CN101577492B - Power supply circuit - Google Patents
Power supply circuit Download PDFInfo
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- CN101577492B CN101577492B CN2008100669689A CN200810066968A CN101577492B CN 101577492 B CN101577492 B CN 101577492B CN 2008100669689 A CN2008100669689 A CN 2008100669689A CN 200810066968 A CN200810066968 A CN 200810066968A CN 101577492 B CN101577492 B CN 101577492B
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Abstract
The invention provides a power supply circuit which comprises an AC-DC converting circuit, an impulse width modulation controller, a switching transistor, a transformer, a rectifying and filtering circuit and an over-voltage protection circuit, wherein under the control of the impulse width modulation controller and the switching transistor, exterior alternating voltage sequentially passes throughthe AC-DC converting circuit, the transformer and the rectifying and filtering circuit and is converted into DC voltage; and the over-voltage protection circuit is arranged between the rectifying and filtering circuit and the impulse width modulation controller. The reliability of the power supply circuit is higher.
Description
Technical field
The present invention relates to a kind of power circuit.
Background technology
See also Fig. 1, it is a kind of circuit diagram of power circuit of prior art.This power circuit 10 mainly comprises an AC-DC (AC-DC) change-over circuit 11, a PWM controller 12, a switching transistor 13, a transformer 14, a current rectifying and wave filtering circuit 15 and a feedback circuit 16.This current rectifying and wave filtering circuit 15 comprises one first output 151 and one second output 152.This AC-DC change-over circuit 11 is used for extraneous alternating voltage is converted to direct voltage, this PWM controller 12 is used for opening or closing this switching transistor 13, and this feedback circuit 16 is used for the output voltage of this current rectifying and wave filtering circuit 15 is fed back to this PWM controller 12.Under the control of this PWM controller 12 and this switching transistor 13, extraneous alternating voltage changes a 16V direct voltage and a 5V direct voltage into by this AC-DC change-over circuit 11, this transformer 14 and this current rectifying and wave filtering circuit 15 successively, respectively from this first output 151 and 152 outputs of this second output.
This first output 151 and this second output 152 are connected with a load circuit respectively.This first output 151 provides 16V direct voltage for load circuit, and this second output 152 provides 5V direct voltage for load circuit.
When a certain load circuit broke down, the output voltage of connected output can raise, and the electric current in this power circuit 10 can corresponding increase.This power circuit 10 and load circuit have the danger of being burnt.So the reliability of this power circuit 10 is lower.
Summary of the invention
In order to solve the lower problem of power circuit reliability in the prior art, the invention provides the higher power circuit of a kind of reliability.
A kind of power circuit, it comprises an AC-DC change-over circuit, a PWM controller, a switching transistor, a transformer, a current rectifying and wave filtering circuit and an overvoltage crowbar.Under the control of this PWM controller and this switching transistor; extraneous alternating voltage is successively by this AC-DC change-over circuit; this transformer and this current rectifying and wave filtering circuit change direct voltage into; this overvoltage crowbar is arranged between this current rectifying and wave filtering circuit and this PWM controller; this overvoltage crowbar comprises a sample circuit; one buffer circuit and a control circuit; this sample circuit is used for the output voltage of this power circuit is sampled; when the output voltage of this power circuit during greater than its rated value; this buffer circuit conducting also is sent to this control circuit with the sampled voltage of this sample circuit; this PWM controller of the corresponding control of this control circuit quits work; this current rectifying and wave filtering circuit comprises a rectification output end; one first output and one second output; this rectification output end is connected with this second output by an inductance; this PWM controller comprises a power port; this control circuit comprises one first resistance; one second resistance and a first transistor; this buffer circuit comprises one the 3rd resistance; one transistor seconds and an optical coupler; this sample circuit comprises one the 4th resistance; one first voltage stabilizing didoe and one second voltage stabilizing didoe; this optical coupler comprises a phototransistor and a light-emitting diode; the control utmost point of this first transistor is connected with the power port of this PWM controller by this first resistance; the control utmost point of this first transistor is simultaneously by this second grounding through resistance; its second conduction utmost point is connected with the power port of this PWM controller; its first conduction utmost point ground connection; one end of the phototransistor of this optical coupler is connected with the control utmost point of this first transistor; its other end ground connection; the anode of the light-emitting diode of this optical coupler is connected with the rectification output end of this current rectifying and wave filtering circuit by the 3rd resistance; its negative electrode is connected with the second conduction utmost point of this transistor seconds; the control utmost point of this transistor seconds is by the 4th grounding through resistance; its first conduction utmost point ground connection; the anode of this first voltage stabilizing didoe is connected with the control utmost point of this transistor seconds; its negative electrode is connected with first output of this current rectifying and wave filtering circuit; the anode of this second voltage stabilizing didoe is connected with the control utmost point of this transistor seconds, and its negative electrode is connected with second output of this current rectifying and wave filtering circuit.
