CN113824301B - Starting circuit of switching power supply and switching power supply thereof - Google Patents
Starting circuit of switching power supply and switching power supply thereof Download PDFInfo
- Publication number
- CN113824301B CN113824301B CN202111061885.2A CN202111061885A CN113824301B CN 113824301 B CN113824301 B CN 113824301B CN 202111061885 A CN202111061885 A CN 202111061885A CN 113824301 B CN113824301 B CN 113824301B
- Authority
- CN
- China
- Prior art keywords
- resistor
- power supply
- voltage stabilizing
- circuit
- switching power
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- 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
- H02M1/36—Means for starting or stopping converters
-
- 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
- H02M1/32—Means for protecting converters other than automatic disconnection
-
- 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
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
-
- 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
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M1/4208—Arrangements for improving power factor of AC input
- H02M1/4225—Arrangements for improving power factor of AC input using a non-isolated boost converter
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/157—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators with digital control
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33561—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having more than one ouput with independent control
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The application relates to a starting circuit of a switching power supply and the switching power supply thereof, wherein the switching power supply comprises: the input end of the voltage stabilizing circuit is connected with a bus of the PFC module of the switching power supply; and the output end of the voltage stabilizing circuit is used for starting the digital control module of the switching power supply. The application is used for solving the problem that a switching power supply realized by a digital control module cannot be started.
Description
Technical Field
The application relates to the technical field of power supplies, in particular to a starting circuit of a switching power supply and the switching power supply thereof.
Background
The power supply of the household appliance is a switching power supply, the common topology of the switching power supply comprises a PFC (Power Factor Correction) module and a flyback power supply module, the common load capacity of the switching power supply is tens of watts, and the common structure of the switching power supply is that a bus of the PFC module takes power, and then low-voltage multi-channel output is realized through the flyback power supply module.
In the scheme of using the analog power chip to control the switching tube, the voltage-controlled digital switch inside the analog power chip charges the auxiliary winding capacitor, and the analog power chip can be started after the voltage rises to the set value. With the progress of digital power technology, the power supply of the household appliances is developed to digitization, high frequency and miniaturization, and digital control modules (micro control units, microcontroller Unit) such as MCU and the like are gradually adopted to control the switch tube; however, since the digital control module such as the MCU has no capacitor in the analog power chip, the digital control module is not powered up at the beginning, and cannot output PWM waves to control the switching tube to work, so that the power supply cannot work.
Disclosure of Invention
The application provides a starting circuit of a switching power supply and the switching power supply thereof, which are used for solving the problem that the switching power supply realized by a digital control module cannot be started.
In a first aspect, an embodiment of the present application provides a starting circuit of a switching power supply, including: a voltage stabilizing circuit;
the input end of the voltage stabilizing circuit is connected with a bus of the PFC module of the switching power supply; and the output end of the voltage stabilizing circuit is used for starting the digital control module of the switching power supply.
Optionally, the output end of the voltage stabilizing circuit is connected with the controlled end of the self-oscillation circuit;
the output end of the self-oscillation circuit is connected with a switching tube of the switching power supply so as to start the digital control module.
Optionally, the voltage stabilizing circuit includes: the first current limiting resistor and the first voltage stabilizing tube;
the first end of the first current limiting resistor is connected with the bus, and the second end of the first current limiting resistor is connected with the cathode of the first voltage stabilizing tube;
the cathode of the first voltage stabilizing tube is connected with the controlled end of the self-oscillation circuit, and the anode of the first voltage stabilizing tube is grounded.
Optionally, the self-oscillation circuit includes: the PWM wave control module and the charging and discharging module;
the controlled end of the PWM wave control module is connected with the cathode of the first voltage stabilizing tube, and the input end of the PWM wave control module is connected with the output end of the charge-discharge module; the output end of the PWM wave control module is connected with the switching tube;
and the input end of the charge-discharge module is connected with the controlled end of the PWM wave control module.
Optionally, the PWM wave control module includes: the circuit comprises an operational amplifier, a capacitor, a first resistor, a second resistor and a fourth resistor;
the first end of the first resistor is grounded, and the second end of the first resistor is connected with the non-inverting input end of the operational amplifier;
the first end of the second resistor is connected with the non-inverting input end of the operational amplifier, and the second end of the second resistor is connected with the cathode of the first voltage stabilizing tube;
one end of the capacitor is grounded, and the other end of the capacitor is connected with the inverting input end of the operational amplifier;
the inverting input end of the operational amplifier is connected with the output end of the charge-discharge module; the output end of the operational amplifier is connected with the first end of the fourth resistor;
the second end of the fourth resistor, the second end of the second resistor and the input end of the charge-discharge module are all connected with the switch tube.
