CN209056923U - Switching power circuit - Google Patents
Switching power circuit Download PDFInfo
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- CN209056923U CN209056923U CN201822090527.4U CN201822090527U CN209056923U CN 209056923 U CN209056923 U CN 209056923U CN 201822090527 U CN201822090527 U CN 201822090527U CN 209056923 U CN209056923 U CN 209056923U
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- circuit
- switching power
- current
- output end
- power circuit
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Abstract
A kind of switching power circuit, including transformer and output end, the output end connects the transformer, the switching power circuit further includes current-limiting protection circuit, photoelectrical coupler and pulse width modulation control circuit, the current-limiting protection circuit is used for the output current limiting when overcurrent occurs in the output end and protects signal to the photoelectrical coupler, the photoelectrical coupler is used to output control signals to the pulse width modulation control circuit according to the current-limiting protection signal, the pulse width modulation control circuit is used to turn off the switch the power control switching of power circuit when receiving the control signal.It is closed in this way, can detect the overcurrent condition that power-supply system occurs and control power-supply system in overcurrent, the electronic component in effective protection power-supply system and in electrical equipment.
Description
Technical field
The utility model relates to a kind of power technique fields more particularly to a kind of switching power circuits.
Background technique
In general, power supply unit of the power supply as all electronic products, in addition to performance will meet the requirement of powered products
Outside, the safeguard measure of its own is also extremely important, such as over-voltage, overcurrent, overheating protection.When electronic product breaks down,
When opening a way such as the short circuit of electronic product input side or outlet side, then power supply must shut off its output voltage, could protect power device
It is not burned out with side apparatus etc. is exported, otherwise may cause the further damage of electronic product, or even cause the touching of operator
Electricity.Therefore, the overcurrent protection function of Switching Power Supply is had to perfect.
Utility model content
In view of above content, it is necessary to provide a kind of switching power circuit.
A kind of switching power circuit, including transformer and output end, the output end connect the transformer, the switch
Power circuit further includes current-limiting protection circuit, photoelectrical coupler and pulse width modulation control circuit, the current-limiting protection circuit
The output end is connected, the photoelectrical coupler connects the current-limiting protection circuit, and the pulse width modulation control circuit connects
The photoelectrical coupler is connect, the current-limiting protection circuit is used for the output current limiting when overcurrent occurs in the output end and protects signal extremely
The photoelectrical coupler, the photoelectrical coupler are used to output control signals to the pulse according to the current-limiting protection signal wide
Modulation control circuit is spent, the pulse width modulation control circuit is for turning off the switch power supply when receiving the control signal
The power control switching of circuit.
As a preferred embodiment, the primary side of the transformer includes the first winding and the second winding, first winding
It is connect by the first current rectifying and wave filtering circuit, EMI circuit with AC power source, the power control switching and second winding and institute
The connection of the first current rectifying and wave filtering circuit is stated, the secondary side of the transformer includes the tertiary winding, and the tertiary winding and the second rectification are filtered
Wave circuit connection.
As a preferred embodiment, the switching power circuit further includes the first output end and second output terminal, and described
One output end and second output terminal draw signal from the tertiary winding on the pair side of the transformer.
As a preferred embodiment, the switching power circuit further includes first resistor, and the first resistor is connected to institute
It states between the second current rectifying and wave filtering circuit and the second output terminal, the current-limiting protection circuit is connected to the first resistor and institute
It states between second output terminal.
As a preferred embodiment, the current-limiting protection circuit includes diode, triode and second resistance, two pole
The cathode of pipe is connected to the node between the first resistor and the second output terminal, described in the anode connection of the diode
The base stage of triode, the emitter ground connection of the triode, the collector of the triode connects the photoelectrical coupler, described
Second resistance is connected between the anode of the diode and first output end.
As a preferred embodiment, the switching power circuit further includes feedback control circuit, the feedback control circuit
It is connected with first output end, the pulse width modulation control circuit is also connected by the photoelectrical coupler.
As a preferred embodiment, the switching power circuit further includes the first connector, first output end and institute
Second output terminal is stated on first connector, is additionally provided with ground terminal on first connector.
As a preferred embodiment, the triode is NPN type triode.
Relative to prior art, the utility model has the beneficial effects that it will be evident that the current-limiting protection circuit of the utility model
The overcurrent condition that the multi-channel output of detectable power-supply system occurs, when overcurrent occurs, timely and effective control power-supply system is closed
It closes, thus the electronic component in effective protection power-supply system and in electrical equipment.
Detailed description of the invention
Fig. 1 shows the block diagram of the switching power circuit of the preferred embodiment of the utility model.
