CN103036427A - Synchronous buck converter - Google Patents
Synchronous buck converter Download PDFInfo
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- CN103036427A CN103036427A CN 201210567428 CN201210567428A CN103036427A CN 103036427 A CN103036427 A CN 103036427A CN 201210567428 CN201210567428 CN 201210567428 CN 201210567428 A CN201210567428 A CN 201210567428A CN 103036427 A CN103036427 A CN 103036427A
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Abstract
The invention provides a synchronous buck converter which solves the problem that inductive current ripples are large under a light-load state of an existing synchronous buck converter. The synchronous buck converter comprises an input port, an output port, a first switch, a second switch, an output inductor, an output capacitor, a sampling resistor, an operational amplifier, a feedback assembly, a voltage comparator, a selective switch, a current comparator and a control and drive circuit. The synchronous buck converter can reduce the inductive current ripples under the light-load state.
Description
Technical field
The present invention relates to electronic technology field, particularly a kind of synchronous buck converter.
Background technology
Synchronous buck converter is applied to usually when the required voltage occasion lower than the voltage of power supply.Typical synchronous buck converter comprises the first switch S 1, second switch S2, output inductor L and the output capacitor Co that couples as shown in Figure 1.Existing synchronous buck converter adopts peak-current mode control usually, makes the peak value of the inductive current of synchronous buck converter be adjusted to a constant peak.Yet use this control mode, no matter synchronous buck converter is in heavy condition or light condition, and its inductive current peak all is adjusted to same peak value.So that converter inductive current ripple under light condition is very large.
Summary of the invention
The present invention proposes a kind of synchronous buck converter, has solved existing synchronous buck converter large problem of ripple under light condition.
Technical scheme of the present invention is achieved in that
A kind of synchronous buck converter comprises: input port receives input voltage; Output port provides output voltage; The first switch and second switch are coupled in series in input port and with reference between the ground; Output inductor is coupled between the coupled in series node and output port of the first switch and second switch; Output capacitor is coupled in output port and with reference between the ground; Sampling resistor is with the first switch coupled in series; Operational amplifier has first input end, the second input terminal and lead-out terminal, and its first input end and the second input terminal are connected across the sampling resistor two ends, and its lead-out terminal produces the inductive current sampled signal; Feedback component is coupled to output port and receives output voltage, and produces the feedback voltage of reflection output voltage; Voltage comparator has in-phase input end, inverting input and lead-out terminal, and its in-phase input end receives reference voltage, and its inverting input is coupled to feedback component and receives feedback voltage, and its lead-out terminal produces voltage comparison signal; Selector switch, have the first terminal, the second terminal, the 3rd terminal and control terminal, its the first terminal couples the first current peak, and its second terminal couples the second current peak, and its control terminal is coupled to the lead-out terminal receiver voltage comparison signal of voltage comparator; Current comparator, have in-phase input end, inverting input and lead-out terminal, its in-phase input end is coupled to the lead-out terminal receiving inductance current sampling signal of operational amplifier, and its inverting input is coupled to the 3rd terminal of selector switch, its lead-out terminal generation current comparison signal; Control and drive circuit are coupled to the lead-out terminal received current comparison signal of current comparator, and based on the electric current comparison signal, produce double switch and drive signal, to control the break-make of the first switch and second switch.
Alternatively, described feedback component comprises and is coupled in series in output port and with reference to the first resistance between the ground and the second resistance that wherein feedback voltage produces at the coupled in series Nodes of the first resistance and the second resistance.
Alternatively, when voltage comparison signal was high level, the 3rd terminal of selector switch was connected to its first terminal, so that the inverting input of current comparator receives the first current peak; When voltage comparison signal was low level, the 3rd terminal of selector switch was connected to its second terminal, so that the inverting input of current comparator receives the second current peak.
Alternatively, described the first current peak is greater than the second current peak.
