CN217427985U - Slow starting circuit and switching power supply - Google Patents
Slow starting circuit and switching power supply Download PDFInfo
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- CN217427985U CN217427985U CN202220471526.8U CN202220471526U CN217427985U CN 217427985 U CN217427985 U CN 217427985U CN 202220471526 U CN202220471526 U CN 202220471526U CN 217427985 U CN217427985 U CN 217427985U
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- 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
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- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
The utility model discloses a slow starting circuit and switching power supply, wherein, slow starting circuit includes: the switch circuit is arranged on the positive voltage bus or the negative voltage bus; a current limiting circuit connected in parallel with the switching circuit; the current detection circuit is used for detecting the current of the positive voltage bus or the negative voltage bus and outputting a bus current detection signal; the controlled end of the discharge control circuit is connected with the output end of the current detection circuit, the input end of the discharge control circuit is connected with the controlled end of the switch circuit, the output end of the discharge control circuit is connected with the positive voltage bus or the negative voltage bus, the discharge control circuit is used for receiving a bus current detection signal and outputting a switch turn-off signal to the switch circuit, and the switch circuit is turned off when receiving the switch turn-off signal. The utility model discloses technical scheme can carry out overcurrent protection at switching power supply's work overall process.
Description
Technical Field
The utility model relates to a switching power supply technical field, in particular to slow starting circuit and switching power supply.
Background
At present, a switching power supply usually adopts a switching device to limit an overlarge power-on impact current during power-on so as to realize slow start, but the switching device used for limiting the current is easily broken down by the overlarge power-on current, so that the switching device fails to play a role in limiting the current.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a slow starting circuit aims at solving switching power supply when going up, and the too big problem that causes rear end circuit damage of electric current in the return circuit.
In order to realize the above object, the utility model provides a slow starting circuit is applied to switching power supply, switching power supply includes bus-bar capacitance, bus-bar capacitance's both ends respectively with positive voltage generating line and negative voltage busbar connection, slow starting circuit includes:
the switch circuit is arranged on the positive voltage bus or the negative voltage bus;
a current limiting circuit connected in parallel with the switching circuit;
the current detection circuit is used for detecting the current of the positive voltage bus or the negative voltage bus and outputting a bus current detection signal; and (c) a second step of,
the controlled end of the discharge control circuit is connected with the output end of the current detection circuit, the input end of the discharge control circuit is connected with the controlled end of the switch circuit, the output end of the discharge control circuit is connected with the positive voltage bus or the negative voltage bus, and the discharge control circuit is used for receiving the bus current detection signal and outputting a switch turn-off signal to the switch circuit;
the switch circuit is used for switching off when receiving the switch switching-off signal.
Optionally, an input end of the negative voltage bus is connected with a negative electrode output end of a rectifying circuit in the switching power supply, and an output end of the negative voltage bus is connected with the bus capacitor;
the switching circuit includes: and the controlled end of the first switching device is the controlled end of the switching circuit, and the input end and the output end of the first switching device are respectively connected with the input end and the output end of the negative voltage bus.
Optionally, the current limiting circuit includes a first resistor, and two ends of the first resistor are respectively connected to the input end and the output end of the first switching device.
Optionally, the current detection circuit includes a second resistor, a first end and a second end of the second resistor are respectively connected to the input end of the negative voltage bus and the input end of the first switching device, and the second end of the second resistor is the output end of the current detection circuit.
Optionally, the current detection circuit is a current sensor, a first end of the current sensor is connected to the input end of the negative voltage bus, a second end of the current sensor is connected to the input end of the first switching device, and a third end of the current sensor is an output end of the current detection circuit.
Optionally, the discharge control circuit includes: the negative pole of the first voltage stabilizing diode is the controlled end of the discharge control circuit, the positive pole of the first voltage stabilizing diode is connected with the controlled end of the second switch device through the fourth resistor, the output end of the second switch device is the output end of the discharge control circuit, the input end of the second switch device is connected with the first end of the third resistor, and the second end of the third resistor is the input end of the discharge control circuit.
Optionally, the soft start circuit further comprises:
the input end of the delay circuit is connected with the positive voltage bus;
and the input end of the switch control circuit is respectively connected with the output end of the delay circuit, the input end of the discharge control circuit and the controlled end of the switch circuit, and the output end of the switch control circuit is connected with the negative voltage bus.
