To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the attached drawings in the embodiments of the present invention are combined to clearly and completely describe the technical solution in the embodiments of the present invention, and obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts all belong to the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a working mode control circuit of a switching power supply according to the present invention, the control circuit includes:
the mode control module 1 is used for generating a first clock signal when the output voltage of the switching power supply is smaller than a first preset voltage threshold and the load of the switching power supply meets a preset overloading condition, and generating a second clock signal according to the input line voltage of the switching power supply when the output voltage is not smaller than the first preset voltage threshold and the load meets the preset overloading condition;
and the power switch control module 2 is used for controlling the state of a power switch in the switching power supply according to the first clock signal so as to control the switching power supply to enter a CCM or DCM working mode, and controlling the state of the power switch according to the second clock signal so as to control the switching power supply to enter the CCM or DCM or QR working mode.
In the application, the output voltage, the load and the input line voltage of the switching power supply are simultaneously used as selection bases for controlling the switching power supply to enter different working modes. Specifically, the switching power supply is divided into two cases of a low output voltage and a high output voltage according to the output voltage, and the division is specifically performed by judging whether the output voltage of the switching power supply is smaller than a first preset voltage threshold. When the output voltage is smaller than the first preset voltage threshold, that is, the output voltage is a low output voltage, if the load is a heavy load, the first clock signal is generated through the mode control module 1, the power switch module can control the switching power supply to work in a CCM or DCM working mode based on the first clock signal after receiving the first clock signal, the frequency of the switching power supply can be improved, the size of the switching power supply can be reduced, and meanwhile, the problems that in the prior art, the system frequency is reduced more due to the fact that the switching power supply is controlled to work in a QR mode, the stress of a transformer is increased, magnetic element saturation easily occurs, and the power supply is damaged are solved.
It should be noted that the specific value of the first preset voltage threshold may be set according to practical situations, and may be set to 7.5V. The preset overloading condition is not particularly limited, and the overload condition can be set according to the actual condition.
The specific working mode of the switching power supply under the conditions that the output voltage is high voltage and the load is heavy load is not particularly limited, and the switching power supply can be selected to work in the QR mode all the time according to the difference of the input line voltage, or work in the QR mode when the input voltage is high line voltage, and work in the CCM or DCM mode when the input voltage is low line voltage. Specifically, the second clock signal is generated when the output voltage is not less than the first preset voltage threshold, that is, the output voltage is a high voltage and the load is a heavy load, and the second clock signal is related to the input line voltage of the switching power supply. The power switch control module 2 controls the switching power supply to enter a CCM or DCM working mode or a QR working mode based on the second clock signal.
To sum up, the utility model discloses a switching power supply's mode of operation control circuit, including mode control module 1 and power switch control module 2. The mode control module 1 comprehensively generates clock signals for controlling the switching power supply to enter different working modes based on the output voltage, the load and the input line voltage of the switching power supply. The power switch control module 2 controls the switching power supply to enter a CCM or DCM mode when the output voltage is smaller than a first preset voltage threshold and the load is a heavy load, so that the problem that the working frequency of the switching power supply is low and the switching power supply is easy to damage due to the restriction of a QR mode when the switching power supply has a low output voltage requirement is solved, the switching power supply enters the CCM or DCM mode when the output voltage is not smaller than the first preset voltage threshold and the load is the heavy load, or the QR mode works, and the working efficiency of the switching power supply is ensured.
On the basis of the above-described embodiment:
as a preferred embodiment, the mode control module 1 includes a clock output selector 011, a first clock module 012 and a second clock module 013;
the output end of the first clock module 012 and the output end of the second clock module 013 are respectively connected with the first clock input end and the second clock input end of the clock output selector 011, and the output end of the clock output selector 011 is used as the output end of the mode control module 1;
the first clock module 012 is configured to generate a first clock signal, where a frequency of the first clock signal is positively correlated to a magnitude of a load;
the second clock module 013 is configured to generate a second clock signal based on the primary side resonance waveform when the number of valley bottoms of the primary side resonance waveform of the switching power supply is not greater than the preset valley bottom threshold value, and generate a second clock signal whose frequency is in positive correlation with the size of the load when the number of valley bottoms of the primary side resonance waveform is greater than the preset valley bottom threshold value;
the clock output selector 011 is configured to output a first clock signal generated by the first clock module 012 when the output voltage is less than a first preset voltage threshold and the load meets a preset reload condition, and output a second clock signal output by the second clock output selector 133 when the output voltage is not less than the first preset voltage threshold and the load meets the preset reload condition.
