CN204597781U - A kind of switching power circuit - Google Patents
A kind of switching power circuit Download PDFInfo
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- CN204597781U CN204597781U CN201520324353.7U CN201520324353U CN204597781U CN 204597781 U CN204597781 U CN 204597781U CN 201520324353 U CN201520324353 U CN 201520324353U CN 204597781 U CN204597781 U CN 204597781U
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Abstract
The utility model discloses a kind of switching power circuit, comprise input rectifying filter circuit, transformer, output rectifier and filter, rectification reduction voltage circuit and pwm control circuit; Input rectifying filter circuit is connected to the control signal output of pwm control circuit by the armature winding of transformer; Output rectifier and filter jumps to the two ends of the secondary winding of transformer, and the output of output rectifier and filter is as the main road supply voltage output of switching power circuit; Rectification reduction voltage circuit has at least one rectification step-down branch road; The input of each rectification step-down branch road connects the output of output rectifier and filter, and the output of rectification step-down branch road is as the bypass supply voltage output of switching power circuit.Because secondary winding only has the output that namely can realize multiple power supplies, cost can be saved; Simplify technique to make, improve qualitative reliability; Conduct radiation source is reduced, and reduces conduct radiation, improves Electro Magnetic Compatibility.
Description
Technical field
The utility model relates to electronic circuit technology field, is specifically related to a kind of switching power circuit.
Background technology
At present, Switching Power Supply is widely used, and in order to meet different source voltage requirements, prior art has a kind of Switching Power Supply can the supply voltage of output multi-channel.
As shown in Figure 1, it is the structural representation of a kind of Switching Power Supply of prior art.In order to brief description, described Switching Power Supply exports the supply voltage on three tunnels.Described Switching Power Supply comprises input rectifying filter circuit, transformer, the first current rectifying and wave filtering circuit, the second current rectifying and wave filtering circuit, the 3rd current rectifying and wave filtering circuit, feedback circuit and pwm control circuit.The output of described input rectifying filter circuit is connected to the control signal output of described pwm control circuit by the armature winding of described transformer.Described first current rectifying and wave filtering circuit is connected across the two ends of the first secondary winding of described transformer, and the output of described first current rectifying and wave filtering circuit exports first via supply voltage V1; Described second current rectifying and wave filtering circuit is connected across the two ends of the second subprime winding of described transformer, and the output of described second current rectifying and wave filtering circuit exports the second road supply voltage V2; Described 3rd current rectifying and wave filtering circuit be connected across described transformer third time level winding two ends, and the output of described 3rd current rectifying and wave filtering circuit exports three-way power voltage V3.The output of described first current rectifying and wave filtering circuit is connected to the feedback signal input terminal of described pwm control circuit by described feedback circuit.
The shortcoming of the Switching Power Supply of prior art is, the out-put supply on each road all needs the secondary winding of configuration one and armature winding coupling, and winding and the coiling of needs are many, and cost is high; Transformer needs four windings altogether, complex process, and consistency is poor, and quality fraction defective is high; Four windings are equivalent to four conduct radiation sources, make Electro Magnetic Compatibility poor.
Utility model content
The purpose of this utility model is, provides a kind of switching power circuit, under the prerequisite realizing multiple power supplies output, can reduce the quantity of winding, thus reduce cost, Simplified flowsheet, improve quality, improve Electro Magnetic Compatibility.。
For solving above technical problem, the utility model embodiment provides a kind of switching power circuit, comprises input rectifying filter circuit, transformer, output rectifier and filter, rectification reduction voltage circuit and pwm control circuit; Described input rectifying filter circuit is connected to the control signal output of described pwm control circuit by the armature winding of described transformer; Described output rectifier and filter jumps to the two ends of the secondary winding of described transformer, and the output of described output rectifier and filter is as the main road supply voltage output of described switching power circuit; Described rectification reduction voltage circuit has at least one rectification step-down branch road; The input of each described rectification step-down branch road connects the output of described output rectifier and filter, and the output of described rectification step-down branch road is as the bypass supply voltage output of described switching power circuit.
