CN218771280U - Short-circuit delay protection device of switching power supply, switching power supply and equipment - Google Patents
Short-circuit delay protection device of switching power supply, switching power supply and equipment Download PDFInfo
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- CN218771280U CN218771280U CN202223402563.2U CN202223402563U CN218771280U CN 218771280 U CN218771280 U CN 218771280U CN 202223402563 U CN202223402563 U CN 202223402563U CN 218771280 U CN218771280 U CN 218771280U
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Abstract
The utility model discloses a switching power supply's short circuit time delay protection device, switching power supply and equipment relates to the short-circuit protection field, through setting up short-circuit switch, output voltage collection module, short circuit detection module and short circuit protection module, output voltage collection module gathers switching power supply's output voltage, short-circuit switch breaks off when switching power supply takes place short-circuit fault, short circuit detection module is according to output voltage and switching power supply's comp pin voltage detection short circuit, short circuit protection module discharges to switching power supply when taking place the short circuit. When short-circuit fault occurs, because the voltage of the comp pin gradually rises, the short-circuit detection module triggers the short-circuit protection module when detecting that the voltage is too high, so that the switching power supply is discharged, the switching power supply can be restarted after being recharged, the switching tube can be turned on again, the time for the switching power supply to turn on the switching tube again and work again is delayed, and the frequency for the switching power supply to trigger the short-circuit protection mechanism is reduced.
Description
Technical Field
The utility model relates to a short-circuit protection field especially relates to a switching power supply's short circuit time delay protection device, switching power supply and equipment.
Background
Because of its advantages such as small, light in weight, conversion efficiency height and stable performance are used in various equipment by the wide range, when switching power supply normally worked, if the condition of output short circuit appeared, because output line short circuit can produce very big electric current, switching power supply can be overheated or even damaged when receiving heavy current, consequently, need carry out short-circuit protection to switching power supply. In the prior art, a short-circuit protection mechanism is usually arranged in a switching power supply, and when the switching power supply detects that the voltage at the I-sense pin of the switching power supply is greater than a preset value, a switching tube inside the switching power supply is turned off, so that the purpose of short-circuit protection is achieved. However, after the switching tube is turned off, the voltage at the I-sense pin is rapidly reduced to be below the preset value, at this time, the switching power supply exits the short-circuit protection state and turns on the switching tube again, and since the output short-circuit condition still exists, the short-circuit protection mechanism of the switching power supply is triggered again, so that the switching tube and the switching power supply are frequently started and stopped, and the service life and the reliability of the switching power supply are reduced.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a switching power supply's short circuit time delay protection device, switching power supply and equipment have delayed switching power supply and have opened the switch tube again and the time of doing work again, have reduced the frequency that switching power supply triggered short-circuit protection mechanism.
In order to solve the technical problem, the utility model provides a switching power supply's short circuit time delay protection device, include:
the short-circuit protection device comprises a short-circuit switch, an output voltage acquisition module, a short-circuit detection module and a short-circuit protection module;
the input end of the output voltage acquisition module is connected with the output end of the switching power supply, the output end of the output voltage acquisition module is connected with one end of the short-circuit switch, and the output voltage acquisition module is used for acquiring the output voltage of the switching power supply;
the short-circuit switch is used for being switched off when the switching power supply has a short-circuit fault;
the input end of the short-circuit detection module is respectively connected with the other end of the short-circuit switch and the comp pin end of the switching power supply, the output end of the short-circuit detection module is connected with the input end of the short-circuit protection module, and the short-circuit detection module is used for generating a short-circuit delay signal when detecting that the voltage of the input end of the short-circuit detection module is greater than a preset voltage value;
the first end of the short-circuit protection module is connected with the power supply, the second end of the short-circuit protection module is connected with the power supply end of the switching power supply, and the short-circuit protection module is used for discharging the switching power supply when receiving the short-circuit delay signal.
Preferably, the short-circuit switch is an optical coupler;
the primary side first end of the optical coupler is connected with the first output end of the output voltage acquisition module, the primary side second end of the optical coupler is connected with the second output end of the output voltage acquisition module, the secondary side first end of the optical coupler is connected with the input end of the short circuit detection module, and the secondary side second end of the optical coupler is grounded.
Preferably, the output voltage collecting module includes:
the circuit comprises a first resistor, a second resistor, a third resistor and a first diode;
the first end of the first resistor is connected with the output end of the switching power supply, the second end of the first resistor is connected with the first primary end of the optocoupler, and the voltage at the first primary end of the optocoupler is used as the output voltage;
a first end of the second resistor is connected with an output end of the switching power supply, and a second end of the second resistor is respectively connected with a first end of the third resistor and an anode of the first diode;
the second end of the third resistor is grounded;
and the cathode of the first diode is connected with the second end of the primary side of the optocoupler.
