CN112583278A - Switching power supply protection device and method and switching power supply - Google Patents

Switching power supply protection device and method and switching power supply Download PDF

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Publication number
CN112583278A
CN112583278A CN202011389584.8A CN202011389584A CN112583278A CN 112583278 A CN112583278 A CN 112583278A CN 202011389584 A CN202011389584 A CN 202011389584A CN 112583278 A CN112583278 A CN 112583278A
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CN
China
Prior art keywords
main
loop
main stable
unit
load
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Pending
Application number
CN202011389584.8A
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Chinese (zh)
Inventor
李港
刘兆斌
鲍依婷
单成龙
褚艳伟
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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Priority to CN202011389584.8A priority Critical patent/CN112583278A/en
Publication of CN112583278A publication Critical patent/CN112583278A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—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
    • 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
    • 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
    • H02M3/33569—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 several active switching elements
    • 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
    • H02M3/33569—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 several active switching elements
    • H02M3/33576—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 several active switching elements having at least one active switching element at the secondary side of an isolation transformer
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention discloses a protection device and a method of a switch power supply and the switch power supply, the device comprises: the sampling unit is used for sampling the output voltage of one path of non-main stable loop to which the sampling unit belongs to obtain a sampling voltage value; the main control unit determines whether the non-main stable load in each non-main stable loop is short-circuited or not according to the sampling voltage value of each non-main stable loop, and controls the disconnection unit and the access unit to act under the condition that the non-main stable load in any non-main stable loop is short-circuited; the disconnection unit is used for disconnecting the non-main stable load in one path of non-main stable loop to which the disconnection unit belongs under the condition of receiving the action signal; and the access unit is used for accessing a preset standby resistor into one path of the non-main stable loop to which the access unit belongs under the condition of receiving the action signal. According to the scheme, the short circuit detection and protection are carried out on the loop where the non-main stable load of the flyback switching power supply is located, and the power supply reliability of the flyback switching power supply can be improved.

Description

Switching power supply protection device and method and switching power supply
Technical Field
The invention belongs to the technical field of switching power supplies, particularly relates to a protection device and method of a switching power supply and the switching power supply, and particularly relates to a secondary side unstable circuit short-circuit detection and load switching circuit and method of the switching power supply and the switching power supply.
Background
The flyback transformer switching power supply is characterized in that when a primary coil of a transformer is just excited by direct-current pulse voltage, a secondary coil of the transformer does not provide power output for a load, and the power output is provided for the load only after the excitation voltage of the primary coil of the transformer is turned off.
In the flyback switching power supply, a loop where a secondary side load of a transformer is located may be short-circuited due to external environment, aging of devices, and the like. When a short circuit condition occurs in a loop where the non-main stable load is located, the whole flyback switching power supply cannot normally work.
The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.
Disclosure of Invention
The invention aims to provide a switching power supply protection device, a switching power supply protection method and a switching power supply, so that the problems that the whole flyback switching power supply cannot normally work and has poor power supply reliability when a loop of an unstable load of the flyback switching power supply is short-circuited are solved, and the effects that the power supply reliability of the flyback switching power supply can be improved by performing short-circuit detection and protection on the loop of the unstable load of the flyback switching power supply are achieved.
The invention provides a protection device of a switch power supply, wherein the switch power supply comprises: the transformer, and a primary side loop and a secondary side loop of the transformer; the secondary side loop comprises: the device comprises a main stable loop and non-main stable loops, wherein the number of the non-main stable loops is more than one; the protection device of the switching power supply comprises: a main control unit; further comprising: the sampling unit, the disconnection unit and the access unit are arranged in each path of the unstable circuit; the sampling unit is configured to sample the output voltage of one path of the non-main stable loop to which the sampling unit belongs, so as to obtain a sampling voltage value; the main control unit is configured to determine whether the non-main stable load in each non-main stable loop is short-circuited according to the sampling voltage value of each non-main stable loop, and control the disconnection unit and the access unit to operate under the condition that the non-main stable load in any non-main stable loop is short-circuited; the disconnection unit is configured to disconnect an unstable load in one path of the unstable load loop to which the disconnection unit belongs under the condition that an action signal is received; the access unit is configured to access a preset standby resistor into one path of the non-main stable loop to which the access unit belongs under the condition of receiving an action signal.
In some embodiments, the determining, by the main control unit, whether a short circuit occurs in an unstable load in each of the paths of the unstable circuit according to a sampled voltage value of each of the paths of the unstable circuit, and controlling the disconnecting unit and the accessing unit to operate when a short circuit occurs in an unstable load in any of the paths of the unstable circuit includes: under the condition that the switching power supply is powered on, sending a signal with a first set level to a disconnection unit in each path of the non-main stable loop, sending a signal with a second set level to an access unit in each path of the non-main stable loop, and receiving a sampling voltage value of each path of the non-main stable loop; when any one of the received sampling voltage values of each path of the non-main stable loop is changed from a set normal value to 0, sending a signal with a second set level to a disconnection unit in the path of the non-main stable loop, and sending a signal with a first set level to an access unit in the path of the non-main stable loop; the disconnection unit, under the condition that the action signal is received, disconnects the non-main stable load in the non-main stable loop to which the disconnection unit belongs, and comprises: under the condition of receiving a signal of a second set level, cutting off an unstable load in one path of the unstable circuit to which the load belongs; the access unit, under the condition of receiving the action signal, accesses a preset backup resistor into one path of the non-main stable loop to which the access unit belongs, and comprises: and under the condition of receiving a signal of a first set level, accessing a preset standby load into the path of the non-main stable loop to which the self belongs.
In some embodiments, each of the non-dominant stable loops comprises: a secondary winding of the transformer, a diode module, and a capacitor module; the dotted end of a secondary winding of the transformer is connected to the anode of the diode module; the cathode of the diode module and the synonym end of a secondary winding of the transformer are connected with two ends of the capacitor module and then connected to an unstable load; the sampling unit includes: the first voltage division module and the second voltage division module; the first voltage division module and the second voltage division module are arranged in series, and the first voltage division module is connected to one end of the non-main stable load connected with the cathode of the diode module; the common end of the first voltage division module and the second voltage division module can output the sampling voltage value of the non-main stable loop to which the first voltage division module and the second voltage division module belong.
In some embodiments, the disconnection unit includes: disconnecting the switch module; the disconnection switch module is arranged in a circuit connecting the non-main stable load and the cathode of the diode module and is positioned at the rear end of the sampling unit.