Optionally, the charge-discharge module includes: the first diode, the second diode, the third resistor, the fifth resistor and the sixth resistor;
the cathode of the first diode is connected with the second end of the third resistor; the anode of the first diode is connected with the first end of the fifth resistor;
the anode of the second diode is connected with the second end of the third resistor; the cathode of the second diode is connected with the first end of the sixth resistor;
the first end of the third resistor is connected with the inverting input end of the operational amplifier;
and the second end of the fifth resistor and the second end of the sixth resistor are connected with the switch tube.
Optionally, the fifth resistor and the sixth resistor are adjustable resistors.
Optionally, the voltage stabilizing circuit includes: the second current limiting resistor and the second voltage stabilizing tube;
the first end of the second current limiting resistor is connected with the bus, and the second end of the second current limiting resistor is connected with the cathode of the second voltage stabilizing tube; the anode of the second voltage stabilizing tube is grounded;
and the second end of the second current limiting resistor and the cathode of the second voltage stabilizing tube are connected with the input end of the digital control module.
Optionally, the voltage stabilizing circuit includes: the third current limiting resistor, the third voltage stabilizing tube and the negative feedback circuit;
the first end of the third current limiting resistor is connected with the bus, and the second end of the third current limiting resistor is connected with the cathode of the third voltage stabilizing tube; the anode of the third voltage stabilizing tube is grounded;
the feedback end of the negative feedback circuit is connected with the bus, the input end of the negative feedback circuit is connected with the cathode of the voltage stabilizing tube, and the output end of the negative feedback circuit is grounded;
the output end of the negative feedback circuit is also connected with the input end of the digital control module.
Optionally, the negative feedback circuit includes: a seventh resistor and a triode;
the collector electrode of the triode is connected with the busbar voltage, and the base electrode of the triode is connected with the cathode of the third voltage stabilizing tube; the emitter of the triode is connected with the first end of the seventh resistor;
the second end of the seventh resistor is grounded; and two ends of the seventh resistor are connected with the input end of the digital control module.
In a second aspect, an embodiment of the present application further provides a switching power supply, including: the starting circuit of the switching power supply of the first aspect.
Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages: according to the starting circuit of the switching power supply, provided by the embodiment of the application, the input end of the voltage stabilizing circuit is powered on from the bus of the PFC module, and the output end of the voltage stabilizing circuit is used for starting the digital control module of the switching power supply, so that the problem that the switching power supply realized by the digital control module cannot be started can be solved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.
In order to more clearly illustrate the embodiments of the application or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, and it will be obvious to a person skilled in the art that other drawings can be obtained from these drawings without inventive effort.
Fig. 1 is a schematic structural diagram of a switching power supply according to an embodiment of the present application;
fig. 2 is a schematic diagram of a second structure of a switching power supply according to an embodiment of the present application;
fig. 3 is a schematic diagram of a third embodiment of a switching power supply according to the present application;
fig. 4a is a schematic diagram of a starting circuit of a switching power supply according to an embodiment of the present application;
fig. 4b is a schematic diagram two of a starting circuit of a switching power supply according to an embodiment of the present application;
fig. 4c is a schematic diagram of a starting circuit of a switching power supply according to an embodiment of the present application;
fig. 5 is a schematic diagram two of a starting circuit of a switching power supply according to an embodiment of the present application;
fig. 6 is a schematic diagram III of a starting circuit of a switching power supply according to an embodiment of the present application.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
In the scheme of using the analog power chip to control the switching tube, the voltage-controlled digital switch inside the analog power chip charges the auxiliary winding capacitor, and the analog power chip can be started after the voltage rises to the set value. However, when the digital control module such as the MCU is used as the main control module, since the digital control module such as the MCU has no capacitance inside the analog power chip, the digital control module is not powered up at the beginning of power-up, and cannot output PWM waves to control the switching tube to work, so that the power supply cannot work.
Based on the technical problems, the embodiment of the application provides a starting circuit of a switching power supply, which aims to solve the problem that the switching power supply realized by a digital control module cannot be started.
Before describing the starting circuit of the switching power supply provided by the application in detail, a feasible scheme of the switching power supply realized by utilizing the digital control module is first described. As shown in fig. 1, the switching power supply mainly includes:
the system comprises a PFC module 1, a flyback power supply module 2 and a digital control module 3; the PFC module 1 comprises a switching tube Q;
the bus voltage end of the PFC module 1 is connected with the voltage acquisition end of the digital control module 3, the current output end of the PFC module 1 is connected with the current acquisition end of the digital control module 3, the inductance end of the PFC module 1 is connected with the input end of the flyback power supply module 2, and the control end of the digital control module 3 is connected with the controlled end of the switching tube Q in the PFC module 1; the primary winding of the transformer T1 in the flyback power supply module 2 serves as an inductance in the PFC module 1.