Preferably, the device also comprises a current acquisition module;
the input end of the current acquisition module is connected with an emitting electrode of a switch tube in the switch power supply, and the output end of the current acquisition module is connected with an I-sense pin end in the switch power supply.
Preferably, the current collection module includes:
a fourth resistor and a first capacitor;
a first end of the fourth resistor is connected with an emitter of a switching tube in the switching power supply, and a second end of the fourth resistor is respectively connected with a first end of the first capacitor and an I-sense pin end in the switching power supply;
the second end of the first capacitor is grounded.
Preferably, the short circuit detection module includes:
a fifth resistor, a sixth resistor, a second capacitor and a third capacitor;
a first end of the fifth resistor is connected to an output end of the output voltage acquisition module, a comp pin end of the switching power supply, and a first end of the second capacitor, a second end of the fifth resistor is connected to a first end of the sixth resistor, a first end of the third capacitor, and an input end of the short-circuit protection module, respectively, and a voltage at the first end of the third capacitor is used as the short-circuit delay signal;
a second end of the sixth resistor is grounded;
the second end of the second capacitor is grounded;
and the second end of the third capacitor is grounded.
Preferably, the short-circuit protection module includes:
the second diode, the triode, the seventh resistor and the fourth capacitor;
the anode of the second diode is connected with the output end of the short-circuit protection module, and the cathode of the second diode is connected with the base electrode of the triode;
the collector of the triode is grounded, and the emitter of the triode is connected with the first end of the seventh resistor;
a second end of the seventh resistor is connected with the anode of the fourth capacitor, the power supply and a power supply end of the switching power supply respectively;
and the negative electrode of the fourth capacitor is grounded.
Preferably, the method further comprises the following steps:
an eighth resistor disposed between the fourth capacitor and the power supply.
The application also provides a switching power supply, which comprises a switching power supply body and the short-circuit time-delay protection device of the switching power supply;
the switching power supply body is connected with the short-circuit time-delay protection device of the switching power supply.
The application also provides equipment, which comprises an equipment body and the switching power supply;
the equipment body is connected with the switching power supply.
The application provides a short-circuit delay protection device of a switching power supply, the switching power supply and equipment. By arranging the short-circuit switch, the output voltage acquisition module, the short-circuit detection module and the short-circuit protection module, the input end of the output voltage acquisition module is connected with the output end of the switch power supply, the output end of the output voltage acquisition module is connected with one end of the short-circuit switch, the output voltage acquisition module is used for acquiring the output voltage of the switch power supply, the short-circuit switch is used for being disconnected when a short-circuit fault occurs, the input end of the short-circuit detection module is respectively connected with the other end of the short-circuit switch and the comp pin end of the switch power supply, the output end of the short-circuit protection module is connected with the input end of the short-circuit protection module, the short-circuit detection module is used for generating a short-circuit delay signal when the voltage of the input end of the short-circuit detection module is larger than a preset voltage value, the first end of the short-circuit protection module is connected with the power supply, the second end of the short-circuit protection module is connected with the power supply, and the short-circuit protection module is used for discharging the switch power supply when the short-circuit delay signal is received. When short-circuit fault occurs, because the voltage of the comp pin gradually rises, the short-circuit detection module triggers the short-circuit protection module when detecting that the voltage is too high, so that the switch power supply is discharged, the switch power supply can be restarted after being recharged, the switch tube can be turned on again, the time for turning on the switch tube again and working again of the switch power supply are delayed, and the frequency for triggering the short-circuit protection mechanism by the switch power supply is reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required in the prior art and the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a short-circuit protection device in the prior art;
fig. 2 is a schematic structural diagram of a short-circuit protection device of a switching power supply provided in the present application;
fig. 3 is a schematic structural diagram of another short-circuit protection device for a switching power supply provided in the present application.