In this embodiment, the first clock module itself may generate the first clock signal, and the frequency of the first clock signal is in positive correlation with the magnitude of the load, so that when the load is a heavy load, the frequency of the first clock signal is higher, and at this time, the power switch control module 2 may cause the switching power supply to enter the CCM operation mode when the state of the power switch is controlled by the first clock signal. When the load is decreased, the frequency of the first clock signal is decreased, and the power switch control module 2 may cause the switching power supply to enter the DCM operation mode when controlling the state of the power switch by the first clock signal.
QR mode switches on for the several valley bottoms of the preceding predetermined valley bottom number threshold value at former limit resonance waveform, DCM mode switches on for the arbitrary moment at former limit resonance waveform, consequently the second clock module is based on former limit resonance waveform generation second clock signal so that switching power supply gets into QR mode when the valley bottom number of switching power supply's former limit resonance waveform is not more than predetermined valley bottom number threshold value, the size that generates frequency and load when former limit resonance waveform is greater than predetermined valley bottom number threshold value is positive correlation's second clock signal so that switching power supply gets into DCM mode.
As a preferred embodiment, the second clock module 013 includes the second clock submodule 131, the valley lock module 132, and the second clock output selector 133;
the output end of the second clock submodule 131 and the output end of the valley bottom locking module 132 are respectively connected with the first input end and the second input end of the second clock output selector 133, and the output end of the second clock output selector 133 is connected with the second clock input end of the clock output selector 011;
the second clock submodule 131 is configured to generate a second clock sub-signal when the number of valley bottoms of a primary-side resonant waveform of the switching power supply is greater than a preset valley bottom threshold, where a frequency of the second clock sub-signal is negatively related to the number of valley bottoms of the primary-side resonant waveform, and the number of valley bottoms of the primary-side resonant waveform is negatively related to a size of a load;
the valley bottom locking module 132 is configured to control the primary side resonance waveform to be opened at a plurality of valley bottoms of the valley bottoms when the number of valley bottoms of the primary side resonance waveform is not greater than the preset valley bottom threshold value, and use the primary side resonance waveform opened at the plurality of valley bottoms as a second clock valley bottom signal;
the second clock output selector 133 is configured to output, to the clock output selector 011, the second clock valley signal generated by the valley bottom locking module 132 as the second clock signal when the number of valleys in the primary-side resonance waveform is greater than the preset valley bottom threshold, and output, to the clock output selector 011, the second clock sub-signal generated by the second clock sub-module 131 as the second clock signal when the number of valleys in the primary-side resonance waveform is not greater than the preset valley bottom threshold.
Referring to fig. 2, fig. 2 is a schematic structural diagram of a mode control module in a working mode control circuit of a switching power supply according to the present invention. In fig. 6, a clock selection 1 is a clock output selector 011, a frequency control 1 and the clock 1 jointly form a first clock module 012, a frequency control 2 and the clock 2 jointly form a second clock module 013, the clock selection 2 is a second clock output selector 133, N is the number of valleys of a primary side resonance waveform, N is a preset Valley threshold, COMP is a parameter positively correlated with a load, valley is a primary side resonance wave, line is an input Line voltage, vout is an output voltage, CLK1 is a first clock signal, CLK2 is a second clock signal, and CLK is a clock signal finally used for controlling a power switch. In addition, the Slope signal in fig. 2 is used to implement Slope compensation of the switching power supply in CCM mode to suppress harmonic oscillation.
The present embodiment provides a specific structure of the mode control module 1 for generating the first clock signal and the second clock signal, and the clock output selector 011 can select whether to output the first clock signal generated by the first clock module 012 or the second clock signal generated by the second clock submodule 131, the bottom-of-valley lock module 132, and the second clock output selector 133 based on the output voltage of the switching power supply.
Specifically, the first clock module itself may generate the first clock signal, and the frequency of the first clock signal is in positive correlation with the size of the load, so that the frequency of the first clock signal is higher when the load is a heavy load, and at this time, the power switch control module 2 may enable the switching power supply to enter the CCM operating mode when the power switch is controlled by the first clock signal. When the load is decreased, the frequency of the first clock signal is decreased, and the power switch control module 2 may cause the switching power supply to enter the DCM operation mode when controlling the state of the power switch by the first clock signal.