In some embodiments, the disconnect switch module comprises: a disconnection control module and a disconnection execution module; the disconnection control module is configured to control the disconnection execution module to act under the condition of receiving an action signal; and the disconnection execution module is configured to disconnect the non-main stable load in the non-main stable loop to which the disconnection execution module belongs under the control of the disconnection control module.
In some embodiments, the access unit includes: a switch module is accessed; the access switch module is arranged in a circuit connecting the non-main stable load and the cathode of the diode module and is positioned at the front end of the sampling unit.
In some embodiments, the access switch module comprises: the access control module and the access execution module; the preset standby resistor is arranged between the access execution module and a circuit where the different name end of the secondary winding is located; the access control module is configured to control the access execution module to act under the condition of receiving an action signal; the access execution module is configured to access a preset backup resistor to one path of the non-main stable loop to which the access execution module belongs under the control of the access control module.
In some embodiments, further comprising: a display unit; the main control unit is also configured to initiate a reminding instruction under the condition that any one of the non-main stable loads in the non-main stable loop is short-circuited; and the display unit is configured to remind the short circuit of the unstable main load in any one path of the unstable main loop under the condition that the reminding instruction is received.
In accordance with another aspect of the present invention, there is provided a switching power supply, including: the protection device of the switching power supply is described above.
In matching with the switching power supply, another aspect of the present invention provides a protection method for a switching power supply, where the switching power supply includes: the transformer, and a primary side loop and a secondary side loop of the transformer; the secondary side loop comprises: the device comprises a main stable loop and non-main stable loops, wherein the number of the non-main stable loops is more than one; the protection method of the switching power supply comprises the following steps: sampling the output voltage of one path of the non-main stable loop to which the sampling unit belongs through the sampling unit to obtain a sampling voltage value; determining whether the short circuit occurs to the non-main stable load in each non-main stable loop or not according to the sampling voltage value of each non-main stable loop through a main control unit, and controlling the action of a disconnection unit and an access unit in any non-main stable loop under the condition that the short circuit occurs to the non-main stable load in the non-main stable loop; by the disconnecting unit, under the condition of receiving the action signal, disconnecting the non-main stable load in the non-main stable loop of the path to which the disconnecting unit belongs; and through the access unit, under the condition of receiving the action signal, accessing a preset standby resistor into the path of the non-main stable loop to which the access unit belongs.
In some embodiments, determining, by a main control unit, whether a short circuit occurs in an unstable circuit in each of the paths of unstable circuits according to a sampled voltage value of each of the paths of unstable circuits, and controlling an operation of a disconnection unit and an access unit in any of the paths of unstable circuits when a short circuit occurs in an unstable circuit in any of the paths of unstable circuits, includes: under the condition that the switching power supply is powered on, sending a signal with a first set level to a disconnection unit in each path of the non-main stable loop, sending a signal with a second set level to an access unit in each path of the non-main stable loop, and receiving a sampling voltage value of each path of the non-main stable loop; when any one of the received sampling voltage values of each path of the non-main stable loop is changed from a set normal value to 0, sending a signal with a second set level to a disconnection unit in the path of the non-main stable loop, and sending a signal with a first set level to an access unit in the path of the non-main stable loop; through the disconnection unit, under the condition of receiving the action signal, disconnecting the non-main stable load in the non-main stable loop to which the disconnection unit belongs, and the disconnection unit comprises: under the condition of receiving a signal of a second set level, cutting off an unstable load in one path of the unstable circuit to which the load belongs; through the access unit, under the condition of receiving an action signal, a preset spare resistor is accessed into one path of the non-main stable loop to which the access unit belongs, and the access unit comprises: and under the condition of receiving a signal of a first set level, accessing a preset standby load into the path of the non-main stable loop to which the self belongs.
In some embodiments, further comprising: through the main control unit, a reminding instruction is initiated under the condition that the non-main stable load in any one path of the non-main stable loop is short-circuited; and reminding the condition that the unstable load in any one path of the unstable circuit is short-circuited by a display unit under the condition that the reminding instruction is received.
Therefore, according to the scheme of the invention, the power supply reliability of the flyback switching power supply can be improved by detecting the output voltage of the non-main stable loop of the flyback switching power supply, judging whether the load of the non-main stable loop is short-circuited or not according to the output voltage of the non-main stable loop, cutting off the load of the non-main stable loop when the load of the non-main stable loop is short-circuited, and connecting a dummy load, and performing short-circuit detection and protection on the loop where the non-main stable load of the flyback switching power supply is located.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
Fig. 1 is a schematic structural diagram of a protection device of a switching power supply according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an embodiment of a flyback switching power supply;
fig. 3 is a schematic structural diagram of an embodiment of a flyback switching power supply secondary side output diode short-circuit detection and load switching circuit;
fig. 4 is a schematic diagram of a working flow of an embodiment of a flyback switching power supply secondary side output diode short-circuit detection and load switching circuit;
fig. 5 is a schematic flowchart of a protection method for a switching power supply according to an embodiment of the present invention;
fig. 6 is a schematic flow chart illustrating an embodiment of determining whether the short circuit occurs in the unstable circuit of each of the ways according to the method of the present invention.
Fig. 7 is a schematic flow chart illustrating an embodiment of a method for reminding a short circuit of an unstable load according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. 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 invention.
According to an embodiment of the present invention, there is provided a protection apparatus of a switching power supply. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The switching power supply includes: a transformer, and a primary loop and a secondary loop of the transformer (e.g., the primary loop of the transformer and the primary loop of the secondary loop of the transformer T1). The secondary side loop comprises: the device comprises a main stable loop and non-main stable loops, wherein the number of the non-main stable loops is more than one. The protection device of the switching power supply comprises: a main control unit (such as a main chip MCU). Further comprising: the sampling unit, the disconnection unit (namely the non-main stable load disconnection unit) and the access unit (namely the dummy load access unit) are arranged in each of more than one non-main stable loops.
The sampling unit is configured to sample the output voltage of the one path of the non-main stable loop to which the sampling unit belongs, and obtain a sampling voltage value of the output voltage of the one path of the non-main stable loop to which the sampling unit belongs.
The main control unit is configured to determine whether the non-primary stable load in each non-primary stable loop is short-circuited according to the sampling voltage value of each non-primary stable loop, and control the disconnection unit and the access unit to operate to disconnect the non-primary stable load in the non-primary stable loop and access a preset backup resistor to the non-primary stable loop when any non-primary stable load in the non-primary stable loop is short-circuited.
The disconnection unit is configured to disconnect the primary unstable load in the primary unstable circuit to which the disconnection unit belongs under the control of the main control unit, that is, under the condition that an action signal is received.