Detailed Description
The core of the utility model is to provide a switching power supply's short circuit time delay protection device, switching power supply and equipment, delayed switching power supply and opened the time of switch tube and rework again, reduced the frequency that switching power supply triggered the short circuit protection mechanism.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In the prior art, when a switching power supply is protected, short-circuit protection is usually realized based on Cycle-by-Cycle current limit (Cycle-by-Cycle) carried by a chip I-Sense pin of the switching power supply. Referring to fig. 1, fig. 1 is a schematic structural diagram of a short-circuit protection device in the prior art, on the basis of a switching power supply body, an emitter of a switching tube Q1 in the switching power supply is connected to a chip I-Sense pin of the switching power supply, and a resistor R1 and a capacitor C1 are provided. When Vout is short-circuited, as the current is increased, the current is reduced in equal proportion along with the turn ratio of a transformer in the switching power supply and then reflected to the primary side of the transformer, after passing through a resistor R2, the current can generate a voltage signal on the R2 and send the voltage signal to an I-Sense pin, so that the voltage at the I-Sense pin is increased along with the increase of the current, when the voltage exceeds a safe voltage, a preset short-circuit protection mechanism in a chip can be triggered, and the chip can close a driving pulse to close a switching tube Q1, so that the short-circuit protection of the switching power supply is realized. However, when Q1 is turned off, the current in the line will gradually decrease, the voltage at the I-Sense pin will also decrease, when the voltage is lower than the safety voltage, the switching power supply will exit the short-circuit protection state, and turn on Q1 again to resume working, because the voltage decreases rapidly, the switching power supply will resume working quickly, but the output short-circuit condition still exists at this time, so the short-circuit protection mechanism will be triggered again, resulting in the switching power supply triggering the short-circuit protection mechanism frequently, and the service life and reliability of the switching power supply are reduced.
To solve the above technical problem, please refer to fig. 2, fig. 2 is a schematic structural diagram of a short-circuit protection device of a switching power supply provided in the present application, including:
the short-circuit protection device comprises a short-circuit switch 14, an output voltage acquisition module 13, a short-circuit detection module 11 and a short-circuit protection module 12;
the input end of the output voltage acquisition module 13 is connected with the output end of the switching power supply 15, the output end of the output voltage acquisition module 13 is connected with one end of the short-circuit switch 14, and the output voltage acquisition module 13 is used for acquiring the output voltage of the switching power supply 15;
the short-circuit switch 14 is used for being turned off when the short-circuit fault occurs in the switching power supply 15;
the input end of the short-circuit detection module 11 is respectively connected with the other end of the short-circuit switch 14 and the comp pin end of the switching power supply 15, the output end of the short-circuit detection module 11 is connected with the input end of the short-circuit protection module 12, and the short-circuit detection module 11 is used for generating a short-circuit delay signal when detecting that the voltage of the input end of the short-circuit detection module is greater than a preset voltage value;
a first end of the short-circuit protection module 12 is connected to the power supply, a second end of the short-circuit protection module 12 is connected to a power supply end of the switching power supply 15, and the short-circuit protection module 12 is configured to discharge the switching power supply 15 when receiving the short-circuit delay signal.
In order to reduce the frequency of triggering the short-circuit protection mechanism, in the present application, it is considered that the comp pin of the chip in the switching power supply 15 is a constant current source, and when a short-circuit fault occurs, the voltage at the comp pin changes, so that voltage detection at the comp pin of the chip in the switching power supply 15 is added, short-circuit protection is implemented according to the output voltage of the switching power supply 15 and the voltage at the comp pin, and the time required for the switching power supply 15 to restart is prolonged by directly cutting off power supply through the short-circuit protection module 12, thereby reducing the frequency of triggering the short-circuit protection mechanism.
Considering that the voltage value is a continuous variable, if it is determined whether there is a short-circuit fault only from the output voltage of the switching power supply 15, some normal operating conditions may be mistaken for a short-circuit fault, for example, when the switching power supply 15 starts to operate, the output voltage of the switching power supply 15 gradually increases from 0; when the load changes, the output voltage of the switching power supply 15 changes accordingly; if the determination is made only based on the output voltage of the switching power supply 15, the output voltage is small when the above-mentioned situation occurs, so that the situation may be erroneously determined as a short-circuit fault, and therefore, the determination needs to be made based on the comp pin together.
