CN114977759A - Switching power supply and control device thereof - Google Patents

Switching power supply and control device thereof Download PDF

Info

Publication number
CN114977759A
CN114977759A CN202210730053.3A CN202210730053A CN114977759A CN 114977759 A CN114977759 A CN 114977759A CN 202210730053 A CN202210730053 A CN 202210730053A CN 114977759 A CN114977759 A CN 114977759A
Authority
CN
China
Prior art keywords
resistor
power supply
voltage
diode
circuit
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.)
Pending
Application number
CN202210730053.3A
Other languages
Chinese (zh)
Inventor
宋蒙恩
霍星星
张岩
翟志伟
郭立星
朱永强
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gree Electric Appliances Inc of Zhuhai
Original Assignee
Gree Electric Appliances Inc of Zhuhai
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Gree Electric Appliances Inc of Zhuhai filed Critical Gree Electric Appliances Inc of Zhuhai
Priority to CN202210730053.3A priority Critical patent/CN114977759A/en
Publication of CN114977759A publication Critical patent/CN114977759A/en
Pending legal-status Critical Current

Links

Images

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
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/083—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the ignition at the zero crossing of the voltage or the current
    • 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
    • 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
    • H02M3/22—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
    • 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
    • H02M3/338—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 in a self-oscillating arrangement
    • 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 control device of a switching power supply and the switching power supply, and belongs to the technical field of switching power supplies. Wherein, a switching power supply's controlling means includes: the automatic starting circuit and the main control unit; the self-starting circuit is used for collecting the voltage of the dotted terminal of the primary side inductor and outputting a square wave signal to the control terminal of the first switching tube so as to start the switching power supply; after the switching power supply is started, the switching power supply supplies power to the main control unit through the flyback power supply circuit; the main control unit is used for collecting bus voltage, bus current and output voltage of the flyback power supply circuit of the power factor correction circuit, and adjusting the on and off of the first switch tube according to the bus voltage, the bus current and the output voltage so as to enable the bus voltage to be stabilized at a set voltage. The control device of the switching power supply solves the starting problem of the switching power supply, and enables the bus voltage to be smoothly stabilized at the set voltage.