Optionally, the delay circuit includes a fifth resistor, a second zener diode, and a first diode, a first end of the fifth resistor is an input end of the delay circuit, a second end of the fifth resistor is connected to a cathode of the second zener diode, an anode of the second zener diode is connected to an anode of the first diode, and a cathode of the first diode is an output end of the delay circuit.
Optionally, the switch control circuit includes a first capacitor and a third zener diode, a cathode of the third zener diode is an input end of the switch control circuit, an anode of the third zener diode is an output end of the switch control circuit, and the first capacitor is connected in parallel with the third zener diode.
The utility model provides a switching power supply, switching power supply includes:
the two ends of the bus capacitor are respectively connected with the positive voltage bus and the negative voltage bus; and the number of the first and second groups,
the slow starting circuit is connected with the bus capacitor through the positive voltage bus and the negative voltage bus.
The utility model discloses technical scheme is through adopting switch circuit, current-limiting circuit, current detection circuit and discharge control circuit to through making the bus current detection signal that discharge control circuit received current detection circuit output, and output switch turn-off signal makes switch circuit turn-off when receiving switch turn-off signal to switch circuit, thereby realizes making current-limiting circuit insert positive voltage generating line or negative voltage generating line and charge for bus-bar capacitance. The utility model discloses technical scheme is through going up at switching power supply, and when the electric current was too big in the return circuit, in time turn-off switch circuit to carry out the current-limiting through the current-limiting circuit, in order to avoid too big last electric current to cause the damage to the rear-end circuit in the phase of slowly starting, thereby the realization is to the last overcurrent protection of rear-end circuit. Furthermore, the utility model discloses technical scheme still can be in switching power supply steady state work, and when the electric current was too big in the return circuit, in time carries out the steady state overcurrent protection to the rear end circuit, therefore can effectively improve switching power supply's operational reliability and stability.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
FIG. 1 is a block diagram of an embodiment of a slow start circuit according to the present invention;
FIG. 2 is a block diagram of another embodiment of a soft start circuit of the present invention;
fig. 3 is a schematic structural diagram of another embodiment of the slow start circuit of the present invention;
FIG. 4 is a schematic diagram of an embodiment of a conventional start-up circuit;
FIG. 5 is a schematic diagram of another embodiment of a conventional start-up circuit;
fig. 6 is a schematic structural diagram of another embodiment of a conventional switching power supply.
The reference numbers illustrate:
the objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without making creative efforts belong to the protection scope of the present invention.
In addition, descriptions in the present application as to "first", "second", and the like are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.
The utility model provides a slow starting circuit.
Referring to fig. 4 and 5, fig. 4 and 5 are two prior art solutions for solving the problem of loop overcurrent when the switching power supply is powered on. In the technical scheme shown in fig. 4, the control unit controls the third switching device Q3 to operate in a linear region to suppress the power-on surge current through a large on-resistance, so as to complete the slow start of the switching power supply, but the instantaneous surge energy of the slow start mode is completely consumed by the third switching device Q3, and when the capacitance value of the bus capacitor C2 is large or the input voltage is high, the generated instantaneous surge energy easily causes avalanche breakdown of the third switching device Q3, so that the overcurrent protection cannot be realized. In the technical solution shown in fig. 5, the voltage of the tenth resistor R10 may be regarded as an input voltage, the input voltage is divided by the seventh resistor R7 and the eighth resistor R8 to drive the fourth switching device Q4 to be turned on, but as the bus capacitor C2 is slowly charged, the voltage of the bus capacitor C2 gradually increases, the voltage of the tenth resistor R10 gradually decreases, and at this time, the fourth switching device Q4 is turned off because the divided voltage is smaller than the threshold of the driving voltage thereof; when the fourth switching device Q4 is turned on, the fourth switching device Q4 pulls the driving voltage of the fifth switching device Q5 down to a low level through the ninth resistor R9 to prevent the fifth switching device Q5 from being turned on at the power-on moment to short-circuit the tenth resistor R10; after the fourth switching device Q4 is turned off, the power port charges the third capacitor C3 through the eleventh resistor R11, and the terminal voltage established by the third capacitor C3 can be regarded as a linear rise and drives the fifth switching device Q5 to be slowly turned on, so that the soft start of the switching power supply is completed. However, in the technical scheme shown in fig. 5, when the input voltage rises or a high voltage ride through condition occurs during the steady-state operation of the switching power supply, the fifth switching device Q5 is in a conducting state for a long time, so that the instantaneous impact current is large, the current limiting effect cannot be achieved, and the fifth switching device Q5 fails.