Specifically, the output voltage collecting module 13 is configured to obtain a voltage at the output end of the switching power supply 15 and send the voltage to the short-circuit switch 14, when the short circuit occurs at the output end of the switching power supply 15, vout may be reduced to approximately 0, the short-circuit switch 14 may be disconnected when detecting the short circuit at the output end of the switching power supply 15, and at this time, the comp pin may not be discharged through the short-circuit switch 14, so that the voltage at the comp pin may be continuously increased. The voltage at the output end of the short-circuit detection module 11 is equal to the sum of the output voltage of the switching power supply 15 and the voltage of the comp pin, when the output end of the switching power supply 15 is short-circuited, the output voltage of the switching power supply 15 is approximately 0, and the voltage at the input end of the short-circuit detection module 11 is approximately equal to the voltage of the comp pin, so that the voltage at the input end of the short-circuit detection module 11 is continuously increased, when the voltage at the input end of the short-circuit detection module 11 is greater than the preset voltage, it can be determined that a short-circuit fault occurs, and then a short-circuit delay signal is sent to the short-circuit protection module 12 to discharge the switching power supply 15. It should be noted that, in a normal operation condition, the comp pin is continuously discharged through the short-circuit switch 14, so that the voltage at the comp pin tends to be stable, and the voltage at the input end of the short-circuit detection module 11 is only affected by the output voltage, so that the preset voltage may be set according to the output voltage in the normal operation and the voltage at the comp pin.
Because the switching tube Q1 of the switching power supply 15 is closed after the output end is short-circuited, although the voltage at the I-sense pin of the switching power supply 15 decreases, the voltage at the comp pin increases, when the voltage at the comp pin is too large, the short-circuit protection module 12 may short-circuit the power supply Vcc of the switching power supply 15, so that the switching power supply 15 is completely discharged and is stopped, thereby preventing the switching power supply 15 from immediately restarting the switching tube Q1 after the voltage at the I-sense pin decreases below the safety voltage, at this time, the switching power supply 15 can only be recharged until the voltage value is greater than the opening voltage, after the switching power supply 15 is restarted, the voltage decrease at the I-sense pin can be detected, and then the switching tube Q1 is closed, so that the switching power supply 15 works.
It can be seen that, in the prior art, once the voltage at the I-sense pin is detected to drop below the safe voltage, the switching tube Q1 is closed again, and in the present application, because the voltage at the I-sense pin rises while the voltage at the comp pin falls, before the voltage at the I-sense pin falls below the safe voltage, the comp pin rises above the preset voltage, so as to trigger the subsequent steps, and the process of detecting the rise of the voltage at the comp pin is a first delay means; after the switching power supply 15 is discharged, the switching power supply 15 needs to be recharged to restore the self-starting state, and the charging process is a second delay means. Therefore, the frequency of the switching power supply 15 triggering the short-circuit protection mechanism can be effectively reduced by the double delay means. For example, in the prior art, the short-circuit protection mechanism is triggered every time tens of microseconds by using a mode of detecting only the voltage at the I-sense pin, whereas in the present application, the short-circuit protection mechanism is triggered after tens of milliseconds or even tens of milliseconds by using the switching power supply 15 according to different types of the short-circuit protection module 12 and the short-circuit detection module 11 which are actually used.
In summary, by providing the short-circuit switch 14, the output voltage acquisition module 13, the short-circuit detection module 11 and the short-circuit protection module 12, an input end of the output voltage acquisition module 13 is connected to an output end of the switching power supply 15, an output end of the output voltage acquisition module 13 is connected to one end of the short-circuit switch 14, the output voltage acquisition module 13 is configured to acquire an output voltage of the switching power supply 15, the short-circuit switch 14 is configured to be disconnected when the switching power supply 15 has a short-circuit fault, an input end of the short-circuit detection module 11 is connected to the other end of the short-circuit switch 14 and a comp pin end of the switching power supply 15, an output end of the short-circuit detection module 11 is connected to an input end of the short-circuit protection module 12, the short-circuit detection module 11 is configured to generate a short-circuit delay signal when detecting that a voltage at its input end is greater than a preset voltage value, a first end of the short-circuit protection module 12 is connected to the power supply, a second end of the short-circuit protection module 12 is connected to a power supply end of the switching power supply 15, and the short-circuit protection module 12 is configured to discharge the switching power supply 15 when receiving the short-circuit delay signal. When short-circuit fault occurs, because the voltage of the comp pin gradually rises, the short-circuit detection module 11 triggers the short-circuit protection module 12 when detecting that the voltage is too high, so that the switching power supply 15 is discharged, the switching power supply 15 is restarted after being recharged, the switching tube Q1 can be turned on again, the time for turning on the switching tube Q1 again and working again of the switching power supply 15 is delayed, and the frequency for triggering the short-circuit protection mechanism by the switching power supply 15 is reduced.
On the basis of the above-described embodiment:
as a preferred embodiment, the short-circuit switch 14 is an opto-coupler;
the first end of the primary side of the optical coupler is connected with the first output end of the output voltage acquisition module 13, the second end of the primary side of the optical coupler is connected with the second output end of the output voltage acquisition module 13, the first end of the secondary side of the optical coupler is connected with the input end of the short circuit detection module 11, and the second end of the secondary side of the optical coupler is grounded.
