CN103698574A - Current detection method of Boost circuit during discontinuous inductive current - Google Patents
Current detection method of Boost circuit during discontinuous inductive current Download PDFInfo
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- CN103698574A CN103698574A CN201310649664.6A CN201310649664A CN103698574A CN 103698574 A CN103698574 A CN 103698574A CN 201310649664 A CN201310649664 A CN 201310649664A CN 103698574 A CN103698574 A CN 103698574A
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- current
- electric current
- boost circuit
- detection method
- inductive current
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Abstract
The invention relates to a current detection method of a Boost circuit during discontinuous inductive current. In the existing input current detection of the Boost circuit, when the circuit operates in a discontinuous inductive current mode (DCM), the mean of the current cannot be detected accurately, the output of a system control ring is inaccurate, the output voltage under light load is influenced, and the ripple of the output voltage is increased. The current detection method of the Boost circuit during the discontinuous inductive current is characterized in that a current sampling point is a middle point in an ascent process or a descent process of a triangular wave of the inductive current in a switching cycle, the middle point is sampled to obtain the sampling point, and a ratio of the input voltage Vin to the output voltage Vo of the sampling point is calculated, and compared with a duty ratio D1 of the current control signal. The detection method is simple, the system control is more accurate, and the output is more stable.
Description
Technical field
The present invention relates to a kind of electric current detecting method, the electric current detecting method of especially a kind of Boost circuit when discontinuous current mode.
Background technology
Existing Boost circuit input current detects, and the main method adopting is: at the midpoint detection electric current of inductive current triangular wave uphill process or decline process, as the mean value of this cycle internal inductance electric current.The method is feasible under the mode of operation (CCM) of continuous current mode, but in inductance value in smaller or underloading situation, circuit working is (DCM) when discontinous mode, cannot accurately detect the mean value of electric current, cause system control loop output out of true, output voltage while affecting underloading, makes it ripple and increases.
As shown in Figure 1, the switch periods of circuit is T to existing Boost circuit input current detection method
s, dutycycle is D, sampling time point is at the mid point D of electric current decline process
s, as shown in Figure 1, the in the situation that of continuous current mode, the electric current that sampled point is adopted is the mean value in this cycle; But the in the situation that of discontinuous current mode, as shown in Figure 2, sampling time point D
sthe electric current of adopting is 0, and the duty that circuit control system cannot accurate control circuit causes that output ripple increases.
Summary of the invention
Technical matters solved by the invention is to provide that a kind of that system is controlled is more accurate, exports the electric current detecting method of more stable Boost circuit when discontinuous current mode.
For solving above-mentioned technical matters, the technical scheme that the present invention takes: the electric current detecting method of a kind of Boost circuit when discontinuous current mode, its special feature is: in a switch periods, input voltage V
in, output voltage V
o, switch periods is T
s, inductance value is L, duty cycle of switching is D
1, current sample point is the mid point of inductive current triangular wave uphill process or decline process, and described mid point is sampled and obtained sampled point, calculates its input voltage
with output voltage V
oratio, and with current control signal dutycycle D
1compare;
If
/ V
o=1-D
1, judge circuit working under CCM pattern, sampled point electric current is exactly the mean value of this cycle internal inductance electric current;
If
/ V
o<1-D
1, judge circuit working under DCM pattern, the area of inductive current triangular wave calculates according to formula (1),
In formula, D2 represents that electric current dropped to for 0 time period used from summit, according to area equivalent principle, by a length of side, is T
srectangle carry out equivalent this triangular form, another length of side obtaining according to formula (2) is the mean value of this cycle internal inductance electric current,
The voltage gain of circuit under discontinuous mode in convolution (3) again, derives the mean value of inductive current.
Compared with prior art, beneficial effect of the present invention: detection method of the present invention is simple, do not need to increase extra firmware, calculate easy, be easy to realize, can accurately detect the electric current of Boost circuit working under discontinous mode, system be controlled more accurate, export more stable.
Accompanying drawing explanation
Fig. 1 is the inductive current sampling schematic diagram of existing detection method;
Fig. 2 is the inductive current sampling schematic diagram of detection method of the present invention;
Fig. 3 is the calculation flow chart of inductive current mean value.
Embodiment
The electric current detecting method of Boost circuit when discontinuous current mode, in a switch periods, current sample point is the mid point of inductive current triangular wave uphill process or decline process, and described mid point is sampled and obtained sampled point, calculates its input voltage
with output voltage V
oratio, and with current control signal dutycycle D
1compare,
If
/ V
o=1-D
1, judge circuit working under CCM pattern, sampled point electric current is exactly the mean value of this cycle internal inductance electric current;
If
/ V
o<1-D
1, judge circuit working under DCM pattern, now sample rate current can not be as the mean value of this cycle internal inductance electric current.