Alternatively, described synchronous buck converter further comprises: compensation condenser is coupled in the lead-out terminal of operational amplifier and with reference between the ground.
The invention has the beneficial effects as follows: can reduce the inductive current ripple of synchronous buck converter under light condition.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, the below will do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art, apparently, accompanying drawing in the following describes only is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is the typical circuit structural representation of existing synchronous buck converter;
Fig. 2 is the electrical block diagram of a kind of synchronous buck converter 100 of the present invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not paying the every other embodiment that obtains under the creative work prerequisite.
As shown in Figure 2, synchronous buck converter 100 of the present invention comprises: input port 101 receives input voltage vin; Output port 102 provides output voltage V o; The first switch 103 and second switch 104 are coupled in series in input port 101 and with reference between the ground; Output inductor 105 is coupled between the coupled in series node and output port 102 of the first switch 103 and second switch 104; Output capacitor 106 is coupled in output port 102 and with reference between the ground; Sampling resistor 107 is with the first switch 103 coupled in series; Operational amplifier 108 has first input end, the second input terminal and lead-out terminal, and its first input end and the second input terminal are connected across sampling resistor 107 two ends, and its lead-out terminal produces inductive current sampled signal Isen; Feedback component 109 is coupled to output port 102 and receives output voltage V o, and produces the feedback voltage Vfb of reflection output voltage V o; Voltage comparator 110 has in-phase input end, inverting input and lead-out terminal, and its in-phase input end receives reference voltage Vref, and its inverting input is coupled to feedback component 109 and receives feedback voltage Vfb, and its lead-out terminal produces voltage comparison signal; Selector switch 111, have the first terminal, the second terminal, the 3rd terminal and control terminal, its the first terminal couples the first current peak Ilim1, and its second terminal couples the second current peak Ilim2, and its control terminal is coupled to the lead-out terminal receiver voltage comparison signal of voltage comparator 110; Current comparator 112, have in-phase input end, inverting input and lead-out terminal, its in-phase input end is coupled to the lead-out terminal receiving inductance current sampling signal Isen of operational amplifier 108, its inverting input is coupled to the 3rd terminal of selector switch 111, its lead-out terminal generation current comparison signal; Control and drive circuit 113 are coupled to the lead-out terminal received current comparison signal of current comparator 112, and based on the electric current comparison signal, produce double switch and drive signal, to control the break-make of the first switch 103 and second switch 104.
Preferably, described synchronous buck converter 100 also comprises: compensation condenser 114 is coupled in the lead-out terminal of operational amplifier 108 and with reference between the ground.
Preferably, feedback component 109 comprises and is coupled in series in output port 102 and with reference to the first resistance between the ground and the second resistance that wherein feedback voltage Vfb produces at the series connection node place of the first resistance and the second resistance.
Preferably, when voltage comparison signal was high level, the 3rd terminal of selector switch 111 was connected to its first terminal, so that the inverting input of current comparator 112 receives the first current peak Ilim1; When voltage comparison signal was low level, the 3rd terminal of selector switch 111 was connected to its second terminal, so that the inverting input of current comparator 112 receives the second current peak Ilim2.
Preferably, the first current peak Ilim1 is greater than the second current peak Ilim2.
When synchronous buck converter 100 normal operation, when the first switch 103 is switched on, second switch 104 is disconnected, input voltage vin is transmitted and is converted into output voltage V o via sampling resistor 107, the first switch 103, output inductor 105 and output capacitor 106.This moment, inductive current was the electric current that flows through sampling resistor 107.This electric current begins to increase.Then the inductive current sampled signal Isen of operational amplifier 108 outputs also begins to increase.When it increases to the signal of current comparator 112 inverting inputs, the electric current comparison signal trigging signal of current comparator 112 outputs.Accordingly, the two-way of control and drive circuit 113 outputs drives the signal trigging signal, so that the first switch 103 is disconnected, second switch 104 is switched on.
