CN215897594U - Switching power supply circuit - Google Patents
Switching power supply circuit Download PDFInfo
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- CN215897594U CN215897594U CN202121656379.3U CN202121656379U CN215897594U CN 215897594 U CN215897594 U CN 215897594U CN 202121656379 U CN202121656379 U CN 202121656379U CN 215897594 U CN215897594 U CN 215897594U
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Abstract
The utility model discloses a switching power supply circuit. The switching power supply circuit includes: the circuit comprises a transformer, an input branch circuit, a first output branch circuit, at least one second output branch circuit, at least one unbalance loading protection module and a control module. The input branch comprises a primary winding; the first output branch comprises a first secondary winding; the second output branch comprises a second secondary winding; the first end of the unbalance loading protection module is electrically connected with the output end of the second output branch circuit, and the second end of the unbalance loading protection module is electrically connected with the second end of the second secondary winding; the offset load protection module is used for conducting when the second output branch circuit is in no-load and the output voltage of the second output branch circuit exceeds a voltage threshold value, so that the second output branch circuit is in short circuit; the control module is used for reducing the output power of the switching power supply circuit when judging that the second output branch is short-circuited according to the output voltage of the first output branch. The embodiment of the utility model can effectively solve the problem of unbalanced temperature rise on the basis of not influencing the normal working performance of the power circuit, and the circuit is simple and reliable and is easy to realize.
Description
Technical Field
The embodiment of the utility model relates to the technical field of power supplies, in particular to a switching power supply circuit.
Background
At present, for a switching power supply circuit with multi-output, when an output branch of a secondary side of a transformer is overloaded, the circuit is turned off by means of overcurrent protection set by a primary side of the transformer. However, in the process of the unbalance loading experiment, the load is added on one output branch independently, and all the over-power values set originally for the multipath output are borne by one branch. The secondary winding carrying the power will heat up seriously, resulting in excessive temperature rise due to unbalance loading.
The existing scheme for solving the problem of excessive unbalance load temperature rise mainly comprises the following steps: firstly, an over-power set value is reduced, so that the output power of an output branch circuit with load when overcurrent protection is triggered is reduced, and the heating of a secondary winding is reduced; however, lowering the overpower setting too much will reduce the load carrying capability of the circuit during normal operation. Secondly, the specifications of a magnetic core and a framework of the transformer are increased, so that the diameter of a winding wire can be increased to solve the problem of temperature rise, but the method needs to change the structure of the transformer, the size of the transformer is increased, and the method is inconvenient to implement. Therefore, the existing unbalance loading temperature rise solution has the problem of influencing the performance of a power circuit or being inconvenient to implement.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a switching power supply circuit, which is used for effectively solving the problem of unbalanced load temperature rise on the basis of not influencing the normal working performance of the power supply circuit, and is simple, reliable and easy to implement.
An embodiment of the present invention provides a switching power supply circuit, including:
a transformer comprising a primary winding, a first secondary winding, and at least one second secondary winding;
an input branch; the input branch comprises the primary winding; a first input end of the input branch circuit is electrically connected with a first end of the primary winding and is connected with an input voltage signal;
a first output branch; the first output branch comprises a first secondary winding; the output end of the first output branch circuit is electrically connected with the first end of the first secondary winding;
at least one second output branch; the second output branch comprises the second secondary winding; the output end of the second output branch circuit is electrically connected with the first end of the second secondary winding;
at least one offset load protection module; the first end of the unbalance loading protection module is electrically connected with the output end of the second output branch circuit, and the second end of the unbalance loading protection module is electrically connected with the second end of the second secondary winding; the offset load protection module is used for conducting when the second output branch circuit is in no-load and the output voltage of the second output branch circuit exceeds a voltage threshold value, so that the second output branch circuit is in short circuit;
a control module; the input end of the control module is electrically connected with the output end of the first output branch circuit, and the output end of the control module is electrically connected with the second input end of the input branch circuit; the control module is used for judging whether the second output branch circuit is short-circuited according to the output voltage of the first output branch circuit and reducing the output power of the switching power supply circuit when the second output branch circuit is short-circuited.
Optionally, the number of the offset protection modules is 1.
Optionally, the number of the offset protection modules is the same as the number of the second output branches.
Optionally, the offset load protection module includes: a transient suppression diode;
the cathode of the transient suppression diode is used as the first end of the offset load protection module, and the anode of the transient suppression diode is used as the second end of the offset load protection module.
