CN101572491B - Switch power circuit and operation method thereof - Google Patents
Switch power circuit and operation method thereof Download PDFInfo
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- CN101572491B CN101572491B CN200810066691XA CN200810066691A CN101572491B CN 101572491 B CN101572491 B CN 101572491B CN 200810066691X A CN200810066691X A CN 200810066691XA CN 200810066691 A CN200810066691 A CN 200810066691A CN 101572491 B CN101572491 B CN 101572491B
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Abstract
The invention relates to a switch power circuit which comprises a direct voltage input end, a switch control circuit, a rectifying and wave-filtering circuit, a transformer, a capacitor, a first resistor, a second resistor, a first transistor and a parasitic diode, wherein a grid pole of the first transistor is grounded by the first resistor, a source pole is grounded by the switch control circuit, a drain pole is connected to the direct voltage input end by the capacitor and also connected to the grid pole of the first transistor by the second resistor, the positive pole of the parasitic diode is connected with the source pole of the first transistor, and the negative pole is connected with the drain pole of the first transistor ; the transformer comprises a primary winding and a secondary winding; the direct voltage input end is grounded by the primary winding and the switch control circuit; and the secondary winding supplies voltage to a load by the rectifying and wave-filtering circuit. The switch power circuit has higher efficiency. The invention also provides a method for operating the switch power circuit.
Description
Technical field
The invention relates to a kind of switching power circuit and How It Works thereof, refer to switching power circuit and How It Works thereof that a kind of efficient is higher especially.
Background technology
Switching power circuit has characteristics such as loss is little, conversion efficiency is high, linear change is little, working stability, therefore is widely used in display device and other consumption electronic products such as LCD TV, cathode-ray tube TV.
See also Fig. 1, it is a kind of schematic diagram of prior art switching power circuit.This switching power circuit 10 comprises that one first current rectifying and wave filtering circuit 11, one second current rectifying and wave filtering circuit 12, absorb circuit 13, a transformer 14, an ON-OFF control circuit 15, one first rectifier diode 16.
This first current rectifying and wave filtering circuit 11 comprises a full bridge rectifier 111, one first filter capacitor 112, two inputs 113,114 and outputs 115.These two inputs 113,114 are used to receive external communication voltage.It is direct voltage that this full bridge rectifier 111 is used for this external communication voltage transitions.These first filter capacitor, 112 1 end ground connection, the other end is connected to this output 115.
This transformer 14 comprises an elementary winding 141, an auxiliary winding 142 and a level winding 143.This elementary winding 141 is in parallel with this absorption circuit 13.This elementary winding 141 comprises a end and b end, and its a end is connected to the output 115 of this first current rectifying and wave filtering circuit 11, and b holds via these ON-OFF control circuit 15 ground connection.This secondary winding 143 comprises c end and d end.
This second current rectifying and wave filtering circuit 12 comprises an inductance 121, a storage capacitor 122, one second filter capacitor 123, one second rectifier diode 124 and a direct current voltage output end 125.The anode of this second rectifier diode 124 (not label) is connected to the c end of this secondary winding 143, and negative electrode (not label) is connected to this dc voltage output end 125 via this inductance 121, also via these storage capacitor 122 ground connection.These second filter capacitor, 123 1 end ground connection, the other end is connected to this dc voltage output end 125.
This ON-OFF control circuit 15 comprises a pulse width modulating chip 151 and a transistor 152.This pulse width modulating chip 151 comprises a voltage input end 153 and a control end 154.Should assist winding 142 1 ends in regular turn via the anode (not label) of this first rectifier diode 16, the voltage input end 153 that negative electrode (not label) is connected to this pulse width modulating chip 151, these auxiliary winding 142 other end ground connection.
This transistor 152 is a N channel enhancement mos field effect transistor (N-Channel Enhancement Mode Metal-Oxide-Semiconductor Field-Effect Transistor, NMOSFET), its grid (not label) is connected to the control end 154 of this pulse width modulating chip 151, source electrode (not label) is via a grounding through resistance, and drain electrode (not label) is connected to the b end of this elementary winding 141.
The How It Works of this switching power circuit 10 is as follows:
External communication voltage inputs to two inputs 113,114 of this first current rectifying and wave filtering circuit 11, by output dc voltage after these first current rectifying and wave filtering circuit, 11 rectifications, the filtering, and offers the elementary winding 141 of this transformer 14.Should produce induced electromotive force by auxiliary winding 142, and provide its required direct-current working volts for this pulse width modulating chip 151 by this first rectifier diode 16.The control end 154 of this pulse width modulating chip 151 sends pulse signal controlling the switch of this transistor 152, thereby controls the work of this transformer 14.