When the load of synchronous buck converter 100 is relatively heavier, output voltage V o less, then also less of feedback voltage Vfb.Feedback voltage Vfb is less than reference voltage Vref at this moment, and the voltage comparison signal of voltage comparator 110 outputs is high level.Then the 3rd terminal of selector switch 111 is connected to its first terminal, so that the inverting input of current comparator 112 receives the first current peak Ilim1.Namely under heavy condition, when inductive current sampled signal Isen reaches the first current peak Ilim1, the electric current comparison signal trigging signal of current comparator 112 output, so via behind control and the drive circuit 113 the first switch 103 is disconnected, with second switch 104 conductings.
When the load of synchronous buck converter 100 was relatively light, output voltage V o was relatively large, and then feedback voltage Vfb is also relatively large.Feedback voltage Vfb is greater than reference voltage Vref at this moment, and the voltage comparison signal of voltage comparator 110 outputs is low level.Then the 3rd terminal of selector switch 111 is connected to its second terminal, so that the inverting input of current comparator 112 receives the second current peak Ilim2.Namely under light condition, when inductive current sampled signal Isen reaches the second current peak Ilim2, the electric current comparison signal trigging signal of current comparator 112 output, so via behind control and the drive circuit 113 the first switch 103 is disconnected, with second switch 104 conductings.
As previously mentioned, the first current peak Ilim1 is greater than the second current peak Ilim2, so that the inductive current peak of synchronous buck converter 100 under light condition be less than the inductive current peak under its heavy condition, thereby reduced inductive current ripple under its light condition.
The above only is preferred embodiment of the present invention, and is in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of doing, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (5)
1. a synchronous buck converter is characterized in that, comprising:
Input port receives input voltage;
Output port provides output voltage;
The first switch and second switch are coupled in series in input port and with reference between the ground;
Output inductor is coupled between the coupled in series node and output port of the first switch and second switch;
Output capacitor is coupled in output port and with reference between the ground;
Sampling resistor is with the first switch coupled in series;
Operational amplifier has first input end, the second input terminal and lead-out terminal, and its first input end and the second input terminal are connected across the sampling resistor two ends, and its lead-out terminal produces the inductive current sampled signal;
Feedback component is coupled to output port and receives output voltage, and produces the feedback voltage of reflection output voltage;
Voltage comparator has in-phase input end, inverting input and lead-out terminal, and its in-phase input end receives reference voltage, and its inverting input is coupled to feedback component and receives feedback voltage, and its lead-out terminal produces voltage comparison signal;
Selector switch, have the first terminal, the second terminal, the 3rd terminal and control terminal, its the first terminal couples the first current peak, and its second terminal couples the second current peak, and its control terminal is coupled to the lead-out terminal receiver voltage comparison signal of voltage comparator;
Current comparator, have in-phase input end, inverting input and lead-out terminal, its in-phase input end is coupled to the lead-out terminal receiving inductance current sampling signal of operational amplifier, and its inverting input is coupled to the 3rd terminal of selector switch, its lead-out terminal generation current comparison signal;
Control and drive circuit are coupled to the lead-out terminal received current comparison signal of current comparator, and based on the electric current comparison signal, produce double switch and drive signal, to control the break-make of the first switch and second switch.
2. synchronous buck converter as claimed in claim 1 is characterized in that, wherein
When voltage comparison signal was high level, the 3rd terminal of selector switch was connected to its first terminal, so that the inverting input of current comparator receives the first current peak;
When voltage comparison signal was low level, the 3rd terminal of selector switch was connected to its second terminal, so that the inverting input of current comparator receives the second current peak.
3. synchronous buck converter as claimed in claim 1 is characterized in that, described the first current peak is greater than the second current peak.
4. synchronous buck converter as claimed in claim 1, it is characterized in that, described feedback component comprises and is coupled in series in output port and with reference to the first resistance between the ground and the second resistance that wherein feedback voltage produces at the coupled in series Nodes of the first resistance and the second resistance.