Because the valley bottom number of the primary side resonance waveform is negatively correlated with the load size, when the load is a heavy load, the valley bottom number of the primary side resonance waveform is smaller than the preset valley bottom threshold value, and therefore the valley bottom locking module 132 is turned on at the valley bottoms of the valley bottoms number to generate a new clock signal, namely, a second clock valley bottom signal and takes the second clock valley bottom signal as the second clock signal, and when the power switch control module 2 controls the state of the power switch by using the signal, the switching power supply can enter the QR working mode. Along with the gradual decrease of the load, the valley bottom number of the primary-side resonance waveform gradually increases until being not less than the preset valley bottom threshold, so that the second clock sub-module 131 generates the second clock sub-signal by itself and the frequency of the second clock sub-signal is in positive correlation with the size of the load, and thus, when the power switch control module 2 utilizes the second clock sub-signal to control the state of the power switch, the switching power supply can enter the DCM working mode.
In summary, the mode control module 1 provided in this embodiment can generate clock signals enabling the switching power supply to enter various operating modes, and then the clock output selector 011 in the mode control module 1 can select different clock signals under different conditions, so as to achieve the purpose of controlling the switching power supply to enter different operating modes under different conditions, and the circuit structure is simple and easy to implement.
As a preferred embodiment, the power switch control module 2 includes an and gate, a D flip-flop and a driving circuit;
the first input end of the AND gate and the clock signal input end of the D trigger are both connected with the output end of the mode control module 1, the positive phase output end of the D trigger is connected with the second input end of the AND gate, the output end of the AND gate is connected with the input end of the drive circuit, and the output end of the drive circuit is connected with the control end of the power switch as the output end of the power switch control module 2;
the driving circuit is used for amplifying a signal output by the output end of the AND gate so as to control the state of the power switch.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a working mode control circuit of a switching power supply according to the present invention, in fig. 1, COMP is a signal reflecting a load size, valley is a primary-side resonant wave, line is an input Line voltage, vout is an output voltage, CLK is a clock signal for controlling a power switch, gate is a signal received by a control terminal of the power switch, and Slope signal is used for realizing Slope compensation of the switching power supply in a CCM mode so as to suppress harmonic oscillation.
The clock signal output by the mode control module 1 is connected with the clock signal input end of the D flip-flop and the first input end of the and gate in the power switch control module 2, the and gate performs and transmission of the clock signal output by the mode control module 11 and the signal output by the D flip-flop to the driving circuit, and the driving circuit amplifies the signal output by the and gate to a signal which can be used for controlling the power switch and then inputs the signal to the control end of the power switch so as to control the state of the power switch, thereby realizing control of the working mode of the switching power supply.
In summary, the power switch control module 2 provided in this embodiment can achieve the purpose of controlling the power switch based on the first clock signal and the second clock signal, and the circuit structure is simple and easy to implement.
As a preferred embodiment, the mode control module 1 is further configured to generate a third clock signal when the output voltage of the switching power supply is less than a first preset voltage threshold and the load meets a preset light load condition;
the power switch control module 2 is further configured to control the state of the power switch based on the third clock signal so as to control the switching power supply to enter the DCM operation mode.
In order to further ensure that the switching power supply can select the most appropriate operating mode under various conditions, the operating mode of the switching power supply under light load is further provided in the embodiment. Referring to fig. 3, fig. 3 is a schematic diagram of a first control method of the operating mode control circuit of the switching power supply according to the present invention, in fig. 3, the horizontal axis is a load, the vertical axis is an input line voltage, vo is an output voltage, and Vref is a first preset voltage threshold. Specifically, it is still necessary to determine whether the switching power supply is a low output voltage or a high output voltage according to the output voltage of the switching power supply. In this embodiment, when the output voltage is smaller than the first preset voltage threshold, that is, the output voltage is a low output voltage, if the load is no-load, the switching power supply is controlled to use DCM as the operating mode, so that the size of the transformer can be reduced, and the system efficiency is also considered.
The preset light load condition required when the load is judged to be light load is not particularly limited, and the no-load condition can be included in the range of the preset light load condition.