Description

Switching power supply and control device thereof
Technical Field
The application relates to the technical field of switching power supplies, in particular to a control device of a switching power supply and the switching power supply.
Background
The common topology of the household appliance power supply is a flyback power supply, the load capacity is generally dozens of watts, the common structure is that a bus gets electricity after power factor correction, and low-voltage multi-path output is realized through the flyback topology of a power supply IC and a high-frequency transformer.
With the progress of digital power supply technology, modern household appliance controller power supplies are developed to digitalization, high frequency and miniaturization, when a bus is not loaded, the voltage of the bus is continuously increased by an IGBT switch, and how to control the starting of a switching power supply becomes a problem to be solved urgently.
Disclosure of Invention
In order to solve the technical problem of controlling the starting of the switching power supply, the application provides a control device of the switching power supply and the switching power supply.
In a first aspect, the present application provides a control apparatus for a switching power supply, where the switching power supply includes a power factor correction circuit, a transformer, a first switching tube, and a flyback power supply circuit; the primary side inductance of the transformer is used as the power factor correction inductance of the power factor correction circuit; the control device includes: the automatic starting circuit and the main control unit;
the self-starting circuit is used for collecting the voltage of the dotted terminal of the primary inductor and outputting a square wave signal to the control terminal of the first switching tube so as to start the switching power supply;
after the switching power supply is started, the switching power supply supplies power to the main control unit through the flyback power supply circuit;
the main control unit is used for acquiring bus voltage, bus current and output voltage of the flyback power supply circuit of the power factor correction circuit, and adjusting the on and off of the first switching tube according to the bus voltage, the bus current and the output voltage so as to stabilize the bus voltage at a set voltage;
optionally, the self-starting circuit comprises a second switching tube, a second diode and a self-oscillation unit;
the anode of the second diode is connected with the same-name end of the primary side inductor, and the cathode of the second diode is connected with the input end of the self-oscillation unit and the square wave signal output end; the square wave signal output end is connected with the control end of the first switching tube;
the first end of the second switching tube is connected with the control end of the self-oscillation unit, the second end of the second switching tube is grounded, and the third end of the second switching tube is connected with the first output end of the main control unit;
the self-oscillation unit is used for generating a square wave signal according to the acquired voltage of the dotted terminal of the primary side inductor and driving the first switching tube to be switched on and off so as to start the switching power supply;
the second switching tube is used for stopping the self-oscillation unit from working under the control of the main control unit;
optionally, the self-oscillation unit includes: the circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a third diode, a fourth diode, a second capacitor and a first operational amplifier;
a first end of the second resistor is used as an input end of the self-oscillation unit and a square wave signal output end, and is connected with a cathode of the second diode, a first end of the fourth resistor, a first end of the fifth resistor and a first end of the sixth resistor; the second end of the second resistor is connected with the non-inverting input end of the first operational amplifier, the first end of the first resistor and the first end of the second switching tube;
the second end of the first resistor is grounded;
the second end of the fourth resistor is connected with the output end of the first operational amplifier;
a second end of the fifth resistor is connected with an anode of the third diode; the cathode of the third diode is connected with the first end of the third resistor and the anode of the fourth diode; the cathode of the fourth diode is connected with the second end of the sixth resistor;
the second end of the third resistor is connected with the first end of the second capacitor and the inverting input end of the first operational amplifier; the second end of the second capacitor is grounded;
optionally, the self-starting circuit further comprises a voltage stabilizing unit; the voltage stabilizing unit comprises a voltage stabilizing resistor and a voltage stabilizing diode;
the voltage stabilizing resistor is connected between the second diode and the second resistor in series; the first end of the voltage stabilizing resistor is connected with the first end of the second resistor and the cathode of the voltage stabilizing diode; the second end of the voltage stabilizing resistor is connected with the cathode of the second diode;
the anode of the voltage stabilizing diode is grounded;
optionally, the self-starting circuit further comprises a voltage detection unit; the voltage detection unit comprises an amplitude detection subunit and a zero crossing point detection subunit;
the amplitude detection subunit is used for detecting the voltage amplitude of the bus voltage;
the zero crossing point detection subunit is used for detecting a zero crossing point of the bus voltage;
the amplitude detection subunit and the zero crossing point detection subunit are used for outputting a high level when the voltage amplitude and/or the zero crossing point detection is abnormal so as to cut off the output of the self-oscillation unit through the second switching tube;
optionally, the zero-crossing point detection subunit includes a seventh resistor, an eighth resistor, a ninth resistor, a third capacitor, and a second operational amplifier;
the first end of the seventh resistor is connected with the first end of the third capacitor and the first end of the voltage stabilizing resistor, and the second end of the third capacitor is connected with the cathode of the voltage stabilizing diode; a second end of the seventh resistor is connected with a first end of the eighth resistor and an inverting input end of the second operational amplifier, and a second end of the eighth resistor is connected with a first end of the ninth resistor; a second end of the ninth resistor is connected with an anode of the voltage stabilizing diode and a non-inverting input end of the second operational amplifier, a second end of the eighth resistor is grounded, and an output end of the second operational amplifier is connected with a third end of the second switching tube;
the amplitude detection subunit comprises a tenth resistor, an eleventh resistor and a third operational amplifier;