Optionally, the input branch further comprises a transistor;
the grid electrode of the transistor is used as a second input end of the input branch, the source electrode of the transistor is connected with a first ground signal, and the drain electrode of the transistor is electrically connected with the second end of the primary winding.
Optionally, the first output branch further includes: the first rectifying and filtering unit comprises an input end, an output end and a grounding end; the input end of the first rectifying and filtering unit is electrically connected with the first end of the first secondary winding, the output end of the first rectifying and filtering unit is used as the output end of the first output branch, and the grounding end of the first rectifying and filtering unit is electrically connected with the second end of the first secondary winding and is connected with a second ground signal.
Optionally, the first rectifying and filtering unit includes: a first diode and a first capacitor; the anode of the first diode is used as the input end of the first rectifying and filtering unit; the cathode of the first diode is electrically connected with the first end of the first capacitor and is used as the output end of the first rectifying and filtering unit; and the second end of the first capacitor is used as the grounding end of the first rectifying and filtering unit.
Optionally, the second output branch further includes: the second rectifying and filtering unit comprises an input end, an output end and a grounding end; the input end of the second rectifying and filtering unit is electrically connected with the first end of the second secondary winding, the output end of the second rectifying and filtering unit is used as the output end of the second output branch, and the grounding end of the second rectifying and filtering unit is electrically connected with the second end of the second secondary winding and is connected with a second ground signal.
Optionally, the control module comprises:
the feedback unit comprises an input end and an output end; the input end of the feedback unit is used as the input end of the control module;
a control unit comprising an input and an output; the input end of the control unit is electrically connected with the output end of the feedback unit, and the output end of the control unit is used as the output end of the control module.
Optionally, the feedback unit includes: the circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a third capacitor, a voltage stabilizing diode and a photoelectric coupler;
the first end of the first resistor is electrically connected with the first end of the third resistor and is used as the input end of the feedback unit; the second end of the first resistor is electrically connected with the first input end of the photoelectric coupler and the first end of the second resistor respectively; the second end of the second resistor is electrically connected with the second input end of the photoelectric coupler, the cathode of the voltage stabilizing diode and the first end of the third capacitor respectively; the second end of the third capacitor is electrically connected with the first end of the fourth resistor; a second end of the fourth resistor is electrically connected with a second end of the third resistor, a reference end of the voltage stabilizing diode and a first end of the fifth resistor respectively; the anode of the voltage stabilizing diode and the second end of the fifth resistor are both connected to a second ground signal; the first output end of the photoelectric coupler is used as the output end of the feedback unit, and the second output end of the photoelectric coupler is connected with a first ground signal.
The switching power supply circuit provided by the embodiment of the utility model is provided with a control module and at least one unbalance loading protection module. When the power circuit is in unbalanced load, the output voltage of the no-load branch circuit will gradually increase along with the increase of the load of the loaded branch circuit due to the existence of the leakage inductance of the transformer. When the output voltage of the second output branch circuit with no load exceeds the voltage threshold, the unbalance loading protection module is conducted to short-circuit the second output branch circuit. Due to the self characteristics of the transformer, the ratios of the output voltage of each output branch circuit to the turns of the corresponding secondary winding are equal, and when the output voltage of the second output branch circuit is reduced to 0, the output voltage of the first output branch circuit is also reduced to 0; accordingly, the control module can judge that the short-circuit condition of the output branch exists. At the moment, the control module relieves the heating of the secondary winding by reducing the output power of the switching power supply circuit, and effectively solves the problem of unbalanced load temperature rise. The threshold voltage can be set as the maximum value when the output branch circuit works normally according to requirements, so that the normal working performance of the switching power supply circuit is not affected; in addition, in the embodiment, only the offset load protection module needs to be additionally arranged at the tail end of at least one second output branch, and the structure and the size of the transformer do not need to be changed, so that the circuit is simple and reliable and is easy to realize.
Drawings
Fig. 1 is a schematic diagram of a switching power supply circuit in the prior art;
fig. 2 is a schematic structural diagram of a switching power supply circuit according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another switching power supply circuit according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of another switching power supply circuit according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting of the utility model. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
As described in the background art, the existing switching power supply circuit has the problem that unbalanced load temperature rise is difficult to solve. Fig. 1 is a schematic structural diagram of a switching power supply circuit in the prior art. The following describes the cause of the unbalanced load temperature rise problem and the influence of the conventional solution on the performance of the switching power supply circuit, taking a flyback power supply circuit with dual output as an example, with reference to fig. 1.
