CN202978686U - Buck converter circuit - Google Patents
Buck converter circuit Download PDFInfo
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- CN202978686U CN202978686U CN 201220609640 CN201220609640U CN202978686U CN 202978686 U CN202978686 U CN 202978686U CN 201220609640 CN201220609640 CN 201220609640 CN 201220609640 U CN201220609640 U CN 201220609640U CN 202978686 U CN202978686 U CN 202978686U
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Abstract
The utility model discloses a BUCK converter circuit. The BUCK converter circuit comprises a direct-current power supply used to provide a supply voltage, a BUCK circuit used to reduce the voltage of the direct-current power supply, a LC filter used to carry out filtering on the voltage of the BUCK circuit after voltage reduction and output to a load, a feedback sampling compensation circuit used to carry out sampling and feedback compensation on an output voltage of the BUCK circuit and the output voltage of the LC filter and a control circuit used to adjust the output voltage of the BUCK circuit according to a sampling voltage of the feedback sampling compensation circuit. By using the circuit of the utility model, stability and a dynamic characteristic of the circuit are increased and simultaneously an output ripple and noises are reduced.
Description
Technical field
The utility model relates to technical field of electronic products, particularly a kind of BUCK converter circuit.
Background technology
In fields such as computer, communication, Industry Control, instrument and meter, Medical Devices, use the design of BUCK converter circuit to transform to the application of Switching Power Supply of low-voltage direct from high voltage direct current very extensive.Especially in modem computer systems, heterogeneous, Multi-path synchronous BUCK converter circuit is able to extensive use.In the synchronous BUCK converter circuit design of multichannel low-voltage, high-current, how to improve the dynamic load characteristic of power supply, the noise and the ripple that reduce simultaneously direct current output are the difficult points of design.In order to reduce noise and ripple, usually understand the series LC filter at the output of the BUCK of voltage-type or current mode converter circuit.The transmission characteristic that facts have proved the LC filter of output series connection can be inserted in the feedback loop of power-supply system, thereby affects the stable of power-supply system.
The utility model content
Main purpose of the present utility model is to provide a kind of BUCK converter circuit, is intended to improve the dynamic characteristic of circuit, reduces simultaneously output ripple and noise.
To achieve these goals, the utility model provides a kind of BUCK converter circuit, and this BUCK converter circuit comprises:
DC power supply is used for providing supply voltage;
The BUCK circuit is for reducing the voltage of described DC power supply;
The LC filter is used for the voltage after the step-down of described BUCK circuit is carried out filtering, and exports load to;
The feedback sample compensating circuit is used for the output voltage of described BUCK circuit and the output voltage of LC filter are sampled and feedback compensation;
Control circuit is used for adjusting described BUCK circuit output voltage according to the sampled voltage of described feedback sample compensating circuit.
Preferably, described BUCK circuit comprises the first field effect transistor, the second field effect transistor, the first inductance and the first electric capacity; Wherein the drain electrode of the first field effect transistor is connected with the positive pole of described DC power supply, and grid is connected with described control circuit, and source electrode is connected with the drain electrode of described the second field effect transistor; The grid of described the second field effect transistor is connected with described control circuit, and source electrode is connected with the negative pole of described DC power supply; One end of described the first inductance is connected with the source electrode of described the first field effect transistor, and the other end is connected with the negative pole of described DC power supply by described the first electric capacity.
Preferably, described BUCK circuit also comprises the first resistance and the second electric capacity, and wherein an end of the first resistance is connected with the source electrode of described the first field effect transistor, and the other end is connected with the negative pole of described DC power supply by described the second electric capacity.
Preferably, described LC filter comprises the second inductance and the 3rd electric capacity, and wherein an end of the second inductance is connected to the end that described the first inductance is connected with described the 3rd electric capacity, and the other end is connected with the negative pole of described DC power supply by the 3rd electric capacity.
Preferably, described feedback sample compensating circuit comprises the second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, the 4th electric capacity, the 5th electric capacity and the 6th electric capacity; Described control circuit comprises pwm control circuit, and this pwm control circuit comprises error amplifier; Wherein an end of the second resistance is connected with the negative pole of described DC power supply, the other end is connected with the feedback end of described control circuit, and is connected with the end that the 3rd electric capacity is connected with described the second inductance, is connected with the other end of described the second inductance with the 4th resistance, is connected with described error amplifier, is connected with described error amplifier with the 5th resistance by the 6th electric capacity that connects successively by the 5th electric capacity by the 4th electric capacity that connects successively by the 3rd resistance respectively.