The access unit is configured to access a preset backup resistor (such as a resistor R1 in the first unstable loop and a resistor R2 in the second unstable loop) to one of the unstable loops to which the access unit belongs under the control of the main control unit, that is, under the condition of receiving an action signal.
Specifically, through the matching arrangement of the main control unit, the sampling unit, the disconnection unit and the access unit, when a load short-circuit signal is detected, the short-circuited loop is immediately disconnected, so that the phenomenon that the switching power supply stops working due to short-circuit protection is avoided, and the normal work of other loops is influenced; the short-circuit load is disconnected, and the dummy load is connected into the loop, so that the stable work of the switching power supply can be ensured, and the reliability of the circuit is improved.
In some embodiments, the determining, by the main control unit, whether a short circuit occurs in an unstable load in each of the unstable loops according to a sampled voltage value of each of the unstable loops, and controlling the disconnecting unit and the accessing unit to operate when a short circuit occurs in an unstable load in any of the unstable loops, includes:
the main control unit is specifically configured to send a signal of a first set level to a disconnection unit in each path of the unstable main circuit, send a signal of a second set level to an access unit in each path of the unstable main circuit, and receive a sampling voltage value of each path of the unstable main circuit when the switching power supply is powered on. Wherein, when the first setting level is high level, the second setting level is low level.
The master control unit is specifically further configured to determine the received sampling voltage value of each of the non-master stable loops, whether the sampling voltage value of any one of the non-main stable loops is changed from a set normal value to 0, so that in the case that any one of the received sampling voltage values of the non-dominant stable loop is changed from the set normal value to 0, sending a signal of a second set level to a disconnection unit in the path of the unstable main loop, to control the disconnection unit in the path of the non-main stable loop to cut off the non-main stable load in the path of the non-main stable loop, and to send a signal of a first set level to the access unit in the path of the non-main stable loop, and controlling the access unit in the path of the non-main stable loop to access a preset dummy load into the path of the non-main stable loop.
Correspondingly, the disconnecting unit, under the control of the main control unit, that is, under the condition of receiving an action signal, disconnects the non-primary stable load in the non-primary stable loop to which the disconnecting unit belongs, and includes: the disconnection unit is specifically configured to, when receiving a signal of a second set level, disconnect the non-primary stable load in the non-primary stable loop to which the disconnection unit belongs.
Correspondingly, the accessing unit accesses a preset backup resistor to one of the paths of the non-main stable loop to which the accessing unit belongs under the control of the main control unit, that is, under the condition of receiving an action signal, and the accessing unit includes: the access unit is specifically configured to access a preset backup load (i.e., a dummy load) to the one of the non-main stable loops to which the access unit belongs when receiving a signal of a first set level.
Specifically, the flyback switching power supply is powered on and reset, the main chip sends two continuous high-level signals, namely a fifth signal and a sixth signal, the main chip also sends two continuous low-level signals, namely a third signal and a fourth signal, and the main chip also receives two digital signals, namely a first signal and a second signal. The first signal and the second signal are sampling voltage values output by the unstable main loop. The main chip can judge whether the two sampling voltage values are normal or not, and further judge whether the load of the non-main stable loop is short-circuited or not.
When the voltage value of the first signal received by the main chip becomes 0, the main chip sends a continuous high-level signal to the third signal, and the relay K1 is pulled in; the master chip sends a continuous low signal to the fifth signal and relay K3 opens. The main chip sends out a fault signal to enable the nixie tube or the liquid crystal display to display that the first non-main stable loop is short-circuited. Or when the voltage value of the second signal received by the main chip becomes 0, the main chip sends a continuous high-level signal to the fourth signal, and the relay K2 is closed; the master chip sends a continuous low signal to the sixth signal and relay K4 opens. The main chip sends out a fault signal to enable the nixie tube or the liquid crystal display to display that the second unstable loop is short-circuited.
In some embodiments, each of the non-dominant stable loops comprises: a secondary winding of the transformer (e.g., a first secondary winding L2, a second secondary winding L3, etc. of the transformer T1), a diode module (e.g., a diode D1 in the first unstable loop, a diode D2 in the second unstable loop, etc.), and a capacitance module (e.g., a capacitor C1 in the first unstable loop, a capacitor C2 in the second unstable loop, etc.). And the dotted end of a secondary winding of the transformer is connected to the anode of the diode module. And the cathode of the diode module and the synonym end of the secondary winding of the transformer are connected to two ends of the capacitor module and then connected to an unstable load.
Specifically, the DC input source DC, the switching tube Q5 and the primary winding L1 of the transformer T1 form a primary loop of the transformer T1. The switching power supply chip controls the on-off of the switching tube Q5 and receives a voltage feedback signal from the main stable output. The switching tube Q5 may be a MOS tube. And a secondary coil L4 of the transformer T1, an output diode D3 and a main stabilizing load form a main stabilizing loop. The capacitor C3 is connected in parallel with the front end of the main stable load and plays the roles of smoothing and stabilizing the wave.
The sampling unit includes: the device comprises a first voltage division module and a second voltage division module. For example: in the first unstable loop, the first voltage divider is a resistor R3, and the second voltage divider is a resistor R5. In the second unstable loop, the first voltage divider is a resistor R4, and the second voltage divider is a resistor R6.
The first voltage division module and the second voltage division module are arranged in series, and the first voltage division module is connected to one end of the non-main stable load connected with the cathode of the diode module, namely one end of the first voltage division module far away from the second voltage division module, and is connected to one end of the non-main stable load connected with the cathode of the diode module. One end of the second voltage division module, which is far away from the first voltage division module, is grounded. The common end of the first voltage division module and the second voltage division module can output the sampling voltage value of the non-main stable loop to which the first voltage division module and the second voltage division module belong.
In some embodiments, the disconnection unit includes: the switch module is disconnected. The disconnection switch module is arranged in a line connecting the non-main stable load and the cathode of the diode module, is positioned at the rear end of the sampling unit, namely is arranged between one end of the first voltage division module, which is far away from the second voltage division module, and the non-main stable load.
In some embodiments, the disconnect switch module comprises: the control module is disconnected (such as a transistor Q3 in the first unstable loop, a transistor Q4 in the second unstable loop and the like), and the execution module is disconnected (such as a relay K3 in the first unstable loop, a relay K4 in the second unstable loop and the like).
Wherein the disconnection control module is configured to control the disconnection execution module to act when an action signal is received.
And the disconnection execution module is configured to disconnect the non-main stable load in the non-main stable loop to which the disconnection execution module belongs under the control of the disconnection control module.
In some embodiments, the access unit includes: and a switch module is connected. The access switch module is arranged in a circuit connecting the non-main stable load and the cathode of the diode module, and is positioned at the front end of the sampling unit, namely, between one end of the capacitor module connected with the cathode of the diode module and one end of the first voltage division module far away from the second voltage division module.