When the first conducting of this transistor 152, this first filter capacitor 112, this elementary winding 141 constitute a loop with this transistor 152, this elementary winding 141 has electric current I to flow through, produce the electromotive force that an a terminal voltage is higher than the b terminal voltage, this secondary winding 143 produces the induced electromotive force that a c terminal voltage is higher than the d terminal voltage, these second rectifier diode, 124 conductings this moment, this secondary winding 143 is via these inductance 121 output dc voltages.
When this transistor 152 ends, the electric current I of this elementary winding 141 absorbs circuit 13 by this and absorbs, electric current I diminishes gradually, because the characteristic of inductance itself, the electromotive force of this elementary winding 141 is reverse, its b terminal voltage is higher than a terminal voltage, makes this secondary winding 143 produce the induced electromotive force that a d terminal voltage is higher than the c terminal voltage, and this moment, this second rectifier diode 124 ended.
Since this transistor 152 by the time, this absorbs the electric current I that circuit 13 will this elementary winding 141 and absorbs, and no longer utilize the electric current I output dc voltage of this elementary winding 141 at this moment, so the efficient of this switching power circuit 10 is lower.
Summary of the invention
In order to solve the lower problem of prior art switch power efficiency, be necessary the switching power circuit that provides a kind of efficient higher.
Also be necessary to provide a kind of How It Works of above-mentioned switching power circuit.
A kind of switching power circuit, it comprises a direct current voltage input end, an ON-OFF control circuit, a current rectifying and wave filtering circuit, a transformer, an electric capacity, one first resistance, one second resistance, a first transistor and a parasitic diode.The grid of this first transistor is via this first grounding through resistance, source electrode is via this ON-OFF control circuit ground connection, drain electrode is connected to this dc voltage input end via this electric capacity, also be connected to its grid via this second resistance, the positive pole of this parasitic diode links to each other with the source electrode of the first transistor, and negative electrode links to each other with the drain electrode of the first transistor.This transformer comprises an elementary winding and a level winding.This dc voltage input end is via this elementary winding and this ON-OFF control circuit ground connection.This secondary winding provides voltage via this current rectifying and wave filtering circuit to load.
A kind of How It Works of above-mentioned switching power circuit, it comprises the steps: this ON-OFF control circuit conducting of a., the elementary winding of this transformer produces one first electromotive force, this secondary winding produces one first induced electromotive force, and this first induced electromotive force provides voltage via this current rectifying and wave filtering circuit to load; B. this ON-OFF control circuit disconnects, the elementary winding of this transformer charges to this electric capacity via this parasitic diode, when this first transistor conducting, this electric capacity is the elementary winding discharge of this transformer, the elementary winding of this transformer produces one second electromotive force, this secondary winding produces one second induced electromotive force, and this second induced electromotive force provides voltage via this current rectifying and wave filtering circuit to load.
Compared to prior art, when the ON-OFF control circuit of switching power circuit of the present invention is ended, this primary winding can charge to this electric capacity via this parasitic diode, this capacitor discharge and transfer to this Secondary winding of transformer then, therefore the electric current of the elementary winding of this transformer is fully utilized, and the efficient of this switching power circuit is higher.
Description of drawings
Fig. 1 is a kind of schematic diagram of prior art switching power circuit.
Fig. 2 is the schematic diagram of switching power circuit first execution mode of the present invention.
Fig. 3 is the schematic diagram of switching power circuit second execution mode of the present invention.
Embodiment
See also Fig. 2, it is the schematic diagram of switching power circuit first execution mode of the present invention.This switching power circuit 20 comprises one first current rectifying and wave filtering circuit 21, one second current rectifying and wave filtering circuit 22, a transformer 23, an ON-OFF control circuit 24, one first resistance 25, one second resistance 26, a first transistor 27 and an electric capacity 28.
This first current rectifying and wave filtering circuit 21 comprises a full bridge rectifier 211, one first filter capacitor 212, two inputs 213,214 and outputs 215.These two inputs 213,214 are used to receive external communication voltage.It is direct voltage that this full bridge rectifier 211 is used for this external communication voltage transitions.These first filter capacitor, 212 1 end ground connection, the other end is connected to this output 215.
