CN212111569U - Inductive current detection circuit for switching power supply - Google Patents
Inductive current detection circuit for switching power supply Download PDFInfo
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- CN212111569U CN212111569U CN202020640133.6U CN202020640133U CN212111569U CN 212111569 U CN212111569 U CN 212111569U CN 202020640133 U CN202020640133 U CN 202020640133U CN 212111569 U CN212111569 U CN 212111569U
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Abstract
The utility model belongs to the technical field of current detection, concretely relates to inductive current detection circuit for among switching power supply, the technical problem of solution is: the inductive current detection circuit for the switching power supply is simple in structure and small in measurement error, and adopts the technical scheme that: an inductor current detection circuit used in a switching power supply, comprising an inductor L1 connected in series in the switching power supply, the inductor current detection circuit comprising: the detection coil L2, the first voltage division circuit, the second voltage division circuit, the power amplification circuit and the filter circuit; the voltage input end of the detection coil L2 is connected with the voltage input end of the inductor L1, the first voltage division circuit is connected with the two ends of the inductor L1 in parallel, the second voltage division circuit is connected with the two ends of the detection coil L2 in parallel, the output end of the first voltage division circuit and the output end of the second voltage division circuit are respectively and electrically connected with the input end of the power amplification circuit, and the output end of the power amplification circuit is connected with the output end of the inductive current detection circuit after being connected with the filter circuit in series.
Description
Technical Field
The utility model belongs to the technical field of current detection, concretely relates to inductance current detection circuit for among switching power supply.
Background
The output filtering of the switching power supply needs an inductor, and the current of the inductor is detected through the direct-current equivalent resistance voltage drop of the inductor, so that the functions of overvoltage protection, overcurrent protection, short-circuit protection and the like of the switching power supply are realized;
in a conventional overvoltage protection scheme, in order to detect whether an output voltage is overvoltage or not, generally, the voltage of an inductor is directly measured, and measurement errors are easily caused due to voltage drop generated by the inductor.
SUMMERY OF THE UTILITY MODEL
The utility model overcomes the deficiencies in the prior art, the technical problem who solves is: the inductive current detection circuit used in the switching power supply is simple in structure and small in measurement error.
In order to solve the technical problem, the utility model discloses a technical scheme be:
an inductor current detection circuit for use in a switching power supply, comprising an inductor L1 connected in series in the switching power supply, the inductor current detection comprising: the detection coil L2, the first voltage division circuit, the second voltage division circuit, the power amplification circuit and the filter circuit; the voltage input end of the detection coil L2 is connected with the voltage input end of the inductor L1, the first voltage division circuit is connected at two ends of the inductor L1 in parallel, the second voltage division circuit is connected at two ends of the detection coil L2 in parallel, the output end of the first voltage division circuit and the output end of the second voltage division circuit are respectively and electrically connected with the input end of the power amplification circuit, and the output end of the power amplification circuit is connected with the output end of the inductive current detection circuit after being connected with the filter circuit in series.
Preferably, the first voltage dividing circuit includes: a resistor R1 and a resistor R2, the second voltage divider circuit comprising: resistance R3 and resistance R4, the power amplifier circuit includes: the circuit comprises an amplifier U1, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R11 and a capacitor C2; one end of the resistor R1 is respectively connected with one end of an inductor L1, one end of a detection coil L2, one end of a resistor R3 and one end of a resistor R7, the other end of the resistor R1 is respectively connected with one end of a resistor R2 and one end of a resistor R6, the other end of the resistor R3 is respectively connected with one end of a resistor R4 and one end of a resistor R5, the other end of the resistor R2 is connected with the other end of the inductor L1, and the other end of the resistor R4 is connected with the other end of the detection coil L2; the other end of the resistor R5 is respectively connected with one end of a resistor R11, one end of a capacitor C2 and the non-inverting input end of an amplifier U1, and the other end of the resistor R11 is connected with the other end of the capacitor C2 and then grounded; the other end of the resistor R6 is respectively connected with one end of a resistor R7, one end of a resistor R8 and the inverting input end of the amplifier U1, and the other end of the resistor R8 is respectively connected with the output end of the amplifier U1 and the input end of the filter circuit.
Preferably, the filter circuit includes: a resistor R9 and a capacitor C3; one end of the resistor R9 is connected with the output end of the amplifier U1, and the other end of the resistor R9 is connected with one end of the capacitor C3 and the output end of the inductive current detection circuit.
Preferably, a current limiting resistor R10 is connected in series between the filter circuit and the output terminal of the inductor current detection circuit.
Preferably, a freewheeling diode D1 is connected in parallel between two ends of the inductor L1.
