CN205786815U - The auxiliary testing circuit of inductive current - Google Patents
The auxiliary testing circuit of inductive current Download PDFInfo
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- CN205786815U CN205786815U CN201620604930.2U CN201620604930U CN205786815U CN 205786815 U CN205786815 U CN 205786815U CN 201620604930 U CN201620604930 U CN 201620604930U CN 205786815 U CN205786815 U CN 205786815U
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- resistance
- input voltage
- inductive current
- electric capacity
- testing circuit
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Abstract
The utility model discloses the auxiliary testing circuit of a kind of inductive current, inductance and the first resistant series between the positive output end and negative output terminal of an input voltage, wherein, one end of the first resistance is connected with the positive output end of input voltage；One end of inductance is connected with the other end of the first resistance, and the other end of inductance is connected with the negative output terminal of input voltage；The auxiliary testing circuit of inductive current includes the second resistance and electric capacity；One end of second resistance is connected with the positive output end of input voltage；One end of electric capacity is connected with the other end of the second resistance, and the other end of electric capacity is connected with the negative output terminal of input voltage.This utility model have simple in construction, be easily achieved, take PCB surface amass little, the feature such as current loop, low cost of manufacture can be reduced.
Description
Technical field
This utility model relates to the auxiliary testing circuit of a kind of inductive current.
Background technology
In order to detect the electric current of inductance in prior art, it is common that with power resistant series inductance, pass through sampled power
The voltage of resistance realizes current sample.This detection mode is primarily present following shortcoming: 1, power resistor not only volume is big, takies
More PCB surface is amassed, and increases current loop, and cost is the highest, if using the power resistor of high accuracy rank,
Then can greatly increase manufacturing cost；2, the voltage conditions at power samples resistance two ends owing to connecting with inductance is complicated (non-connects
Ground, high pressure etc.), cause sample circuit to realize difficulty.
Utility model content
Technical problem to be solved in the utility model is to provide a kind of simple in construction, is easily achieved, takies PCB surface and amass
Little, the auxiliary testing circuit of the inductive current of current loop, low cost can be reduced.
For solving above-mentioned technical problem, this utility model embodiment provides the auxiliary testing circuit of a kind of inductive current, electricity
Sense and the first resistant series are between the positive output end and negative output terminal of an input voltage, and wherein, one end of the first resistance is with defeated
The positive output end entering voltage connects；One end of inductance is connected with the other end of the first resistance, the other end of inductance and input voltage
Negative output terminal connect；The auxiliary testing circuit of inductive current includes the second resistance and electric capacity；One end of second resistance and input
The positive output end of voltage connects；One end of electric capacity is connected with the other end of the second resistance, the other end of electric capacity and input voltage
Negative output terminal connects.
This utility model is at least up to one of following beneficial effect:
1, the auxiliary testing circuit of this utility model embodiment does not change original inductive circuit, by filling of detection electric capacity
Piezoelectric voltage, can go out the current value on inductance by indirectly testing, not only circuit structure is simple, and is easily achieved, it is to avoid directly
Sample circuit is caused to realize the problem that difficulty is big by voltage conditions complexity due to resistance two ends during resistance sample rate current；
2, the auxiliary testing circuit of this utility model embodiment is owing to need not use power resistor to carry out current sample, because of
This compared with prior art reduces PCB area occupied and current loop, also reduces manufacturing cost simultaneously.
Accompanying drawing explanation
In order to be illustrated more clearly that the technical scheme in this utility model embodiment, required in embodiment being described below
Accompanying drawing to be used is briefly introduced, it should be apparent that, the accompanying drawing in describing below is only enforcements more of the present utility model
Example, from the point of view of those of ordinary skill in the art, on the premise of not paying creative work, it is also possible to attached according to these
Figure obtains other accompanying drawing.
Fig. 1 shows the circuit theory of the auxiliary testing circuit of a kind of inductive current according to this utility model one embodiment
Figure.
Fig. 2 shows the graph of relation of inductive current and time.
Fig. 3 shows the charging voltage of electric capacity and the graph of relation in charging interval.
Detailed description of the invention
Below in conjunction with the accompanying drawings this utility model is made and further illustrating.
Fig. 1 shows the schematic diagram of the auxiliary testing circuit of a kind of inductive current according to this utility model one embodiment,
Wherein, inductance L and the first resistance R1 is connected between positive output end and the negative output terminal of an input voltage Uin, constitutes RL circuit,
Further, one end of the first resistance R1 is connected with the positive output end of input voltage Uin；One end of inductance L is another with the first resistance R1's
One end connects, and the other end of inductance L is connected with the negative output terminal of input voltage Uin.
As it is shown in figure 1, include second according to the auxiliary testing circuit of a kind of inductive current of this utility model one embodiment
Resistance R2 and electric capacity C；One end of second resistance R2 is connected with the positive output end of input voltage Uin；One end of electric capacity C and the second electricity
The other end of resistance R2 connects, and the other end of electric capacity C is connected with the negative output terminal of input voltage Uin.This second resistance R2 and electric capacity C
Constitute RC circuit.Above-mentioned input voltage Uin can be such as a DC source, but is not limited to this.