Preferably, described control circuit comprises a PDM keyer, and this PDM keyer comprises the second pulse-width signal output that the first pulse-width signal output of being connected with the grid of described the first field effect transistor is connected with grid with described the second field effect transistor.
The utility model consists of slow feedback loop by be made of the rapid feedback loop above-mentioned the 4th resistance and the 4th electric capacity by the 3rd resistance and the second resistance; Simultaneously consist of the rapid feedback compensating circuit by the 4th resistance, the 4th electric capacity, the 5th electric capacity, the 6th electric capacity and the 5th resistance, consist of feedback compensation circuit at a slow speed by the 3rd resistance, the 5th electric capacity, the 6th electric capacity and the 5th resistance.In addition the sampled point in rapid feedback loop is arranged between the input of the output of BUCK circuit and LC filter, so the ripple of BUCK circuit output and the dynamic load variations signal can be through quick compensation circuit to the BUCK controller fast; The rapid feedback compensating circuit has wider bandwidth, lower low-frequency gain and higher high-frequency gain.The sampled point of slow feedback loop is arranged at the LC filter output afterwards that the BUCK circuit is contacted, ripple and the quick dynamic load variations signal exported due to the BUCK circuit become comparatively stable direct current after the LC filter filtering, this direct current signal can be through slow feedback loop to the BUCK controller; The feedback compensation circuit has narrower bandwidth at a slow speed, higher low-frequency gain and lower high-frequency gain.Therefore the BUCK converter circuit that provides of the utility model can possess dynamic load response speed and lower ripple and noise faster simultaneously, and has the higher precision of voltage regulation and sufficient phase margin and gain margin.
Description of drawings
Fig. 1 is the structural representation of the utility model BUCK converter circuit preferred embodiment;
Fig. 2 is the circuit diagram of the utility model BUCK converter circuit preferred embodiment.
The realization of the utility model purpose, functional characteristics and advantage are described further with reference to accompanying drawing in connection with embodiment.
Embodiment
Should be appreciated that specific embodiment described herein only in order to explaining the utility model, and be not used in restriction the utility model.
In conjunction with seeing figures.1.and.2, Fig. 1 is the structural representation of the utility model BUCK converter circuit preferred embodiment, and Fig. 2 is the circuit diagram of the utility model BUCK converter circuit preferred embodiment.The BUCK converter circuit that the present embodiment provides comprises:
Feedback sample compensating circuit 40 is used for the output voltage of BUCK circuit 20 and the output voltage of LC filter 30 are sampled and feedback compensation;
In the present embodiment, above-mentioned BUCK circuit 20 comprises the first field effect transistor Q1, the second field effect transistor Q2, the first inductance L 1 and the first capacitor C 1; Wherein the drain electrode of the first field effect transistor Q1 is connected with the positive pole of DC power supply 10, and grid is connected with control circuit 50, and source electrode is connected with the drain electrode of the second field effect transistor Q2; The grid of the second field effect transistor Q2 is connected with control circuit 50, and source electrode is connected with the negative pole of DC power supply 10; One end of the first inductance L 1 is connected with the source electrode of the first field effect transistor Q1, and the other end is connected with the negative pole of DC power supply 10 by the first capacitor C 1.
During work, when above-mentioned the first field effect transistor Q1 conducting, the second field effect transistor Q2 cut-off, thus make DC power supply V2 directly be loaded on the first inductance L 1, this first inductance L 1 is charged, and provide supply power voltage for load R; When first field effect transistor Q1 when cut-off, the second field effect transistor Q2 conducting, at this moment, electric energy stored on inductance L 1 is by this second field effect transistor Q2 discharge, and provides supply power voltage for load R.Should be noted that and to pass through to regulate the first field effect transistor Q1 and the conducting of the second field effect transistor Q2 and the time of cut-off, thereby adjust the voltage of BUCK circuit 20 outputs.
Particularly, above-mentioned BUCK circuit 20 also comprises the first resistance R 1 and the second capacitor C 2, and wherein an end of the first resistance R 1 is connected with the source electrode of the first field effect transistor Q1, and the other end is connected with the negative pole of DC power supply V2 by the second capacitor C 2.
Above-mentioned the first resistance R 1 and the second capacitor C 2 form buffer circuit, owing to being provided with buffer circuit, in the moment of the first field effect transistor Q1 conducting moment and cut-off, can playing cushioning effect to circuit, thereby improve the stability of circuit.
Above-mentioned LC filter 30 comprises the second inductance L 2 and the 3rd capacitor C 3, and wherein an end of the second inductance L 2 is connected to the end that the first inductance L 1 is connected with the 3rd capacitor C 3, and the other end is connected with the negative pole of DC power supply 10 by the 3rd capacitor C 3.