In some embodiments, the access switch module comprises: the control module (such as a triode Q1 in the first unstable loop, a triode Q2 in the second unstable loop and the like) is accessed, and the execution module (such as a relay K1 in the first unstable loop, a relay K2 in the second unstable loop and the like) is accessed. The preset standby resistor is arranged between the access execution module and a circuit where the different name end of the secondary winding is located, namely, the preset standby resistor is connected between one end, far away from the cathode of the diode module, of the access execution module and the circuit where the different name end of the secondary winding is located.
Wherein the access control module is configured to control the access execution module to act on the condition that an action signal is received.
The access execution module is configured to access a preset backup resistor to one path of the non-main stable loop to which the access execution module belongs under the control of the access control module.
Specifically, the secondary winding L2 of the transformer T1, the output diode D1, the relay K3, and the first load form a first unstable primary circuit. And the capacitor C1 is connected in parallel with the front end of the first load and plays the roles of energy storage and filtering. The relay K1 is connected in series with the resistor R1 and at the rear end of the capacitor C1, and the relay K1 is controlled by a third signal through a transistor Q1. Relay K3 is controlled by a fifth signal via transistor Q3. The voltage output by the first unstable non-main loop is divided by the resistor R3 and the resistor R5 to generate a first signal, and the first signal enters the main chip. The secondary winding L3 of the transformer T1, the output diode D2, the relay K4, and the second load form a second unstable primary circuit. And the capacitor C2 is connected in parallel at the front end of the second load and plays the roles of energy storage and filtering. The relay K2 is connected in series with the resistor R2, and the relay K2 is controlled by a fourth signal through a transistor Q2 at the rear end of the capacitor C2. Relay K4 is controlled by a sixth signal via transistor Q4. The voltage output by the second unstable non-main loop is divided by the resistor R4 and the resistor R6, and a generated second signal enters the main chip.
Therefore, the output of the short-circuited path is cut off, and the dummy load is connected, so that the stable output of other paths is ensured. When the use of one short circuit loop does not affect the normal short-term operation of the whole system, the relay is used for cutting off the fault circuit, and the normal output of other loop power supplies is ensured.
In some embodiments, further comprising: a display unit.
The main control unit is further configured to initiate a reminding instruction to remind a user of the short circuit of the non-primary stable load in any one of the non-primary stable loops when any one of the non-primary stable loops is short-circuited.
The display unit is configured to remind, under the control of the main control unit, when any one of the non-primary stable loads in the non-primary stable loops is short-circuited, that is, when the reminding instruction is received, the situation that the non-primary stable load in any one of the non-primary stable loops is short-circuited.
Specifically, when the load of the first unstable line is short-circuited, the sampled voltage value obtained by voltage division through the resistor R3 and the resistor R5 originally becomes 0 from a normal value, that is, the first signal becomes 0 from a normal value, at this time, the main chip determines that the first load is short-circuited, changes the fifth signal from a high level to a low level, switches off the relay K3, and switches off the short-circuited first load. The third signal changes from low level to high level, the resistor R1 is connected into the circuit to ensure the normal operation of the circuit, and the main chip displays that the first load is short-circuited through a digital tube, a liquid crystal display or the like.
When the second unstable main loop is short-circuited, the sampling voltage obtained by voltage division through the resistor R4 and the resistor R6 is changed from a normal value to 0, namely the second signal is changed from a normal value to 0, at the moment, the main chip judges that the load is short-circuited, the sixth signal is changed from a high level to a low level, the relay K4 is disconnected, and the short-circuited second load is cut off. The fourth signal changes from low level to high level, the resistor R2 is connected into the circuit to ensure the normal operation of the circuit, and the main chip displays that the second load is short-circuited through a digital tube, a liquid crystal display or the like.
Therefore, the maintenance is prompted to people by displaying the fault reason, the fault reason is accurately positioned, and the maintenance time and cost are saved.
Through a large number of tests, the technical scheme of the invention is adopted, whether the load of the non-main stable loop is short-circuited or not is judged according to the output voltage of the non-main stable loop by detecting the output voltage of the non-main stable loop of the flyback switching power supply, when the load of the non-main stable loop is short-circuited, the load of the non-main stable loop is cut off and a dummy load is connected, and the power supply reliability of the flyback switching power supply can be improved by carrying out short-circuit detection and protection on the loop of the non-main stable load of the flyback switching power supply.
According to an embodiment of the present invention, there is also provided a switching power supply corresponding to a protection apparatus of the switching power supply. The switching power supply may include: the protection device of the switching power supply is described above.
The flyback switching power supply has the advantages of simple structure, small size and small number of devices, is generally suitable for multi-path isolated output, and generally uses the path with the largest load as a main stable path, and uses other paths with lighter loads as a power supply for isolated communication, an isolated driving power supply or other power supplies needing isolation.
Fig. 2 is a schematic structural diagram of an embodiment of a flyback switching power supply. The flyback switching power supply shown in fig. 2 includes: the power supply comprises a direct current power supply DC, a switching power supply chip, a MOS tube Q1, a transformer, diodes D1, D2 and D3, capacitors C1, C2 and C3, a main stable load and an non-main stable load. The positive pole of the direct current power supply DC is connected to the synonym end of the primary winding of the transformer, the negative pole of the direct current power supply DC is connected to the source electrode of the MOS tube Q1, the switching power supply chip is connected to the grid electrode of the MOS tube Q1, and the drain electrode of the MOS tube Q1 is connected to the synonym end of the primary winding of the transformer. In the first to third secondary windings of the transformer, the dotted terminal of the first secondary winding is connected to the anode of a diode D1, the cathode of a diode D1 is connected to the different-dotted terminal of the first secondary winding through a capacitor C1, and an unstable load is connected to the output terminal of the capacitor C1. The dotted terminal of the second secondary winding is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the different-dotted terminal of the second secondary winding after passing through the capacitor C2, and the other non-main stable load is connected to the output terminal of the capacitor C2. The dotted terminal of the third secondary winding is connected to the anode of the diode D3, the cathode of the diode D3 is connected to the different-dotted terminal of the third secondary winding after passing through the capacitor C3, and a main stable load is connected to the output terminal of the capacitor C3.
In the flyback switching power supply, the secondary side loop (i.e., the loop in which the secondary side winding is located) may be short-circuited due to external environment, device aging, and the like, which may occur. Once short circuit occurs, the instantaneous current is too large, so that the switching power supply chip triggers short circuit protection, and no output is generated on other loops. The whole switching power supply cannot work normally.