Fig. 2 shows the physical circuit figures of current-limiting protection circuit in switching power circuit shown in Fig. 1.
Main element symbol description
Switching power circuit 100
AC power source 200
EMI circuit 10
Fuse 12
Current rectifying and wave filtering circuit 20,70
First winding 22
Second winding 24
The tertiary winding 26
Power control switching 30
Pwm control circuit 40
Feedback control circuit 50
Current-limiting protection circuit 60
Connector 80
Transformer T1
Photoelectrical coupler U1
Diode group D1, D2
Controllable accurate source of stable pressure D3
Diode D4
Triode Q1
Resistance R1-R10
Capacitor C1-C5
Inductance L1
The following detailed description will be further explained with reference to the above drawings the utility model.
Specific embodiment
The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model
It clearly and completely describes, it is clear that the embodiments are a part of the embodiments of the present invention, rather than whole implementation
Example.Based on the embodiments of the present invention, those of ordinary skill in the art are obtained without making creative work
The every other embodiment obtained, fall within the protection scope of the utility model.It is used it is appreciated that attached drawing provides reference and description,
Not it is used to limit the utility model.The size shown in attached drawing is and not limit ratio for convenient for clearly describing
Relationship.
It should be noted that it can be directly to separately when a component is considered as " connection " another component
One component may be simultaneously present component placed in the middle.Unless otherwise defined, all technologies used herein and section are academic
Language has the same meaning as commonly understood by one of ordinary skill in the art to which the utility model belongs.Herein in the utility model
Term used in the description, which is only for the purpose of describing specific embodiments, to be not intended to limit the utility model.
Referring to FIG. 1, being the block diagram of the embodiment of the utility model switching power circuit 100, the Switching Power Supply
Circuit 100 includes transformer T1, EMI circuit 10, current rectifying and wave filtering circuit 20, power control switching 30, pulse width modulation
(Pulse Width Modulation, PWM) control circuit 40, feedback control circuit 50, current-limiting protection circuit 60, rectifying and wave-filtering
Circuit 70, photoelectrical coupler U1, multi-channel output (such as+12V output end, -12V output end).
The primary side of the transformer T1 includes the first winding 22 and the second winding 24, and first winding 22 passes through rectification filter
Wave circuit 20, EMI circuit 10 are connect with AC power source 200.The power control switching 30 and first winding 22 and described
Current rectifying and wave filtering circuit 20 connects, with normally turning on and off for the input terminal for controlling the transformer T1 primary side, to make
The output end normal output voltage drawn by the secondary side of the transformer T1.
The secondary side of the transformer T1 includes the tertiary winding 26, and+12V the output end, -12V output end are from the third
Winding 26 draws signal.+ 12V the output end, -12V output end pass through the current rectifying and wave filtering circuit 70 and the tertiary winding
26 connections.The current rectifying and wave filtering circuit 20,70 is used for the AC power source 200 under the control of the power control switching 30
The waveform for carrying out transformation through the transformer T1 carries out rectifying and wave-filtering to reach corresponding ripple requirement.
The feedback control circuit 50 is connected with the output end of the switching power circuit 100, also passes through the photoelectricity coupling
The clutch U1 connection pwm control circuit 40.
The pwm control circuit 40 connects the power control switching 30, second winding 24 and the rectifying and wave-filtering
Circuit 20.
When the voltage change of the AC power source 200 or output end with carry curent change, output end output voltage
Variable quantity feeds back to the pwm control circuit 40 by the photoelectrical coupler U1, and the pwm control circuit 40 is corresponding to carry out
PWM adjustment, and then the power control switching 30 is controlled to achieve the purpose that stabilize the output voltage.Second winding 24 is used for
It powers after the switching power circuit 100 starts and establishes balance to the pwm control circuit 40, to improve power-efficient.
The current-limiting protection circuit 60 is connected to the output end and output current limiting is protected when overcurrent occurs in the output end
Signal is protected to the photoelectrical coupler U1, the photoelectrical coupler U1 exports control letter after receiving the current-limiting protection signal
Number to the pwm control circuit 40, the pwm control circuit 40 closes the power control switching 30 when receiving control signal
To carry out current-limiting protection to power-supply system in time.
For filtering out the various interference signals come in by power grid, the current rectifying and wave filtering circuit 20 is used for the EMI circuit 10
The alternating current that the AC power source 200 inputs is converted into the small direct current of smooth pulsation.The EMI circuit 10 and the friendship
Fuse 12 is also connected between galvanic electricity source 200.In the present embodiment, the AC power source 200 can be mains supply, such as
For 120V (volt), 220V, the mains supply that frequency is 50 hertz or 60 hertz.