Above-mentioned feedback sample compensating circuit 40 comprises the second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4, the 5th resistance R 5, the 4th capacitor C 4, the 5th capacitor C 5 and the 6th capacitor C 6; Wherein an end of the second resistance R 2 is connected with the negative pole of DC power supply 10, the other end is connected with the feedback end of control circuit 50, and is connected with the end that the 3rd electric capacity R3 is connected with the second inductance L 2, is connected with the other end of the second inductance L 2 with the 4th resistance R 4, is connected with the internal error output of control circuit 50, is connected with the internal error output with the 5th resistance R 5 by the 6th capacitor C 6 that connects successively by the 5th capacitor C 5 by the 4th capacitor C 4 that connects successively by the 3rd resistance R 3 respectively.
Above-mentioned control circuit 50 comprises a PDM keyer U1, and this PDM keyer U1 comprises the second pulse-width signal output CLN that the first pulse-width signal output CLP of being connected with the grid of the first field effect transistor Q1 is connected with grid with the second field effect transistor.Above-mentioned feedback end is the IN pin of PDM keyer U1, the COMP pin that above-mentioned internal error output is PDM keyer U1.
In the present embodiment, the ripple of above-mentioned BUCK circuit 20 output voltages and quick dynamic load variations signal can form the lead compensation circuit feedback to the IN pin of PDM keyer U1 by the 4th resistance R 4 and the 4th capacitor C 4.If the operating frequency Fw of BUCK converter circuit, the frequency range of the cross-over frequency Fb when this Fw controls output gain and is 0dB higher than the BUCK converter circuit is high band, and the frequency range of some Fp1 that consists of lower than L1 and C2 is low-frequency range.Therefore the rapid feedback compensating circuit that is comprised of the 4th resistance R 4, the 4th capacitor C 4, the 5th capacitor C 5, the 6th capacitor C 6 and the 5th resistance R 5 has wider bandwidth, lower low-frequency gain and higher high-frequency gain.
The ripple of above-mentioned BUCK circuit 20 output voltages and fast the dynamic load variations signal obtain comparatively galvanic current after by 30 filtering of LC filter and press signal.The compensation circuit that this d. c. voltage signal consists of by the 3rd resistance R 3 feeds back to the IN pin of PDM keyer U1.If the operating frequency Fw of BUCK converter circuit, the frequency range of the cross-over frequency Fb when this Fw controls output gain and is 0dB higher than the BUCK converter circuit is high band, and the frequency range of some Fp1 that consists of lower than L1 and C2 is low-frequency range.Therefore the circuit of feedback compensation at a slow speed that is comprised of the 3rd resistance R 3, the 5th capacitor C 5, the 6th capacitor C 6 and the 5th resistance R 5 has narrower bandwidth, higher low-frequency gain and lower high-frequency gain.
In sum, the BUCK converter circuit that the utility model provides has dynamic load response speed and lower Ripple Noise faster, has guaranteed that simultaneously circuit has the higher precision of voltage regulation and sufficient phase margin and gain margin.
The utility model consists of slow feedback loop 402 by be made of rapid feedback loop 401 above-mentioned the 4th resistance R 4 and the 4th capacitor C 4 by the 3rd resistance R 3 and the second resistance R 2; Simultaneously consist of the rapid feedback compensating circuit by the 4th resistance R 4, the 4th capacitor C 4, the 5th capacitor C 5, the 6th capacitor C 6 and the 5th resistance R 5, consist of feedback compensation circuit at a slow speed by the 3rd resistance R 3, the 5th capacitor C 5, the 6th capacitor C 6 and the 5th resistance R 5.In addition the sampled point in rapid feedback loop 401 is arranged between the input of the output of BUCK circuit 20 and LC filter 30, due to the ripple of BUCK circuit 40 outputs with the dynamic load variations signal can be through quick compensation circuit 401 to BUCK controllers fast; Therefore make the rapid feedback compensating circuit have wider bandwidth, lower low-frequency gain and higher high-frequency gain.The sampled point of slow feedback loop 402 is arranged at LC filter 30 output afterwards that BUCK circuit 20 is contacted, ripple and the quick dynamic load variations signal exported due to BUCK circuit 20 become comparatively stable direct current after 30 filtering of LC filter, this direct current signal can be through slow feedback loop 402 to BUCK controllers; Therefore make at a slow speed that the feedback compensation circuit has narrower bandwidth, higher low-frequency gain and lower high-frequency gain.Therefore the BUCK converter circuit that provides of the utility model can possess dynamic load response speed and lower ripple and noise faster simultaneously, and has the higher precision of voltage regulation and sufficient phase margin and gain margin.Should be noted that above-mentioned BUCK controller is the part of control circuit 50.