a first end of the tenth resistor is connected with an anode of the second diode, and a second end of the tenth resistor is connected with a first end of the eleventh resistor and a non-inverting input end of the third operational amplifier; a second end of the eleventh resistor is grounded; the inverting input end of the third operational amplifier is connected with a set voltage, and the output end of the third operational amplifier is connected with the third end of the second switching tube; the set voltage is used for representing the maximum value allowed to be reached by the bus voltage;
optionally, the control device further comprises a bus voltage control circuit; the bus voltage control circuit is used for controlling the bus voltage not to exceed a set voltage when the flyback power supply circuit is not connected with a load; the set voltage is used for representing the maximum value allowed to be reached by the bus voltage.
In a second aspect, the present application provides a switching power supply, including a power factor correction circuit, a transformer, a first switching tube, a flyback power supply circuit, and a control device of the switching power supply of any one of the first aspect;
the first end of the power factor correction circuit is connected with the first end of the first switch tube, the second end of the power factor correction circuit is connected with the second end of the first switch tube, and the first end of the control device is connected with the control end of the first switch tube; the primary side inductance of the transformer is used as the power factor correction inductance of the power factor correction circuit; the secondary winding of the transformer is used as a secondary inductor of the flyback power supply circuit; the second end of the control device is used for collecting the output voltage of the flyback power supply circuit;
optionally, the power factor correction circuit comprises a first capacitor and a first diode; the first switching tube is used as a switching tube of the power factor correction circuit;
the first end of the first capacitor is grounded, the first end of the first capacitor is connected with the second end of the first switch tube, the second end of the first capacitor is connected with the cathode of the first diode, and the anode of the first diode is connected with the first end of the first switch tube and the synonym end of the primary side inductor of the transformer;
optionally, the flyback power supply circuit includes at least one flyback power supply sub-circuit; the transformer comprises at least one secondary winding, the number of the secondary windings is the same as that of the flyback power supply sub-circuits, the secondary windings correspond to the flyback power supply sub-circuits one by one, and the secondary windings are used as secondary inductors of the flyback power supply sub-circuits;
the flyback power supply sub-circuit comprises the secondary winding, a fourth capacitor and a fifth diode; the different-name end of the secondary winding is connected with the anode of the fifth diode, the cathode of the fifth diode is connected with the first end of the fourth capacitor, and the second end of the fourth capacitor is connected with the same-name end of the secondary winding;
two ends of the fourth capacitor are used for outputting low-voltage direct current;
and the low-voltage direct current output by at least one flyback power supply sub-circuit meets the working voltage of the main control unit.
Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:
according to the control device of the switching power supply provided by the embodiment of the application, the switching power supply comprises a power factor correction circuit, a transformer, a first switching tube and a flyback power circuit; the primary side inductor of the transformer is used as a power factor correction inductor of the power factor correction circuit; the control device includes: the self-starting circuit and the main control unit. According to the control device of the switching power supply, when the switching power supply is started, the main control unit is not powered, firstly, the voltage of the same-name end of the primary side inductor of the transformer is collected through the self-starting circuit, a square wave signal is output to the control end of the first switching tube, the switching power supply is started, and after the switching power supply is started, the flyback power supply circuit supplies power to the main control unit; the main control unit collects bus voltage, bus current and output voltage of the flyback power supply circuit after the power supply works normally, and the first switch tube is adjusted to be switched on and off according to the bus voltage, the bus current and the output voltage, so that the bus voltage is stabilized at a set voltage. The control device of the switching power supply solves the starting problem of the switching power supply, and enables the bus voltage to be smoothly stabilized at the set voltage.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.
In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a control device of a switching power supply according to an embodiment of the present application;
fig. 2 is a schematic diagram of a topology of a novel switching power supply according to an embodiment of the present application;
fig. 3 is a schematic diagram of a topology of a self-starting circuit according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of a self-starting circuit according to an embodiment of the present application;
fig. 5 is a schematic diagram of bus voltage control according to an embodiment of the present application.
The reference numbers are as follows:
q1-first switch tube; q2-second switch tube;
c1 — first capacitance; c2 — second capacitance; c3 — third capacitance; c4-fourth capacitance; c5 — fifth capacitance; c6 — sixth capacitance;
d1 — first diode; d2 — second diode; d3 — third diode; d4 — fourth diode; d5-fifth diode; d6-sixth diode; d7-seventh diode; DZ 1-zener diode;
r1 — first resistance; r2 — second resistance; r3 — third resistance; r4-fourth resistor; r5-fifth resistor; r6-sixth resistance; r7 — seventh resistor; r8 — eighth resistance; r9 — ninth resistor; r10 — tenth resistance; r11 — eleventh resistor; RZ-voltage stabilization resistor; 1A-a first operational amplifier; 1B-a second operational amplifier; 1C-third operational amplifier.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
A first embodiment of the present application provides a control device of a switching power supply, which can be applied to a switching power supply architecture shown in fig. 1, where the switching power supply includes a power factor correction circuit 101, a transformer 102, a first switching tube 104, and a flyback power supply circuit 103, a primary inductor of the transformer 102 is used as a power factor correction inductor of the power factor correction circuit 101, and the control device 105 includes: the self-starting circuit and the main control unit.
In the control device 105, the self-starting circuit is used for collecting the voltage of the same-name end of the primary inductor and outputting a square wave signal to the control end of the first switching tube so as to start the switching power supply, the switching power supply supplies power to the main control unit through the flyback power circuit after being started, and the main control unit is used for collecting the bus voltage, the bus current and the output voltage of the flyback power circuit of the power factor correction circuit and regulating the connection and disconnection of the first switching tube according to the bus voltage, the bus current and the output voltage so as to enable the bus voltage to be stabilized at the set voltage.