In summary, in this embodiment, if it is preferable to reduce the size of the switching power supply and consider the efficiency of the switching power supply in practical applications, the switching power supply is controlled to enter the DCM operation mode when the switching power supply simultaneously satisfies the condition that the load is no load and the output voltage is low.
As a preferred embodiment, the mode control module 1 is further configured to generate a fourth clock signal when the output voltage of the switching power supply is not less than the first preset voltage threshold and the load meets the preset light load condition;
the power switch control module 2 is further configured to control the state of the power switch based on the fourth clock signal so as to control the switching power supply to enter the DCM operation mode.
In order to further ensure that the switching power supply can select the most appropriate operating mode under various conditions, the operating mode of the switching power supply under light load is further provided in the embodiment. Specifically, it is still necessary to determine whether the switching power supply is a low output voltage or a high output voltage according to the output voltage of the switching power supply. In this embodiment, when the output voltage is not less than the first predetermined voltage threshold, that is, the output voltage is a high output voltage, if the load is no load, the switching power supply is controlled to use DCM as the operating mode, so that the stability of the system can be ensured, and the switching loss can be reduced.
Referring to fig. 4, fig. 4 is a schematic diagram of a second control method of the operating mode control circuit of the switching power supply according to the present invention, in fig. 4, the horizontal axis is a load, the vertical axis is an input line voltage, vo is an output voltage, and Vref is a first preset voltage threshold.
As a preferred embodiment, the mode control module 1 is specifically configured to generate a first clock signal when the output voltage of the switching power supply is less than a first preset voltage threshold and the load of the switching power supply meets a preset heavy load condition; generating a fifth clock signal when the output voltage is not less than the first preset voltage threshold, the load meets the preset overloading condition, and the input line voltage is greater than the second preset voltage threshold; generating a sixth clock signal when the output voltage is not less than the first preset voltage threshold, the load meets the preset overloading condition, and the input line voltage is not greater than the second preset voltage threshold;
the power switch control module 2 is specifically configured to control a state of a power switch in the switching power supply according to the first clock signal so as to control the switching power supply to enter a CCM or DCM operating mode; controlling the state of the power switch according to the fifth clock signal so as to control the switching power supply to enter a QR (quick response) working mode; and controlling the state of the power switch according to the sixth clock signal so as to control the switching power supply to enter a CCM or DCM working mode.
In order to further ensure that the switching power supply can select the most appropriate operating mode under various conditions, in this embodiment, when the load at the rear end of the switching power supply is heavy load or full load, different operating modes are further selected according to different input line voltages. Specifically, when the load is heavy and the input line voltage is greater than a second preset voltage threshold value, namely, the input line voltage is a high line voltage, the switching power supply is controlled to enter a QR working mode, so that the system efficiency is improved; when the load is heavy and the input line voltage is not greater than the second preset voltage threshold value, that is, the line voltage is low, the switching power supply is controlled to enter a CCM or DCM working mode, the system efficiency is further improved, and the small size of the switching power supply is ensured.
Referring to fig. 4, fig. 4 is a schematic diagram of a second control method of the operating mode control circuit of the switching power supply according to the present invention, in fig. 4, the horizontal axis is a load, the vertical axis is an input line voltage, vo is an output voltage, vref is a first preset voltage threshold, and VL1 is a second preset voltage threshold.
The specific value of the second preset voltage threshold is not particularly limited, for example, when the output voltage of the switching power supply ranges from 3.3V to 20V or from 5V to 20V, the first preset voltage threshold may be 7.5V, and the second preset voltage threshold may be 180V.
As a preferred embodiment, the mode control module 1 is specifically configured to generate a first clock signal when the output voltage of the switching power supply is less than a first preset voltage threshold and the load of the switching power supply meets a preset overloading condition, and generate a second clock signal when the output voltage is not less than the first preset voltage threshold, the load meets the preset overloading condition and the voltage of the input line is within a full voltage range;
the power switch control module 2 is specifically configured to control the state of the power switch according to the first clock signal so as to control the switching power supply to enter the CCM or DCM operating mode, and control the state of the power switch according to the second clock signal so as to control the switching power supply to enter the QR operating mode.
Referring to fig. 5, fig. 5 is a schematic diagram of a third control method of the operating mode control circuit of the switching power supply according to the present invention, in fig. 5, the horizontal axis is a load, the vertical axis is an input line voltage, vo is an output voltage, and Vref is a first preset voltage threshold.