These are only preferred embodiment of the present utility model; not thereby limit the scope of the claims of the present utility model; every equivalent structure or equivalent flow process conversion that utilizes the utility model specification and accompanying drawing content to do; or directly or indirectly be used in other relevant technical fields, all in like manner be included in scope of patent protection of the present utility model.
Claims (6)
1. a BUCK converter circuit, is characterized in that, comprising:
DC power supply is used for providing supply voltage;
The BUCK circuit is for reducing the voltage of described DC power supply;
The LC filter is used for the voltage after the step-down of described BUCK circuit is carried out filtering, and exports load to;
The feedback sample compensating circuit is used for the output voltage of described BUCK circuit and the output voltage of LC filter are sampled and feedback compensation;
Control circuit is used for adjusting described BUCK circuit output voltage according to the sampled voltage of described feedback sample compensating circuit.
2. BUCK converter circuit as claimed in claim 1, is characterized in that, described BUCK circuit comprises the first field effect transistor, the second field effect transistor, the first inductance and the first electric capacity; Wherein the drain electrode of the first field effect transistor is connected with the positive pole of described DC power supply, and grid is connected with described control circuit, and source electrode is connected with the drain electrode of described the second field effect transistor; The grid of described the second field effect transistor is connected with described control circuit, and source electrode is connected with the negative pole of described DC power supply; One end of described the first inductance is connected with the source electrode of described the first field effect transistor, and the other end is connected with the negative pole of described DC power supply by described the first electric capacity.
3. BUCK converter circuit as claimed in claim 2, it is characterized in that, described BUCK circuit also comprises the first resistance and the second electric capacity, and wherein an end of the first resistance is connected with the source electrode of described the first field effect transistor, and the other end is connected with the negative pole of described DC power supply by described the second electric capacity.
4. BUCK converter circuit as claimed in claim 2, it is characterized in that, described LC filter comprises the second inductance and the 3rd electric capacity, wherein an end of the second inductance is connected to the end that described the first inductance is connected with described the 3rd electric capacity, and the other end is connected with the negative pole of described DC power supply by the 3rd electric capacity.
5. BUCK converter circuit as claimed in claim 4, is characterized in that, described feedback sample compensating circuit comprises the second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, the 4th electric capacity, the 5th electric capacity and the 6th electric capacity; Described control circuit comprises pwm control circuit, and this pwm control circuit comprises error amplifier; Wherein an end of the second resistance is connected with the negative pole of described DC power supply, the other end is connected with the feedback end of described control circuit, and is connected with the end that the 3rd electric capacity is connected with described the second inductance, is connected with the other end of described the second inductance with the 4th resistance, is connected with described error amplifier, is connected with described error amplifier with the 5th resistance by the 6th electric capacity that connects successively by the 5th electric capacity by the 4th electric capacity that connects successively by the 3rd resistance respectively.
6. BUCK converter circuit as claimed in claim 2, it is characterized in that, described control circuit comprises a PDM keyer, and this PDM keyer comprises the second pulse-width signal output that the first pulse-width signal output of being connected with the grid of described the first field effect transistor is connected with grid with described the second field effect transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220609640 CN202978686U (en) | 2012-11-16 | 2012-11-16 | Buck converter circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220609640 CN202978686U (en) | 2012-11-16 | 2012-11-16 | Buck converter circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202978686U true CN202978686U (en) | 2013-06-05 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220609640 Expired - Lifetime CN202978686U (en) | 2012-11-16 | 2012-11-16 | Buck converter circuit |
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| Country | Link |
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| CN (1) | CN202978686U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103825439A (en) * | 2012-11-16 | 2014-05-28 | 深圳市航嘉驰源电气股份有限公司 | Buck converter circuit |
| CN104753348A (en) * | 2015-04-23 | 2015-07-01 | 四川正冠科技有限公司 | Direct-current-to-direct-current conversion switch power supply |
-
2012
- 2012-11-16 CN CN 201220609640 patent/CN202978686U/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103825439A (en) * | 2012-11-16 | 2014-05-28 | 深圳市航嘉驰源电气股份有限公司 | Buck converter circuit |
| CN103825439B (en) * | 2012-11-16 | 2016-08-10 | 深圳市航嘉驰源电气股份有限公司 | Buck converter circuit |
| CN104753348A (en) * | 2015-04-23 | 2015-07-01 | 四川正冠科技有限公司 | Direct-current-to-direct-current conversion switch power supply |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130605 |
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| CX01 | Expiry of patent term |