The grid 271 of this first transistor 27 is via these first resistance, 25 ground connection; Drain electrode 273 is connected to its grid 271 via this second resistance 26, also is connected to the output 215 of this first current rectifying and wave filtering circuit 21 via this electric capacity 28.
This ON-OFF control circuit 24 comprises a pulse width modulating chip 241 and a transistor seconds 242.The grid of this transistor seconds 242 (not indicating) is connected to the control end 243 of this pulse width modulating chip 241, source electrode (not indicating) ground connection, and drain electrode (not indicating) is connected to the source electrode 272 of this first transistor.
This transformer 23 comprises an elementary winding 231 and a level winding 232.This elementary winding 231 comprises one first end 2311 and one second end 2312, and output 215, the second ends 2312 that its first end 2311 is connected to this first current rectifying and wave filtering circuit 21 are connected to the drain electrode of this transistor seconds 242.This secondary winding 232 comprises one the 3rd end 2321, one the 4th end 2322 and a tap terminals 2323.
This second current rectifying and wave filtering circuit 22 comprises one the 3rd transistor 221, one the 4th transistor 222 and one second filter capacitor 223.The grid of the 3rd transistor 221 (not indicating) is connected to the 4th end 2322 of this secondary winding 232, source electrode (not indicating) ground connection, and drain electrode (not indicating) is connected to the 3rd end 2321 of this secondary winding 232.The grid of the 4th transistor 222 (not indicating) is connected to the 3rd end 2321 of this secondary winding 232, source electrode (not indicating) ground connection, and drain electrode (not indicating) is connected to the 4th end 2322 of this secondary winding 232.These second filter capacitor, 223 1 end ground connection, the other end is connected to the tap terminals 2323 of this secondary winding 232.
The How It Works of this switching power circuit 20 is as follows:
External communication voltage inputs to two inputs 213,214 of this first current rectifying and wave filtering circuit 21, by output 310V direct voltage after these first current rectifying and wave filtering circuit, 21 rectifications, the filtering, and offers the elementary winding 231 of this transformer 23.Simultaneously, the control end 243 of this pulse width modulating chip 241 sends a high level and makes this transistor seconds 242 conductings.This first filter capacitor 212, this elementary winding 231 constitute a loop with this transistor seconds 242, this elementary winding 231 has electric current I to flow through, produce the electromotive force that one first end, 2311 voltages are higher than second end, 2312 voltages, this secondary winding 232 produces an induced electromotive force, the voltage of this tap terminals 2323 is higher than the voltage of the 3rd end 2321, and the voltage of the 4th end 2322 is higher than the voltage of this tap terminals 2323.At this moment, 221 conductings of the 3rd transistor, the 4th transistor 222 ends, secondary winding 232 between this second filter capacitor 223, the 3rd transistor 221, the 3rd end 2321 and this tap terminals 2323 constitutes a loop, produce electric current I 1, the voltage of these tap terminals 2323 outputs offers load after via these second filter capacitor, 223 filtering.
The control end 243 of this pulse width modulating chip 241 sends a low level ends this transistor seconds 242, the electric current I of the elementary winding 231 of this transformer 23 via the parasitic diode corresponding with this first transistor 27 to these electric capacity 28 chargings, because the voltage of the top electrode of this electric capacity 28 is 310V, so this electric capacity 28 is in charging process, the voltage of its bottom electrode is higher than 310V, when the difference of the source electrode 272 of this first transistor 27 and the voltage of drain electrode 273 during less than the conducting voltage of this parasitic diode, this parasitic diode ends, make source electrode 272 voltages of this first transistor 27 reduce to the 310V direct voltage of these first current rectifying and wave filtering circuit, 21 outputs, at this moment, the difference of the grid 271 of this first transistor 27 and the voltage of source electrode 272 can reach the conducting voltage of this first transistor 27, therefore these the first transistor 27 conductings, this electric capacity 28 is via the drain electrode 273 of this first transistor 27, elementary winding 231 discharges of source electrode 272 and this transformer 23, this elementary winding 231 has electric current I 2 to flow through, produce the electromotive force that one second end, 2312 voltages are higher than first end, 2311 voltages, this secondary winding 232 produces an induced electromotive force, the voltage of the 3rd end 2321 is higher than the voltage of this tap terminals 2323, and the voltage of this tap terminals 2323 is higher than the voltage of the 4th end 2322.At this moment, the 3rd transistor 221 ends, 222 conductings of the 4th transistor, secondary winding between this second filter capacitor 223, the 4th transistor 222, the 4th end 2322 and this tap terminals 2323 constitutes a loop, produce electric current I 1, the voltage of these tap terminals 2323 outputs offers load after via these second filter capacitor, 223 filtering.