In one alternate embodiment, described rectification step-down branch road comprises forward and is connected on N number of diode on described rectification step-down branch road; N be more than or equal to 1 integer.
In one alternate embodiment, described rectification step-down branch road comprises low pressure difference linear voltage regulator; The input of described low pressure difference linear voltage regulator is the input of described rectification step-down branch road, the ground end ground connection of described low pressure difference linear voltage regulator; The output of described low pressure difference linear voltage regulator is the output of described rectification step-down branch road.
In one alternate embodiment, described rectification step-down branch road comprises voltage-dropping type DC/DC pressurizer; The input of described voltage-dropping type DC/DC pressurizer is the input of described rectification step-down branch road, the ground end ground connection of described voltage-dropping type DC/DC pressurizer; The output of described voltage-dropping type DC/DC pressurizer is the output of described rectification step-down branch road.
In one alternate embodiment, described rectification step-down branch road comprises the first diode and the first electric capacity; The positive pole of described first diode is connected to the output of described output rectifier and filter, and negative pole is connected to the positive pole of described first electric capacity, and as the output of described rectification step-down branch road; The minus earth of described first electric capacity.
More preferably, described switching power circuit also comprises charging resistor; The output of described input rectifying filter circuit is connected to the positive pole of described first electric capacity by described charging resistor; And the positive pole of described first electric capacity is connected to the power end of described pwm control circuit.
More preferably, described output rectifier and filter comprises the second diode and the second electric capacity; Be connected across the two ends of the secondary winding of described transformer after described second diode and described second capacitances in series, and the junction of described second diode and described second electric capacity is as the output of described output rectifier and filter; The minus earth of described second electric capacity.
More preferably, described pwm control circuit comprises PWM chip and field effect transistor; The power end of described PWM chip is the power end of described pwm control circuit; The grid of described field effect transistor is connected to the output of described PWM chip, the source ground of described field effect transistor, and the drain electrode of described field effect transistor is the output of described pwm control circuit.
More preferably, described field effect transistor is the field effect transistor with parasitic diode.Described parasitic diode can prevent the source electrode of field effect transistor and drain electrode from connecing and inverse time burn out field effect transistor, also can, when circuit has reverse induced potential, for reverse induced potential provides path, avoid reverse induced potential to puncture field effect transistor.
More preferably, described switching power circuit also comprises feedback circuit; The input of described feedback circuit connects the output of described output rectifier and filter; The output of described feedback circuit connects the feedback signal input terminal of described pwm control circuit.
Compared to prior art, the beneficial effect of a kind of switching power circuit of the present utility model is: only need a secondary winding in the transformer T1 of switching power circuit of the present utility model, namely can realize the output of multiple power supplies voltage.Specifically at secondary winding two ends access output rectifier and filter, the output of described output rectifier and filter accesses a rectification reduction voltage circuit again; Described rectification reduction voltage circuit has the rectification step-down branch road that can export different electrical power voltage.Because secondary winding only has the output that namely can realize multiple power supplies, cost can be saved; Simplify technique to make, improve qualitative reliability; Conduct radiation source is reduced, and reduces conduct radiation, improves Electro Magnetic Compatibility.Described switching power circuit is applicable to air-conditioning etc. to be needed in the household appliances of different operating supply voltage.
Accompanying drawing explanation
Fig. 1 is the structural representation of a kind of switching power circuit of prior art;
Fig. 2 is the structural representation of a kind of switching power circuit of the utility model embodiment.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, be clearly and completely described the technical scheme in the utility model embodiment, obviously, described embodiment is only the utility model part embodiment, instead of whole embodiments.Based on the embodiment in the utility model, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the utility model protection.