It is appreciated that in the other embodiments of the utility model, it can according to the design needs, inside power-supply system
Selection setting EMI circuit 10, current rectifying and wave filtering circuit and feedback control circuit 50.
In a better embodiment, the switching power circuit 100 further includes resistance R1, and the resistance R1 is connected to institute
It states between current rectifying and wave filtering circuit 70 and the -12V output end, the current-limiting protection circuit 60 is connected to the resistance R1 and institute
It states between -12V output end.
Referring to Figure 2 together, the photoelectrical coupler U1 includes a luminescence unit and a switch unit.The switch unit
Including an emitter and a collector.The collector of the switch unit is connected to the pwm control circuit 40, and the switch is single
The emitter of member is grounded.
The current-limiting protection circuit 60 includes the cathode company of diode D4, triode Q1 and resistance R2, the diode D4
The node being connected between the resistance R1 and the -12V output end, the anode of the diode D4 connect the triode Q1's
Base stage, the emitter ground connection of the triode Q1, the collector of the triode Q1 connects the cathode of the luminescence unit, described
Resistance R2 is connected between the anode of the diode D4 and the+12V output end.In a better embodiment, described three
Pole pipe Q1 is NPN type triode.Wherein, the diode D4 is used to carry out clamper to power circuit, and clamp voltage is
0.55V。
The current rectifying and wave filtering circuit 70 includes diode group D1, diode group D2, three capacitor C1-C3, two resistance R3-
R4 and inductance L1.
The diode group D1 and the diode group D2 are made of two diodes in parallel.The diode group D1
And the common anode of the diode group D2 is connected to one end of the tertiary winding 26, the diode group D1 and described two
The common cathode of pole pipe group D2 passes through the other end that the capacitor C1 is connected to the tertiary winding 26, the tertiary winding 26
The other end also pass through the resistance R1 and be connected to -12V the output end.The diode group D1's and diode group D2
Common cathode also passes through the inductance L1 and is connected to+12V the output end, and one end of the capacitor C2 is connected to the diode
Between the common cathode and the inductance L1 of group D1, the other end of the capacitor C2 is grounded.One end of described resistance R3, R4 connect
One end of the capacitor C2 is connect, the other end of described resistance R3, R4 are grounded.One end of the capacitor C3 is connected to described
Between inductance L1 and the+12V output end, the other end of the capacitor C3 is grounded.
The feedback control circuit 50 includes a controllable accurate source of stable pressure D3, six resistance R5-R10 and two capacitors
C4-C5.The anode of the luminescence unit passes through+12V output end, the controllable accurate source of stable pressure D3 described in the resistance R5 connection
First end the anode of the luminescence unit, the second termination of the controllable accurate source of stable pressure D3 are connected to by the resistance R6
Ground.One end of the resistance R7 is connected to the node between the resistance R6 and the first end of the controllable accurate source of stable pressure D3,
The other end of the resistance R7 connects one end of the capacitor C4, and the other end of the capacitor C4 is connected to by the resistance R8
+ 12V the output end.One end of the capacitor C5 is connected to the first end of the controllable accurate source of stable pressure D3, the capacitor C5
The other end pass through the resistance R9 be grounded.One end of the resistance R10 connects the adjustable side of the controllable accurate source of stable pressure D3,
The other end of the resistance R10 is grounded.
The switching power circuit 100 further includes connector 80, and+12V the output end and -12V output end are set to institute
It states on connector 80, is additionally provided with ground terminal on the connector 80.
The working principle of the utility model switching power circuit is illustrated below.
When work, the base voltage of the triode Q1 is provided by the resistance R2, and the diode D4 and described
Resistance R1 is extremely.
When electric power outputting current is less than pre-set current value (i.e. not overcurrent), the electric current on the resistance R1 is I=
(12-0.55)/(15000+0.1)=0.00076A, it follows that the voltage on the resistance R1 is 0.00076*0.1=
0.076mV.At this point, the voltage of the base stage of the triode Q1 is (0.55+0.000076V) ≈ 0.55V, which is not up to institute
State the minimum conducting voltage 0.7V of triode Q1.In this way, the triode Q1 is in off state, at the photoelectrical coupler U1
In off state, the maintenance of switching power circuit 100 is stabilized the output voltage.