5. synchronous buck converter as claimed in claim 1 is characterized in that, described synchronous buck converter further comprises:
Compensation condenser is coupled in the lead-out terminal of operational amplifier and with reference between the ground.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201210567428 CN103036427A (en) | 2012-12-11 | 2012-12-11 | Synchronous buck converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201210567428 CN103036427A (en) | 2012-12-11 | 2012-12-11 | Synchronous buck converter |
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| CN103036427A true CN103036427A (en) | 2013-04-10 |
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| CN 201210567428 Pending CN103036427A (en) | 2012-12-11 | 2012-12-11 | Synchronous buck converter |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105466536A (en) * | 2015-12-25 | 2016-04-06 | 青岛讯达捷电子科技有限公司 | Electronic weighing instrument |
| CN105491484A (en) * | 2015-12-28 | 2016-04-13 | 青岛玻莱莫斯新材料技术有限公司 | Hearing assistance device |
| CN105491499A (en) * | 2015-12-28 | 2016-04-13 | 青岛玻莱莫斯新材料技术有限公司 | Elderly hearing aid |
| CN105515497A (en) * | 2015-12-25 | 2016-04-20 | 青岛朝阳华泰管理咨询服务有限公司 | New energy power generation device |
| CN105554668A (en) * | 2015-12-25 | 2016-05-04 | 青岛北斗星云通信科技有限公司 | Hearing impairment assist device |
| CN105628166A (en) * | 2015-12-25 | 2016-06-01 | 青岛北斗星云通信科技有限公司 | Electronic weighing instrument |
| CN105790406A (en) * | 2015-12-26 | 2016-07-20 | 青岛讯达捷电子科技有限公司 | New energy power generation device |
| CN106936318A (en) * | 2015-12-31 | 2017-07-07 | 德克萨斯仪器股份有限公司 | For the load regulation of the isolation and amplifier in isolated buck converter |
| WO2021057851A1 (en) * | 2019-09-24 | 2021-04-01 | 上海晶丰明源半导体股份有限公司 | Control circuit with high power factor and ac/dc conversion circuit |
-
2012
- 2012-12-11 CN CN 201210567428 patent/CN103036427A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105466536A (en) * | 2015-12-25 | 2016-04-06 | 青岛讯达捷电子科技有限公司 | Electronic weighing instrument |
| CN105515497A (en) * | 2015-12-25 | 2016-04-20 | 青岛朝阳华泰管理咨询服务有限公司 | New energy power generation device |
| CN105554668A (en) * | 2015-12-25 | 2016-05-04 | 青岛北斗星云通信科技有限公司 | Hearing impairment assist device |
| CN105628166A (en) * | 2015-12-25 | 2016-06-01 | 青岛北斗星云通信科技有限公司 | Electronic weighing instrument |
| CN105790406A (en) * | 2015-12-26 | 2016-07-20 | 青岛讯达捷电子科技有限公司 | New energy power generation device |
| CN105491484A (en) * | 2015-12-28 | 2016-04-13 | 青岛玻莱莫斯新材料技术有限公司 | Hearing assistance device |
| CN105491499A (en) * | 2015-12-28 | 2016-04-13 | 青岛玻莱莫斯新材料技术有限公司 | Elderly hearing aid |
| CN106936318A (en) * | 2015-12-31 | 2017-07-07 | 德克萨斯仪器股份有限公司 | For the load regulation of the isolation and amplifier in isolated buck converter |
| WO2021057851A1 (en) * | 2019-09-24 | 2021-04-01 | 上海晶丰明源半导体股份有限公司 | Control circuit with high power factor and ac/dc conversion circuit |
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Legal Events
| Date | Code | Title | Description |
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| C06 | Publication | ||
| PB01 | Publication | ||
| DD01 | Delivery of document by public notice |
Addressee: Lianmeng Electronic Instrument Co., Ltd. Document name: Notification that Application Deemed to be Withdrawn |
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| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20130410 |