In the flyback switching power supply shown in fig. 2, when a short circuit occurs in a loop where the non-main stable load is located, the entire switching power supply cannot normally operate; however, under normal conditions, if the power supply on the non-primary stable loop is only supplied to a communication circuit which does not affect the operation of the whole machine, the shutdown caused by the short circuit of the non-primary stable loop can be avoided as much as possible.
In some embodiments, the scheme of the invention provides a switching power supply secondary side unstable circuit short-circuit detection and load switching circuit, which can detect whether an unstable circuit of a flyback switching power supply is short-circuited or not, and accurately display a fault position during short-circuit, thereby facilitating subsequent maintenance; and when the non-main stable loop is short-circuited, the short-circuit load is cut off, and a dummy load is connected to ensure the stable operation of the switching power supply.
Specifically, according to the scheme of the invention, the protection circuit of the switching power supply is accessed into the secondary side non-main stable output loop of the flyback switching power supply to judge whether the load of the non-main stable output loop is short-circuited or not, and if the load of the non-main stable output loop is short-circuited, the fault position and the reason can be accurately displayed.
According to the scheme, the short-circuit detection signal is used for controlling devices such as the relay and the like, cutting off the short-circuit load on the path with the fault, and connecting the dummy load into the circuit to ensure the normal operation of the circuit.
In the related scheme, all the output is cut off after the short circuit of the switching power supply is detected, so that related devices are protected. The scheme of the invention is to cut off the short-circuited output and connect the dummy load to ensure the stable output of other paths. When the use of one short circuit loop does not affect the normal short-term operation of the whole system, the relay is used for cutting off the fault circuit, the normal output of other loop power supplies is ensured, and the fault reason and the fault point are reported.
For example: communication circuits of a single machine and a centralized controller in a commercial air conditioner multi-split air conditioner. The circuit does not affect the single operation of the whole machine. If only the circuit has a fault, the whole machine cannot operate, which is unreasonable. Therefore, the switching power supply secondary side unstable circuit short-circuit detection and load switching circuit provided by the scheme of the invention can prevent the phenomenon from occurring.
Fig. 3 is a schematic structural diagram of an embodiment of a flyback switching power supply secondary side output diode short-circuit detection and load switching circuit. As shown in fig. 3, the circuit for detecting the short circuit of the secondary side output diode and switching the load of the flyback switching power supply includes: the direct current power supply can be a direct current input source DC or a direct current formed by alternating current passing through a rectifier bridge and a filter capacitor; a switching tube Q5; a switching power supply chip; a transformer T1, the transformer T1 comprising a primary winding L1, a magnetic core, and secondary windings L2, L3, and L4; secondary side output diodes D1, D2, D3; filter capacitors C1, C2, C3; relays K1, K2, K3, and K4; transistors Q1, Q2, Q3, and Q4; resistors R1, R2, R3, R4, R5 and R6; a master chip (i.e., MCU); display units such as a digital tube, a liquid crystal display, and the like; isolating the power supply chip; the device comprises a main stable load and an non-main stable load, wherein the non-main stable load comprises a first load and a second load.
In the example shown in fig. 3, the DC input source DC, the switching transistor Q5 and the primary winding L1 of the transformer T1 form a primary loop of the transformer T1. The switching power supply chip controls the on-off of the switching tube Q5 and receives a voltage feedback signal from the main stable output. The switching tube Q5 may be a MOS tube.
For example: the switching power supply chip can be selected from chips with the model number of STR-6A161HZS or NCP1377BDR 2G.
In the example shown in fig. 3, the secondary winding L4 of the transformer T1, the output diode D3 and the main ballast constitute a main ballast circuit. The capacitor C3 is connected in parallel with the front end of the main stable load and plays the roles of smoothing and stabilizing the wave.
In the example shown in fig. 3, the secondary winding L2 of the transformer T1, the output diode D1, the relay K3, and the first load form a first unstable main circuit. And the capacitor C1 is connected in parallel with the front end of the first load and plays the roles of energy storage and filtering. The relay K1 is connected in series with the resistor R1 and at the rear end of the capacitor C1, and the relay K1 is controlled by a third signal through a transistor Q1.
Relay K3 is controlled by a fifth signal via transistor Q3. The voltage output by the first unstable non-main loop is divided by the resistor R3 and the resistor R5 to generate a first signal, and the first signal enters the main chip.
In the example shown in fig. 3, the secondary winding L3 of the transformer T1, the output diode D2, the relay K4, and the second load form a second unstable main circuit. And the capacitor C2 is connected in parallel at the front end of the second load and plays the roles of energy storage and filtering. The relay K2 is connected in series with the resistor R2, and the relay K2 is controlled by a fourth signal through a transistor Q2 at the rear end of the capacitor C2.
Relay K4 is controlled by a sixth signal via transistor Q4. The voltage output by the second unstable non-main loop is divided by the resistor R4 and the resistor R6, and a generated second signal enters the main chip.
The state of the flyback switching power supply secondary side output diode short-circuit detection and load switching circuit shown in fig. 3 during normal operation includes:
the switching power supply is electrified for the first time, the main chip is reset, the fifth signal and the sixth signal sent by the main chip are both high level, the third signal and the fourth signal are low level, and the received first signal and the received second signal are sampling voltage values output by the non-main stable loop. And the switching power supply is powered on, and the power supply voltage of the MCU is established.
A primary side switching tube Q5 is turned on, a primary side inductor L1 of the transformer T1 (namely, a primary side winding L1 of the transformer T1) is excited, the primary winding induces upper, positive and lower negative electromotive forces, corresponding secondary side coils L2, L3 and L4 of the flyback transformer T1 (namely, secondary side windings L2, L3 and L4 of the transformer T1) induce upper, negative and lower positive electromotive forces due to coupling, at this time, the output diodes D1, D2 and D3 are not conducted, and each load is supplied with current by electricity stored in a capacitor.
When the primary side switching tube Q5 is turned off, energy accumulated by a primary side inductor L1 of the transformer T1 (namely, a primary side winding L1 of the transformer T1) is transferred to a secondary side (namely, secondary side windings L2, L3 and L4 of the transformer T1), at this time, a primary side generates an electromotive force of up-negative and down-positive, a secondary side generates an electromotive force of up-positive and down-negative, the output diodes D1, D2 and D3 are in a conducting state at this time, and a load is simultaneously supplied with power by the secondary side winding of the transformer T1 and the capacitor.