Compared with prior art; power circuit of the present invention has adopted this overvoltage crowbar; this overvoltage crowbar is arranged between this current rectifying and wave filtering circuit and this PWM controller; when the direct voltage of this current rectifying and wave filtering circuit output during greater than its rated value; this PWM controller of the corresponding control of this overvoltage crowbar quits work; promptly this overvoltage crowbar is controlled this power circuit at the output voltage of this power circuit during greater than its rated value and is quit work, thereby realizes over-voltage protecting function.Therefore, the reliability of this power circuit is higher.
Description of drawings
Fig. 1 is a kind of circuit diagram of power circuit of prior art.
Fig. 2 is the circuit diagram of power circuit one better embodiment of the present invention.
Embodiment
See also Fig. 2, it is the circuit diagram of power circuit one better embodiment of the present invention.This power circuit 20 mainly comprises an AC-DC change-over circuit 21, a PWM controller 22, a switching transistor 23, a transformer 24, a current rectifying and wave filtering circuit 25, a feedback circuit 26 and an overvoltage crowbar 27.This current rectifying and wave filtering circuit 25 comprises a rectification output end 250, one first output 251 and one second output 252, and this rectification output end 250 is connected with this second output 252 by an inductance (not indicating) and a fuse (not indicating).This AC-DC change-over circuit 21 is used for extraneous alternating voltage is converted to direct voltage, and this PWM controller 22 is used for opening or closing this switching transistor 23.This PWM controller 22 comprises a power port VCC, when this power port VCC receives a 5V direct voltage, and these PWM controller 22 operate as normal.This feedback circuit 26 is used for the output voltage of this current rectifying and wave filtering circuit 25 is fed back to this PWM controller 22.Under the control of this PWM controller 22 and this switching transistor 23, extraneous alternating voltage changes a 16V direct voltage and a 5V direct voltage into by this AC-DC change-over circuit 21, this transformer 24 and this current rectifying and wave filtering circuit 25 successively, respectively from this first output 251 and 252 outputs of this second output.
This overvoltage crowbar 27 comprises a sample circuit (not indicating), a buffer circuit (not indicating) and a control circuit (not indicating).This sample circuit is used for this first output 251 and the output voltage of this second output 252 are sampled.When the output voltage of this first output 251 and this second output 252 during greater than its rated value, this buffer circuit conducting also is sent to this control circuit with the sampled voltage of this sample circuit, and this PWM controller 22 of the corresponding control of this control circuit quits work.This control circuit comprises one first resistance R 1, one second resistance R 2 and a first transistor T1.This buffer circuit comprises one the 3rd resistance R 3, a transistor seconds T2 and an optical coupler 270.This sample circuit comprises one the 4th resistance R 4, one first voltage stabilizing didoe ZD1 and one second voltage stabilizing didoe ZD2.This first transistor T1 is a P type channel mos field-effect transistor, and this transistor seconds T2 is a npn type bipolar transistor.The voltage stabilizing value of this first voltage stabilizing didoe ZD1 is 15.4V, and the voltage stabilizing value of this second voltage stabilizing didoe ZD2 is 4.4V.This optical coupler 270 comprises a phototransistor 271 and a light-emitting diode 272.