The primary winding of the transformer T1 in the flyback power supply module 2 serves as an inductance in the PFC module 1, i.e. the primary winding of the transformer T1 in the flyback power supply module 2 is common to the inductance in the PFC module 1.
In a specific implementation, the digital control module 3 may be implemented using an MCU.
In the embodiment of the application, the primary winding of the transformer in the flyback power supply module is used as the inductor in the power factor correction (PFC, power Factor Correction) module, so that the primary winding of the transformer in the flyback power supply module and the inductor in the PFC module are shared, the material of the inductor in the PFC module is saved, the cost of the switching power supply and the area of a PCB (Printed Circuit Board ) are further effectively reduced, and the problem of higher cost of the switching power supply comprising the PFC module and the flyback power supply module is solved.
In a specific embodiment, the PFC module 1 may be a BOOST circuit, or may be a BUCK circuit, which is generally used as a BOOST circuit, and the present application is not limited to the type of PFC module 1.
The black dots in transformer T1 in fig. 1 represent the same name ends.
When the PFC module 1 is a BOOST circuit, the switching tube Q in the PFC module 1 is also the switching tube Q in the flyback power module 2, that is, the switching tube Q in the PFC module 1 and the switching tube Q in the flyback power module 2 share the same, so that the material of the switching tube Q in the flyback power module 2 is saved, and the cost of the switching power supply and the area of the PCB are effectively reduced.
The switching power supply further comprises a rectifying and filtering module 4, and the output end of the rectifying and filtering module 4 is connected with the inductance end of the PFC module 1. The rectifying and filtering module 4 may be a rectifying circuit plus a filtering circuit, and outputs a rectifying and filtering signal to the PFC module 1 and the flyback power module 2 after rectifying and filtering the alternating current.
The PFC module 1 comprises a primary winding of a transformer T1, a switching tube Q, a third diode D3 and a first capacitor C1;
the first end of the primary winding of the transformer T1 is connected with the output end of the rectifying and filtering module 4, the second end of the primary winding of the transformer T1 is connected with the drain electrode of the switching tube Q, the source electrode of the switching tube Q is grounded GND, the controlled end (grid electrode) of the switching tube Q is connected with the control end of the digital control module 3, the anode of the third diode D3 is connected with the second end of the primary winding of the transformer T1, the cathode of the third diode D3 is connected with the first end of the first capacitor C1, the second end of the first capacitor C1 is connected with the source electrode of the switching tube Q, the first end of the first capacitor C1 is connected with the voltage acquisition end of the digital control module 3, and the second end of the first capacitor C1 is connected with the current acquisition end of the digital control module 3.
The voltage acquisition end of the digital control module 3 receives PFC bus voltage output by the first end of the first capacitor C1, the current acquisition end of the digital control module 3 receives PFC current output by the second end of the first capacitor C1, and the control end of the digital control module 3 outputs a driving signal to the controlled end of the switching tube Q. The digital control module can be a main control unit MCU or other control units, and the application does not limit the type of the digital control module.
In fig. 1, 3 paths of output are taken as an example to illustrate that the power is respectively supplied to a load 1, a load 2 and a load 3, the number of output circuits can be N, N is an integer greater than or equal to 1 according to the need, the number of the output circuits can be increased or decreased according to the type of a magnetic core of a transformer T1 and the size of the load, and the turns ratio of a primary winding and a secondary winding of the transformer can be changed according to the size of an output voltage output to the load.
As shown in fig. 1, the output end of the rectifying and filtering module 4 is connected to the first end of the primary winding of the transformer T1, the second end of the primary winding of the transformer T1 is connected to the drain electrode of the switching tube Q, the source electrode of the switching tube Q is grounded GND, the controlled end (gate) of the switching tube Q is connected to the control end of the digital control module 3, the first end of the first secondary winding of the transformer T1 is connected to the anode of the fourth diode D4, the cathode of the fourth diode D4 is connected to the first end of the second capacitor C2, and the second end of the second capacitor C2 is connected to the second end of the first secondary winding of the transformer T1; the first end of the second secondary winding of the transformer T1 is connected with the anode of a fifth diode D5, the cathode of the fifth diode D5 is connected with the first end of a third capacitor C3, and the second end of the third capacitor C3 is connected with the second end of the second secondary winding of the transformer T1; the first end of the third secondary winding of the transformer T1 is connected with the anode of a sixth diode D6, the cathode of the sixth diode D6 is connected with the first end of a fourth capacitor C4, and the second end of the fourth capacitor C4 is connected with the second end of the third secondary winding of the transformer T1.