Compared to prior art, when this transistor seconds 242 ends, the electric current I of this elementary winding 231 is charged to this electric capacity 28, this electric capacity 28 discharges then also transfer to the secondary winding 232 of this transformer 23, therefore this electric current I is fully utilized the corresponding raising of the efficient of this switching power circuit 20.
See also Fig. 3, it is the schematic diagram of switching power circuit second execution mode of the present invention.The switching power circuit 20 of this switching power circuit 30 and first execution mode is roughly the same, its difference is: this switching power circuit 30 further comprises one first current-limiting resistance 301, one second current-limiting resistance 302, one the 3rd current-limiting resistance 303, one second electric capacity 304 and one the 3rd electric capacity 305, these first current-limiting resistance, 301 1 ends are connected to the grid 371 of this first transistor 37, and the other end is via these first resistance, 35 ground connection; These second current-limiting resistance, 302 1 ends are connected to the grid (not indicating) of the 3rd transistor 321, and the other end is connected to the 4th end 3322 of this secondary winding 332; The 3rd current-limiting resistance 303 1 ends are connected to the grid of the 4th transistor 322, and the other end is connected to the 3rd end 3321 of this secondary winding 332.This second electric capacity 304 is connected between the drain electrode 373 and source electrode 372 of this first transistor 37, and the 3rd electric capacity 305 is connected between the drain electrode (not indicating) and source electrode (not indicating) of this transistor seconds 342, shields.
Claims (12)
1. switching power circuit, it comprises a direct current voltage input end, an ON-OFF control circuit, a current rectifying and wave filtering circuit and a transformer, this transformer comprises an elementary winding and a level winding, and this dc voltage input end is via this elementary winding and this ON-OFF control circuit ground connection; This secondary winding provides voltage via this current rectifying and wave filtering circuit to load, it is characterized in that: this switching power circuit further comprises an electric capacity, one first resistance, one second resistance, a first transistor and a parasitic diode, the grid of this first transistor is via this first grounding through resistance, source electrode is via this ON-OFF control circuit ground connection, drain electrode is connected to this dc voltage input end via this electric capacity, also be connected to its grid via this second resistance, the positive pole of described parasitic diode links to each other with the source electrode of the first transistor, and negative pole links to each other with the drain electrode of the first transistor.
2. switching power circuit as claimed in claim 1, it is characterized in that: this ON-OFF control circuit comprises a pulse width modulating chip and a transistor seconds, the grid of this transistor seconds is connected to this pulse width modulating chip, and this dc voltage input end is via the drain electrode and the source ground of this elementary winding, this transistor seconds.
3. switching power circuit as claimed in claim 2, it is characterized in that: this Secondary winding of transformer comprises that one first end, one second end and are used for the tap terminals of output voltage, this current rectifying and wave filtering circuit comprises one the 3rd transistor and one the 4th transistor, the 3rd transistorized grid is connected to second end of this secondary winding, source ground, drain electrode is connected to first end of this secondary winding, the 4th transistorized grid is connected to first end of this secondary winding, source ground, drain electrode is connected to second end of this secondary winding.
4. switching power circuit as claimed in claim 3 is characterized in that: this current rectifying and wave filtering circuit further comprises a filter capacitor, this filter capacitor one end ground connection, and the other end is connected to the tap terminals of this secondary winding.
5. the How It Works of switching power circuit as claimed in claim 1, it comprises the steps:
A. this ON-OFF control circuit conducting, the elementary winding of this transformer produces one first electromotive force, and this secondary winding produces one first induced electromotive force, and this first induced electromotive force provides voltage via this current rectifying and wave filtering circuit to load;
B. this ON-OFF control circuit disconnects, the elementary winding of this transformer charges to this electric capacity via this parasitic diode, when this first transistor conducting, this electric capacity is via the elementary winding discharge of this transformer, the elementary winding of this transformer produces one second electromotive force, this secondary winding produces one second induced electromotive force, and this second induced electromotive force provides voltage via this current rectifying and wave filtering circuit to load.