In the switching power supply architecture, a power factor correction inductor (PFC inductor) and a transformer are combined into a whole, a primary side inductor of the transformer is used as the PFC inductor, a first switching tube in the switching power supply is used as a switching tube of a PFC circuit (namely the PFC circuit), and a main control unit in a control device is used for controlling, so that an analog power supply IC and the PFC inductor can be saved, the cost of a controller is effectively reduced, and the area of a PCB is reduced. The control device firstly collects the voltage of the same-name end of the primary side inductor of the transformer through the self-starting circuit, outputs a square wave signal to the control end of the first switching tube, starts the switching power supply, and supplies power to the main control unit through the flyback power circuit after the switching power supply is started; the main control unit collects the bus voltage and the bus current of the power factor correction circuit and the output voltage of the flyback power circuit after the main control unit works normally when power is supplied, and regulates the connection and disconnection of the first switching tube according to the bus voltage, the bus current and the output voltage so as to enable the bus voltage to be stabilized at a set voltage. The control device of the switching power supply solves the starting problem of the switching power supply, and enables the bus voltage to be smoothly stabilized at the set voltage.
In one embodiment, as shown in fig. 2, the power factor correction circuit includes a first capacitor C1 and a first diode D1, the first switch Q1 (i.e., the first switch 104 in fig. 1) is simultaneously used as a switch of the power factor correction circuit, and the primary inductor of the transformer 102 is simultaneously used as a PFC inductor of the PFC circuit, so that the PFC inductor and the switch can be saved, and the cost of the hardware circuit can be effectively reduced.
After the switching power supply supplies power, the main control unit MCU is not powered yet, cannot output the PWM wave to control the switching tube, a self-starting circuit is needed to generate the PWM wave to control the switching power supply to work, the topology structure of the self-starting circuit is as shown in fig. 3, and after the bus voltage is stabilized by the voltage stabilizing unit, a square wave signal, such as the PWM wave, is generated in the self-excited oscillation unit to control the switching tube of the switching power supply to turn on and off (such as controlling the first switching tube Q1), thereby starting the switching power supply.
In one embodiment, as shown in fig. 4, the self-starting circuit includes a second switching tube Q2, a second diode D2 and a self-oscillation unit. The connection relationship is as follows:
the anode of the second diode D2 is connected with the dotted terminal of the primary inductor, the cathode of the second diode D2 is connected with the input terminal of the self-oscillation unit and the square wave signal output terminal, the square wave signal output terminal is connected with the control terminal of the first switch tube Q1, the first terminal of the second switch tube Q2 is connected with the control terminal of the self-oscillation unit, the second terminal of the second switch tube Q2 is grounded, the third terminal of the second switch tube Q2 is connected with the first output terminal of the main control unit, the self-oscillation unit is used for generating square wave signals according to the collected voltage of the dotted terminal of the primary inductor, the first switch tube Q1 is driven to be switched on and off to start the switch power supply, and the second switch tube Q2 is used for stopping the self-oscillation unit under the control of the main control unit.
In this embodiment, after the switching power supply is started, the main control unit may output a high level through the GPIO port, so that the first end and the second end of the second switching tube Q2 are turned on, thereby stopping the self-oscillation unit from outputting the square wave signal. And, get the electricity through second diode D2, standby loss is littleer.
Wherein, the self-oscillation unit may specifically include: the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the third diode D3, the fourth diode D4, the second capacitor C2 and the first operational amplifier 1A are connected as follows:
a first end of the second resistor R2 serves as an input end of the self-oscillation unit and an output end of the square wave signal, a first end of the second resistor R2 is connected to a cathode of the second diode D2, a first end of the fourth resistor R4, a first end of the fifth resistor R5 and a first end of the sixth resistor R6, a second end of the second resistor R2 is connected to a non-inverting input end of the first operational amplifier 1A, a first end of the first resistor R1 and a first end of the second switching tube Q2, a second end of the first resistor R1 is grounded, a second end of the fourth resistor R4 is connected to an output end of the first operational amplifier 1A, a second end of the fifth resistor R5 is connected to an anode of the third diode D3, a cathode of the third diode D3 is connected to a first end of the third resistor R3 and an anode of the fourth diode D4, a cathode of the fourth diode D366 is connected to a second end of the sixth resistor R6, a second end of the third resistor R3 is connected to an inverting input end of the first capacitor 2C and an inverting input end of the operational amplifier 361A, the second terminal of the second capacitor C2 is connected to ground.
In one embodiment, as shown in fig. 4, the self-starting circuit may further include a voltage stabilizing unit, and the voltage stabilizing unit may include a voltage stabilizing resistor RZ and a voltage stabilizing diode DZ1, and the connection relationship is as follows:
the voltage stabilizing resistor RZ is connected between the second diode D2 and the second resistor R2 in series, the first end of the voltage stabilizing resistor RZ is connected with the first end of the second resistor R2 and the cathode of the voltage stabilizing diode DZ1, the second end of the voltage stabilizing resistor RZ is connected with the cathode of the second diode D2, and the anode of the voltage stabilizing diode DZ1 is grounded.
In this embodiment, the self-starting circuit takes power before the PFC inductor (i.e. VR in fig. 4 represents a position of VR in fig. 2), and a voltage at VR is much lower than a bus voltage Vp, which is beneficial to reducing power consumption at a current-limiting resistor RZ, so as to reduce power consumption of the whole self-starting circuit, and power is taken through a second diode D2, so that only a conduction voltage drop of a diode is consumed during standby, and power consumption during standby can be reduced.