Refer to Fig. 2, it is the structural representation of a kind of switching power circuit of the utility model embodiment.Described switching power circuit comprises input rectifying filter circuit 11, transformer T1, output rectifier and filter 12, rectification reduction voltage circuit 13 and pwm control circuit 14; Described input rectifying filter circuit 11 is connected to the control signal output of described pwm control circuit 14 by the armature winding of described transformer T1; Described output rectifier and filter 12 jumps to the two ends of the secondary winding of described transformer T1, and the output of described output rectifier and filter 12 is as the main road supply voltage output Vp of described switching power circuit; Described rectification reduction voltage circuit 13 has at least one rectification step-down branch road; The input of each described rectification step-down branch road connects the output of described output rectifier and filter 12, and the output of described rectification step-down branch road is as the bypass supply voltage output of described switching power circuit.
Wherein, described output rectifier and filter 12 comprises the second diode D2 and the second electric capacity C2; Be connected across the two ends of the secondary winding of described transformer T1 after described second diode D2 and described second electric capacity C2 connects, and the junction of described second diode D2 and described second electric capacity C2 is as the output of described output rectifier and filter 12; The minus earth of described second electric capacity C2.
In an optional embodiment, described rectification step-down branch road comprises forward and is connected on N number of diode on described rectification step-down branch road; N be more than or equal to 1 integer.Each diode plays the effect of step-down and rectification, is equivalent to the magnitude of voltage exporting the N*1.5V that declines again on the basis of main road supply voltage Vp.
In an optional embodiment, described rectification step-down branch road comprises low pressure difference linear voltage regulator (LDO, low dropout regulator); The input of described low pressure difference linear voltage regulator is the input of described rectification step-down branch road, the ground end ground connection of described low pressure difference linear voltage regulator; The output of described low pressure difference linear voltage regulator is the output of described rectification step-down branch road.
In an optional embodiment, described rectification step-down branch road comprises voltage-dropping type DC/DC pressurizer; The input of described voltage-dropping type DC/DC (DC-DC) pressurizer is the input of described rectification step-down branch road, the ground end ground connection of described voltage-dropping type DC/DC pressurizer; The output of described voltage-dropping type DC/DC pressurizer is the output of described rectification step-down branch road.
In an optional embodiment, described rectification step-down branch road comprises the first diode D1 and the first electric capacity C1; The positive pole of described first diode D1 is connected to the output of described output rectifier and filter 12, and negative pole is connected to the positive pole of described first electric capacity C1, and as the output of described rectification step-down branch road; The minus earth of described first electric capacity C1.
In the present embodiment, described rectification reduction voltage circuit 13 has three rectification step-down branch roads, and namely described rectification reduction voltage circuit 13 can export the bypass supply voltage on three tunnels.Wherein, in first rectification step-down branch road, comprise the 3rd diode D3 and the 4th diode D4; The input of just very this first rectification step-down branch road of described 3rd diode D3; The positive pole of described 4th diode D4 is connected with the negative pole of described 3rd diode D3; The negative pole of described 4th diode D4 is the output of described rectification step-down branch road, exports first bypass supply voltage Vaux1.In second rectification step-down branch road, comprise a low pressure difference linear voltage regulator LDO; The input of described low pressure difference linear voltage regulator LDO is the input of this second rectification step-down branch road, the ground end ground connection of described low pressure difference linear voltage regulator LDO; The output of described low pressure difference linear voltage regulator LDO is the output of this second rectification step-down branch road, exports second bypass supply voltage Vaux2.In the 3rd rectification step-down branch road, comprise the first diode D1 and the first electric capacity C1; The positive pole of described first diode D1 is connected to the output of described output rectifier and filter 12, and negative pole is connected to the positive pole of described first electric capacity C1, and as the output of the 3rd rectification step-down branch road, exports the 3rd bypass supply voltage Vaux3; The minus earth of described first electric capacity C1.