6. the How It Works of switching power circuit as claimed in claim 5, it is characterized in that: this ON-OFF control circuit comprises a pulse width modulating chip and a transistor seconds, the grid of this transistor seconds is connected to this pulse width modulating chip, this dc voltage input end is via the drain electrode and the source ground of this elementary winding, this transistor seconds, among the step a, this pulse width modulating chip sends a high level and makes this transistor seconds conducting, i.e. this ON-OFF control circuit conducting.
7. the How It Works of switching power circuit as claimed in claim 6, it is characterized in that: among the step b, this pulse width modulating chip sends a low level ends this transistor seconds, and promptly this ON-OFF control circuit disconnects.
8. the How It Works of switching power circuit as claimed in claim 7, it is characterized in that: this Secondary winding of transformer comprises one first end, one second end and a tap terminals, this current rectifying and wave filtering circuit comprises one the 3rd transistor and one the 4th transistor, the 3rd transistorized grid is connected to second end of this secondary winding, source ground, drain electrode is connected to first end of this secondary winding, the 4th transistorized grid is connected to first end of this secondary winding, source ground, drain electrode is connected to second end of this secondary winding, among the step a, the voltage of this tap terminals is higher than the voltage of this first end, and the voltage of this second end is higher than the voltage of this tap terminals, the 3rd transistor turns, the 4th transistor ends, and this tap terminals output voltage is given load.
9. the How It Works of switching power circuit as claimed in claim 8, it is characterized in that: among the step b, the voltage of this first end is higher than the voltage of this tap terminals, the voltage of this tap terminals is higher than the voltage of this second end, the 3rd transistor ends, the 4th transistor turns, this tap terminals output voltage is given load.
10. switching power circuit, it comprises a direct current voltage input end, an ON-OFF control circuit, a current rectifying and wave filtering circuit and a transformer, this transformer comprises an elementary winding and a level winding, and this dc voltage input end is via this elementary winding and this ON-OFF control circuit ground connection; This secondary winding provides voltage via this current rectifying and wave filtering circuit to load, it is characterized in that: this switching power circuit further comprises one first electric capacity, one first resistance, one second resistance, a first transistor and one second electric capacity, the grid of this first transistor is via this first grounding through resistance, source electrode is via this ON-OFF control circuit ground connection, drain electrode is connected to this dc voltage input end via this first electric capacity, also be connected to its grid via this second resistance, described second electric capacity is connected between the drain electrode and source electrode of the first transistor.
11. switching power circuit as claimed in claim 10, it is characterized in that: this ON-OFF control circuit comprises a pulse width modulating chip and a transistor seconds, the grid of this transistor seconds is connected to this pulse width modulating chip, and this dc voltage input end is via the drain electrode and the source ground of this elementary winding, this transistor seconds.
12. switching power circuit as claimed in claim 11 is characterized in that: this switching power circuit further comprises one the 3rd electric capacity, and described the 3rd electric capacity is connected between the drain electrode and source electrode of described transistor seconds.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810066691XA CN101572491B (en) | 2008-04-28 | 2008-04-28 | Switch power circuit and operation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810066691XA CN101572491B (en) | 2008-04-28 | 2008-04-28 | Switch power circuit and operation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101572491A CN101572491A (en) | 2009-11-04 |
| CN101572491B true CN101572491B (en) | 2011-09-28 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200810066691XA Expired - Fee Related CN101572491B (en) | 2008-04-28 | 2008-04-28 | Switch power circuit and operation method thereof |
Country Status (1)
| Country | Link |
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| CN (1) | CN101572491B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012051739A1 (en) * | 2010-10-21 | 2012-04-26 | Integrated Device Technology, Inc. | Switch used in programmable gain amplifilier and programmable gain amplifilier |
| US11444000B2 (en) * | 2018-04-14 | 2022-09-13 | Alpha And Omega Semiconductor (Cayman) Ltd. | Charger |
| JP7149757B2 (en) * | 2018-08-02 | 2022-10-07 | 株式会社日立産機システム | SWITCHING POWER SUPPLY CIRCUIT AND POWER CONVERSION DEVICE INCLUDING THE SAME |
| CN116404888A (en) * | 2023-03-21 | 2023-07-07 | 三峡大学 | Bipolar self-voltage-equalizing center tap type rectifying circuit |
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2008
- 2008-04-28 CN CN200810066691XA patent/CN101572491B/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| CN101572491A (en) | 2009-11-04 |
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Granted publication date: 20110928 Termination date: 20200428 |