In this embodiment, DZ1 is a voltage regulator, the voltage value of the model-selection regulated voltage of DZ1 is not higher than the voltage value of the power supply of the operational amplifier, when the operational amplifier output voltage UO is + VDZ1, UO charges the capacitor C2 positively through D3, R5 and R3, neglecting the equivalent resistance when the diode is turned on, when UO is-VDZ 1, UO discharges the capacitor C2 through D4, R6 and R3, neglecting the equivalent resistance when the diode is turned on, and the cycle and duty cycle can be solved by using the three-element method of the first-order RC circuit, and the duty cycle and cycle (i.e. the adjustment frequency) can be adjusted to control the bus voltage and output voltage.
In this embodiment, after the power supply of the main control unit is stably established, the output of the self-oscillation unit may be cut off, and the GPIO port of the main control unit outputs a high level, which may turn on the first terminal and the second terminal of the Q2, and further cut off the input of the non-inverting terminal of the operational amplifier, which may reduce the loss on RZ more than when the self-oscillation output terminal is cut off.
In one embodiment, the self-starting circuit further comprises a voltage detection unit, and the voltage detection unit may comprise an amplitude detection subunit and a zero-crossing point detection subunit. The amplitude detection subunit is used for detecting the voltage amplitude of the bus voltage, the zero crossing point detection subunit is used for detecting the zero crossing point of the bus voltage, the amplitude detection subunit outputs a high level when detecting that the voltage amplitude is abnormal, the zero crossing point detection subunit outputs a high level when detecting that the zero crossing point is abnormal, and any detection subunit can cut off the output of the self-oscillation unit through the second switching tube Q2.
In one embodiment, the zero crossing point detection subunit specifically includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a third capacitor C3, and a second operational amplifier 1B, and the connection relationship is as follows:
a first end of the seventh resistor R7 is connected to a first end of the third capacitor C3 and a first end of the voltage stabilizing resistor RZ, a second end of the third capacitor C3 is connected to a cathode of the zener diode DZ1, a second end of the seventh resistor R7 is connected to a first end of the eighth resistor R8 and an inverting input end of the second operational amplifier 1B, a second end of the eighth resistor R8 is connected to a first end of the ninth resistor R9, a second end of the ninth resistor R9 is connected to an anode of the zener diode DZ1 and a non-inverting input end of the second operational amplifier 1B, a second end of the eighth resistor R8 is grounded, and an output end of the second operational amplifier 1B is connected to a third end of the second switch tube Q2.
The amplitude detection subunit may specifically include a tenth resistor R10, an eleventh resistor R11, and a third operational amplifier 1C, and the connection relationship is as follows:
a first end of the tenth resistor R10 is connected to the anode of the second diode D2, a second end of the tenth resistor R10 is connected to the first end of the eleventh resistor R11 and the non-inverting input end of the third operational amplifier 1C, a second end of the eleventh resistor R11 is grounded, the inverting input end of the third operational amplifier 1C is connected to a set voltage, the output end of the third operational amplifier 1C is connected to the third end of the second switch tube Q2, and the set voltage is used for representing the maximum value allowed to be reached by the bus voltage.
The voltage amplitude detection and zero-crossing detection of the bus voltage are arranged at the front end of the self-starting circuit, and when the bus voltage value is abnormal, the 1B and the 1C can also output high level to cut off the input of the in-phase end of the operational amplifier, so that the bus voltage is prevented from being overhigh, and the safety and reliability of the self-starting circuit are further improved. In the embodiment, the output loss is smaller when the self-excitation is cut off, and the reliability is higher by adopting multi-path detection to cut off the self-excitation output.
It should be noted that the first operational amplifier 1A, the second operational amplifier 1B, and the third operational amplifier 1C may be different ports in the same multi-operational amplifier, for example, belong to a four-operational amplifier, which can ensure that the three operational amplifiers work simultaneously, ensure the safety of operation, and save space at the same time.
In one embodiment, as shown in fig. 5, the control device further includes a bus voltage control circuit, wherein the bus voltage control circuit is configured to control the bus voltage not to exceed a set voltage when the flyback power supply circuit is not connected to the load, and the set voltage is used to represent a maximum value that the bus voltage is allowed to reach.
In the embodiment, when a power supply is powered on, a bus is not loaded, the IGBT switch is driven by self excitation to enable the bus voltage to continuously rise, the relay Q3 can be switched on in a delayed mode through the other control I/O port of the main control unit, intermittent pulses are given to the fan, the fan does not rotate, a motor coil can serve as the bus load, and the bus voltage is stabilized at the set voltage by combining a single-cycle control algorithm.
It should be noted that the fan may be a heat dissipation fan of the switching power supply, or may be a fan externally connected in advance, and when the load is not connected, partial power consumption may be generated by the fan, so that the bus voltage is prevented from rising all the time during no-load.
In one embodiment, a PFC inductor and a high-frequency transformer are combined into a whole, a primary inductor of the transformer serves as the PFC inductor and forms a BOOST type PFC circuit with a switching tube Q1 and a power diode D1, wherein the switching tube Q1 of the PFC circuit has the same function as the switching tube in a flyback power supply, direct current is converted into alternating current through the on-off of the switching tube, energy is transmitted to a secondary side through a high-frequency transformer T1, a Main Control Unit (MCU) adjusts the duty ratio of a driving signal of the switching tube by sampling bus voltage VP, PFC current IPFC and output voltage VO, high-voltage is converted into low voltage through the high-frequency transformer according to the turn ratio of the primary side and the secondary side of the high-frequency transformer, and then required low-voltage direct current is obtained through a rectifier diode and a filter capacitor and is supplied to loads of each circuit.
As shown in fig. 2, the switching power supply circuit is a new switching power supply circuit improved based on a common power supply topology, and this example has 3 outputs, including a BOOST PFC circuit composed of a primary inductor of a transformer, Q1, D1 and C1, a high frequency transformer T1, and a flyback power supply circuit composed of rectifier diodes D5, D6 and D7 and filter capacitors C4, C5 and C6 thereof.
The PFC inductor and the high-frequency transformer are combined into one, the primary inductor of the transformer serves as the PFC inductor, the switching tube Q1 of the PFC plays the same role as the switching tube in the flyback power supply, and the main control unit MCU is used for controlling, so that an analog power supply IC and the PFC inductor are omitted, the cost of the controller is effectively reduced, and the area of a PCB is reduced.