In order to realize the function of the short-circuit switch 14, in the present application, the function of the short-circuit switch 14 is realized by an optical coupler. Specifically, referring to fig. 3, fig. 3 is a schematic structural diagram of another short-circuit protection device for a switching power supply provided in the present application, in which a second end of a secondary side of an optocoupler is grounded, and since a comp pin of the switching power supply 15 and a first end of the secondary side of the optocoupler are both connected to an input end of the short-circuit detection module 11, during normal operation, the comp pin of the switching power supply 15 discharges to the second end of the secondary side through the first end of the secondary side of the optocoupler. When switching power supply 15's output short circuit, switching power supply 15's output voltage drops to 0, and output voltage collection module 13 sends the voltage for the opto-coupler also to be 0, leads to the opto-coupler to not switch on, and switching power supply 15's comp pin can't discharge through the opto-coupler to lead to comp pin voltage to rise gradually. Therefore, the optocoupler is used as the short-circuit switch 14, the purpose of disconnection when the output end is short-circuited can be achieved only by utilizing the conduction characteristic of the optocoupler, and the interference of the output end to the switch power supply 15 can be isolated when the optocoupler works normally, so that the optocoupler can be used as the short-circuit switch 14 well.
As a preferred embodiment, the output voltage collecting module 13 includes:
the circuit comprises a first resistor R1, a second resistor R2, a third resistor R3 and a first diode U1;
a first end of the first resistor R1 is connected with an output end of the switching power supply 15, a second end of the first resistor R1 is connected with a first end of a primary side of the optocoupler, and a voltage at the first end of the primary side of the optocoupler is used as an output voltage;
a first end of the second resistor R2 is connected to an output end of the switching power supply 15, and a second end of the second resistor R2 is connected to a first end of the third resistor R3 and an anode of the first diode U1, respectively;
the second end of the third resistor R3 is grounded;
and the cathode of the first diode U1 is connected with the second end of the primary side of the optocoupler.
In order to simply implement the function of the output voltage collecting module 13, please refer to fig. 3 in the present application, and fig. 3 is a schematic structural diagram of another short-circuit protection device of a switching power supply provided in the present application, in which the output voltage collecting module 13 is composed of a first resistor R1, a second resistor R2, a third resistor R3 and a first diode U1, a second end of the first resistor R1 is used as a first output end of an output voltage collecting unit, a cathode of the first diode U1 is used as a second output end of the output voltage collecting unit, when the device normally works, the first resistor R1 is directly connected with the output end of the switching power supply 15, a voltage at the first output end is equivalent to an output voltage of the switching power supply 15, a voltage at the second output end is divided by the second resistor R2 and the third resistor R3, so that a voltage at the second output end is smaller than a voltage at the first output end, and a primary side of an optocoupler is turned on because voltages at two ends are not identical; when the output end of the switching power supply 15 is short-circuited, because the second output end is provided with the first diode U1, the output voltage during short-circuiting is much smaller than the on-state voltage of the first diode U1 after being divided by the second resistor R2 and the third resistor R3, so that the first diode U1 is not on, and the primary side of the optical coupler is disconnected without forming a current loop. Based on this, through first resistance R1, second resistance R2, third resistance R3 and first diode U1 constitution output voltage collection module 13, can normally gather output voltage when normal operating, can accurately break off the opto-coupler after taking place the output short circuit, can realize output voltage collection module 13's function simply and reliably.
As a preferred embodiment, the device further comprises a current acquisition module;
the input end of the current collection module is connected with the emitter of the switching tube Q1 in the switching power supply 15, and the output end of the current collection module is connected with the I-sense pin end in the switching power supply 15.
In order to ensure the reliability of short-circuit protection, in the present application, after a short-circuit fault occurs at the output end of the switching power supply 15, the switching power supply 15 may control the switching tube Q1 inside itself to be turned off to implement short-circuit protection, but in consideration of the fact that in practical applications, the switching tube Q1 may not be normally turned off, for example, the switching power supply 15 does not normally turn off the driving pulse, and therefore, it is required to detect whether the switching tube Q1 is normally turned off. Specifically, a current collection module is arranged to collect current at an emitter in the switching tube Q1 and send the current at the emitter to the I-sense pin, if the switching tube Q1 is normally closed, the current collected by the I-sense pin should be approximately 0, and if the switching tube Q1 is not normally closed, the current collected by the I-sense pin is not 0; when the switch tube Q1 is not normally turned off, since the chip in the switching power supply 15 detects that the current of the I-sense pin is large, the driving pulse is turned off again, so that the switch tube Q1 is turned off. Based on this, can guarantee that switching tube Q1 closes after the output short circuit to guarantee the reliability of short-circuit protection.