The grid of this first transistor T1 is connected with the power port VCC of this PWM controller 22 by this first resistance R 1, the grid of this first transistor T1 is simultaneously by these second resistance R, 2 ground connection, its drain electrode is connected its source ground by a resistance (not indicating) with the power port VCC of this PWM controller 22.One end of the phototransistor 271 of this optical coupler 270 is connected with the grid of this first transistor T1, its other end ground connection.The anode of the light-emitting diode 272 of this optical coupler 270 is connected with the rectification output end 250 of this current rectifying and wave filtering circuit 25 by the 3rd resistance R 3, and its negative electrode is connected with the collector electrode of this transistor seconds T2.The base stage of this transistor seconds T2 is by the 4th resistance R 4 ground connection, its grounded emitter.The anode of this first voltage stabilizing didoe ZD1 is connected with the base stage of this transistor seconds T2, and its negative electrode is connected with first output 251 of this current rectifying and wave filtering circuit 25.The anode of this second voltage stabilizing didoe ZD2 is connected with the base stage of this transistor seconds T2, and its negative electrode is connected with second output 252 of this current rectifying and wave filtering circuit 25.
This first output 251 and this second output 252 are connected with a load circuit (figure does not show) respectively.This first output 251 provides 16V direct voltage for load circuit, and this second output 252 provides 5V direct voltage for load circuit.
When each load circuit operate as normal, the output voltage of this first output 251 is no more than 16V, and the output voltage of this second output 252 is no more than 5V.The corresponding 0.6V that is no more than of the voltage of the 4th resistance R 4, this transistor seconds T2 ends.The grid of this first transistor T1 is a high level, and this first transistor T1 ends.At this moment, this overvoltage crowbar 27 is inoperative.
When a certain load circuit broke down, the output voltage of connected first output 251 or second output 252 can raise.When the output voltage of this first output 251 greater than the output voltage of its rated value (16V) or this second output 252 during greater than its rated value (5V), the voltage of the 4th resistance R 4 is corresponding to 0.6V, this transistor seconds T2 conducting.At this moment, this rectification output end 250, the 3rd resistance R 3, this light-emitting diode 272, this transistor seconds T2 constitute a conductive path, and this light-emitting diode 272 is started working, the also corresponding conducting state that is in of this phototransistor 271.At this moment, the grid of this first transistor T1 by this phototransistor 271 by drop-down be low level, this first transistor T1 conducting.The power port VCC of this PWM controller 22 by this first transistor T1 by drop-down be low level, this PWM controller 22 quits work, these power circuit 20 corresponding quitting work.
Compared with prior art; power circuit 20 of the present invention is because adopted this overvoltage crowbar 27; when the output voltage of this first output 251 greater than the output voltage of 16V or this second output 252 during greater than 5V; this PWM controller 22 quits work; this power circuit 20 is also corresponding to quit work, thereby realizes over-voltage protecting function.Therefore, the reliability of this power circuit 20 is higher.
Claims (7)
1. power circuit; it comprises an AC-DC change-over circuit; one PWM controller; one switching transistor; one transformer and a current rectifying and wave filtering circuit; under the control of this PWM controller and this switching transistor; extraneous alternating voltage is successively by this AC-DC change-over circuit; this transformer and this current rectifying and wave filtering circuit change direct voltage into; it is characterized in that: this power circuit also comprises an overvoltage crowbar; this overvoltage crowbar is arranged between this current rectifying and wave filtering circuit and this PWM controller; this overvoltage crowbar comprises a sample circuit; one buffer circuit and a control circuit; this sample circuit is used for the output voltage of this power circuit is sampled; when the output voltage of this power circuit during greater than its rated value; this buffer circuit conducting also is sent to this control circuit with the sampled voltage of this sample circuit; this PWM controller of the corresponding control of this control circuit quits work; this current rectifying and wave filtering circuit comprises a rectification output end; one first output and one second output; this rectification output end is connected with this second output by an inductance; this PWM controller comprises a power port; this control circuit comprises one first resistance; one second resistance and a first transistor; this buffer circuit comprises one the 3rd resistance; one transistor seconds and an optical coupler; this sample circuit comprises one the 4th resistance; one first voltage stabilizing didoe and one second voltage stabilizing didoe; this optical coupler comprises a phototransistor and a light-emitting diode; the control utmost point of this first transistor is connected with the power port of this PWM controller by this first resistance; the control utmost point of this first transistor is simultaneously by this second grounding through resistance; its second conduction utmost point is connected with the power port of this PWM controller; its first conduction utmost point ground connection; one end of the phototransistor of this optical coupler is connected with the control utmost point of this first transistor; its other end ground connection; the anode of the light-emitting diode of this optical coupler is connected with the rectification output end of this current rectifying and wave filtering circuit by the 3rd resistance; its negative electrode is connected with the second conduction utmost point of this transistor seconds; the control utmost point of this transistor seconds is by the 4th grounding through resistance; its first conduction utmost point ground connection; the anode of this first voltage stabilizing didoe is connected with the control utmost point of this transistor seconds; its negative electrode is connected with first output of this current rectifying and wave filtering circuit; the anode of this second voltage stabilizing didoe is connected with the control utmost point of this transistor seconds, and its negative electrode is connected with second output of this current rectifying and wave filtering circuit.