As more preferably, described switching power circuit also comprises charging resistor R1; The output of described input rectifying filter circuit 11 is connected to the positive pole of described first electric capacity C1 by described charging resistor R1; And the positive pole of described first electric capacity C1 is connected to the power end of described pwm control circuit 14.Namely the 3rd bypass supply voltage is used for powering to described pwm control circuit 14.Described charging resistor R1 is used for charging to described first electric capacity C1 when circuit starts.
As more preferably, described pwm control circuit 14 comprises PWM chip and field effect transistor FET; The power end of described PWM chip is the power end of described pwm control circuit 14; The grid of described field effect transistor FET is connected to the output of described PWM chip, the source ground of described field effect transistor FET, and the drain electrode of described field effect transistor FET is the output of described pwm control circuit 14.
As more preferably, described field effect transistor FET is the field effect transistor with parasitic diode.Described parasitic diode can prevent the source electrode of field effect transistor FET and drain electrode from connecing and inverse time burn out field effect transistor, also can, when circuit has reverse induced potential, for reverse induced potential provides path, avoid reverse induced potential to puncture field effect transistor FET.
As more preferably, described switching power circuit also comprises feedback circuit 15; The input of described feedback circuit 15 connects the output of described output rectifier and filter 12; The output of described feedback circuit 15 connects the feedback signal input terminal of described pwm control circuit 14.
The operation principle of switching power circuit of the present utility model is as follows: when starting to power on, owing to not reaching the operating voltage of described pwm control circuit 14, so the voltage that described input rectifying filtering exports charges to described first electric capacity C1 through described charging resistor R1; Now described first diode D1 plays the effect of isolation, and charging current can not be flow in the circuit of transformer T1 level.When described first electric capacity C1 charges until described pwm control circuit 14 reaches operating voltage, described pwm control circuit 14 normally works.AC power is converted to direct voltage after the rectifying and wave-filtering of described input rectifying filter circuit 11, through the conversion of transformer T1 transformation, then after described output rectifier and filter 12 the main road supply voltage of output smoothing; Meanwhile, the rectification step-down branch road of main road supply voltage Vp through three tunnels of output obtains different bypass supply voltages, and wherein the bypass supply voltage Vaux3 on the 3rd tunnel supplies described pwm control circuit 14 and works, and thus whole Switching Power Supply reaches stable state.In the present embodiment, described transformer T1 only has a secondary winding, just can export a road main road supply voltage Vp and three road bypass supply voltages, exports four-way power supply supply voltage altogether.
Compared to prior art, the beneficial effect of a kind of switching power circuit of the present utility model is: only need a secondary winding in the transformer T1 of switching power circuit of the present utility model, namely can realize the output of multiple power supplies voltage.Specifically at secondary winding two ends access output rectifier and filter 12, the output of described output rectifier and filter 12 accesses a rectification reduction voltage circuit 13 again; Described rectification reduction voltage circuit 13 has the rectification step-down branch road that can export different electrical power voltage.Because secondary winding only has the output that namely can realize multiple power supplies, cost can be saved; Simplify technique to make, improve qualitative reliability; Conduct radiation source is reduced, and reduces conduct radiation, improves Electro Magnetic Compatibility.
The above is preferred implementation of the present utility model; it should be pointed out that for those skilled in the art, under the prerequisite not departing from the utility model principle; can also make some improvements and modifications, these improvements and modifications are also considered as protection range of the present utility model.
Claims (10)
1. a switching power circuit, is characterized in that, comprises input rectifying filter circuit, transformer, output rectifier and filter, rectification reduction voltage circuit and pwm control circuit; Described input rectifying filter circuit is connected to the control signal output of described pwm control circuit by the armature winding of described transformer; Described output rectifier and filter jumps to the two ends of the secondary winding of described transformer, and the output of described output rectifier and filter is as the main road supply voltage output of described switching power circuit; Described rectification reduction voltage circuit has at least one rectification step-down branch road; The input of each described rectification step-down branch road connects the output of described output rectifier and filter, and the output of described rectification step-down branch road is as the bypass supply voltage output of described switching power circuit.