As a preferred embodiment, the current collection module includes:
a fourth resistor R4 and a first capacitor C1;
a first end of the fourth resistor R4 is connected to an emitter of the switching tube Q1 in the switching power supply 15, and a second end of the fourth resistor R4 is connected to a first end of the first capacitor C1 and an I-sense pin end in the switching power supply 15, respectively;
the second terminal of the first capacitor C1 is grounded.
In order to avoid interference, in the present application, it is considered that when the output terminal has a short-circuit fault, the current and the voltage received by the I-sense pin may fluctuate, so that the chip in the switching power supply 15 cannot accurately determine whether the short-circuit fault exists. Therefore, referring to fig. 3, fig. 3 is a schematic structural diagram of another short-circuit protection device of a switching power supply provided in the present application, in which a fourth resistor R4 and a first capacitor C1 are arranged to filter an I-sense pin, when a current signal flows, the first capacitor C1 needs to be charged first, and after the first capacitor C1 is charged, the I-sense pin can receive a stable current signal, so that a chip in the switching power supply 15 can accurately determine whether a short-circuit fault exists, and influence of interference and fluctuation on the current signal is avoided.
As a preferred embodiment, the short circuit detection module 11 includes:
a fifth resistor R5, a sixth resistor R6, a second capacitor C2 and a third capacitor C3;
a first end of the fifth resistor R5 is connected to an output end of the output voltage acquisition module 13, a comp pin end of the switching power supply 15, and a first end of the second capacitor C2, a second end of the fifth resistor R5 is connected to a first end of the sixth resistor R6, a first end of the third capacitor C3, and an input end of the short-circuit protection module 12, respectively, and a voltage at the first end of the third capacitor C3 is used as a short-circuit delay signal;
the second end of the sixth resistor R6 is grounded;
the second end of the second capacitor C2 is grounded;
the second terminal of the third capacitor C3 is grounded.
In order to simply implement the function of the short circuit detection module 11, in the present application, the short circuit detection module 11 is composed of a fifth resistor R5, a sixth resistor R6, a second capacitor C2 and a third capacitor C3. Specifically, referring to fig. 3, fig. 3 is a schematic structural diagram of another short-circuit protection device of a switching power supply provided by the present application, in which the short-circuit delay signal is actually a voltage signal, the short-circuit protection module 12 executes a short-circuit protection mechanism according to the voltage of the voltage signal, when a short-circuit fault occurs at the output end of the switching power supply 15, the output voltage becomes 0, and the voltage at the comp pin gradually rises, but when a fault just starts to occur, because the output voltage and the voltage at the comp pin are both low, both the second capacitor C2 and the third capacitor C3 will discharge to ground, so that the input voltage at the first end of the third capacitor C3, that is, the input voltage of the short-circuit protection module 12, decreases to approximately 0. With the increase of the voltage at the comp pin, the second capacitor C2 is charged first, after the second capacitor C2 is charged, the third capacitor C3 starts to be charged through the divided voltage signal of the fifth resistor R5 and the sixth resistor R6, and when the voltage value of the third capacitor C3 reaches the voltage value that is the short-circuit delay signal, the short-circuit protection module 12 receives the short-circuit delay signal, so that the short-circuit protection module 12 performs the subsequent discharging step. Based on this, by using the two capacitors and the resistor as the short-circuit detection module 11, it is not necessary to detect whether a short-circuit fault exists through a software algorithm, and the execution time of the short-circuit protection module 12 is also delayed through the charging of the two capacitors, so that the time for the switching power supply 15 to reopen the switching tube Q1 to work again is further delayed, and the function of the short-circuit detection module 11 can be simply and effectively realized.
As a preferred embodiment, the short-circuit protection module 12 includes:
the second diode U2, the triode Q2, the seventh resistor R7 and the fourth capacitor C4;
the anode of the second diode U2 is connected with the output end of the short-circuit protection module 12, and the cathode of the second diode U2 is connected with the base electrode of the triode Q2;
the collector of the triode Q2 is grounded, and the emitter of the triode Q2 is connected with the first end of the seventh resistor R7;
a second end of the seventh resistor R7 is connected to the anode of the fourth capacitor C4, the power supply, and the power supply end of the switching power supply 15;
the negative pole of the fourth capacitor C4 is grounded.