The cathode of the fourth diode D4 is connected to the voltage input terminal of the digital control module 3. In the present application, the cathode of the fifth diode D5 may be connected to the voltage input terminal of the digital control module 3, or the cathode of the sixth diode D6 may be connected to the voltage input terminal of the digital control module 3, that is, in a specific implementation, the cathode of the diode in any load may be connected to the voltage input terminal of the digital control module 3.
It should be further noted that three paths of loads are exemplarily shown in fig. 1, and in actual implementation, the number of paths of the loads is at least one.
The voltage input end of the digital control module 3 receives the output voltage output by the cathode of the fourth diode D4, and the control end of the digital control module 3 outputs a driving signal to the controlled end of the switching tube Q.
Compared with the prior art that the switching tube Q is controlled to be turned on and off by the output driving signal of the analog power supply chip, the application realizes the control of the switching tube Q to be turned on and off by the output driving signal of the digital control module, saves the material of the analog power supply chip, and further effectively reduces the cost of the switching power supply and the area of the PCB.
In the above embodiment, the inductance of the PFC module and the primary inductance of the transformer are combined into one, and the primary inductance of the transformer is used as the PFC inductance to form a BOOST circuit with the switching tube Q and the third diode D3, and the switching tube Q in the PFC module is also the switching tube in the transformer. When the switching power supply starts to work, direct current is changed into alternating current through the on and off of the switching tube, energy is transmitted to the secondary side through the transformer, the digital control module adjusts the duty ratio of a driving signal of the switching tube by sampling bus voltage Vp, PFC current and output voltage Vo, the turn ratio of the primary side and the secondary side of the transformer is set according to the output voltage, the transformer converts high voltage into high voltage, and the high voltage is obtained through the rectifying diode and the filter capacitor to be supplied to loads of all paths.
In fig. 1, the number of secondary windings of the transformer T1 is 3, the number of diodes is 3, and the number of capacitors is 3, and in one embodiment of the present application, as shown in fig. 2, the number of secondary windings of the transformer T1 is N, where N is an integer greater than or equal to 1; the number of diodes, the number of capacitors and the number of secondary windings of the transformer remain the same for the load part.
As shown in fig. 2, in a specific embodiment, the flyback power supply module 2 further includes a DC-DC conversion module 5;
the first end of the capacitor in each path of load is connected with the first end of each DC-DC conversion module 5, and the second end of the capacitor in each path of load is connected with the second end of each DC-DC conversion module 5.
Taking the multi-path load shown in fig. 2 as an example, a first end of the second capacitor C2 is connected to the first end of the first DC-DC conversion module 5, and a second end of the second capacitor C2 is connected to the second end of the first DC-DC conversion module 5. The first end of the third capacitor C3 is connected to the first end of the second DC-DC conversion module 5, and the second end of the third capacitor C3 is connected to the second end of the second DC-DC conversion module 5. The first end of the fourth capacitor C4 is connected to the first end of the third DC-DC conversion module 5, and the second end of the fourth capacitor C4 is connected to the second end of the third DC-DC conversion module 5. The first end of the (n+1) th capacitor CN+1 is connected with the first end of the (N) th DC-DC conversion module 5, and the second end of the (n+1) th capacitor CN+1 is connected with the second end of the (N) th DC-DC conversion module 5.
The DC-DC conversion module 5 may be a linear voltage stabilizing module or other DC conversion circuits, so that the output voltage output to the load is more stable, and even if the turns ratio of the primary winding and the secondary winding of the transformer is not accurate enough, the output voltage is higher, the voltage value required by the load can be adjusted by the DC-DC conversion module.
In one embodiment, as shown in fig. 3, the cathodes of the diodes in each load may not be connected to the voltage input terminal of the digital control module 3.
When the output load power is smaller, the switching tube Q can be controlled to be switched on and off without output voltage, the high voltage is converted into low voltage directly through the turn ratio of the primary winding and the secondary winding of the transformer T1, then the DC-DC conversion is realized through the DC-DC conversion module 5, and the voltage value required by the load is adjusted.
In addition, it should be noted that the above embodiment of the present application only provides a specific implementation circuit of the switching power supply and a modification circuit thereof by way of example, and the starting circuit of the switching power supply provided by the present application may also be applicable to other switching power supplies implemented by using a digital control module.
The following specifically describes a starting circuit of a switching power supply according to an embodiment of the present application, as shown in fig. 4a, where the starting circuit of the switching power supply includes: a voltage stabilizing circuit;
the input end of the voltage stabilizing circuit 41 is connected with a bus of the PFC module 1 of the switching power supply; the output end of the voltage stabilizing circuit 41 is used for starting the digital control module 3 of the switching power supply.