In order to further ensure that the switching power supply can select the most appropriate working mode under various conditions, in this embodiment, when the load at the rear end of the switching power supply is a heavy load, the switching power supply is controlled to always work in the working mode of QR no matter whether the input line voltage is a low line voltage or a high line voltage, that is, the switching power supply is controlled to always work in the working mode of QR within the full voltage range of the input line voltage, so that the efficiency of the switching power supply can be ensured to the greatest extent, and the performance of the switching power supply is improved. Therefore, the circuit in the present embodiment can be selected in the case where the switching power supply is heavily loaded and the output voltage is high, with priority given to improving the system efficiency.
In order to solve the above technical problem, the present application further provides a switching power supply, including the above operating mode control circuit of the switching power supply, further including:
the rectifier filter module is used for converting input alternating current into direct current and outputting the filtered direct current to the primary side of the transformer;
a transformer;
the output module is arranged between the secondary side of the transformer and the load and used for generating voltage based on the voltage of the secondary side of the transformer, and the voltage values of the output voltages are different from each other;
and the control end of the power switch is connected with the output end of the control device of the switching power supply.
The switching power supply in the present application may be a switching power supply with a wide voltage output range, which is capable of selecting the most suitable operation mode when facing different output voltage requirements. Referring to fig. 6, fig. 6 is a circuit diagram of a switching power supply according to the present invention. The switching power supply in fig. 6 is a flyback switching power supply, and the switching power supply works in different working modes by controlling the conduction condition of the power switch through a control device of the switching power supply, so that the working performance of the switching power supply is ensured.
It should be noted that, in the present specification, relational terms such as first and second, and the like are used only for distinguishing one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, article, or apparatus. Without further limitation, an element defined by the phrases "comprising a" \8230; "does not exclude the presence of additional like elements in a process, article, or device that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (9)
1. An operation mode control circuit of a switching power supply, comprising:
the mode control module is used for generating a first clock signal when the output voltage of the switching power supply is smaller than a first preset voltage threshold and the load of the switching power supply meets a preset overloading condition, and generating a second clock signal according to the input line voltage of the switching power supply when the output voltage is not smaller than the first preset voltage threshold and the load meets the preset overloading condition;
and the power switch control module is used for controlling the state of a power switch in the switching power supply according to the first clock signal so as to control the switching power supply to enter a CCM or DCM working mode, and controlling the state of the power switch according to the second clock signal so as to control the switching power supply to enter the CCM or DCM working mode or QR working mode.
2. The operation mode control circuit of the switching power supply according to claim 1, wherein the mode control module comprises a clock output selector, a first clock module and a second clock module;
the output end of the first clock module and the output end of the second clock module are respectively connected with the first clock input end and the second clock input end of the clock output selector, and the output end of the clock output selector is used as the output end of the mode control module;
the first clock module is used for generating the first clock signal, and the frequency of the first clock signal is positively correlated with the size of the load;
the second clock module is used for generating a second clock signal based on the primary side resonance waveform when the valley number of the primary side resonance waveform of the switching power supply is not more than a preset valley number threshold value, and generating a second clock signal with the frequency positively correlated with the load size when the valley number of the primary side resonance waveform is more than the preset valley number threshold value;
the clock output selector is used for outputting a first clock signal generated by the first clock module when the output voltage is smaller than the first preset voltage threshold and the load meets the preset heavy load condition, and outputting a second clock signal output by the second clock output selector when the output voltage is not smaller than the first preset voltage threshold and the load meets the preset heavy load condition.
3. The operation mode control circuit of the switching power supply according to claim 2, wherein the second clock module includes a second clock submodule, a valley lock module, and a second clock output selector;
the output end of the second clock submodule and the output end of the valley bottom locking module are respectively connected with the first input end and the second input end of the second clock output selector, and the output end of the second clock output selector is connected with the second clock input end of the clock output selector;
the second clock submodule is used for generating a second clock sub-signal when the valley number of the primary side resonance waveform of the switching power supply is larger than a preset valley number threshold value, the frequency of the second clock sub-signal is in negative correlation with the valley number of the primary side resonance waveform, and the valley number of the primary side resonance waveform is in negative correlation with the size of the load;
the valley bottom locking module is used for controlling the primary side resonance waveform to be opened at a plurality of valley bottoms when the number of valley bottoms of the primary side resonance waveform is not more than the preset valley bottom threshold value, and taking the primary side resonance waveform opened at the valley bottoms as a second clock valley bottom signal;
the second clock output selector is configured to output a second clock valley signal generated by the valley bottom locking module to the clock output selector as the second clock signal when the number of valleys of the primary-side resonant waveform is greater than the preset valley bottom threshold value, and output a second clock sub-signal generated by the second clock sub-module to the clock output selector as the second clock signal when the number of valleys of the primary-side resonant waveform is not greater than the preset valley bottom threshold value.
4. The operation mode control circuit of the switching power supply according to claim 1, wherein the power switch control module comprises an and gate, a D flip-flop and a driving circuit;
the first input end of the AND gate and the clock signal input end of the D trigger are both connected with the output end of the mode control module, the normal phase output end of the D trigger is connected with the second input end of the AND gate, the output end of the AND gate is connected with the input end of the driving circuit, and the output end of the driving circuit is used as the output end of the power switch control module and is connected with the control end of the power switch;
the driving circuit is used for amplifying a signal output by the output end of the AND gate so as to control the state of the power switch.
5. The operating mode control circuit of the switching power supply according to claim 1, wherein the mode control module is further configured to generate a third clock signal when the output voltage of the switching power supply is less than the first preset voltage threshold and the load meets a preset light load condition;
the power switch control module is further configured to control a state of the power switch based on the third clock signal so as to control the switching power supply to enter a DCM operation mode.
6. The operating mode control circuit of the switching power supply according to claim 1, wherein the mode control module is further configured to generate a fourth clock signal when the output voltage of the switching power supply is not less than the first preset voltage threshold and the load meets a preset light load condition;
the power switch control module is further configured to control a state of the power switch based on the fourth clock signal so as to control the switching power supply to enter a DCM operation mode.
7. The operation mode control circuit of the switching power supply according to any one of claims 1 to 6, wherein the mode control module is specifically configured to generate a first clock signal when the output voltage of the switching power supply is less than a first predetermined voltage threshold and the load of the switching power supply meets a predetermined overload condition; generating a fifth clock signal when the output voltage is not less than the first preset voltage threshold, the load meets the preset overloading condition, and the input line voltage is greater than a second preset voltage threshold; generating a sixth clock signal when the output voltage is not less than the first preset voltage threshold, the load meets the preset overloading condition, and the input line voltage is not greater than a second preset voltage threshold;
the power switch control module is specifically used for controlling the state of a power switch in the switching power supply according to the first clock signal so as to control the switching power supply to enter a CCM or DCM working mode; controlling the state of the power switch according to the fifth clock signal so as to control the switching power supply to enter a QR (quick response) working mode; and controlling the state of the power switch according to the sixth clock signal so as to control the switching power supply to enter a CCM or DCM working mode.
8. The operational mode control circuit of the switching power supply according to any one of claims 1 to 6, wherein the mode control module is specifically configured to generate a first clock signal when an output voltage of the switching power supply is less than a first preset voltage threshold and a load of the switching power supply meets a preset heavy load condition, and generate a second clock signal when the output voltage is not less than the first preset voltage threshold and the load meets the preset heavy load condition and the input line voltage is within a full voltage range;
the power switch control module is specifically configured to control a state of the power switch according to the first clock signal so as to control the switching power supply to enter a CCM or DCM operating mode, and control a state of the power switch according to the second clock signal so as to control the switching power supply to enter a QR operating mode.
9. A switching power supply, characterized by comprising an operation mode control circuit of the switching power supply according to any one of claims 1 to 8, and further comprising:
the rectifier filter module is used for converting input alternating current into direct current and outputting the filtered direct current to the primary side of the transformer;
the transformer;
the output module is arranged between the secondary side of the transformer and a load and used for generating voltage based on the voltage of the secondary side of the transformer, and the voltage values of the output voltages are different from each other;
and the control end of the power switch is connected with the output end of the control device of the switching power supply.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2024078078A1 (en) * | 2022-10-13 | 2024-04-18 | 上海新进芯微电子有限公司 | Switch mode power supply operating mode control method, circuit, and switch mode power supply |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2024078078A1 (en) * | 2022-10-13 | 2024-04-18 | 上海新进芯微电子有限公司 | Switch mode power supply operating mode control method, circuit, and switch mode power supply |
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