As shown in fig. 1, the power circuit includes a transformer T0, a primary winding N01 of the transformer T0 is an input winding, and both the first secondary winding N02 and the second secondary winding N03 are output windings. The flyback set overpower point of the input branch, i.e., the branch in which the primary winding N01 is located, is denoted as P1. Under the normal working condition, the output power of the first secondary winding N02 is recorded as P2; recording the output power of the second secondary winding N03 as P3; then, when P3+ P2 > P1, over-power protection of the power circuit is triggered. In the offset load test, when the second secondary winding N03 is unloaded (the load circuit at the rear end of the second secondary winding N03 stops working), only the first secondary winding N02 is loaded, and the output power of the first secondary winding N02 at this time is denoted as P21. Then overpower protection is triggered only if P21 > P1. At this time, the output power P21 of the first secondary winding N02 is greater than the normal output power P2, and the current passing through the first secondary winding N02 is greatly increased, so that the first secondary winding N02 generates heat seriously, and the temperature rise exceeds the unbalance loading experimental standard.
If the above problem of exceeding the temperature rise is solved by reducing the flyback set overpower point P1, the heat generation of the first secondary winding N02 can be reduced by reducing the value of the output power P21 of the first secondary winding N02 when the overcurrent protection is triggered. However, the flyback set over-power point P1 is reduced, which reduces the capacity of the circuit with capacitive load when the circuit normally works, limits the maximum value of the output power of the two secondary windings when the circuit normally works, and affects the performance of the switching power supply circuit when the circuit normally works.
Based on the above research, the embodiment of the utility model provides a switching power supply circuit. Fig. 2 is a schematic structural diagram of a switching power supply circuit according to an embodiment of the present invention. Referring to fig. 2, the switching power supply circuit includes: transformer T1, input branch 110, first output branch 120, at least one second output branch 130, at least one offset protection module 140, and control module 150.
Wherein the transformer T1 includes a primary winding N1, a first secondary winding N2, and at least one second secondary winding N3. The input branch 110 includes a primary winding N1; a first input terminal of the input branch 110 is electrically connected to a first terminal of the primary winding N1 and is coupled to the input voltage signal Vin. The first output branch 120 includes a first secondary winding N2; the output terminal of the first output branch 120 is electrically connected to the first terminal of the first secondary winding N2. The second output branch 130 includes a second secondary winding N3; the output terminal of the second output branch 130 is electrically connected to the first terminal of the second secondary winding N3. A first end of the offset protection module 140 is electrically connected to the output end of the second output branch 130, and a second end of the offset protection module 140 is electrically connected to a second end of the second secondary winding N3; the offset load protection module 140 is configured to be turned on when the second output branch 130 is idle and the output voltage of the second output branch 130 exceeds the voltage threshold, so as to short-circuit the second output branch 130. The input end of the control module 150 is electrically connected to the output end of the first output branch 120, and the output end is electrically connected to the second input end of the input branch 110; the control module 150 is configured to determine whether the second output branch 130 is short-circuited according to the output voltage of the first output branch 120, and reduce the output power of the switching power supply circuit when the second output branch 130 is short-circuited.
Illustratively, the transformer T1 may be a high frequency transformer, and the switching power supply circuit may be a flyback power supply. For the transformer T1, the number of turns of the secondary winding in each output branch of the secondary side may be different, but the ratio of the output voltage of each output branch to the number of turns of the corresponding secondary winding is equal, that is, (Vo1/N11) ═ Vo 2/N21; vo1 is the output voltage of the first output branch 120, N11 is the number of turns of the first secondary winding N1, Vo2 is the output voltage of the second output branch 130, and N21 is the number of turns of the second secondary winding N2. Due to the existence of the leakage inductance of the transformer T1, when the circuit works, a part of the energy of the leakage inductance of the primary side of the transformer T1 is transferred to the secondary side, and when the energy transferred to the output branch is larger than the energy consumed by the load of the output branch, the output voltage of the output branch is increased. Therefore, when the circuit is biased, the output voltage of the unloaded output branch will be high.