As shown in fig. 1 to 3, the input terminal of the voltage stabilizing circuit may be connected between the first terminal of the first capacitor and the cathode of the third diode.
When the digital control module is specifically implemented, the voltage stabilizing circuit can be connected with the self-oscillation circuit to drive the switching tube to work according to the self-load of the digital control module, and can also be directly used for supplying power to the digital control module.
In a specific embodiment, when the load of the digital control module is large, a starting circuit of the switching power supply shown in fig. 4b may be adopted, which specifically includes: a voltage stabilizing circuit 41 and a self-oscillation circuit 42; the input end of the voltage stabilizing circuit 41 is connected with a bus of the PFC module 1 of the switching power supply and is used for taking electricity from the bus; the output end of the voltage stabilizing circuit 41 is connected with the controlled end of the self-oscillation circuit 42; the output end of the self-oscillation circuit 42 is connected with a switching tube Q of the switching power supply, and specifically, the output end of the self-oscillation circuit 42 is connected with the controlled end of the switching tube Q to start the digital control module 3.
In the embodiment of the application, when the load of the digital control module is large, the voltage stabilizing circuit is utilized to take electricity from the bus, and then the self-oscillation circuit is utilized to generate PWM waves to control the switching tube to work, so as to control the power supply to work, thereby solving the problem that the switching power supply realized by the digital control module cannot be started.
In one embodiment, as shown in fig. 4c, the embodiment of the present application provides a circuit diagram of a starting circuit of a switching power supply, and the voltage stabilizing circuit 41 includes: a first current limiting resistor RZ and a first voltage stabilizing tube DZ1;
a first end of the first current limiting resistor RZ is connected with a bus (such as Vp in FIG. 4 c), and a second end of the first current limiting resistor RZ is connected with a cathode of the first voltage stabilizing tube DZ1;
the cathode of the first voltage stabilizing tube DZ1 is connected with the controlled end of the self-oscillation circuit 42, and the anode of the first voltage stabilizing tube DZ1 is grounded.
In the embodiment of the application, the voltage stabilizing circuit not only plays a role in conventional voltage stabilization, but also plays a role in taking electricity from the bus and further supplying power to the subsequent self-oscillation circuit.
In one particular embodiment, as shown in FIG. 4c, self-oscillating circuit 42 includes: a PWM wave control module 421 and a charge and discharge module 422;
the controlled end of the PWM wave control module 421 is connected with the cathode of the first voltage stabilizing tube DZ1, and the input end of the PWM wave control module 421 is connected with the output end of the charge-discharge module 422; the output end of the PWM wave control module 421 is connected with the switching tube Q; the input terminal of the charge-discharge module 422 is connected to the controlled terminal of the PWM wave control module 421.
As shown in fig. 4c, in a specific embodiment, the PWM wave control module 421 includes: the operational amplifier A, the capacitor C, the first resistor R1, the second resistor R2 and the fourth resistor R4;
the first end of the first resistor R1 is grounded, and the second end of the first resistor R1 is connected with the non-inverting input end of the operational amplifier A;
the first end of the second resistor R2 is connected with the non-inverting input end of the operational amplifier A, and the second end of the second resistor R2 is connected with the cathode of the first voltage stabilizing DZ1 tube;
one end of the capacitor C is grounded, and the other end of the capacitor C is connected with the inverting input end of the operational amplifier A;
the inverting input terminal of the operational amplifier A is connected with the output terminal of the charge-discharge module 422; the output end of the operational amplifier A is connected with the first end of the fourth resistor R4;
the second end of the fourth resistor R4, the second end of the second resistor R2, and the input end of the charge-discharge module 422 are all connected to the switching tube Q.
As shown in fig. 4c, in one specific embodiment, the charge-discharge module 422 includes: a first diode D1, a second diode D2, a third resistor R3, a fifth resistor RW1, and a sixth resistor RW2;
the cathode of the first diode D1 is connected with the second end of the third resistor R3; the anode of the first diode D1 is connected to the first end of the fifth resistor RW 1;
the anode of the second diode D2 is connected with the second end of the third resistor R3; the cathode of the second diode D2 is connected to the first end of the sixth resistor RW2;
the first end of the third resistor R3 is connected with the inverting input end of the operational amplifier A;
the second terminal of the fifth resistor RW1 and the second terminal of the sixth resistor RW2 are both connected to the switching transistor Q.
The first diode D1, the fifth resistor RW1, and the third resistor R3 form a charging circuit. The second diode D2, the sixth resistor RW2, and the third resistor R3 constitute a discharge circuit.
As shown in fig. 4c, VP is a bus voltage, RZ is a current limiting resistor, DZ1 is a regulator tube, and the selected regulated voltage value of DZ1 is not higher than the power supply voltage value of the operational amplifier.