Compared with the prior art, the utility model following beneficial effect has:
the utility model discloses in, including detection coil L2 that is used for detecting inductance L1 electric current, be provided with first divider circuit between inductance L1's the both ends, be provided with the second divider circuit between detection coil L2's the both ends, the output of first divider circuit, the output of second divider circuit links to each other with power amplifier circuit's input respectively, power amplifier circuit's output concatenates filter circuit after and links to each other with inductance current detection circuit's output;
when the detection coil is used, the input voltage entering the power amplification circuit has the same voltage level through the first voltage division circuit and the second voltage division circuit, and compared with the traditional mode, the detection coil L2 detection value is eliminated, wherein the detection coil L2 detection value comprises the following steps: the equivalent inductance voltage which is not counteracted except the equivalent resistance voltage of the inductance L1 reduces the measurement error; the voltage is detected and differentially amplified through the power amplifying circuit, an amplified signal of the direct current equivalent resistance voltage of the inductance power coil is obtained at the output end of the power amplifying circuit, and the current of the overcurrent inductor is accurately detected;
the utility model discloses compare with traditional inductive current detection circuit, require to be low (if: do not require detection coil L2 the same with inductance L1's the coil number of turns) to detection coil L2 and inductance L1, the utility model discloses in, according to inductance L1 and detection coil L2's turn ratio, through adjusting the voltage division ratio between first voltage division circuit and the second voltage division circuit, can make the input voltage electricity that enters into power amplification circuit have the same voltage level, simple structure, the practicality is strong.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings.
Fig. 1 is a schematic circuit diagram of an inductive current detection circuit for a switching power supply according to the present invention;
in the figure: 1 is a first voltage division circuit, 2 is a second voltage division circuit, 3 is a power amplification circuit, and 4 is a filter circuit.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention; based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
Example one
Fig. 1 is the utility model relates to a schematic circuit diagram for inductive current detection circuit among switching power supply, as shown in fig. 1, the inductive current detection circuit for among switching power supply that this embodiment provided, including the inductance L1 of concatenating in switching power supply, its characterized in that: the inductor current detection comprises: the detection coil L2, the first voltage division circuit 1, the second voltage division circuit 2, the power amplification circuit 3, and the filter circuit 4;
the voltage input end of the detection coil L2 is connected with the voltage input end of the inductor L1, the first voltage division circuit 1 is connected at two ends of the inductor L1 in parallel, the second voltage division circuit 2 is connected at two ends of the detection coil L2 in parallel, the output end of the first voltage division circuit 1 and the output end of the second voltage division circuit 2 are respectively and electrically connected with the input end of the power amplification circuit 3, and the output end of the power amplification circuit 3 is connected with the output end of the inductive current detection circuit after being connected with the filter circuit 4 in series.
The utility model discloses in, including detection coil L2 that is used for detecting inductance L1 electric current, be provided with first divider circuit between inductance L1's the both ends, be provided with the second divider circuit between detection coil L2's the both ends, the output of first divider circuit, the output of second divider circuit links to each other with power amplifier circuit's input respectively, power amplifier circuit's output concatenates filter circuit after and links to each other with inductance current detection circuit's output; when the detection coil is used, the input voltage entering the power amplification circuit has the same voltage level through the first voltage division circuit and the second voltage division circuit, and compared with the traditional mode, the detection coil L2 detection value is eliminated, wherein the detection coil L2 detection value comprises the following steps: the equivalent inductance voltage which is not counteracted except the equivalent resistance voltage of the inductance L1 reduces the measurement error; the voltage is detected and differentially amplified through the power amplifying circuit, an amplified signal of the direct current equivalent resistance voltage of the inductance power coil is obtained at the output end of the power amplifying circuit, and the current of the overcurrent inductor is accurately detected; the utility model discloses compare with traditional inductive current detection circuit, require to be low (if: do not require detection coil L2 the same with inductance L1's the coil number of turns) to detection coil L2 and inductance L1, the utility model discloses in, according to inductance L1 and detection coil L2's turn ratio, through adjusting the voltage division ratio between first voltage division circuit and the second voltage division circuit, can make the input voltage electricity that enters into power amplification circuit have the same voltage level, simple structure, the practicality is strong.