According to the above characteristics of the transformer T1, the unbalanced load protection module 140 is added to the switching power supply circuit, and the control module 150 is used to implement the unbalanced load temperature rise protection. Specifically, when the second output branch 130 connected with the offset load protection module is unloaded and the first output branch 120 or other second output branches 130 are loaded, the output voltage of the unloaded branch gradually increases as the load of the loaded branch increases. When the output voltage of the unloaded second output branch 130 exceeds the voltage threshold, the unbalanced load protection module 140 is turned on, so that the second output branch 130 is short-circuited and the output voltage thereof is reduced to 0. Due to the characteristics of the transformer T1, when the output voltage of the second output branch 130 drops to 0, the output voltage of the first output branch 120 also drops to 0. Then, the control module 150 can determine whether there is an abnormal output branch in the power circuit according to the value of the output voltage Vo1 of the first output branch 120. When there is a short-circuited output branch, the control module 150 controls the switching power supply circuit to enter a short-circuit protection mode, and reduces the output power of the switching power supply circuit by reducing the duty ratio or frequency, so as to alleviate the heat generated by the secondary winding and effectively solve the problem of unbalanced load temperature rise.
In summary, the switching power supply circuit provided in the embodiment of the utility model can effectively solve the problem of unbalanced temperature rise by arranging the unbalanced protection module 140. In addition, the threshold voltage can be set as the maximum value when the output branch circuit works normally according to the requirement, so that the normal working performance of the switching power supply circuit is not influenced; in addition, in the embodiment, only the offset load protection module 140 needs to be added to the end of the at least one second output branch 130, and the structure and size of the transformer T1 do not need to be changed, so that the circuit is simple and reliable and is easy to implement.
It should be noted that the first output branch 120 and the second output branch 130 are substantially the same output branch. However, when the output end of one output branch is connected to the control module 150, the output branch becomes a controlled branch; the control module 150 can directly collect the output voltage of the output branch circuit, and accordingly, whether the output branch circuit is abnormal is judged; the second control module 150 can control the output branch to output voltage-stabilizing, and the output voltage of the output branch will not be high during the offset load. Therefore, for the sake of convenience of distinction, the output branch to which the control module 150 is connected is referred to as a first output branch 120, wherein the secondary winding is referred to as a first secondary winding N2; the other output branch is referred to as the second output branch 130, wherein the secondary winding is referred to as the second secondary winding N3. The number of the second output branches 130 can be selected according to the requirement.
In addition to the above embodiments, there are various alternative installation manners of the offset protection module 140, and some of them will be described below, but the present invention is not limited thereto.
In one embodiment, the number of the offset protection modules 140 is optionally 1. The unbalance loading protection function can be basically realized only by adding the unbalance loading protection module 140 at the tail ends of 1 second output branch 130, and the overall circuit is guaranteed to be simplest, the size is minimum, and the cost is minimum. However, this embodiment cannot solve the problem of temperature rise when the second output branch provided with the unbalanced load protection module 140 is loaded and the other output branches are unloaded.
In another embodiment, the number of the offset protection modules 140 is optionally the same as the number of the second output branches 130. By the arrangement, the unbalance loading protection function can cover each output branch. Although the number of the offset load protection modules 140 is increased, the embodiment realizes the overall protection of the output branch in the circuit and improves the safety and reliability of the circuit.
Fig. 3 is a schematic structural diagram of another switching power supply circuit according to an embodiment of the present invention. Referring to fig. 3, based on the above embodiments, optionally, the offset protection module 140 includes: transient suppression diode ZD 1. The cathode of the transient suppression diode ZD1 serves as the first terminal of the offset protection module 140 and the anode serves as the second terminal of the offset protection module 140. The threshold voltage at this time is the breakdown voltage of the transient suppression diode ZD 1. When ZD1 breaks down, second output branch 130 is short-circuited, and control module 150 controls the switching power supply circuit to enter the short-circuit protection mode. In the working mode, the temperature rise of the transformer is extremely low, and the problem of unbalance load temperature rise of the transformer can be solved. And, control module 150 can report to the police at this moment, reminds the staff to overhaul and maintain switching power supply circuit. In this embodiment, the offset protection module 140 includes only one transient suppression diode ZD1, so that the circuit structure is simple and easy to implement.
With continued reference to fig. 3, based on the above embodiments, the input branch 110 further optionally includes a transistor Q1; a gate of the transistor Q1 serves as a second input terminal of the input branch 110, a source thereof is connected to the first ground signal SGND, and a drain thereof is electrically connected to a second terminal of the primary winding N1. The transistor Q1 may be a MOS transistor, and the first ground signal SGND may be a digital ground signal. The control module 150 may control the duty cycle or frequency of the circuit by controlling the switching of the transistor Q1.