In view of the above problem, referring to fig. 1 to 3, in an embodiment, the slow start circuit includes:
a switch circuit 10 provided on the positive voltage bus P or the negative voltage bus N;
a current limiting circuit 20 connected in parallel with the switching circuit 10;
a current detection circuit 30 for detecting a current of the positive voltage bus P or the negative voltage bus N and outputting a bus current detection signal; and the number of the first and second groups,
the controlled end of the discharge control circuit 40 is connected with the output end of the current detection circuit 30, the input end of the discharge control circuit 40 is connected with the controlled end of the switch circuit 10, the output end of the discharge control circuit 40 is connected with the positive voltage bus P or the negative voltage bus N, and the discharge control circuit 40 is used for receiving the bus current detection signal and outputting a switch turn-off signal to the controlled end of the switch circuit 10;
the switch circuit 10 is configured to turn off when receiving the switch turn-off signal.
In this embodiment, the switching circuit 10 may be implemented by using a switching device. The switch circuit 10 can control its on/off state according to the potential of the controlled terminal to control the circulation of the upper current of the positive voltage bus P or the negative voltage bus N. Specifically, when the switch circuit 10 is turned on, the positive voltage bus P or the negative voltage bus N can normally transmit the accessed current to the rear-end power conversion circuit 80; when the switch circuit 10 is turned off, the positive voltage bus P or the negative voltage bus N may stop transmitting the inputted current to the back-end power conversion circuit 80.
The current limiting circuit 20 may be implemented using resistive devices. The overall impedance of the current limiting circuit 20 may be set to be much greater than the on-resistance of the switching circuit 10, so as to limit the current with its own large impedance when the switching circuit 10 is turned off; when the switch circuit 10 is turned on, the switch circuit 10 bypasses itself, i.e., short-circuits, so as not to affect the normal operation of the positive voltage bus P or the negative voltage bus N.
The current detection circuit 30 may be implemented by using a resistor device, so as to detect the magnitude of the current transmitted by the positive voltage bus P or the negative voltage bus N in real time by using the principle of resistance shunting, and output a bus current detection signal in the form of voltage or current.
The discharge control circuit 40 may be implemented by using a switching device and discrete electronic devices such as a resistance device and a capacitance device. The discharge control circuit 40 can control the on/off state of the switching device according to the received bus current detection signal and the preset parameter, so as to control the controlled end potential of the switching circuit 10, thereby realizing the on/off state control of the switching circuit 10; the preset parameters can be set according to the overcurrent threshold of the positive voltage bus P or the negative voltage bus N. The method specifically comprises the following steps: when the current value transmitted by the positive voltage bus P or the negative voltage bus N is normal, that is, the current value corresponding to the bus current detection signal is smaller than the current value corresponding to the preset parameter, at this time, the discharge control circuit 40 may pull up or pull down the controlled end potential of the switch circuit 10, so as to turn on the switch circuit 10; when the current value transmitted by the positive voltage bus P or the negative voltage bus N is overcurrent, that is, the current value corresponding to the bus current detection signal is greater than the current value corresponding to the preset parameter, at this time, the discharge control circuit 40 may pull down or pull up the controlled end potential of the switching circuit 10, so as to turn off the switching circuit 10. In other words, the switch off signal is a voltage signal that is pulled down or pulled up.