As shown in Figure 2, circuit working is at discontinous mode, and the known quantity in this control system has input voltage
, output voltage V
o, switch periods T
s, inductance value L, duty cycle of switching D
1, the area of inductive current triangular wave calculates according to formula (1),
D in formula
2representing that electric current dropped to for 0 time period used from summit, according to area equivalent principle, is T by a length of side
srectangle carry out equivalent this triangular form, another length of side obtaining according to formula (2) is the mean value of this cycle internal inductance electric current,
In conjunction with the voltage gain of circuit under discontinuous mode in formula (3), can derive the mean value of inductive current,
Fig. 3 is the process flow diagram that control system judges and calculate inductive current mean value.
Claims (1)
1. the electric current detecting method of Boost circuit when discontinuous current mode, is characterized in that: in a switch periods, and input voltage
, output voltage V
o, switch periods is T
s, inductance value is L, duty cycle of switching is D
1, current sample point is the mid point of inductive current triangular wave uphill process or decline process, and described mid point is sampled and obtained sampled point, calculates its input voltage
with output voltage V
oratio, and with current control signal dutycycle D
1compare;
If
/ V
o=1-D
1, judge circuit working under CCM pattern, sampled point electric current is exactly the mean value of this cycle internal inductance electric current;
If
/ V
o<1-D
1, judge circuit working under DCM pattern, the area of inductive current triangular wave calculates according to formula (1),
In formula, D2 represents that electric current dropped to for 0 time period used from summit, according to area equivalent principle, by a length of side, is T
srectangle carry out equivalent this triangular form, another length of side obtaining according to formula (2) is the mean value of this cycle internal inductance electric current,
（2）
The voltage gain of circuit under discontinuous mode in convolution (3) again, derives the mean value of inductive current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310649664.6A CN103698574A (en) | 2013-12-06 | 2013-12-06 | Current detection method of Boost circuit during discontinuous inductive current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310649664.6A CN103698574A (en) | 2013-12-06 | 2013-12-06 | Current detection method of Boost circuit during discontinuous inductive current |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103698574A true CN103698574A (en) | 2014-04-02 |
Family
ID=50360171
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310649664.6A Pending CN103698574A (en) | 2013-12-06 | 2013-12-06 | Current detection method of Boost circuit during discontinuous inductive current |
Country Status (1)
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|---|---|
| CN (1) | CN103698574A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110086197A (en) * | 2019-04-18 | 2019-08-02 | 江苏固德威电源科技股份有限公司 | Inductive current sampling calculation method |
| WO2020061727A1 (en) * | 2018-09-25 | 2020-04-02 | 深圳市华芯邦科技有限公司 | Load current detection method and circuit for inductive switching power converter |
| CN112782633A (en) * | 2020-12-24 | 2021-05-11 | 深圳市优优绿能电气有限公司 | Inductive current sampling calibration method, system and computer readable storage medium |
| CN113853040A (en) * | 2020-06-28 | 2021-12-28 | 华润微集成电路(无锡)有限公司 | Sectional type output current control method and circuit for LED driving and LED driving system |
| CN114448023A (en) * | 2021-12-24 | 2022-05-06 | 致瞻科技(上海)有限公司 | Electric energy converter control system and hydrogen fuel cell system |
-
2013
- 2013-12-06 CN CN201310649664.6A patent/CN103698574A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020061727A1 (en) * | 2018-09-25 | 2020-04-02 | 深圳市华芯邦科技有限公司 | Load current detection method and circuit for inductive switching power converter |
| CN110086197A (en) * | 2019-04-18 | 2019-08-02 | 江苏固德威电源科技股份有限公司 | Inductive current sampling calculation method |
| CN110086197B (en) * | 2019-04-18 | 2022-07-19 | 固德威技术股份有限公司 | Inductive current sampling calculation method |
| CN113853040A (en) * | 2020-06-28 | 2021-12-28 | 华润微集成电路(无锡)有限公司 | Sectional type output current control method and circuit for LED driving and LED driving system |
| CN113853040B (en) * | 2020-06-28 | 2023-11-21 | 华润微集成电路(无锡)有限公司 | LED driving sectional type output current control method, circuit and LED driving system |
| CN112782633A (en) * | 2020-12-24 | 2021-05-11 | 深圳市优优绿能电气有限公司 | Inductive current sampling calibration method, system and computer readable storage medium |
| CN114448023A (en) * | 2021-12-24 | 2022-05-06 | 致瞻科技(上海)有限公司 | Electric energy converter control system and hydrogen fuel cell system |
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Application publication date: 20140402 |