When the operational amplifier outputs the voltage U O =+V DZ1 When U O The capacitor C is positively charged through RW1, D1 and R3, and the equivalent resistance of the diode when the diode is conducted is ignored, so that the time constant is obtainedThe method comprises the steps of carrying out a first treatment on the surface of the Where C represents the capacitance of the capacitor C.
When U is O = -V DZ1 When U O Discharging the capacitor C through RW2, D2 and R3, ignoring the equivalent resistance of the diode when it is on, the time constant；
The three-element method using the first-order RC circuit can be solved:
wherein T1 represents the time when the self-oscillation circuit outputs a high level, i.e., the time when the capacitor C is charged; t2 represents the time when the self-oscillation circuit outputs a low level, i.e., the time when the capacitor C is discharged.
Period t=t1+t2The method comprises the steps of carrying out a first treatment on the surface of the Duty cycle of。
In a specific implementation, the fifth resistor RW1 and the sixth resistor RW2 are adjustable resistors, so that the duty ratio of the driving signal of the switching tube is adjusted according to the requirement, and the period (that is, the frequency) is adjusted, so that the circuit is more flexible, and the application range of the starting circuit can be effectively expanded.
Through analysis of the digital switching power supply, the inventor finds that when the switching power supply is powered on, the MCU of the digital control module is not powered on yet, and cannot output PWM waves to control the switching tube, and if the switching power supply realized by the digital control module such as the MCU is required to be utilized, the problem needs to be solved. In the embodiment of the application, the voltage stabilizing circuit is used for taking electricity from the bus, the self-excited oscillation circuit is used for generating PWM waves to control the power supply to work, and after the output of the flyback power supply module is stable, the starting circuit can be disconnected, so that the whole switching power supply starts to work normally.
In a specific embodiment, when the load of the digital control module is small, the starting of the digital control module can be directly implemented by using a voltage stabilizing circuit, and specifically, as shown in fig. 5, the voltage stabilizing circuit includes: a second current limiting resistor RZ2 and a second voltage stabilizing tube DZ2;
the first end of the second current limiting resistor RZ2 is connected with the bus, and the second end of the second current limiting resistor RZ2 is connected with the cathode of the second voltage stabilizing tube DZ2; the anode of the second voltage stabilizing tube DZ2 is grounded;
the second end of the second current limiting resistor RZ2 and the cathode of the second voltage stabilizing tube DZ2 are connected with the input end of the digital control module 3.
In the embodiment of the application, the voltage stabilizing circuit not only plays a role in conventional voltage stabilization, but also plays a role in taking electricity from the bus to supply power to the digital control module, and the simplest circuit is utilized to solve the problem that the MCU is used as a switching power supply realized by the digital control module and cannot be started.
To make the start-up more stable, a voltage stabilizing circuit as shown in fig. 6 may also be employed, see fig. 6, which includes: a third current limiting resistor RZ3, a third voltage stabilizing tube DZ3 and a negative feedback circuit 61;
the first end of the third current limiting resistor RZ3 is connected with the bus, and the second end of the third current limiting resistor RZ3 is connected with the cathode of the third voltage stabilizing tube DZ 3; the anode of the third voltage stabilizing tube DZ3 is grounded;
the feedback end of the negative feedback circuit 61 is connected with the bus, the input end of the negative feedback circuit 61 is connected with the cathode of the voltage stabilizing tube, and the output end of the negative feedback circuit 61 is grounded;
the output of the negative feedback circuit 61 is also connected to the input of the digital control module 3.
In one particular embodiment, as shown in FIG. 6, the negative feedback circuit 61 includes: a seventh resistor R7 and a triode Q1;
the collector of the triode Q1 is connected with the bus voltage, and the base of the triode Q1 is connected with the cathode of the third voltage stabilizing tube DZ 3; the emitter of the triode Q1 is connected with the first end of a seventh resistor R7;
the second end of the seventh resistor R7 is grounded; both ends of the seventh resistor R7 are connected with the input end of the digital control module 3.
Under the condition that the load of the digital control module is small, the voltage stabilizing circuit can be directly utilized for supplying power to start the digital control module. Furthermore, in order to make the output voltage of the voltage stabilizing circuit more stable, negative feedback is introduced on the basis of the voltage stabilizing circuit.
In the embodiment of the application, the voltage stabilizing circuit not only plays a role in conventional voltage stabilization, but also plays a role in taking electricity from the bus to supply power to the digital control module, and the simplest circuit is utilized to solve the problem that the MCU is used as a switching power supply realized by the digital control module and cannot be started.