Therefore, the utility model discloses technical scheme can be on switching power supply, and when the electric current was too big in the return circuit, in time turn-offed switching circuit 10 to avoid too big last electric current to cause the damage to rear end power conversion circuit 80, thereby realize the last electric overcurrent protection to power conversion circuit 80. Furthermore, the utility model discloses still can be at switching power supply steady state work, and when the electric current was too big in the return circuit, in time turn-off switch circuit 10 to make current limiting circuit 20 insert positive voltage generating line P or negative voltage generating line N, thereby realize carrying out the current-limiting through current limiting circuit 20, and then realize the steady state overcurrent protection to power conversion circuit 80. In other words, the utility model discloses slow starting circuit can carry out overcurrent protection to rear end power conversion circuit 80 at switching power supply's work overall process, can effectively improve switching power supply's operational reliability and stability. It should be noted that, compared with the technical solution shown in fig. 4, when the capacitance value of the bus capacitor C2 is large or the input voltage is very high, the current forms a loop through the current limiting circuit 20, so that each switching device in the switching circuit 10 does not have the risk of being broken down by avalanche; compared with the technical scheme shown in fig. 5, when the switching power supply is in a steady-state operation process, and the input voltage rises or the high voltage ride through occurs, because the current limiting circuit 20 is connected while the switching circuit 10 is turned off, the transient impact current is transmitted through the current limiting circuit 20, and the switching circuit 10 cannot fail. In the prior art, a scheme of serially connecting a current-limiting resistor in a loop exists, specifically, as shown in fig. 6, a twelfth resistor R12 in fig. 6 is a current-limiting resistor, but in the technical scheme shown in fig. 6, after the switching power supply is started, the twelfth resistor R12 continuously consumes energy, so that the efficiency of the switching power supply is reduced, and the thermal design difficulty is increased.
Referring to fig. 1 to 3, in an embodiment, an input end of the negative voltage bus N is connected to a negative output end of a rectifying circuit 70 in a switching power supply, and an output end of the negative voltage bus N is connected to the bus capacitor C2;
the switching circuit 10 includes: and a first switching device Q1, wherein the controlled terminal of the first switching device Q1 is the controlled terminal of the switching circuit 10, and the input terminal and the output terminal of the first switching device Q1 are respectively connected with the input terminal and the output terminal of the negative voltage bus N.
Optionally, the current limiting circuit 20 includes a first resistor R1, and two ends of the first resistor R1 are respectively connected to the input end and the output end of the first switching device Q1.
In this embodiment, the first switching device Q1 may be one or a combination of a triode, an MOS transistor, a thyristor, an optocoupler, or a relay; in the embodiment shown in fig. 2 and 3, the first switching device Q1 is an N-type MOS transistor. The first switching device Q1 is disposed on the negative voltage bus N, and the first switching device Q1 is configured to enable the input end of the negative voltage bus N to be communicated with the output end thereof when the negative voltage bus N is turned on, so that the power conversion circuit 80 can form a loop to work normally; when the power conversion circuit is turned off, the input end of the negative voltage bus N is disconnected from the output end thereof, so that the power conversion circuit 80 cannot form a loop, and the operation is stopped.
Either one of the two ends of the first resistor R1 may be connected to an input terminal of the first switching device Q1, and the other end may be connected to an output terminal of the first switching device Q1. The resistance of the first resistor R1 can be configured to be much larger than the on-resistance of the first switching device Q1, so that when the switching power supply operates normally, the current on the negative voltage bus N flows through the first switching device Q1; when the first switching device Q1 is turned off, the current on the negative voltage bus N flows through the first resistor R1 for transmission, and at this time, the first resistor R1 realizes overcurrent protection for the power conversion circuit 80 by using its own large impedance. In addition, the charging speed of the bus capacitor C2 can be adjusted by arranging the resistance value of the first resistor R1. The utility model discloses technical scheme realizes switching circuit 10 and current-limiting circuit 20 respectively through the low impedance that utilizes switching device and resistance device's high impedance, and circuit structure is simple, and the cost is lower, easily realizes.
Referring to fig. 1 to 3, in an embodiment, the current detection circuit 30 includes a second resistor R2, a first terminal and a second terminal of the second resistor R2 are respectively connected to the input terminal of the negative voltage bus N and the input terminal of the first switching device Q1, and a second terminal of the second resistor R2 is an output terminal of the current detection circuit 30.
In this embodiment, the second resistor R2 is disposed on the negative voltage bus N. The second resistor R2 can form a voltage at the first and second terminals using the current transmitted by the negative voltage bus N, and output a bus current detection signal in the form of a voltage at the second terminal. The resistance value of the second resistor R2 may be configured to be small, so that when the switching power supply normally works, the voltage value of the second end of the second resistor R2 is smaller than the preset overcurrent threshold, so that the discharge control circuit 40 does not work, and the switching circuit 10 is in a conducting state; when the current in the loop is too large, the voltage value of the second end of the second resistor R2 is greater than the preset overcurrent threshold value, so as to trigger the discharge control circuit 40 to control the switch circuit 10 to turn off. By the arrangement, the circuit structure of the current detection circuit 30 can be effectively simplified, and the second resistor R2 can be arranged at a smaller island position on the PCB, so that the layout of each electric control device on the PCB can be optimized.