With continued reference to fig. 3, based on the above embodiments, optionally, the first output branch further includes: the first rectifying and filtering unit 121. The input end of the first rectifying and filtering unit 121 is electrically connected to the first end of the first secondary winding N2, the output end is used as the output end of the first output branch 120, and the ground end is electrically connected to the second end of the first secondary winding N2 and is connected to the second ground signal GND.
Specifically, the first rectifying and filtering unit 121 includes: a first diode D1 and a first capacitor C1; the anode of the first diode D1 is used as the input terminal of the first rectifying and filtering unit 121; the cathode of the first diode D1 is electrically connected to the first end of the first capacitor C1 and serves as the output end of the first rectifying and filtering unit 121; the second end of the first capacitor C1 is used as the ground terminal of the first rectifying-filtering unit 121. The first capacitor C1 may be an electrolytic capacitor, and the second ground signal GND may be an analog ground signal.
With continued reference to fig. 3, based on the above embodiments, the second output branch 130 optionally further includes: and a second rectifying and filtering unit 131. The input end of the second rectifying and filtering unit 131 is electrically connected to the first end of the second secondary winding N3, the output end is used as the output end of the second output branch 130, and the ground end is electrically connected to the second end of the second secondary winding N3 and is connected to the second ground signal GND.
Specifically, the second rectifying and filtering unit 131 includes: a second diode D2 and a second capacitor C2; the anode of the second diode D2 is used as the input terminal of the second rectifying and filtering unit 131; the cathode of the second diode D2 is electrically connected to the first end of the second capacitor C2 and serves as the output end of the second rectifying and filtering unit 131; the second end of the second capacitor C2 is used as the ground terminal of the second rectifying-filtering unit 131. Wherein the second capacitor C2 may be an electrolytic capacitor.
With continued reference to fig. 3, based on the above embodiments, optionally, the control module 150 includes: a feedback unit 151 and a control unit 152. The input of the feedback unit 151 serves as the input of the control module 150; the input end of the control unit 152 is electrically connected to the output end of the feedback unit 151, and the output end of the control unit 152 serves as the output end of the control module 150.
The present embodiment defines the internal structure of the control module 150, and the feedback unit 151 is configured to collect the output voltage Vo1 of the first output branch 120, convert the output voltage Vo1 into a feedback signal, and transmit the feedback signal to the control unit 152; the control unit is used for analyzing whether the feedback signal is abnormal or not and controlling the power circuit to enter a short-circuit protection mode when the feedback signal indicates that the short-circuited output branch exists. Illustratively, the control unit 152 may be composed of a PWM (Pulse Width Modulation) control chip and its necessary peripheral circuits.
Fig. 4 is a schematic structural diagram of another switching power supply circuit according to an embodiment of the present invention. Referring to fig. 4, on the basis of the above embodiments, optionally, the feedback unit 151 includes: the circuit comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a third capacitor C3, a zener diode UD1 and a photoelectric coupler U1.
A first end of the first resistor R1 is electrically connected to a first end of the third resistor R3, and serves as an input end of the feedback unit 151; a second end of the first resistor R1 is electrically connected with a first input end of the photoelectric coupler U1 and a first end of the second resistor R2 respectively; a second end of the second resistor R2 is electrically connected with a second input end of the photocoupler U1, a cathode of the zener diode UD1 and a first end of the third capacitor C3 respectively; a second end of the third capacitor C3 is electrically connected with a first end of the fourth resistor R4; a second end of the fourth resistor R4 is electrically connected with a second end of the third resistor R3, a reference end of the zener diode UD1 and a first end of the fifth resistor R5 respectively; the anode of the zener diode UD1 and the second end of the fifth resistor R5 are both connected to the second ground signal GND; a first output terminal of the photocoupler U1 is used as an output terminal of the feedback unit 151, and a second output terminal of the photocoupler U1 is connected to the first ground signal SGND.