In order to simply implement the function of the short-circuit protection module 12, in the present application, the short-circuit protection module 12 is composed of a second diode U2, a triode Q2, a seventh resistor R7 and a fourth capacitor C4. Specifically, referring to fig. 3, fig. 3 is a schematic structural diagram of another short-circuit protection device of a switching power supply provided in the present application, when the switching power supply 15 is in a normal operating state without short-circuit fault, because the output voltage and the comp pin voltage are not high, the voltage at the second diode U2 is also not high, and only when the short-circuit fault occurs, the comp pin voltage becomes high, the voltage at the second diode U2 is increased, so that a diode that is not conducting in a normal state and conducting in a short-circuit state can be used as the second diode U2. When the short-circuit detection module 11 detects a short-circuit fault, the short-circuit detection module 11 sends a short-circuit delay signal (equivalent to a voltage signal capable of turning on the second diode U2) to the second diode U2 to turn on the second diode U2, and then the short-circuit delay signal enters the transistor Q2 through the second diode U2 to reduce the base voltage of the transistor Q2 and turn on the transistor Q2, so that the current also passes through the emitter of the transistor Q2, and since the emitter of the transistor Q2 is connected to the Vcc pin of the chip in the switching power supply 15, the fourth capacitor C4 and the power Vin, when the transistor Q2 is turned on, the fourth capacitor C4 discharges through the seventh resistor R7 and the transistor Q2, and when the voltage discharge on the capacitor is lower than the under-voltage threshold of the chip in the switching power supply 15, the chip in the switching power supply 15 will stop working under-voltage until the power Vin charges the fourth capacitor C4 slowly until the fourth capacitor C4 is full, and the chip in the switching power supply 15 can be restarted. Based on this, the fourth capacitor C4 is controlled to discharge through the second diode U2 and the triode Q2, so that the purpose of discharging the switching power supply 15 can be simply achieved, and the switching power supply 15 can be restarted only after waiting for the fourth capacitor C4 to be recharged, which is equivalent to that the fourth capacitor C4 is used as a layer of time delay measure, so that the frequency of the switching power supply 15 triggering the short-circuit protection mechanism is further reduced.
As a preferred embodiment, further comprising:
and an eighth resistor R8 disposed between the fourth capacitor C4 and the power supply.
In order to protect the fourth capacitor C4, in the present application, an eighth resistor R8 is further disposed between the power supply and the fourth capacitor C4, and considering that the voltage input into the fourth capacitor C4 may be unstable due to interference, fluctuation and the like of the input voltage at the power supply, the eighth resistor R8 is disposed as a filter resistor, so that interference and fluctuation in the input voltage can be effectively eliminated, and the fourth capacitor C4 can receive a stable voltage signal. Accordingly, the eighth resistor R8 is provided, so that the fourth capacitor C4 can be effectively protected.
The application also provides a switching power supply, which comprises a switching power supply body and the short-circuit time-delay protection device of the switching power supply;
the switch power supply body is connected with the short-circuit time-delay protection device of the switch power supply.
For a detailed description of the switching power supply provided in the present application, please refer to the above-mentioned embodiment of the short-circuit delay protection device of the switching power supply, which is not described herein again.
The application also provides equipment, which comprises an equipment body and the switching power supply;
the equipment body is connected with a switching power supply.
For a detailed description of an apparatus provided in the present application, please refer to the above-mentioned embodiment of the short-circuit delay protection device for a switching power supply, which is not described herein again.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the switching power supply and the device disclosed in the embodiments, since the short-circuit delay protection device of the switching power supply disclosed in the embodiments corresponds to the switching power supply disclosed in the embodiments, the description is relatively simple, and the relevant points can be referred to the description of the embodiment corresponding to the short-circuit delay protection device of the switching power supply.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A short-circuit delay protection device of a switching power supply is characterized by comprising:
the short-circuit protection device comprises a short-circuit switch, an output voltage acquisition module, a short-circuit detection module and a short-circuit protection module;
the input end of the output voltage acquisition module is connected with the output end of the switching power supply, the output end of the output voltage acquisition module is connected with one end of the short-circuit switch, and the output voltage acquisition module is used for acquiring the output voltage of the switching power supply;
the short-circuit switch is used for being switched off when the switching power supply has a short-circuit fault;
the input end of the short-circuit detection module is respectively connected with the other end of the short-circuit switch and the comp pin end of the switching power supply, the output end of the short-circuit detection module is connected with the input end of the short-circuit protection module, and the short-circuit detection module is used for generating a short-circuit delay signal when detecting that the voltage of the input end of the short-circuit detection module is greater than a preset voltage value;
the first end of the short-circuit protection module is connected with the power supply, the second end of the short-circuit protection module is connected with the power supply end of the switching power supply, and the short-circuit protection module is used for discharging the switching power supply when receiving the short-circuit delay signal.