Referring to fig. 1 to 3, in an embodiment, the current detection circuit 30 is a current sensor, a first terminal of the current sensor is connected to the input terminal of the negative voltage bus N, a second terminal of the current sensor is connected to the input terminal of the first switching device Q1, and a third terminal of the current sensor is an output terminal of the current detection circuit 30.
In this embodiment, the current sensor is disposed on the negative voltage bus N. The current sensor may include: a sixth resistor R6, a second diode D2 and a transformer CT 1; the transformer CT1 may be an isolated transformer CT 1. The first end and the second end of the primary side of the transformer CT1 can be the first end and the second end of the current sensor respectively, the first end of the primary side of the transformer CT1 and the first end of the secondary side thereof are homonymous ends, the first end of the secondary side of the transformer CT1 can be grounded, the second end of the secondary side of the transformer CT1 can be grounded through a second diode D2 and a sixth resistor R6, and the common end of the sixth resistor R6 and the second diode D2 is the third end of the current sensor. It can be understood that the current flowing through the primary side of the transformer CT1 is the current transmitted by the negative voltage bus N, so that the secondary side thereof can induce a corresponding induced current according to the turn ratio, and the induced current can be converted into a voltage signal under the action of the sixth resistor R6 and then output as a bus current detection signal from the third end. Of course, in other embodiments, the current sensor may also be implemented by using a dedicated current detection chip or a hall sensing device, which is not described herein. By the arrangement, the second resistor R2 is eliminated, and power consumption of the switching power supply during steady-state operation is reduced.
Referring to fig. 1 to 3, in an embodiment, the discharge control circuit 40 includes: the discharge control circuit comprises a third resistor R3, a fourth resistor R4, a first zener diode ZD1 and a second switch device Q2, wherein the cathode of the first zener diode ZD1 is the controlled end of the discharge control circuit 40, the anode of the first zener diode ZD1 is connected with the controlled end of the second switch device Q2 through the fourth resistor R4, the output end of the second switch device Q2 is the output end of the discharge control circuit 40, the input end of the second switch device Q2 is connected with the first end of the third resistor R3, and the second end of the third resistor R3 is the input end of the discharge control circuit 40.
In this embodiment, the second switching device Q2 may be one or a combination of a triode, a MOS transistor, a thyristor, an optocoupler, or a relay, and the on-voltage of the second switching device Q2 is the preset overcurrent threshold. In the embodiment shown in fig. 2 and fig. 3, the second switching device Q2 is an N-type MOS transistor, and when the current in the loop is normal, the potential of the controlled terminal of the second switching device Q2 makes itself in an off state, so that the potential of the controlled terminal of the first switching device Q1 can be maintained at a high level, thereby controlling the first switching device Q1 to be turned on; when the current in the loop is over-current, the potential of the controlled terminal of the second switching device Q2 makes itself in a conducting state, so that the potential of the controlled terminal of the first switching device Q1 is pulled down to a low level, thereby realizing the control of the turning-off of the first switching device Q1. The fourth resistor R4 is a current-limiting resistor to prevent the second switching device Q2 from being damaged by an excessive bus current detection signal; the third resistor R3 is a pull-down resistor.
Referring to fig. 1 to 3, in an embodiment, the slow start circuit further includes:
the input end of the delay circuit 50 is connected with the positive voltage bus P;
and an input end of the switch control circuit 60 is respectively connected with an output end of the delay circuit 50, an input end of the discharge control circuit 40 and a controlled end of the switch circuit 10, and an output end of the switch control circuit 60 is connected with the negative voltage bus N.
Optionally, the delay circuit 50 includes a fifth resistor R5, a second zener diode ZD2, and a first diode D1, a first end of the fifth resistor R5 is an input end of the delay circuit 50, a second end of the fifth resistor R5 is connected to a cathode of the second zener diode ZD2, an anode of the second zener diode ZD2 is connected to an anode of the first diode D1, and a cathode of the first diode D1 is an output end of the delay circuit 50.