The principle of above-mentioned RC electric circuit inspection inductive current is as follows.
When RL circuit accesses input voltage Uin, inductive current can (Δ t be the most micro-in the least time range Δ t
Second level) linear rise, as shown in Equation 1.
Ipeak=Uin* t/L (formula 1)
Wherein, Ipeak is inductive current, and Uin is input voltage, and L is winding inductance quantity, and Δ t is that input voltage is when powering on
Between, the relation curve of its inductive current and time is as shown in Figure 2.
As RC circuit external input voltage Uin, if the relation curve in the voltage of electric capacity C and charging interval as it is shown on figure 3,
During charging interval Δ t < τ (τ=RC, Δ t are generally Microsecond grade), its charging curve is similar to straight line, its expression formula such as formula
Shown in 2.
Uchg=0.632Uin* Δ t/ τ (formula 2)
Wherein Uchg is the electric capacity C charging voltage in Δ t, and Uin is input voltage, and Δ t is that input voltage is when powering on
Between (namely charging interval), τ is capacity time constant, τ=RC.
Above-mentioned formula 1 and formula 2 can merge abbreviation, obtain formula 3 after merging abbreviation:
Ipeak=Uchg* τ/(0.632*L) (formula 3)
By formula 3, to measure the current value Ipeak flow through on inductance L, we can be by measuring electric capacity C
Charging voltage Uchg indirectly obtain, it is achieved equivalent measurement inductive current function.
Charging voltage Uchg of electric capacity C can be obtained by the detection such as voltage detecting circuit, comparator, and the voltage detected can
For follow-up process.In the present embodiment, the auxiliary testing circuit of inductive current also includes a comparator OP, comparator OP's
In-phase end is connected to the common contact of the second resistance R2 and electric capacity C, and the end of oppisite phase of comparator OP connects corresponding to predetermined threshold value electric current
Reference voltage V1；Comparator OP for the input voltage Uchg of in-phase end is compared with reference voltage V1, and according to than
Relatively result output control signal, for the current-limiting protection of circuit.
Further, comparator OP is quick comparator, and the output delay time of this quick comparator was less than for 150 nanoseconds,
Preferably less than 100 nanoseconds.Owing to the output delay time of quick comparator to be significantly smaller than common comparator so that electric current
The actual value of protection is closer to desired value, it is thus possible to obtain more preferable switching tube current-limiting protection effect.
The auxiliary testing circuit of this utility model embodiment does not change original inductive circuit, by detecting the charging of electric capacity
Voltage, can go out the current value on inductance by indirectly testing, not only circuit structure is simple, and is easily achieved, it is to avoid direct use
Sample circuit is caused to realize the problem that difficulty is big due to the voltage conditions complexity at resistance two ends during resistance sampling electric current.Additionally, this
The auxiliary testing circuit of utility model embodiment carries out current sample, therefore with prior art phase owing to need not use power resistor
Ratio, reduces PCB area occupied and current loop, also reduces manufacturing cost simultaneously.
Obviously, those skilled in the art can carry out various change and modification without deviating from this practicality to this utility model
Novel spirit and scope.So, if of the present utility model these amendment and modification belong to this utility model claim and
Within the scope of its equivalent technologies, then this utility model is also intended to comprise these change and modification.
Claims (3)
1. an auxiliary testing circuit for inductive current, described inductance and the first resistant series are at the positive output end of an input voltage
And between negative output terminal, wherein, one end of described first resistance is connected with the positive output end of described input voltage；Described inductance
One end is connected with the other end of described first resistance, and the other end of described inductance is connected with the negative output terminal of described input voltage；
It is characterized in that, the auxiliary testing circuit of described inductive current includes the second resistance and electric capacity；One end of described second resistance with
The positive output end of described input voltage connects；One end of described electric capacity is connected with the other end of described second resistance, described electric capacity
The other end be connected with the negative output terminal of described input voltage.
2. the auxiliary testing circuit of inductive current as claimed in claim 1, it is characterised in that the auxiliary inspection of described inductive current
Slowdown monitoring circuit also includes that a comparator, the in-phase end of described comparator are connected to the common contact of described second resistance and described electric capacity,
The end of oppisite phase of described comparator connects the reference voltage corresponding to predetermined threshold value electric current.
3. the auxiliary testing circuit of inductive current as claimed in claim 2, it is characterised in that described comparator is for quickly to compare
Device, the output delay time of described quick comparator was less than for 150 nanoseconds.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620604930.2U CN205786815U (en) | 2016-06-20 | 2016-06-20 | The auxiliary testing circuit of inductive current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620604930.2U CN205786815U (en) | 2016-06-20 | 2016-06-20 | The auxiliary testing circuit of inductive current |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205786815U true CN205786815U (en) | 2016-12-07 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620604930.2U Active CN205786815U (en) | 2016-06-20 | 2016-06-20 | The auxiliary testing circuit of inductive current |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205786815U (en) |
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2016
- 2016-06-20 CN CN201620604930.2U patent/CN205786815U/en active Active
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