The state of the flyback switching power supply when the secondary side output diode short-circuit detection and load switching circuit abnormally operates as shown in fig. 3 includes:
when the load of the first unstable main loop is in short circuit, the sampling voltage value obtained by voltage division through the resistor R3 and the resistor R5 is changed from a normal value to 0, namely the first signal is changed from a normal value to 0, at the moment, the main chip judges that the first load is in short circuit, the fifth signal is changed from a high level to a low level, the relay K3 is disconnected, and the first load in short circuit is cut off. The third signal changes from low level to high level, the resistor R1 is connected into the circuit to ensure the normal operation of the circuit, and the main chip displays that the first load is short-circuited through a digital tube, a liquid crystal display or the like.
When the second unstable main loop is short-circuited, the sampling voltage obtained by voltage division through the resistor R4 and the resistor R6 is changed from a normal value to 0, namely the second signal is changed from a normal value to 0, at the moment, the main chip judges that the load is short-circuited, the sixth signal is changed from a high level to a low level, the relay K4 is disconnected, and the short-circuited second load is cut off. The fourth signal changes from low level to high level, the resistor R2 is connected into the circuit to ensure the normal operation of the circuit, and the main chip displays that the second load is short-circuited through a digital tube, a liquid crystal display or the like.
Fig. 4 is a schematic diagram of a working flow of an embodiment of a flyback switching power supply secondary side output diode short-circuit detection and load switching circuit. As shown in fig. 4, the working process of the flyback switching power supply secondary side output diode short-circuit detection and load switching circuit includes:
step 1, the flyback switching power supply is powered on and reset, the main chip sends two continuous high-level signals, namely a fifth signal and a sixth signal, the main chip also sends two continuous low-level signals, namely a third signal and a fourth signal, and the main chip also receives two digital signals, namely a first signal and a second signal. The first signal and the second signal are sampling voltage values output by the unstable main loop. The main chip can judge whether the two sampling voltage values are normal or not, further judge whether the load of the non-main stable loop is short-circuited or not, and execute the step 2, the step 3 and the like.
Wherein, continuously means: after the switching power supply is powered on, as long as the main chip is powered on, the two high-level signals are sent out all the time unless the load is in a short-circuit condition.
And 2, when the voltage value of the first signal received by the main chip is changed into 0, the main chip sends a continuous high-level signal to the third signal, and the relay K1 is closed. The master chip sends a continuous low signal to the fifth signal and relay K3 opens. The main chip sends out a fault signal to enable the nixie tube or the liquid crystal display to display that the first non-main stable loop is short-circuited.
And 3, when the voltage value of the second signal received by the main chip is changed into 0, the main chip sends a continuous high-level signal to the fourth signal, and the relay K2 is closed. The master chip sends a continuous low signal to the sixth signal and relay K4 opens. The main chip sends out a fault signal to enable the nixie tube or the liquid crystal display to display that the second unstable loop is short-circuited.
In the scheme of the invention, the secondary side output diode short-circuit detection and load switching circuit of the flyback switching power supply immediately disconnects the short-circuited loop when detecting a load short-circuit signal, so that the switching power supply is prevented from stopping working due to short-circuit protection, and normal working of other loops is prevented from being influenced. The short-circuit load is disconnected firstly, and then the dummy load is connected into the loop, so that the stable work of the switching power supply can be ensured, and the reliability of the circuit is improved. Meanwhile, the fault reason is displayed to remind people of maintenance, the fault reason is accurately positioned, and the maintenance time and cost are saved.
Since the processing and functions implemented by the switching power supply of this embodiment substantially correspond to the embodiments, principles, and examples of the apparatus shown in fig. 1, reference may be made to the related descriptions in the foregoing embodiments without details in the description of this embodiment.
Through a large number of tests, the technical scheme of the invention is adopted, whether the load of the unstable circuit of the flyback switching power supply is short-circuited or not is detected, and when a load short-circuit signal is detected, the short-circuited circuit is immediately disconnected, so that the switching power supply is prevented from being short-circuited and stopping working, and the normal working of other circuits is prevented from being influenced.
According to an embodiment of the present invention, there is also provided a protection method for a switching power supply corresponding to the switching power supply, as shown in fig. 5, which is a schematic flow chart of an embodiment of the method of the present invention. The switching power supply includes: a transformer, and a primary loop and a secondary loop of the transformer (e.g., the primary loop of the transformer and the primary loop of the secondary loop of the transformer T1). The secondary side loop comprises: the device comprises a main stable loop and non-main stable loops, wherein the number of the non-main stable loops is more than one. The protection method of the switching power supply comprises the following steps: step S110 to step S140.
In step S110, the sampling unit samples the output voltage of the one of the non-primary stable circuits to which the sampling unit belongs, so as to obtain a sampling voltage value of the output voltage of the one of the non-primary stable circuits to which the sampling unit belongs.
At step S120, a main control unit (e.g., a main chip MCU) determines whether a short circuit occurs to an unstable load in each of the unstable loops according to a sampled voltage value of each of the unstable loops, and controls the disconnecting unit and the accessing unit to operate to disconnect the unstable load in the unstable loop and access a preset backup resistor to the unstable loop in any of the unstable loops.
In step S130, the disconnecting unit disconnects the non-primary stable load in the non-primary stable loop to which the disconnecting unit belongs under the control of the main control unit, that is, under the condition of receiving the action signal.
In step S140, a preset backup resistor (e.g., the resistor R1 in the first unstable loop, the resistor R2 in the second unstable loop, etc.) is connected to one of the unstable loops to which the access unit belongs under the control of the main control unit, that is, under the condition of receiving the action signal.
The sampling unit, the disconnection unit (namely, an unstable load disconnection unit) and the access unit (namely, a dummy load access unit) are arranged in each of the unstable loops.
Specifically, through the matching arrangement of the main control unit, the sampling unit, the disconnection unit and the access unit, when a load short-circuit signal is detected, the short-circuited loop is immediately disconnected, and the phenomenon that the switching power supply stops working due to short-circuit protection is avoided, so that the normal work of other loops is influenced. The short-circuit load is disconnected, and the dummy load is connected into the loop, so that the stable work of the switching power supply can be ensured, and the reliability of the circuit is improved.
In some embodiments, in step S120, it is determined, by the main control unit, whether a short circuit occurs in the unstable circuit in each of the paths according to the sampled voltage value of each of the unstable circuits, and when any one of the unstable circuits in the unstable circuit in all of the unstable circuits has a short circuit, a specific process of the actions of the disconnection unit and the access unit is controlled, which can be referred to in the following exemplary description.
The following further describes, with reference to a schematic flow chart of an embodiment of determining whether the short circuit occurs to the non-dominant stable load in each of the non-dominant stable loops in the method shown in fig. 6, a specific process of determining whether the short circuit occurs to the non-dominant stable load in each of the non-dominant stable loops in step S120, which may include: step S210 to step S220.