Optionally, the switch control circuit 60 includes a first capacitor C1 and a third zener diode ZD3, a cathode of the third zener diode ZD3 is an input terminal of the switch control circuit 60, an anode of the third zener diode ZD3 is an output terminal of the switch control circuit 60, and the first capacitor C1 is connected in parallel with the third zener diode ZD 3.
In this embodiment, the delay circuit 50 and the switch control circuit 60 constitute a slow start module. The operation of the delay circuit 50 and the switch control circuit 60 of the present application will be described in detail with reference to the embodiments shown in fig. 2 and 3 as examples.
At the moment of electrifying the switching power supply, because the terminal voltage of the capacitor cannot suddenly change, the voltage values of the first capacitor C1 and the bus capacitor C2 are still 0V, at the moment, the first switching device Q1 is turned off, and the bus capacitor C2 is charged through the first resistor R1. As the power-on time increases, the first capacitor C1 is charged through the delay circuit 50 formed by the fifth resistor R5, the second zener diode ZD2 and the first diode D1, and when the voltage value of the first capacitor C1 reaches the turn-on voltage of the first switching device Q1, the first switching device Q1 is turned on, and the first resistor R1 is short-circuited, so that power consumption can be significantly reduced because the turn-on impedance of the first switching device Q1 is low. When the switching power supply normally operates, the current flowing through the second resistor R2 or the current sensor is small, the bus current detection signal cannot drive the second switching device Q2 to be turned on, and the discharge control circuit 40 does not operate. When the output of the rectifying circuit 70 is over-current, the current in the loop increases instantly because the first resistor R1 is bypassed, and at this time, the bus current detection signal drives the second switching device Q2 to turn on, so as to pull down the potential of the controlled end of the first switching device Q1 and turn off the controlled end, so that the current in the loop is transmitted through the first resistor R1 and charges the bus capacitor C2, thereby implementing over-current protection of the rear-end power variation circuit 80. It should be noted that, after the bus capacitor C2 is charged, the current in the loop decreases, the second switching device Q2 is restored to the off state, the discharge control circuit 40 is restored to the non-operating state, and the first switching device Q1 is restored to the on state, so that the real-time current limiting function is realized, and the switching power supply enters the steady-state operation.
The utility model also provides a switching power supply, this switching power supply include bus capacitance C2 and slow starting circuit, and this slow starting circuit's concrete structure refers to above-mentioned embodiment, because this switching power supply has adopted the whole technical scheme of above-mentioned all embodiments, consequently has all beneficial effects that the technical scheme of above-mentioned embodiment brought at least, and the repeated description is no longer given here.
In this embodiment, the switching power supply may further include a rectifier circuit 70 and a power conversion circuit 80. The power conversion circuit 80 may include an inverter circuit, etc., the input terminal of the power conversion circuit 80 includes a positive input terminal and a negative input terminal, and the output terminal of the rectification circuit 70 includes a positive output terminal and a negative output terminal; the positive input terminal of the power conversion circuit 80 is connected to the positive output terminal of the rectifier circuit 70 via a positive voltage bus P, and the negative input terminal of the power conversion circuit 80 is connected to the negative output terminal of the rectifier circuit 70 via a negative voltage bus N. The bus capacitor C2 may be disposed between the power conversion circuit 80 and the rectification circuit 70, and is used to filter the ac component in the input voltage of the power conversion circuit 80, so that the power conversion circuit 80 can perform power conversion on the input dc voltage and output the converted dc voltage as the output voltage of the switching power supply. The soft start circuit may be connected between the rectifier circuit 70 and the bus capacitor C2.
The above is only the optional embodiment of the present invention, and not limiting the patent scope of the present invention, all under the inventive concept of the present invention, the equivalent structure transformation made by the contents of the specification and the attached drawings is utilized, or the direct/indirect application is included in other related technical fields in the patent protection scope of the present invention.
Claims (10)
1. The utility model provides a slow start circuit, is applied to switching power supply, switching power supply includes bus capacitor, bus capacitor's both ends respectively with positive voltage generating line and negative voltage generating line connection, its characterized in that, slow start circuit includes:
the switch circuit is arranged on the positive voltage bus or the negative voltage bus;
a current limiting circuit connected in parallel with the switching circuit;
the current detection circuit is used for detecting the current of the positive voltage bus or the negative voltage bus and outputting a bus current detection signal; and the number of the first and second groups,
the controlled end of the discharge control circuit is connected with the output end of the current detection circuit, the input end of the discharge control circuit is connected with the controlled end of the switch circuit, the output end of the discharge control circuit is connected with the positive voltage bus or the negative voltage bus, and the discharge control circuit is used for receiving the bus current detection signal and outputting a switch turn-off signal to the switch circuit;
the switch circuit is used for switching off when receiving the switch turn-off signal.