2. switching power circuit as claimed in claim 1, is characterized in that, described rectification step-down branch road comprises forward and is connected on N number of diode on described rectification step-down branch road; N be more than or equal to 1 integer.
3. switching power circuit as claimed in claim 1, it is characterized in that, described rectification step-down branch road comprises low pressure difference linear voltage regulator; The input of described low pressure difference linear voltage regulator is the input of described rectification step-down branch road, the ground end ground connection of described low pressure difference linear voltage regulator; The output of described low pressure difference linear voltage regulator is the output of described rectification step-down branch road.
4. switching power circuit as claimed in claim 1, it is characterized in that, described rectification step-down branch road comprises voltage-dropping type DC/DC pressurizer; The input of described voltage-dropping type DC/DC pressurizer is the input of described rectification step-down branch road, the ground end ground connection of described voltage-dropping type DC/DC pressurizer; The output of described voltage-dropping type DC/DC pressurizer is the output of described rectification step-down branch road.
5. switching power circuit as claimed in claim 1, it is characterized in that, described rectification step-down branch road comprises the first diode and the first electric capacity; The positive pole of described first diode is connected to the output of described output rectifier and filter, and negative pole is connected to the positive pole of described first electric capacity, and as the output of described rectification step-down branch road; The minus earth of described first electric capacity.
6. switching power circuit as claimed in claim 5, it is characterized in that, described switching power circuit also comprises charging resistor; The output of described input rectifying filter circuit is connected to the positive pole of described first electric capacity by described charging resistor; And the positive pole of described first electric capacity is connected to the power end of described pwm control circuit.
7. the switching power circuit as described in claim as arbitrary in claim 1-6, is characterized in that, described output rectifier and filter comprises the second diode and the second electric capacity; Be connected across the two ends of the secondary winding of described transformer after described second diode and described second capacitances in series, and the junction of described second diode and described second electric capacity is as the output of described output rectifier and filter; The minus earth of described second electric capacity.
8. switching power circuit as claimed in claim 7, it is characterized in that, described pwm control circuit comprises PWM chip and field effect transistor; The power end of described PWM chip is the power end of described pwm control circuit; The grid of described field effect transistor is connected to the output of described PWM chip, the source ground of described field effect transistor, and the drain electrode of described field effect transistor is the output of described pwm control circuit.
9. switching power circuit as claimed in claim 8, it is characterized in that, described field effect transistor is the field effect transistor with parasitic diode.
10. switching power circuit as claimed in claim 1, it is characterized in that, described switching power circuit also comprises feedback circuit; The input of described feedback circuit connects the output of described output rectifier and filter; The output of described feedback circuit connects the feedback signal input terminal of described pwm control circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520324353.7U CN204597781U (en) | 2015-05-18 | 2015-05-18 | A kind of switching power circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520324353.7U CN204597781U (en) | 2015-05-18 | 2015-05-18 | A kind of switching power circuit |
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| CN204597781U true CN204597781U (en) | 2015-08-26 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111769751A (en) * | 2020-05-15 | 2020-10-13 | 海信（山东）空调有限公司 | Direct current power supply circuit and air conditioner |
| TWI777736B (en) * | 2021-01-13 | 2022-09-11 | 立錡科技股份有限公司 | Buck-boost switching regulator having bypass mode and control method thereof |
-
2015
- 2015-05-18 CN CN201520324353.7U patent/CN204597781U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111769751A (en) * | 2020-05-15 | 2020-10-13 | 海信（山东）空调有限公司 | Direct current power supply circuit and air conditioner |
| TWI777736B (en) * | 2021-01-13 | 2022-09-11 | 立錡科技股份有限公司 | Buck-boost switching regulator having bypass mode and control method thereof |
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