In the embodiment, the third resistor R3, the fifth resistor R5 and the zener diode UD1 form a sampling circuit; the third capacitor C3 and the fourth resistor R4 form a compensation circuit, so that the feedback strength can be increased; the photoelectric coupler U1 can realize electrical isolation and improve the circuit safety.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the utility model. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A switching power supply circuit, comprising:
a transformer comprising a primary winding, a first secondary winding, and at least one second secondary winding;
an input branch; the input branch comprises the primary winding; a first input end of the input branch circuit is electrically connected with a first end of the primary winding and is connected with an input voltage signal;
a first output branch; the first output branch comprises a first secondary winding; the output end of the first output branch circuit is electrically connected with the first end of the first secondary winding;
at least one second output branch; the second output branch comprises the second secondary winding; the output end of the second output branch circuit is electrically connected with the first end of the second secondary winding;
at least one offset load protection module; the first end of the unbalance loading protection module is electrically connected with the output end of the second output branch circuit, and the second end of the unbalance loading protection module is electrically connected with the second end of the second secondary winding; the offset load protection module is used for conducting when the second output branch circuit is in no-load and the output voltage of the second output branch circuit exceeds a voltage threshold value, so that the second output branch circuit is in short circuit;
a control module; the input end of the control module is electrically connected with the output end of the first output branch circuit, and the output end of the control module is electrically connected with the second input end of the input branch circuit; the control module is used for judging whether the second output branch circuit is short-circuited according to the output voltage of the first output branch circuit and reducing the output power of the switching power supply circuit when the second output branch circuit is short-circuited.
2. The switching power supply circuit according to claim 1, wherein the number of the offset protection modules is 1.
3. The switching power supply circuit according to claim 1, wherein the number of the offset protection modules is the same as the number of the second output branches.
4. The switching power supply circuit according to claim 1, wherein the offset protection module comprises: a transient suppression diode;
the cathode of the transient suppression diode is used as the first end of the offset load protection module, and the anode of the transient suppression diode is used as the second end of the offset load protection module.
5. The switching power supply circuit according to claim 1, wherein the input branch further comprises a transistor;
the grid electrode of the transistor is used as a second input end of the input branch, the source electrode of the transistor is connected with a first ground signal, and the drain electrode of the transistor is electrically connected with the second end of the primary winding.
6. The switching power supply circuit according to claim 1, wherein the first output branch further comprises: the first rectifying and filtering unit comprises an input end, an output end and a grounding end; the input end of the first rectifying and filtering unit is electrically connected with the first end of the first secondary winding, the output end of the first rectifying and filtering unit is used as the output end of the first output branch, and the grounding end of the first rectifying and filtering unit is electrically connected with the second end of the first secondary winding and is connected with a second ground signal.
7. The switching power supply circuit according to claim 6, wherein the first rectifying and filtering unit includes: a first diode and a first capacitor; the anode of the first diode is used as the input end of the first rectifying and filtering unit; the cathode of the first diode is electrically connected with the first end of the first capacitor and is used as the output end of the first rectifying and filtering unit; and the second end of the first capacitor is used as the grounding end of the first rectifying and filtering unit.
8. The switching power supply circuit according to claim 1, wherein the second output branch further comprises: the second rectifying and filtering unit comprises an input end, an output end and a grounding end; the input end of the second rectifying and filtering unit is electrically connected with the first end of the second secondary winding, the output end of the second rectifying and filtering unit is used as the output end of the second output branch, and the grounding end of the second rectifying and filtering unit is electrically connected with the second end of the second secondary winding and is connected with a second ground signal.
9. The switching power supply circuit according to claim 1, wherein the control module comprises:
the feedback unit comprises an input end and an output end; the input end of the feedback unit is used as the input end of the control module;
a control unit comprising an input and an output; the input end of the control unit is electrically connected with the output end of the feedback unit, and the output end of the control unit is used as the output end of the control module.
10. The switching power supply circuit according to claim 9, wherein the feedback unit includes: the circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a third capacitor, a voltage stabilizing diode and a photoelectric coupler;
the first end of the first resistor is electrically connected with the first end of the third resistor and is used as the input end of the feedback unit; the second end of the first resistor is electrically connected with the first input end of the photoelectric coupler and the first end of the second resistor respectively; the second end of the second resistor is electrically connected with the second input end of the photoelectric coupler, the cathode of the voltage stabilizing diode and the first end of the third capacitor respectively; the second end of the third capacitor is electrically connected with the first end of the fourth resistor; a second end of the fourth resistor is electrically connected with a second end of the third resistor, a reference end of the voltage stabilizing diode and a first end of the fifth resistor respectively; the anode of the voltage stabilizing diode and the second end of the fifth resistor are both connected to a second ground signal; the first output end of the photoelectric coupler is used as the output end of the feedback unit, and the second output end of the photoelectric coupler is connected with a first ground signal.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121656379.3U CN215897594U (en) | 2021-07-20 | 2021-07-20 | Switching power supply circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121656379.3U CN215897594U (en) | 2021-07-20 | 2021-07-20 | Switching power supply circuit |
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| CN215897594U true CN215897594U (en) | 2022-02-22 |
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- 2021-07-20 CN CN202121656379.3U patent/CN215897594U/en active Active
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