A PFC (power factor correction) inductor is used as a primary side of a high-frequency transformer, a main chip is not powered when a power supply is started, a PWM (pulse-width modulation) wave control switch tube cannot be output, a self-starting circuit is needed to generate the PWM wave to control the power supply to work, and the topology is as shown in figure 3.
VR is the voltage behind the rectifier bridge, in front of the PFC inductance, and the voltage of getting electricity here can be much lower than busbar voltage Vp, is favorable to reducing the power consumption of current-limiting resistance RZ department, and the front end is got the electricity through the diode, can reduce standby power consumption.
DZ1 is the stabilivolt, and the voltage value of the lectotype steady voltage of DZ1 is not higher than the operational amplifier supply voltage value, and when the operational amplifier output voltage UO ═ VDZ1, UO charges the capacitor C positive direction through R5, D3 and R3. Neglecting the equivalent resistance when the diode is conducted, the period and the duty ratio can be solved by utilizing a three-element method of a first-order RC circuit, the duty ratio and the period (namely, the frequency) can be adjusted, and the control of the bus voltage and the output of the voltage are realized.
As shown in fig. 4, after the power supply of the main chip is stably established, the output of the self-excited circuit can be cut off, the GPIO port of the main control unit outputs high level to cut off the input of the non-inverting terminal of the operational amplifier, which can reduce the loss on RZ much more than that when the self-excited output terminal is cut off, the bus voltage detection and the zero-crossing detection are arranged at the front end, and when the bus voltage value is abnormal, the bus voltage 1B and the bus voltage 1C can also output high level to cut off the input of the non-inverting terminal of the operational amplifier, thereby preventing the bus voltage from being too high and increasing the reliability.
As shown in fig. 5, when the power supply is powered on, the bus is not loaded, the self-excited driving of the IGBT switch enables the secondary side of the power supply to output, but also enables the bus voltage to continuously rise, the relay Q3 can be turned on by delaying, and the IGBT in the fan inverter circuit is subjected to intermittent pulse to prevent the fan from rotating, the motor coil can be used as the bus load, the bus voltage is stabilized at the set voltage by combining with the single-cycle control algorithm, and the purpose of power factor verification is achieved at the same time.
Based on the same technical concept, a second embodiment of the present application provides a switching power supply, which includes a power factor correction circuit, a transformer, a first switching tube, a flyback power supply circuit, and a control device of the switching power supply described in any one of the first embodiments.
The first end of the power factor correction circuit is connected with the first end of the first switching tube, the second end of the power factor correction circuit is connected with the second end of the first switching tube, and the first end of the control device is connected with the control end of the first switching tube; the primary side inductance of the transformer is used as the power factor correction inductance of the power factor correction circuit; the secondary winding of the transformer is used as a secondary inductor of the flyback power supply circuit; and the second end of the control device is used for acquiring the output voltage of the flyback power supply circuit.
In the embodiment, the switching power supply comprising the switching power supply control device can obviously improve the performance of the switching power supply when being started, can well control the starting of the switching power supply, saves an analog power supply IC, a PFC inductor and a switching tube, effectively reduces the cost of the controller and reduces the area of a PCB.
The power factor correction circuit may include a first capacitor C1 and a first diode D1, and the first switch Q1 is used as a switch of the power factor correction circuit. The first end of the first capacitor C1 is grounded, the first end of the first capacitor C1 is connected to the second end of the first switch Q1, the second end of the first capacitor C1 is connected to the cathode of the first diode D1, and the anode of the first diode D1 is connected to the first end of the first switch Q1 and the synonym end of the primary inductor of the transformer.
In one embodiment, the flyback power supply circuit includes at least one path of flyback power supply sub-circuit, the transformer includes at least one secondary winding, the number of the secondary windings is the same as the number of the flyback power supply sub-circuits, the secondary windings correspond to the flyback power supply sub-circuits one by one, and the secondary windings are used as secondary inductors of the flyback power supply sub-circuits.
As shown in fig. 2, the three-way flyback power supply sub-circuit may include three-way flyback power supply sub-circuits, the connection modes of the three-way flyback power supply sub-circuits are the same, and one of the three-way flyback power supply sub-circuits is exemplified, where one of the three-way flyback power supply sub-circuits includes a secondary winding, a fourth capacitor C4, and a fifth diode D5, an synonym terminal of the secondary winding is connected to an anode of the fifth diode D5, a cathode of the fifth diode D5 is connected to a first terminal of a fourth capacitor C4, a second terminal of the fourth capacitor C4 is connected to a homonym terminal of the secondary winding, and two terminals of the fourth capacitor C4 are used for outputting low-voltage direct current. The low-voltage direct current output by at least one flyback power supply sub-circuit in the three flyback power supply sub-circuits meets the working voltage of the main control unit. One path includes a fifth capacitor C5 and a sixth diode D6, one path includes a sixth capacitor C6 and a seventh diode D7, and two ends of the fifth capacitor C5 and two ends of the sixth capacitor C6 may output low-voltage direct current respectively, which is not described in detail.
The flyback power supply sub-circuit outputs different low-voltage direct currents according to different turns of the secondary winding, for example, N2, N3, and N4 in fig. 2 may have different turns, and may output voltages of, for example, 15V, 12V, 5V, or 3.3V, and each of the two paths may output different voltages, or the voltages output by the two paths may be the same.
It is noted that, in this document, relational terms such as "first" and "second," and the like, may be 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. Also, 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 an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In the description, suffixes such as "module", "part", or "unit" used to denote elements are used only for facilitating the description of the present invention, and have no specific meaning in themselves. Thus, "module", "component" or "unit" may be used mixedly.
The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice 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 (10)