2. power circuit as claimed in claim 1, it is characterized in that: this first transistor is a metal oxide semiconductcor field effect transistor, its control utmost point i.e. the grid of this metal oxide semiconductcor field effect transistor, its first conduction utmost point i.e. the source electrode of this metal oxide semiconductcor field effect transistor, its i.e. drain electrode of this metal oxide semiconductcor field effect transistor of second conduction utmost point.
3. power circuit as claimed in claim 2 is characterized in that: this first transistor is a P type channel mos field-effect transistor.
4. power circuit as claimed in claim 1, it is characterized in that: this transistor seconds is a bipolar transistor, its control utmost point i.e. the base stage of this bipolar transistor, and its first conduction utmost point i.e. the emitter of this bipolar transistor, and its second conduction utmost point i.e. the collector electrode of this bipolar transistor.
5. power circuit as claimed in claim 4 is characterized in that: this first transistor is a npn type bipolar transistor.
6. power circuit as claimed in claim 1 is characterized in that: the voltage stabilizing value of this first voltage stabilizing didoe is 15.4V, and the voltage stabilizing value of this second voltage stabilizing didoe is 4.4V.
7. power circuit as claimed in claim 1 is characterized in that: this current rectifying and wave filtering circuit also comprises a fuse, and this fuse is serially connected between this inductance and this second output.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008100669689A CN101577492B (en) | 2008-05-07 | 2008-05-07 | Power supply circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008100669689A CN101577492B (en) | 2008-05-07 | 2008-05-07 | Power supply circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101577492A CN101577492A (en) | 2009-11-11 |
| CN101577492B true CN101577492B (en) | 2011-06-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008100669689A Expired - Fee Related CN101577492B (en) | 2008-05-07 | 2008-05-07 | Power supply circuit |
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| Country | Link |
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| CN (1) | CN101577492B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109510458A (en) * | 2017-09-12 | 2019-03-22 | 株洲中车时代电气股份有限公司 | Boost filter |
| CN107861417B (en) * | 2017-10-23 | 2020-08-04 | 天津市英贝特航天科技有限公司 | Rail transit output signal control system |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2096775U (en) * | 1991-06-19 | 1992-02-19 | 机电部北京电工综合技术经济研究所 | Efficiency high-pow switch power using mosfet |
| CN2225109Y (en) * | 1994-11-28 | 1996-04-17 | 国营成都宏明无线电器材总厂 | Switch DC-DC inverter |
| CN1255771A (en) * | 1998-11-19 | 2000-06-07 | 横河电机株式会社 | Switch power source |
| US6094362A (en) * | 1998-04-01 | 2000-07-25 | Compaq Computer Corporation | Switched-mode power converter with triple protection in a single latch |
| CN2518260Y (en) * | 2001-08-13 | 2002-10-23 | 周立峰 | High voltage and frequency pulse d.c. generator |
-
2008
- 2008-05-07 CN CN2008100669689A patent/CN101577492B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2096775U (en) * | 1991-06-19 | 1992-02-19 | 机电部北京电工综合技术经济研究所 | Efficiency high-pow switch power using mosfet |
| CN2225109Y (en) * | 1994-11-28 | 1996-04-17 | 国营成都宏明无线电器材总厂 | Switch DC-DC inverter |
| US6094362A (en) * | 1998-04-01 | 2000-07-25 | Compaq Computer Corporation | Switched-mode power converter with triple protection in a single latch |
| CN1255771A (en) * | 1998-11-19 | 2000-06-07 | 横河电机株式会社 | Switch power source |
| CN2518260Y (en) * | 2001-08-13 | 2002-10-23 | 周立峰 | High voltage and frequency pulse d.c. generator |
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| Publication number | Publication date |
|---|---|
| CN101577492A (en) | 2009-11-11 |
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