Step S210, by the main control unit, specifically, under the condition that the switching power supply is powered on, sending a signal of a first set level to a disconnection unit in each of the non-primary stable circuits, sending a signal of a second set level to an access unit in each of the non-primary stable circuits, and receiving a sampling voltage value of each of the non-primary stable circuits. Wherein, when the first setting level is high level, the second setting level is low level.
Step S220, through the main control unit, specifically, in the received sampling voltage value of each path of the unstable main loop, whether the sampling voltage value of any one of the non-main stable loops is changed from a set normal value to 0, so that in the case that any one of the received sampling voltage values of the non-dominant stable loop is changed from the set normal value to 0, sending a signal of a second set level to a disconnection unit in the path of the unstable main loop, to control the disconnection unit in the path of the non-main stable loop to cut off the non-main stable load in the path of the non-main stable loop, and to send a signal of a first set level to the access unit in the path of the non-main stable loop, and controlling the access unit in the path of the non-main stable loop to access a preset dummy load into the path of the non-main stable loop.
Correspondingly, in step S130, under the control of the main control unit, that is, under the condition of receiving the action signal, the disconnecting unit disconnects the non-primary stable load in the one path of the non-primary stable loop to which the disconnecting unit belongs, including: and by the disconnection unit, particularly, under the condition of receiving a signal of a second set level, the non-main stable load in the non-main stable loop to which the disconnection unit belongs is disconnected.
Correspondingly, in step S140, under the control of the main control unit, that is, under the condition of receiving an action signal, a preset backup resistor is connected to one of the non-main stable loops to which the access unit belongs, and the preset backup resistor includes: through the access unit, a preset standby load (i.e., a dummy load) is accessed to the one path of the non-main stable loop to which the access unit belongs under the condition that a signal of a first set level is received.
Specifically, the flyback switching power supply is powered on and reset, the main chip sends two continuous high-level signals, namely a fifth signal and a sixth signal, the main chip also sends two continuous low-level signals, namely a third signal and a fourth signal, and the main chip also receives two digital signals, namely a first signal and a second signal. The first signal and the second signal are sampling voltage values output by the unstable main loop. The main chip can judge whether the two sampling voltage values are normal or not, and further judge whether the load of the non-main stable loop is short-circuited or not.
When the voltage value of the first signal received by the main chip becomes 0, the main chip sends a continuous high-level signal to the third signal, and the relay K1 is pulled in; the master chip sends a continuous low signal to the fifth signal and relay K3 opens. The main chip sends out a fault signal to enable the nixie tube or the liquid crystal display to display that the first non-main stable loop is short-circuited. Or when the voltage value of the second signal received by the main chip becomes 0, the main chip sends a continuous high-level signal to the fourth signal, and the relay K2 is closed; the master chip sends a continuous low signal to the sixth signal and relay K4 opens. The main chip sends out a fault signal to enable the nixie tube or the liquid crystal display to display that the second unstable loop is short-circuited.
In some embodiments, further comprising: and reminding the short circuit of the unstable load.
With reference to the flowchart of fig. 7, a specific process of reminding the condition of the short circuit of the non-main stable load is further described, which includes: step S310 and step S320.
Step S310, through the main control unit, a reminding instruction is also initiated under the condition that any one of the non-main stable circuits has short circuit, so as to remind the condition that the non-main stable load in any one of the non-main stable circuits has short circuit.
Step S320, under the control of the main control unit, by using a display unit, under the condition that any one of the non-primary stable loads in the non-primary stable loops is short-circuited, that is, under the condition that the reminding instruction is received, reminding the short-circuited non-primary stable load in any one of the non-primary stable loops.
Specifically, when the load of the first unstable line is short-circuited, the sampled voltage value obtained by voltage division through the resistor R3 and the resistor R5 originally becomes 0 from a normal value, that is, the first signal becomes 0 from a normal value, at this time, the main chip determines that the first load is short-circuited, changes the fifth signal from a high level to a low level, switches off the relay K3, and switches off the short-circuited first load. The third signal changes from low level to high level, the resistor R1 is connected into the circuit to ensure the normal operation of the circuit, and the main chip displays that the first load is short-circuited through a digital tube, a liquid crystal display or the like.
When the second unstable main loop is short-circuited, the sampling voltage obtained by voltage division through the resistor R4 and the resistor R6 is changed from a normal value to 0, namely the second signal is changed from a normal value to 0, at the moment, the main chip judges that the load is short-circuited, the sixth signal is changed from a high level to a low level, the relay K4 is disconnected, and the short-circuited second load is cut off. The fourth signal changes from low level to high level, the resistor R2 is connected into the circuit to ensure the normal operation of the circuit, and the main chip displays that the second load is short-circuited through a digital tube, a liquid crystal display or the like.
Therefore, the maintenance is prompted to people by displaying the fault reason, the fault reason is accurately positioned, and the maintenance time and cost are saved.
Since the processing and functions implemented by the method of this embodiment substantially correspond to the embodiments, principles, and examples of the switching power supply, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.
Through a large number of tests, the technical scheme of the embodiment is adopted, whether the load of the non-main stable loop of the flyback switching power supply is short-circuited or not is detected, when a load short-circuit signal is detected, the short-circuit load is disconnected, and the dummy load is connected into the loop, so that the stable work of the switching power supply can be ensured, and the reliability of the circuit is improved.
In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.
The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims (12)

1. A protection device for a switching power supply, the switching power supply comprising: the transformer, and a primary side loop and a secondary side loop of the transformer; the secondary side loop comprises: the device comprises a main stable loop and non-main stable loops, wherein the number of the non-main stable loops is more than one; the protection device of the switching power supply comprises: a main control unit; further comprising: the sampling unit, the disconnection unit and the access unit are arranged in each path of the unstable circuit; wherein the content of the first and second substances,
the sampling unit is configured to sample the output voltage of one path of the non-main stable loop to which the sampling unit belongs, so as to obtain a sampling voltage value;
the main control unit is configured to determine whether the non-main stable load in each non-main stable loop is short-circuited according to the sampling voltage value of each non-main stable loop, and control the disconnection unit and the access unit to operate under the condition that the non-main stable load in any non-main stable loop is short-circuited;
the disconnection unit is configured to disconnect an unstable load in one path of the unstable load loop to which the disconnection unit belongs under the condition that an action signal is received;
the access unit is configured to access a preset standby resistor into one path of the non-main stable loop to which the access unit belongs under the condition of receiving an action signal.
2. The protection device for a switching power supply according to claim 1, wherein,
the main control unit determines whether the non-main stable load in each non-main stable loop is short-circuited according to the sampling voltage value of each non-main stable loop, and controls the disconnecting unit and the accessing unit to act under the condition that the non-main stable load in any non-main stable loop is short-circuited, and the method comprises the following steps:
under the condition that the switching power supply is powered on, sending a signal with a first set level to a disconnection unit in each path of the non-main stable loop, sending a signal with a second set level to an access unit in each path of the non-main stable loop, and receiving a sampling voltage value of each path of the non-main stable loop;
when any one of the received sampling voltage values of each path of the non-main stable loop is changed from a set normal value to 0, sending a signal with a second set level to a disconnection unit in the path of the non-main stable loop, and sending a signal with a first set level to an access unit in the path of the non-main stable loop;
the disconnection unit, under the condition that the action signal is received, disconnects the non-main stable load in the non-main stable loop to which the disconnection unit belongs, and comprises:
under the condition of receiving a signal of a second set level, cutting off an unstable load in one path of the unstable circuit to which the load belongs;
the access unit, under the condition of receiving the action signal, accesses a preset backup resistor into one path of the non-main stable loop to which the access unit belongs, and comprises:
and under the condition of receiving a signal of a first set level, accessing a preset standby load into the path of the non-main stable loop to which the self belongs.
3. The protection device for the switching power supply according to claim 1 or 2, wherein each of the non-primary stable loops comprises: a secondary winding of the transformer, a diode module, and a capacitor module; the dotted end of a secondary winding of the transformer is connected to the anode of the diode module; the cathode of the diode module and the synonym end of a secondary winding of the transformer are connected with two ends of the capacitor module and then connected to an unstable load;
the sampling unit includes: the first voltage division module and the second voltage division module;
the first voltage division module and the second voltage division module are arranged in series, and the first voltage division module is connected to one end of the non-main stable load connected with the cathode of the diode module; the common end of the first voltage division module and the second voltage division module can output the sampling voltage value of the non-main stable loop to which the first voltage division module and the second voltage division module belong.
4. The protection device of the switching power supply according to claim 3, wherein the disconnection unit includes: disconnecting the switch module; the disconnection switch module is arranged in a circuit connecting the non-main stable load and the cathode of the diode module and is positioned at the rear end of the sampling unit.
5. The protection device for the switching power supply according to claim 4, wherein the disconnection switch module comprises: a disconnection control module and a disconnection execution module;
the disconnection control module is configured to control the disconnection execution module to act under the condition of receiving an action signal;
and the disconnection execution module is configured to disconnect the non-main stable load in the non-main stable loop to which the disconnection execution module belongs under the control of the disconnection control module.
6. The protection device for the switching power supply according to claim 3, wherein the access unit comprises: a switch module is accessed; the access switch module is arranged in a circuit connecting the non-main stable load and the cathode of the diode module and is positioned at the front end of the sampling unit.
7. The protection device of the switching power supply according to claim 6, wherein the access switch module comprises: the access control module and the access execution module; the preset standby resistor is arranged between the access execution module and a circuit where the different name end of the secondary winding is located;
the access control module is configured to control the access execution module to act under the condition of receiving an action signal;
the access execution module is configured to access a preset backup resistor to one path of the non-main stable loop to which the access execution module belongs under the control of the access control module.
8. The protection device for a switching power supply according to claim 1 or 2, further comprising: a display unit;
the main control unit is also configured to initiate a reminding instruction under the condition that any one of the non-main stable loads in the non-main stable loop is short-circuited;
and the display unit is configured to remind the short circuit of the unstable main load in any one path of the unstable main loop under the condition that the reminding instruction is received.
9. A switching power supply, comprising: the protection device of the switching power supply according to any one of claims 1 to 8.
10. A protection method of a switching power supply, characterized in that the switching power supply comprises: the transformer, and a primary side loop and a secondary side loop of the transformer; the secondary side loop comprises: the device comprises a main stable loop and non-main stable loops, wherein the number of the non-main stable loops is more than one; the protection method of the switching power supply comprises the following steps:
sampling the output voltage of one path of the non-main stable loop to which the sampling unit belongs through the sampling unit to obtain a sampling voltage value;
determining whether the short circuit occurs to the non-main stable load in each non-main stable loop or not according to the sampling voltage value of each non-main stable loop through a main control unit, and controlling the action of a disconnection unit and an access unit in any non-main stable loop under the condition that the short circuit occurs to the non-main stable load in the non-main stable loop;
by the disconnecting unit, under the condition of receiving the action signal, disconnecting the non-main stable load in the non-main stable loop of the path to which the disconnecting unit belongs;
and through the access unit, under the condition of receiving the action signal, accessing a preset standby resistor into the path of the non-main stable loop to which the access unit belongs.
11. The protection method of a switching power supply according to claim 10,
determining whether the short circuit occurs to the non-main stable load in each non-main stable loop according to the sampling voltage value of each non-main stable loop through a main control unit, and controlling the actions of a disconnection unit and an access unit in any non-main stable loop under the condition that the short circuit occurs to the non-main stable load in the non-main stable loop, wherein the actions comprise:
under the condition that the switching power supply is powered on, sending a signal with a first set level to a disconnection unit in each path of the non-main stable loop, sending a signal with a second set level to an access unit in each path of the non-main stable loop, and receiving a sampling voltage value of each path of the non-main stable loop;
when any one of the received sampling voltage values of each path of the non-main stable loop is changed from a set normal value to 0, sending a signal with a second set level to a disconnection unit in the path of the non-main stable loop, and sending a signal with a first set level to an access unit in the path of the non-main stable loop;
through the disconnection unit, under the condition of receiving the action signal, disconnecting the non-main stable load in the non-main stable loop to which the disconnection unit belongs, and the disconnection unit comprises:
under the condition of receiving a signal of a second set level, cutting off an unstable load in one path of the unstable circuit to which the load belongs;
through the access unit, under the condition of receiving an action signal, a preset spare resistor is accessed into one path of the non-main stable loop to which the access unit belongs, and the access unit comprises:
and under the condition of receiving a signal of a first set level, accessing a preset standby load into the path of the non-main stable loop to which the self belongs.
12. The protection method of the switching power supply according to claim 10 or 11, further comprising:
through the main control unit, a reminding instruction is initiated under the condition that the non-main stable load in any one path of the non-main stable loop is short-circuited;
and reminding the condition that the unstable load in any one path of the unstable circuit is short-circuited by a display unit under the condition that the reminding instruction is received.
CN202011389584.8A 2020-12-01 2020-12-01 Switching power supply protection device and method and switching power supply Pending CN112583278A (en)

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