1. The control device of the switching power supply is characterized in that the switching power supply comprises a power factor correction circuit, a transformer, a first switching tube and a flyback power supply circuit; the primary side inductance of the transformer is used as the power factor correction inductance of the power factor correction circuit; the control device includes: the automatic starting circuit and the main control unit;
the self-starting circuit is used for collecting the voltage of the dotted terminal of the primary inductor and outputting a square wave signal to the control terminal of the first switching tube so as to start the switching power supply;
after the switching power supply is started, the switching power supply supplies power to the main control unit through the flyback power supply circuit;
the main control unit is used for collecting bus voltage, bus current and output voltage of the flyback power supply circuit of the power factor correction circuit, and adjusting the on and off of the first switch tube according to the bus voltage, the bus current and the output voltage so as to enable the bus voltage to be stabilized at a set voltage.
2. The control device of claim 1, wherein the self-starting circuit comprises a second switching tube, a second diode and a self-oscillation unit;
the anode of the second diode is connected with the same-name end of the primary side inductor, and the cathode of the second diode is connected with the input end of the self-oscillation unit and the square wave signal output end; the square wave signal output end is connected with the control end of the first switching tube;
the first end of the second switching tube is connected with the control end of the self-oscillation unit, the second end of the second switching tube is grounded, and the third end of the second switching tube is connected with the first output end of the main control unit;
the self-oscillation unit is used for generating a square wave signal according to the acquired voltage of the dotted terminal of the primary side inductor and driving the first switching tube to be switched on and off so as to start the switching power supply;
and the second switching tube is used for stopping the self-oscillation unit under the control of the main control unit.
3. The control device according to claim 2, wherein the self-oscillation unit includes: the circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a third diode, a fourth diode, a second capacitor and a first operational amplifier;
a first end of the second resistor is used as an input end of the self-oscillation unit and a square wave signal output end, and is connected with a cathode of the second diode, a first end of the fourth resistor, a first end of the fifth resistor and a first end of the sixth resistor; the second end of the second resistor is connected with the non-inverting input end of the first operational amplifier, the first end of the first resistor and the first end of the second switch tube;
the second end of the first resistor is grounded;
the second end of the fourth resistor is connected with the output end of the first operational amplifier;
a second end of the fifth resistor is connected with an anode of the third diode; the cathode of the third diode is connected with the first end of the third resistor and the anode of the fourth diode; the cathode of the fourth diode is connected with the second end of the sixth resistor;
the second end of the third resistor is connected with the first end of the second capacitor and the inverting input end of the first operational amplifier; and the second end of the second capacitor is grounded.
4. The control device of claim 3, wherein the self-starting circuit further comprises a voltage stabilizing unit; the voltage stabilizing unit comprises a voltage stabilizing resistor and a voltage stabilizing diode;
the voltage stabilizing resistor is connected between the second diode and the second resistor in series; the first end of the voltage stabilizing resistor is connected with the first end of the second resistor and the cathode of the voltage stabilizing diode; the second end of the voltage stabilizing resistor is connected with the cathode of the second diode;
and the anode of the voltage stabilizing diode is grounded.
5. The control device according to claim 4, wherein the self-starting circuit further comprises a voltage detection unit; the voltage detection unit comprises an amplitude detection subunit and a zero crossing point detection subunit;
the amplitude detection subunit is used for detecting the voltage amplitude of the bus voltage;
the zero crossing point detection subunit is used for detecting a zero crossing point of the bus voltage;
the amplitude detection subunit and the zero crossing point detection subunit are used for outputting a high level when the voltage amplitude and/or the zero crossing point detection is abnormal, so as to cut off the output of the self-oscillation unit through the second switching tube.
6. The control device according to claim 5, wherein the zero-crossing point detecting subunit includes a seventh resistor, an eighth resistor, a ninth resistor, a third capacitor, and a second operational amplifier;
a first end of the seventh resistor is connected with a first end of the third capacitor and a first end of the voltage stabilizing resistor, and a second end of the third capacitor is connected with a cathode of the voltage stabilizing diode; a second end of the seventh resistor is connected with a first end of the eighth resistor and an inverting input end of the second operational amplifier, and a second end of the eighth resistor is connected with a first end of the ninth resistor; a second end of the ninth resistor is connected with an anode of the voltage stabilizing diode and a non-inverting input end of the second operational amplifier, a second end of the eighth resistor is grounded, and an output end of the second operational amplifier is connected with a third end of the second switching tube;
the amplitude detection subunit comprises a tenth resistor, an eleventh resistor and a third operational amplifier;
a first end of the tenth resistor is connected with an anode of the second diode, and a second end of the tenth resistor is connected with a first end of the eleventh resistor and a non-inverting input end of the third operational amplifier; a second end of the eleventh resistor is grounded; the inverting input end of the third operational amplifier is connected with a set voltage, and the output end of the third operational amplifier is connected with the third end of the second switching tube; the set voltage is used for representing the maximum value allowed to be reached by the bus voltage.
7. The control device of claim 1, further comprising a bus voltage control circuit; the bus voltage control circuit is used for controlling the bus voltage not to exceed a set voltage when the flyback power supply circuit is not connected with a load; the set voltage is used for representing the maximum value allowed to be reached by the bus voltage.
8. A switching power supply, comprising a power factor correction circuit, a transformer, a first switch tube, a flyback power supply circuit, and a control device of the switching power supply of any one of claims 1 to 7;
the first end of the power factor correction circuit is connected with the first end of the first switch tube, the second end of the power factor correction circuit is connected with the second end of the first switch tube, and the first end of the control device is connected with the control end of the first switch tube; the primary side inductance of the transformer is used as the power factor correction inductance of the power factor correction circuit; the secondary winding of the transformer is used as a secondary inductor of the flyback power supply circuit; and the second end of the control device is used for collecting the output voltage of the flyback power supply circuit.
9. The switching power supply according to claim 8, wherein the power factor correction circuit comprises a first capacitor and a first diode; the first switch tube is used as a switch tube of the power factor correction circuit;
the first end of the first capacitor is grounded, the first end of the first capacitor is connected with the second end of the first switch tube, the second end of the first capacitor is connected with the cathode of the first diode, and the anode of the first diode is connected with the first end of the first switch tube and the synonym end of the primary side inductor of the transformer.
10. The switching power supply of claim 8, wherein the flyback power supply circuit comprises at least one flyback power supply sub-circuit; the transformer comprises at least one secondary winding, the number of the secondary windings is the same as that of the flyback power supply sub-circuits, the secondary windings correspond to the flyback power supply sub-circuits one by one, and the secondary windings are used as secondary inductors of the flyback power supply sub-circuits;
the flyback power supply sub-circuit comprises the secondary winding, a fourth capacitor and a fifth diode; the different-name end of the secondary winding is connected with the anode of the fifth diode, the cathode of the fifth diode is connected with the first end of the fourth capacitor, and the second end of the fourth capacitor is connected with the same-name end of the secondary winding;
two ends of the fourth capacitor are used for outputting low-voltage direct current;
and the low-voltage direct current output by at least one flyback power supply sub-circuit meets the working voltage of the main control unit.
CN202210730053.3A 2022-06-24 2022-06-24 Switching power supply and control device thereof Pending CN114977759A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210730053.3A CN114977759A (en) 2022-06-24 2022-06-24 Switching power supply and control device thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210730053.3A CN114977759A (en) 2022-06-24 2022-06-24 Switching power supply and control device thereof