When electric power outputting current is 1.5A (being in over-current state), the voltage of the resistance R1 is 0.1*1.5=
0.15V, and the clamp voltage 0.55V of the diode D4 is added, the voltage of the base stage of the triode Q1 is (0.1* at this time
1.5+0.55)=0.7V, the triode Q1 is in critical conduction mode at this time.When electric current continues to increase, the triode
The voltage of the base stage of Q1 will be greater than 0.7V, the triode Q1 conducting, so that obtaining after photoelectrical coupler U1 conducting electric
Work, the photoelectrical coupler U1 export low level control signal to the pwm control circuit 40, the pwm control circuit
40 close the power control switching 30 when receiving control signal, to carry out current-limiting protection to power-supply system in time.
Above-mentioned switching power circuit 100 can be applied in a variety of electrical equipments, such as to electric appliances such as sound equipment, disc player, computers
Equipment power supply.The current-limiting protection circuit of the utility model can detect the overcurrent condition that the multi-channel output of power-supply system occurs,
When overcurrent occurs, timely and effective control power-supply system is closed, thus the electronics in effective protection power-supply system and in electrical equipment
Element, in addition, the current-limiting mode of above-mentioned switching power circuit, to electric power output voltage without limitation, when output voltage is not being powered
When range, individually power woth no need to add a winding.And the layout of printed circuit board is more flexible, convenient for miniaturization.
Claims (8)
1. a kind of switching power circuit, including transformer and output end, the output end connects the transformer, and feature exists
In the switching power circuit further includes current-limiting protection circuit, photoelectrical coupler and pulse width modulation control circuit, the limit
Output end described in stream protection circuit connection, the photoelectrical coupler connect the current-limiting protection circuit, the pulse width modulation
Control circuit connects the photoelectrical coupler, and the current-limiting protection circuit is used for the output current limiting when overcurrent occurs in the output end
Protect signal to the photoelectrical coupler, the photoelectrical coupler according to the current-limiting protection signal for outputing control signals to
The pulse width modulation control circuit, the pulse width modulation control circuit are used for the pass when receiving the control signal
Close the power control switching of switching power circuit.
2. switching power circuit as described in claim 1, which is characterized in that the primary side of the transformer include the first winding and
Second winding, first winding are connect by the first current rectifying and wave filtering circuit, EMI circuit with AC power source, the power control
Switch is connect with second winding and first current rectifying and wave filtering circuit, and the secondary side of the transformer includes the tertiary winding, institute
The tertiary winding is stated to connect with the second current rectifying and wave filtering circuit.
3. switching power circuit as claimed in claim 2, which is characterized in that the switching power circuit further includes the first output
End and second output terminal, first output end and second output terminal are drawn from the tertiary winding on the pair side of the transformer to be believed
Number.
4. switching power circuit as claimed in claim 3, which is characterized in that the switching power circuit further includes the first electricity
Resistance, the first resistor are connected between second current rectifying and wave filtering circuit and the second output terminal, the current-limiting protection electricity
Road is connected between the first resistor and the second output terminal.
5. switching power circuit as claimed in claim 4, which is characterized in that the current-limiting protection circuit includes diode, three
Pole pipe and second resistance, the cathode of the diode are connected to the node between the first resistor and the second output terminal,
The anode of the diode connects the base stage of the triode, the emitter ground connection of the triode, the current collection of the triode
Pole connects the photoelectrical coupler, and the second resistance is connected between the anode of the diode and first output end.
6. switching power circuit as claimed in claim 3, which is characterized in that the switching power circuit further includes feedback control
Circuit, the feedback control circuit are connected with first output end, and it is wide also to connect the pulse by the photoelectrical coupler
Spend modulation control circuit.
7. switching power circuit as claimed in claim 3, which is characterized in that the switching power circuit further includes the first connection
Device, first output end and the second output terminal are set on first connector, are additionally provided on first connector
Ground terminal.
8. switching power circuit as claimed in claim 5, which is characterized in that the triode is NPN type triode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201822090527.4U CN209056923U (en) | 2018-12-12 | 2018-12-12 | Switching power circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201822090527.4U CN209056923U (en) | 2018-12-12 | 2018-12-12 | Switching power circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN209056923U true CN209056923U (en) | 2019-07-02 |
Family
ID=67055070
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201822090527.4U Active CN209056923U (en) | 2018-12-12 | 2018-12-12 | Switching power circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN209056923U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110324034A (en) * | 2019-07-04 | 2019-10-11 | 东莞市卓品电子科技有限公司 | A kind of DC power supply output-controlling device |
-
2018
- 2018-12-12 CN CN201822090527.4U patent/CN209056923U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110324034A (en) * | 2019-07-04 | 2019-10-11 | 东莞市卓品电子科技有限公司 | A kind of DC power supply output-controlling device |
| CN110324034B (en) * | 2019-07-04 | 2023-04-18 | 东莞市卓品电子科技有限公司 | DC power supply output control device |
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