2. The slow start circuit as claimed in claim 1, wherein an input terminal of said negative voltage bus is connected to a negative output terminal of a rectifying circuit in the switching power supply, and an output terminal of said negative voltage bus is connected to said bus capacitor;
the switching circuit includes: and the controlled end of the first switching device is the controlled end of the switching circuit, and the input end and the output end of the first switching device are respectively connected with the input end and the output end of the negative voltage bus.
3. The slow start circuit as claimed in claim 2, wherein said current limiting circuit includes a first resistor, and both ends of said first resistor are connected to an input terminal and an output terminal of said first switching device, respectively.
4. The slow start circuit as claimed in claim 2, wherein the current detection circuit comprises a second resistor, a first terminal and a second terminal of the second resistor are respectively connected to the input terminal of the negative voltage bus and the input terminal of the first switch device, and the second terminal of the second resistor is the output terminal of the current detection circuit.
5. The slow start circuit as claimed in claim 2, wherein the current detecting circuit is a current sensor, a first terminal of the current sensor is connected to the input terminal of the negative voltage bus, a second terminal of the current sensor is connected to the input terminal of the first switching device, and a third terminal of the current sensor is an output terminal of the current detecting circuit.
6. The slow start circuit as claimed in claim 1, wherein said discharge control circuit comprises: the negative pole of the first voltage stabilizing diode is the controlled end of the discharge control circuit, the positive pole of the first voltage stabilizing diode is connected with the controlled end of the second switch device through the fourth resistor, the output end of the second switch device is the output end of the discharge control circuit, the input end of the second switch device is connected with the first end of the third resistor, and the second end of the third resistor is the input end of the discharge control circuit.
7. The slow start circuit as claimed in any one of claims 1-6, further comprising:
the input end of the delay circuit is connected with the positive voltage bus;
and the input end of the switch control circuit is respectively connected with the output end of the delay circuit, the input end of the discharge control circuit and the controlled end of the switch circuit, and the output end of the switch control circuit is connected with the negative voltage bus.
8. The slow start circuit as claimed in claim 7, wherein the delay circuit comprises a fifth resistor, a second zener diode and a first diode, a first terminal of the fifth resistor is an input terminal of the delay circuit, a second terminal of the fifth resistor is connected to a cathode of the second zener diode, an anode of the second zener diode is connected to an anode of the first diode, and a cathode of the first diode is an output terminal of the delay circuit.
9. The slow start circuit as claimed in claim 7, wherein said switch control circuit comprises a first capacitor and a third zener diode, a cathode of said third zener diode being an input terminal of said switch control circuit, an anode of said third zener diode being an output terminal of said switch control circuit, said first capacitor being connected in parallel with said third zener diode.
10. A switching power supply, characterized in that the switching power supply comprises:
the two ends of the bus capacitor are respectively connected with the positive voltage bus and the negative voltage bus; and the number of the first and second groups,
the slow start circuit of any one of claims 1 to 9, said slow start circuit being connected to said bus capacitor via said positive voltage bus and said negative voltage bus.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202220471526.8U CN217427985U (en) | 2022-03-03 | 2022-03-03 | Slow starting circuit and switching power supply |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202220471526.8U CN217427985U (en) | 2022-03-03 | 2022-03-03 | Slow starting circuit and switching power supply |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116488446A (en) * | 2023-06-21 | 2023-07-25 | 深圳市联明电源有限公司 | Laser pumping source discharging circuit, switching power supply and laser |
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2022
- 2022-03-03 CN CN202220471526.8U patent/CN217427985U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116488446A (en) * | 2023-06-21 | 2023-07-25 | 深圳市联明电源有限公司 | Laser pumping source discharging circuit, switching power supply and laser |
| CN116488446B (en) * | 2023-06-21 | 2023-12-29 | 深圳市联明电源有限公司 | Laser pumping source discharging circuit, switching power supply and laser |
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