Publications (1)

Publication Number Publication Date
CN114977759A true CN114977759A (en) 2022-08-30

Family

ID=82966518

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210730053.3A Pending CN114977759A (en) 2022-06-24 2022-06-24 Switching power supply and control device thereof

Country Status (1)

Country Link
CN (1) CN114977759A (en)

Similar Documents

Publication Publication Date Title
US7061212B2 (en) Circuit for maintaining hold-up time while reducing bulk capacitor size and improving efficiency in a power supply
US7486030B1 (en) Universal input voltage device
Fernandez et al. Multiple output AC/DC converter with an internal DC UPS
US7974110B2 (en) Switching power supply unit and method for setting switching frequency
EP1102387A2 (en) DC power supply apparatus
JP2010068688A (en) Switching power supply unit
US6396724B1 (en) Charge-pumped DC bias supply
US6778411B2 (en) Start-up circuit for power converters with controller power supply connected at output side
JP2007295800A (en) Power-supply circuit
EP0813767A1 (en) Switched-mode power supply with synchronous preconverter
JPH11113191A (en) Uninterruptible power-supply apparatus and its charging control method
JP2801621B2 (en) Power supply device by PWM control
JPH11150952A (en) Switching dc power supply equipment
JP3588429B2 (en) Power converter
CN114977759A (en) Switching power supply and control device thereof
CN112152468B (en) Single-stage isolation type converter supporting direct current source input
CN213782946U (en) Charging circuit and uninterruptible power supply comprising same
JP4138497B2 (en) Power factor improvement method for power supply system, power supply system, switching power supply device and uninterruptible power supply device
JPS60194757A (en) Switching power source
JP3483128B2 (en) Power supply circuit for lamp
CN217486375U (en) Sputtering power supply
CN219960397U (en) Power supply circuit and electronic product
CN219322275U (en) Power supply circuit, auxiliary power supply and electronic equipment
JP4649728B2 (en) Power supply device and discharge lamp lighting device
CN111641334B (en) Variable frequency control device and air conditioner

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