Through analysis of the digital switching power supply, the inventor finds that when the switching power supply is powered on, the digital control module is not powered on yet, and cannot output PWM waves to control the switching tube, and if the digital control module is used for realizing the switching power supply, the problem needs to be solved. In the embodiment of the application, the input end of the voltage stabilizing circuit is powered from the bus of the PFC module, and the output end of the voltage stabilizing circuit is used for starting the digital control module of the switching power supply, so that the problem that the switching power supply realized by the digital control module cannot be started can be solved.
In addition, the embodiment of the application also provides a switching power supply, which comprises: the starting circuit of the switching power supply.
It should be noted that, the modules of other parts of the switching power supply may refer to the circuit design in the switching power supply provided in the embodiment of the present application, and may also be other circuit designs besides the circuit design provided in the embodiment of the present application.
It should be noted that in this document, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, 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, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The foregoing is only a specific embodiment of the application to enable those skilled in the art to understand or practice the application. 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 application. Thus, the present application 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 (8)
1. A starting circuit of a switching power supply, comprising: a voltage stabilizing circuit;
the input end of the voltage stabilizing circuit is connected with a bus of the PFC module of the switching power supply; the output end of the voltage stabilizing circuit is used for starting the digital control module of the switching power supply;
the output end of the voltage stabilizing circuit is connected with the controlled end of the self-oscillation circuit; the output end of the self-oscillation circuit is connected with a switching tube of the switching power supply so as to start the digital control module;
the voltage stabilizing circuit includes: the first current limiting resistor and the first voltage stabilizing tube; the first end of the first current limiting resistor is connected with the bus, and the second end of the first current limiting resistor is connected with the cathode of the first voltage stabilizing tube; the cathode of the first voltage stabilizing tube is connected with the controlled end of the self-oscillation circuit, and the anode of the first voltage stabilizing tube is grounded;
the self-oscillation circuit includes: the PWM wave control module and the charging and discharging module; the controlled end of the PWM wave control module is connected with the cathode of the first voltage stabilizing tube, and the input end of the PWM wave control module is connected with the output end of the charge-discharge module; the output end of the PWM wave control module is connected with the switching tube; and the input end of the charge-discharge module is connected with the controlled end of the PWM wave control module.
2. The start-up circuit of a switching power supply according to claim 1, wherein the PWM wave control module includes: the circuit comprises an operational amplifier, a capacitor, a first resistor, a second resistor and a fourth resistor;
the first end of the first resistor is grounded, and the second end of the first resistor is connected with the non-inverting input end of the operational amplifier;
the first end of the second resistor is connected with the non-inverting input end of the operational amplifier, and the second end of the second resistor is connected with the cathode of the first voltage stabilizing tube;
one end of the capacitor is grounded, and the other end of the capacitor is connected with the inverting input end of the operational amplifier;
the inverting input end of the operational amplifier is connected with the output end of the charge-discharge module; the output end of the operational amplifier is connected with the first end of the fourth resistor;
the second end of the fourth resistor, the second end of the second resistor and the input end of the charge-discharge module are all connected with the switch tube.
3. The starting circuit of the switching power supply according to claim 2, wherein the charge and discharge module includes: the first diode, the second diode, the third resistor, the fifth resistor and the sixth resistor;
the cathode of the first diode is connected with the second end of the third resistor; the anode of the first diode is connected with the first end of the fifth resistor;
the anode of the second diode is connected with the second end of the third resistor; the cathode of the second diode is connected with the first end of the sixth resistor;
the first end of the third resistor is connected with the inverting input end of the operational amplifier;
and the second end of the fifth resistor and the second end of the sixth resistor are connected with the switch tube.
4. A start-up circuit for a switching power supply according to claim 3, wherein the fifth resistor and the sixth resistor are both adjustable resistors.
5. The startup circuit of a switching power supply according to claim 1, wherein the voltage stabilizing circuit comprises: the second current limiting resistor and the second voltage stabilizing tube;
the first end of the second current limiting resistor is connected with the bus, and the second end of the second current limiting resistor is connected with the cathode of the second voltage stabilizing tube; the anode of the second voltage stabilizing tube is grounded;
and the second end of the second current limiting resistor and the cathode of the second voltage stabilizing tube are connected with the input end of the digital control module.
6. The startup circuit of a switching power supply according to claim 1, wherein the voltage stabilizing circuit comprises: the third current limiting resistor, the third voltage stabilizing tube and the negative feedback circuit;
the first end of the third current limiting resistor is connected with the bus, and the second end of the third current limiting resistor is connected with the cathode of the third voltage stabilizing tube; the anode of the third voltage stabilizing tube is grounded;
the feedback end of the negative feedback circuit is connected with the bus, the input end of the negative feedback circuit is connected with the cathode of the voltage stabilizing tube, and the output end of the negative feedback circuit is grounded;
the output end of the negative feedback circuit is also connected with the input end of the digital control module.