2. The short-circuit delay protection device of the switching power supply according to claim 1, wherein the short-circuit switch is an optocoupler;
the primary side first end of the optocoupler is connected with the first output end of the output voltage acquisition module, the primary side second end of the optocoupler is connected with the second output end of the output voltage acquisition module, the secondary side first end of the optocoupler is connected with the input end of the short circuit detection module, and the secondary side second end of the optocoupler is grounded.
3. The short-circuit delay protection device of the switching power supply according to claim 2, wherein the output voltage acquisition module comprises:
the circuit comprises a first resistor, a second resistor, a third resistor and a first diode;
the first end of the first resistor is connected with the output end of the switching power supply, the second end of the first resistor is connected with the first primary end of the optocoupler, and the voltage at the first primary end of the optocoupler is used as the output voltage;
a first end of the second resistor is connected with an output end of the switching power supply, and a second end of the second resistor is respectively connected with a first end of the third resistor and an anode of the first diode;
the second end of the third resistor is grounded;
and the cathode of the first diode is connected with the second end of the primary side of the optocoupler.
4. The short-circuit delay protection device of the switching power supply according to claim 1, further comprising a current collection module;
the input end of the current acquisition module is connected with an emitting electrode of a switch tube in the switch power supply, and the output end of the current acquisition module is connected with an I-sense pin end in the switch power supply.
5. The short-circuit delay protection device of the switching power supply according to claim 4, wherein the current collection module comprises:
a fourth resistor and a first capacitor;
a first end of the fourth resistor is connected with an emitter of a switching tube in the switching power supply, and a second end of the fourth resistor is respectively connected with a first end of the first capacitor and an I-sense pin end in the switching power supply;
the second end of the first capacitor is grounded.
6. The short-circuit delay protection device of the switching power supply as claimed in claim 1, wherein the short-circuit detection module comprises:
a fifth resistor, a sixth resistor, a second capacitor and a third capacitor;
a first end of the fifth resistor is connected to an output end of the output voltage acquisition module, a comp pin end of the switching power supply, and a first end of the second capacitor, a second end of the fifth resistor is connected to a first end of the sixth resistor, a first end of the third capacitor, and an input end of the short-circuit protection module, respectively, and a voltage at the first end of the third capacitor is used as the short-circuit delay signal;
a second end of the sixth resistor is grounded;
the second end of the second capacitor is grounded;
and the second end of the third capacitor is grounded.
7. The short-circuit delay protection device of the switching power supply according to any one of claims 1 to 6, wherein the short-circuit protection module comprises:
the second diode, the triode, the seventh resistor and the fourth capacitor;
the anode of the second diode is connected with the output end of the short-circuit protection module, and the cathode of the second diode is connected with the base electrode of the triode;
the collector of the triode is grounded, and the emitter of the triode is connected with the first end of the seventh resistor;
a second end of the seventh resistor is connected with the anode of the fourth capacitor, the power supply and a power supply end of the switching power supply respectively;
and the negative electrode of the fourth capacitor is grounded.
8. The short-circuit delay protection device of the switching power supply as claimed in claim 7, further comprising:
an eighth resistor disposed between the fourth capacitor and the power supply.
9. A switching power supply, comprising a switching power supply body, and further comprising a short-circuit delay protection device of the switching power supply according to any one of claims 1 to 8;
the switching power supply body is connected with the short circuit time-delay protection device of the switching power supply.
10. An apparatus comprising an apparatus body, further comprising the switching power supply according to claim 9;
the equipment body is connected with the switching power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223402563.2U CN218771280U (en) | 2022-12-19 | 2022-12-19 | Short-circuit delay protection device of switching power supply, switching power supply and equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223402563.2U CN218771280U (en) | 2022-12-19 | 2022-12-19 | Short-circuit delay protection device of switching power supply, switching power supply and equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218771280U true CN218771280U (en) | 2023-03-28 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202223402563.2U Active CN218771280U (en) | 2022-12-19 | 2022-12-19 | Short-circuit delay protection device of switching power supply, switching power supply and equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218771280U (en) |
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2022
- 2022-12-19 CN CN202223402563.2U patent/CN218771280U/en active Active
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