Specifically, the first voltage dividing circuit 1 includes: a resistor R1 and a resistor R2, and the second voltage divider circuit 2 includes: a resistor R3 and a resistor R4, and the power amplifier circuit 3 includes: the circuit comprises an amplifier U1, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R11 and a capacitor C2; one end of the resistor R1 is respectively connected with one end of an inductor L1, one end of a detection coil L2, one end of a resistor R3 and one end of a resistor R7, the other end of the resistor R1 is respectively connected with one end of a resistor R2 and one end of a resistor R6, the other end of the resistor R3 is respectively connected with one end of a resistor R4 and one end of a resistor R5, the other end of the resistor R2 is connected with the other end of the inductor L1, and the other end of the resistor R4 is connected with the other end of the detection coil L2; the other end of the resistor R5 is respectively connected with one end of a resistor R11, one end of a capacitor C2 and the non-inverting input end of an amplifier U1, and the other end of the resistor R11 is connected with the other end of the capacitor C2 and then grounded; the other end of the resistor R6 is respectively connected with one end of a resistor R7, one end of a resistor R8 and the inverting input end of the amplifier U1, and the other end of the resistor R8 is respectively connected with the output end of the amplifier U1 and the input end of the filter circuit 4.
Example two
On the basis of the first embodiment, the filter circuit 4 includes: a resistor R9 and a capacitor C3; one end of the resistor R9 is connected with the output end of the amplifier U1, and the other end of the resistor R9 is connected with one end of the capacitor C3 and the output end of the inductive current detection circuit.
EXAMPLE III
In the first embodiment, a current limiting resistor R10 is connected in series between the filter circuit 4 and the output terminal of the inductor current detection circuit, and a freewheeling diode D1 is connected in parallel between the two ends of the inductor L1.
The utility model discloses can wide application in switching power supply's inductive current detection, circuit structure is simple, extensive applicability, the practicality is strong.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.
Claims (5)
1. An inductor current detection circuit used in a switching power supply, comprising an inductor L1 connected in series in the switching power supply, characterized in that: the inductor current detection comprises: the detection coil L2, the first voltage division circuit (1), the second voltage division circuit (2), the power amplification circuit (3) and the filter circuit (4);
the voltage input end of the detection coil L2 is connected with the voltage input end of the inductor L1, the first voltage division circuit (1) is connected at two ends of the inductor L1 in parallel, the second voltage division circuit (2) is connected at two ends of the detection coil L2 in parallel, the output end of the first voltage division circuit (1) and the output end of the second voltage division circuit (2) are respectively and electrically connected with the input end of the power amplification circuit (3), and the output end of the power amplification circuit (3) is connected with the output end of the inductor current detection circuit after being connected with the filter circuit (4) in series.
2. The inductor current sense circuit for use in a switching power supply of claim 1, wherein: the first voltage dividing circuit (1) includes: a resistor R1 and a resistor R2, the second voltage divider circuit (2) comprising: a resistor R3 and a resistor R4, the power amplification circuit (3) comprising: the circuit comprises an amplifier U1, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R11 and a capacitor C2; one end of the resistor R1 is respectively connected with one end of an inductor L1, one end of a detection coil L2, one end of a resistor R3 and one end of a resistor R7, the other end of the resistor R1 is respectively connected with one end of a resistor R2 and one end of a resistor R6, the other end of the resistor R3 is respectively connected with one end of a resistor R4 and one end of a resistor R5, the other end of the resistor R2 is connected with the other end of the inductor L1, and the other end of the resistor R4 is connected with the other end of the detection coil L2; the other end of the resistor R5 is respectively connected with one end of a resistor R11, one end of a capacitor C2 and the non-inverting input end of an amplifier U1, and the other end of the resistor R11 is connected with the other end of the capacitor C2 and then grounded; the other end of the resistor R6 is respectively connected with one end of a resistor R7, one end of a resistor R8 and the inverting input end of the amplifier U1, and the other end of the resistor R8 is respectively connected with the output end of the amplifier U1 and the input end of the filter circuit (4).
3. The inductor current detection circuit for use in a switching power supply of claim 2, wherein: the filter circuit (4) comprises: a resistor R9 and a capacitor C3; one end of the resistor R9 is connected with the output end of the amplifier U1, and the other end of the resistor R9 is connected with one end of the capacitor C3 and the output end of the inductive current detection circuit.
4. The inductor current sense circuit for use in a switching power supply of claim 3, wherein: and a current-limiting resistor R10 is connected in series between the filter circuit (4) and the output end of the inductive current detection circuit.
5. The inductor current sense circuit for use in a switching power supply of claim 1, wherein: a freewheeling diode D1 is connected in parallel between two ends of the inductor L1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020640133.6U CN212111569U (en) | 2020-04-24 | 2020-04-24 | Inductive current detection circuit for switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020640133.6U CN212111569U (en) | 2020-04-24 | 2020-04-24 | Inductive current detection circuit for switching power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212111569U true CN212111569U (en) | 2020-12-08 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020640133.6U Active CN212111569U (en) | 2020-04-24 | 2020-04-24 | Inductive current detection circuit for switching power supply |
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| Country | Link |
|---|---|
| CN (1) | CN212111569U (en) |
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2020
- 2020-04-24 CN CN202020640133.6U patent/CN212111569U/en active Active
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