7. The startup circuit of a switching power supply according to claim 6, wherein the negative feedback circuit comprises: a seventh resistor and a triode;
the collector electrode of the triode is connected with the bus, and the base electrode of the triode is connected with the cathode of the third voltage stabilizing tube; the emitter of the triode is connected with the first end of the seventh resistor;
the second end of the seventh resistor is grounded; and two ends of the seventh resistor are connected with the input end of the digital control module.
8. A switching power supply, comprising: the start-up circuit of a switching power supply according to any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111061885.2A CN113824301B (en) | 2021-09-10 | 2021-09-10 | Starting circuit of switching power supply and switching power supply thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111061885.2A CN113824301B (en) | 2021-09-10 | 2021-09-10 | Starting circuit of switching power supply and switching power supply thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113824301A CN113824301A (en) | 2021-12-21 |
| CN113824301B true CN113824301B (en) | 2023-09-12 |
Family
ID=78922085
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111061885.2A Active CN113824301B (en) | 2021-09-10 | 2021-09-10 | Starting circuit of switching power supply and switching power supply thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113824301B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102361402A (en) * | 2011-10-21 | 2012-02-22 | 广州金升阳科技有限公司 | Switching power supply circuit |
| CN104113957A (en) * | 2013-04-22 | 2014-10-22 | 欧普照明股份有限公司 | Self-excited oscillation driving circuit |
| CN209805684U (en) * | 2019-03-19 | 2019-12-17 | 厦门科司特电子工业有限公司 | Self-excitation driving power circuit |
| CN112510985A (en) * | 2020-12-10 | 2021-03-16 | 珠海格力电器股份有限公司 | Soft start circuit and power supply circuit |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105375777B (en) * | 2015-11-30 | 2018-12-07 | 深圳创维－Rgb电子有限公司 | Constant voltage outputting circuit, reverse exciting switching voltage regulator and its electronic equipment |
-
2021
- 2021-09-10 CN CN202111061885.2A patent/CN113824301B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102361402A (en) * | 2011-10-21 | 2012-02-22 | 广州金升阳科技有限公司 | Switching power supply circuit |
| CN104113957A (en) * | 2013-04-22 | 2014-10-22 | 欧普照明股份有限公司 | Self-excited oscillation driving circuit |
| CN209805684U (en) * | 2019-03-19 | 2019-12-17 | 厦门科司特电子工业有限公司 | Self-excitation driving power circuit |
| CN112510985A (en) * | 2020-12-10 | 2021-03-16 | 珠海格力电器股份有限公司 | Soft start circuit and power supply circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113824301A (en) | 2021-12-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8488340B2 (en) | Power converter with boost-buck-buck configuration utilizing an intermediate power regulating circuit | |
| CN111884513B (en) | Control circuit applied to power adapter and power adapter | |
| US20120155139A1 (en) | Electrical Energy Conversion Circuit Device | |
| US6650095B2 (en) | Low power, dual output AC/DC and DC/DC converter | |
| US6239585B1 (en) | Self-oscillating switch-mode DC to DC conversion with current switching threshold hysteresis | |
| CN113472207B (en) | Switching power supply and control circuit thereof | |
| CN114189166A (en) | Light-load control circuit and method and resonant converter | |
| CN114531033A (en) | Converter with a voltage detection circuit | |
| CN113824301B (en) | Starting circuit of switching power supply and switching power supply thereof | |
| CN210669601U (en) | Battery charging circuit | |
| Sobhan et al. | A novel Split-Pi converter with high step-up ratio | |
| CN114337264B (en) | Boost conversion circuit, device and method | |
| CN112467989B (en) | Quasi-single-stage high-power-factor alternating current-direct current converter | |
| CN113746348A (en) | Push-pull series resonance soft switch switching circuit and switching method and chip thereof | |
| CN216531070U (en) | Switching power supply | |
| CN212343642U (en) | PFC auxiliary power supply circuit, switching power supply device and air conditioner | |
| CN113794368B (en) | Control device and method of flyback switching power supply and flyback switching power supply | |
| CN113241949B (en) | But BUCK-BOOST electrical power generating system of PWM pressure regulating | |
| CN217406409U (en) | Non-isolated DC/DC boost switch converter circuit | |
| Wai et al. | Design of high-efficiency single-input triple-outputs DC-DC converter | |
| CN215185998U (en) | Charging circuit based on boost framework | |
| CN216146251U (en) | Flyback switching power supply and control device thereof | |
| CN216599429U (en) | Low-power-consumption green low-carbon power supply | |
| CN113271024B (en) | AC/DC converter for low-power microcircuit system | |
| CN219535894U (en) | Multi-output switching power supply and power supply system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |