CN105242190A - Current detection circuit - Google Patents
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- CN105242190A CN105242190A CN201510675379.0A CN201510675379A CN105242190A CN 105242190 A CN105242190 A CN 105242190A CN 201510675379 A CN201510675379 A CN 201510675379A CN 105242190 A CN105242190 A CN 105242190A
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Abstract
The invention discloses a current detection circuit. When a current passing through a power transistor is higher than a certain threshold, a first current detection circuit is adopted to obtain a current detection signal; when the current passing through the power transistor is lower than a certain threshold, a second current detection circuit is intermittently adopted to obtain a current detection signal. The invention aims to obtain a current detection signal with high accuracy without increasing extra consumption of the system.
Description
Technical field
The present invention relates to a kind of Power Electronic Technique, more particularly, relate to a kind of current detection circuit of the transistor be applied in electronic product.
Background technology
In power electronic system, generally all need testing circuit, in order to detect the signal in main circuit or site of deployment, then form corresponding control signal according to these signals and according to the job requirement of system.Voltage detecting circuit and current detection circuit is needed according to system.
At application occasions such as USB portable power sources (PowerBank), usually require that system is carried out zero load (or underloading) and detected, in order to judge that system is the need of entering sleep pattern.Here the detection with regard to needing a current detection circuit to carry out loading condition, enters corresponding mode of operation with indication mechanism.
In prior art, in some chips, there is no the occasion of integrated power transistor, as shown in Figure 1, need to connect a detection resistance Rsense in power feed lines, realize current sense function by the pressure reduction detecting resistance two ends.The shortcoming done like this is: the electric current 1, due to required detection is very little, is that the pressure reduction at event resistance two ends is very little, needs the circuit that precision is very high just can carry out accurately current detecting.2, due to a detection resistance of connecting in power feed lines, so add extra power consumption.
Being integrated with the occasion of power transistor in inside, by detecting the electric current that it flows through, judging the size of load current.Conventional current detection circuit, when electric current is less, higher to the accuracy requirement of components and parts, otherwise it is very large to detect time error at small area analysis.The shortcoming of this current detecting mode is: because need accurately small area analysis to be detected, very high to the requirement of components and parts precision, greatly can increase cost.
Summary of the invention
In view of this, the invention provides a kind of current detection circuit, to solve the problem that in prior art, current detection accuracy is not high or loss is larger.
First aspect, provides a kind of current detection circuit, for detecting the size flowing through power crystal tube current, comprising:
First testing circuit, for detect in a first condition flow through power transistor current signal to obtain the first current detection signal of sign loading condition;
Second testing circuit, for detect in a second condition flow through power transistor current signal to obtain the second current detection signal of sign loading condition;
Comparator circuit, receives described first current detection signal and first threshold, exports comparison signal;
Logical circuit, receives described comparison signal and a clock signal, and output detection circuit selects signal;
Wherein, described current detection circuit selects signal behavior first testing circuit or the second testing circuit for detecting the current signal flowing through power transistor according to described testing circuit.
Preferably, described first testing circuit comprises:
Transistor seconds, its drain electrode is connected with the drain electrode of described power transistor, and grid is connected with the grid of described power transistor, and source electrode is connected to the first input end of the first error amplifier;
Described first error amplifier, the second input end is connected to the source electrode of described power transistor, exports the first error amplification signal;
Third transistor, one end is connected to the first input end of described first error amplifier, and the other end is connected to the first end of the first detection resistance, and control end receives described first error amplification signal;
Described first detects resistance, and the second termination controls ground, and the voltage on its first end is the first current detection signal.
Preferably, described second testing circuit comprises:
4th transistor, its drain electrode is connected with the drain electrode of described power transistor by the 3rd resistance, and source electrode is connected with the source electrode of described power transistor, and grid is also connected with the grid of described power transistor;
Second error amplifier, first input end is connected to the source electrode of described power transistor by a voltage source, second input end is connected to the drain electrode of described power transistor, exports the second error amplification signal, and described second error amplification signal is for controlling described power transistor and the 4th transistor;
3rd error amplifier, first input end is connected to the points of common connection of the 4th resistance and a current source, second input end is connected to the points of common connection of the 5th resistance and another current source, and export the 3rd error amplification signal, described 5th resistance is also connected with described 3rd resistance;
5th transistor, one end is connected to the first input end of described 3rd error amplifier, and the other end is connected to the first end of the second detection resistance, and control end receives described 3rd error amplification signal;
Described second detects resistance, and the second termination controls ground, and the voltage on its first end is the second current detection signal;
Wherein, when described second testing circuit work, described power transistor and described 4th transistor are all operated in variable resistor district.
Preferably, under same gate source voltage, the conducting resistance of described transistor seconds and the 4th transistor and the conducting resistance of described power transistor proportional, and the conducting resistance of described power transistor is less than the conducting resistance of described transistor seconds and the 4th transistor.
Preferably, described comparator circuit comprises:
Comparer, first input end receives described first current detection signal, and the second input end receives described first threshold, exports comparison signal;
Described comparison signal is significant level when described first threshold is greater than described first current detection signal.
Preferably, described logical circuit is when described clock signal and described comparison signal are significant level, and the testing circuit exported as significant level selects signal.
Preferably, described current detection circuit also comprises the first switch and second switch, in order to work in described first testing circuit access current detection circuit during described first switch conduction, in order to work in described second testing circuit access current detection circuit during described second switch conducting;
Described first switch and described second switch are controlled by described testing circuit and select signal conduction or shutoff, wherein, when described testing circuit selects signal to be significant level, and described second switch conducting, described first switch OFF; When described testing circuit selects signal to be inactive level, described first switch conduction, described second switch turns off.
Preferably, when switching to described second testing circuit work from described first testing circuit, generate the second current detection signal after described second testing circuit postpones predetermined time, described predetermined time is in order to switch the conducting state of described power transistor.
Preferably, regulate the width of described clock signal significant level, in order to change the working time of described second testing circuit.
Second aspect, provides a kind of control circuit, comprising:
Current detection circuit as above.
The technology of the present invention is by making to adopt the first current detection circuit to obtain current detection signal when the electric current flowing through power transistor is greater than certain threshold value, when the electric current flowing through power transistor is less than certain threshold value, the second current detection circuit is intermittently adopted to obtain current detection signal, reach and obtain the higher current detection signal of precision, and the object of the excess loss of system can not be increased.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only embodiments of the invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to the accompanying drawing provided.
Fig. 1 is the circuit structure diagram of the current detection circuit of prior art;
Fig. 2 is the circuit structure diagram of the current detection circuit of the embodiment of the present invention;
Fig. 3 is the circuit diagram of the first testing circuit in the current detection circuit of the embodiment of the present invention;
Fig. 4 is the circuit diagram of the second testing circuit in the current detection circuit of the embodiment of the present invention;
Fig. 5 is the working waveform figure of the current detection circuit of the embodiment of the present invention.
Embodiment
Based on embodiment, present invention is described below, but the present invention is not restricted to these embodiments.In hereafter details of the present invention being described, detailedly describe some specific detail sections.Do not have the description of these detail sections can understand the present invention completely for a person skilled in the art yet.In order to avoid obscuring essence of the present invention, known method, process, flow process, element and circuit do not describe in detail.
In addition, it should be understood by one skilled in the art that the accompanying drawing provided at this is all for illustrative purposes, and accompanying drawing is not necessarily drawn in proportion.
Meanwhile, should be appreciated that in the following description, " circuit " refers to the galvanic circle connected and composed by electrical connection or electromagnetism by least one element or electronic circuit.When " being connected to " another element when claiming element or circuit or claiming element/circuit " to be connected to " between two nodes, it can be directly couple or be connected to another element or can there is intermediary element, the connection between element can be physically, in logic or its combine.On the contrary, " be directly coupled to " when claiming element or " being directly connected to " another element time, mean that both do not exist intermediary element.
Unless the context clearly requires otherwise, similar words such as " comprising ", " comprising " otherwise in whole instructions and claims should be interpreted as the implication that comprises instead of exclusive or exhaustive implication; That is, be the implication of " including but not limited to ".
In describing the invention, it is to be appreciated that term " first ", " second " etc. are only for describing object, and instruction or hint relative importance can not be interpreted as.In addition, in describing the invention, except as otherwise noted, the implication of " multiple " is two or more.
Figure 2 shows that the circuit structure diagram of the current detection circuit of the embodiment of the present invention, as shown in Figure 2, the current detection circuit of the embodiment of the present invention comprises the first testing circuit 21, second testing circuit 22, comparator circuit 23 and logical circuit 24, wherein:
First testing circuit 21, for detect in a first condition flow through power transistor M1 current signal to obtain the first current detection signal Vsense1 of sign loading condition.
Second testing circuit 22, for detect in a second condition flow through power transistor M1 current signal to obtain the second current detection signal Vsense2 of sign loading condition.
Comparator circuit 23, in embodiments of the present invention, be comparer CMP, its first input end receives the first current detection signal Vsense1, and the second input end receives described first threshold Vth1, exports comparison signal Vcmp.First threshold Vth1 is corresponding to a certain predetermined value of electric current I o flowing through power transistor M1, and when the first current detection signal Vsense1 is less than first threshold Vth1, characterize the electric current I o flowing through transistor M1 less, also namely load is lighter.Due to the positive input termination first threshold Vth1 of comparer CMP, negative input termination first current detection signal Vsense1, therefore when the first current detection signal Vsense1 is less than first threshold Vth1, the comparison signal Vcmp that comparer CMP exports is high level, i.e. significant level.
Logical circuit 24, receives a comparison signal Vcmp and clock signal clock, and output detection circuit selects signal Vcho.Current detection circuit selects signal Vcho to select the first testing circuit 21 or the second testing circuit 22 for detecting the current signal Io flowing through power transistor M1 according to testing circuit.Logical circuit 24 is when clock signal clock and comparison signal Vcmp is significant level, and the testing circuit exported as significant level selects signal Vcho.According to this logical relation, logical circuit 24 can adopt and such as realize with circuit such as doors.
Current detection circuit also comprises the first K switch 1 and second switch K2, work in order to the first testing circuit 21 is accessed in current detection circuit during the first K switch 1 conducting, work in order to the second testing circuit 22 is accessed in current detection circuit during second switch K2 conducting.First K switch 1 and described second switch K2 are controlled by testing circuit and select signal Vcho conducting or shutoff, wherein, when testing circuit selects signal Vcho to be significant level, and second switch K2 conducting, the first K switch 1 turns off; When testing circuit selects signal Vcho to be inactive level, the first K switch 1 conducting, second switch K2 turns off.
The current detection circuit of the embodiment of the present invention, when starting working, the first testing circuit 21 is adopted to obtain the first current detection signal Vsense1 characterizing loading condition, and compare with first threshold Vth1, if the first current detection signal Vsense1 is greater than first threshold Vth1, then characterize the electric current I o now flowing through transistor M1 larger, system is in normal operating conditions, adopt the first current detection circuit can meet the accuracy requirement of current detecting, the first current detection signal Vsense1 is the output signal of current detection circuit; If the first current detection signal Vsense1 is less than first threshold Vth1, then characterize the electric current I o now flowing through transistor M1 less, also namely load is lighter, adopt the first current detection circuit can not meet the accuracy requirement of current detecting, now make current detection circuit enter intermittently to adopt the pattern of the second current detection circuit work, also when namely clock signal clock is significant level, the second testing circuit is adopted to carry out current detecting, regulate the width of clock signal clock significant level, the working time of described second testing circuit can be changed.The reason done like this is, if meet the accuracy requirement of current detecting, adopts the second current detection circuit to carry out current detecting always, can cause larger excess loss when electric current I o is less.And adopt step mode, be also based in most of underloading or spaceborne system to the instantaneity of current detecting and successional less demanding, just make the technology of the present invention can realize the accurate detection of small area analysis but too much power consumption can not be increased again simultaneously.Introduce circuit structure and the principle of work of the first current detection circuit 21 and the second current detection circuit 22 below in detail:
Fig. 3 is the circuit diagram of the first testing circuit 21 in the current detection circuit of the embodiment of the present invention.As shown in Figure 3, the first current detection circuit 21 comprises:
Transistor seconds M2, its drain electrode is connected with the drain electrode of power transistor M1, and grid is connected with the grid of power transistor M1, and source electrode is connected to the first input end of the first error amplifier EA1;
First error amplifier EA1, the second input end is connected to the source electrode of power transistor M1, exports the first error amplification signal Vea1;
Third transistor M3, one end is connected to the first input end of the first error amplifier EA1, and the other end is connected to the first end of the first detection resistance, and control end receives described first error amplification signal Vea1;
First detects resistance R1, and the second termination controls ground, and the voltage on its first end is the first current detection signal Vsense1.
Power transistor M1 in the embodiment of the present invention is inner integrated PowerFET, by detecting the electric current I o that it flows through, can judge the size of load current.In the first testing circuit in 21, the effective width ratio power transistor M1 of transistor seconds M2 is much little, the effective width of power transistor should be transistor seconds M2 several thousand or even several ten thousand times more than.When transistor seconds M2 is identical with the gate source voltage of power transistor M1, the conducting resistance of its conducting resistance and power transistor M1 is proportional, and the conducting resistance of power transistor M1 is far smaller than the conducting resistance of transistor seconds M2, in the present embodiment, be 1/K times of transistor seconds M2 conducting resistance.The drain and gate of transistor seconds M2 is connected with the drain and gate of power transistor M1 respectively, two input ends of the first error amplifier EA1 connect the source electrode of power transistor M1 and the source electrode of transistor seconds M2 respectively, the source voltage of transistor seconds M2 is made to follow the source voltage of power transistor M1, also be, the voltage of each corresponding pole of the power transistor M1 and transistor seconds M2 with certain proportion conducting resistance is all set to identical, so, according to the operating characteristic of transistor, namely the electric current flowing through transistor seconds M2 can reflect the electric current of the M1 flowing through power transistor, but because this electric current is far smaller than the electric current I o flowing through power transistor, therefore it is also less in the first loss detected on resistance R1, first voltage detecting resistance R1 first end is the first current detection signal Vsense1.
Although this kind of current detecting mode is simple, but it is higher to the accuracy requirement of the first error amplifier EA1, if exist biased at the occasion first error amplifier EA1 that electric current is larger, still can meet the accuracy requirement of current detecting, electric current less even close to zero time, the biased meeting of the first error amplifier EA1 causes current detecting to occur great error.
Fig. 4 is the circuit diagram of the second testing circuit 22 in the current detection circuit of the embodiment of the present invention.As shown in Figure 4, the second current detection circuit 22 comprises:
4th transistor M4, its drain electrode is connected with the drain electrode of power transistor M1 by the 3rd resistance R3, and source electrode is connected with the source electrode of power transistor M1, and grid is also connected with the grid of power transistor M1;
Second error amplifier EA2, first input end by a voltage source V s be connected to the source electrode of rate transistor M1, second input end is connected to the drain electrode of power transistor M1, export the second error amplification signal Vea2, the second error amplification signal Vea2 is for controlling power transistor M1 and the 4th transistor M4;
3rd error amplifier EA3, first input end is connected to the points of common connection of the 4th resistance R4 and a current source Ib1, second input end is connected to the points of common connection of the 5th resistance R5 and another current source Ib2, export the 3rd error amplification signal Vea3, the 5th resistance R5 is also connected with described 3rd resistance R3;
5th transistor M5, one end is connected to the first input end of the 3rd error amplifier EA3, and the other end is connected to the first end of the second detection resistance R2, and control end receives described 3rd error amplification signal Vea3;
Second detects resistance R2, and the second termination controls ground, and the voltage on its first end is the second current detection signal Vsense2.
Be understandable that, in other embodiments, second detects resistance can detect resistance and share same resistance with first, with this, first current detection signal Vsense1 and the second current detection signal Vsense2 just can obtain from the same node circuit, also save a resistance simultaneously, reduce volume and cost.
In the second testing circuit 22, the effective width ratio power transistor M1 of the 4th transistor M4 is much little, the effective width of power transistor should be the 4th transistor M4 several thousand or even several ten thousand times more than.When 4th transistor M4 is identical with the gate source voltage of power transistor M1, the conducting resistance of its conducting resistance and power transistor M1 is proportional, and the conducting resistance of power transistor M1 is far smaller than the conducting resistance of the 4th transistor M4.In embodiments of the present invention, choosing the 4th transistor M4 and transistor seconds M2 is identical model, and namely its conducting resistance is the K of power transistor M1 conducting resistance doubly under the same conditions, then its electric current flow through is Io/K.Certainly, be understandable that, when the 4th transistor M4 is different from the proportionate relationship of power transistor M1 conducting resistance with the conducting resistance of transistor seconds M2, also be allow, can, by the parameter of other components and parts in regulating circuit, make the first current detection signal Vsense1 consistent with the benchmark of the second current detection signal Vsense2.
Wherein, when the second testing circuit 22 works, in-phase input end due to the second error amplifier EA2 is connected to the drain electrode of power transistor M1, inverting input is connected to the source electrode of power transistor M1 by a voltage source V s, and using the grid voltage of the output signal Vea2 of the second error amplifier EA2 as power transistor M1, so just by constant in Second Threshold Vth2 for the drain-source voltage of power transistor M1 difference, power transistor M1 can be made to be operated in variable resistor district, also to claim saturation region.The grid of the 4th transistor M4 is connected with source electrode with the grid of power transistor M1 respectively with source electrode, though drain electrode is connected to the drain electrode of power transistor M1 by the 3rd resistance R3, but because the 3rd resistance R3 is general less, it has very little pressure reduction, so can think that the 4th transistor M4 is all consistent with the voltage of each pole of power transistor M1, power transistor M1 and the 4th transistor M4 is all operated in variable resistor district.Therefore the electric current that the 4th transistor M4 flows through is Io/K, become certain proportionate relationship, and K is far longer than 1 with the electric current I o that power transistor M1 flows through.
Second current detection circuit 22 also comprises identical little current source Ib1 and Ib2 of two current values.One end ground connection of current source Ib1, the other end is connected to the inverting input of the 3rd error amplifier EA3; One end ground connection of current source Ib2, the other end is connected to the in-phase input end of the 3rd error amplifier EA3.The output signal Vea3 of the 3rd error amplifier EA3 is as the grid voltage of the 5th transistor M5.According to circuit theory, when the 3rd error amplifier EA3 steady operation, the voltage of its in-phase input end and inverting input can remain equal, can draw accordingly, the value of the second current detection signal Vsense2 is (R3/R4) * (Io/K) * R2, thus can characterize and flow through power brilliant M1 body tube current size Io.
In the second testing circuit 22, because the second error amplifier EA2 just makes power transistor M1 and the 4th transistor M4 work variable resistor district, therefore it is not high to its accuracy requirement, when system power is smaller, even if the second error amplifier EA2 exists certain being biased, the second testing circuit 22 also can realize the current detecting of higher precision.And transistor is when variable resistor district, and under specific grid source current, its electric current is constant value, this also considerably increases operating accuracy and the reliability of the second testing circuit 22.And if the 3rd error amplifier EA3 exists biased, its biased value is compared with the input voltage of two input ends also less, little on the impact of input signal, therefore can not cause detecting error.Thus, can find out, when the electric current flowing through power transistor M1 is less, the second testing circuit 22 can meet the accuracy requirement of current detecting.
But operationally, power transistor M1 is operated in variable resistor district to the second testing circuit 22, does not have complete conducting, its conducting resistance is comparatively large, so can produce larger power attenuation.But, the embodiment of the present invention is by a clock signal clock, control the second testing circuit 22 intermittently to work, namely first threshold Vth1 is less than at the first current detection signal Vsense1, and clock signal is when being effective high level, just switches to the second testing circuit 22 and start working and carry out current detecting.If therefore the time of clock signal clock high level account for the ratio of one-period less time, it is not long time second testing circuit 22 works, little on the impact of system loss, therefore can less at the electric current flowing through power transistor M1 time, accurately carry out current detecting.This is also based on less demanding to the instantaneity and continuity that detect electric current in most no-load detection system, so can by intermittently power transistor M1 being operated in the detection that variable resistor district carries out electric current.In this way, while the accurate detection realizing small area analysis, power attenuation can be increased hardly again.
Fig. 5 is the working waveform figure of the current detection circuit of the embodiment of the present invention.
Within the t1 period, current detection circuit adopts the first testing circuit 21 to carry out current detecting, the the first current detection signal Vsense1 now obtained is greater than first threshold Vth1, therefore K switch 1 keeps conducting state, continues the first testing circuit 21 to access in current detection circuit.During this period, the drain-source voltage of power transistor M1 is greater than Second Threshold Vth2, and grid voltage is also higher, and power transistor M1 is operated in the state of complete conducting.
Within the t2 period, first current detection signal Vsense1 is less than first threshold Vth1, but clock signal is invalid low level, so time logical circuit 24 testing circuit that exports select signal Vcho to be inactive level, current detection circuit still continues employing first testing circuit 21 and carries out current detecting.
Within the t3 period, clock signal clock changes effective high level into, and the testing circuit that now logical circuit 24 exports selects signal Vcho to be significant level, makes K switch 2 conducting, K switch 1 turns off, and is switched to by current detection circuit employing second testing circuit 22 to carry out current detecting.The grid voltage V of power transistor M1 is controlled by the second error amplifier EA2
gATE, make the drain-source pole V of power transistor M1
dS(V
d-V
s) constant in Second Threshold Vth2, even if power transistor M1 begins operating in variable resistor district.Because now power transistor M1 changes to be operated in variable resistor zone state, so the stage is not detected electric current from being operated in complete conducting state.
Within the t4 period, power transistor M1 has been fully operational in variable resistor district, now utilizes the second testing circuit to obtain the second current detection signal Vsense2.
And the work judgement of subsequent period is carried out with this logic.
Preferably, when the first current detection signal Vsense1 is greater than first threshold Vth1, the first testing circuit 21 can obtain the first current detection signal Vsense1 in real time; When the first current detection signal Vsense1 is less than first threshold Vth1, system intermittently generates the second current detection signal Vsense2 at employing second testing circuit 22 according to clock signal clock, or adopt the first testing circuit 21 to generate the first current detection signal Vsense1, within this stage, current detection circuit can shield the first current detection signal Vsense1, only from the second testing circuit 22, obtain the second current detection signal Vsense2 as current detection signal, to improve the precision of current detecting.
Thus, according to the embodiment of the present invention, two kinds of current detection circuits can be adopted in varied situations respectively to obtain the higher current detection signal of precision, and the excess loss of system can not be increased.
The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, to those skilled in the art, the present invention can have various change and change.All do within spirit of the present invention and principle any amendment, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (10)
1. a current detection circuit, for detecting the size flowing through power crystal tube current, is characterized in that, described current detection circuit comprises:
First testing circuit, for detect in a first condition flow through power transistor current signal to obtain the first current detection signal of sign loading condition;
Second testing circuit, for detect in a second condition flow through power transistor current signal to obtain the second current detection signal of sign loading condition;
Comparator circuit, receives described first current detection signal and first threshold, exports comparison signal;
Logical circuit, receives described comparison signal and a clock signal, and output detection circuit selects signal;
Wherein, described current detection circuit selects signal behavior first testing circuit or the second testing circuit for detecting the current signal flowing through power transistor according to described testing circuit.
2. current detection circuit according to claim 1, is characterized in that, described first testing circuit comprises:
Transistor seconds, its drain electrode is connected with the drain electrode of described power transistor, and grid is connected with the grid of described power transistor, and source electrode is connected to the first input end of the first error amplifier;
Described first error amplifier, the second input end is connected to the source electrode of described power transistor, exports the first error amplification signal;
Third transistor, one end is connected to the first input end of described first error amplifier, and the other end is connected to the first end of the first detection resistance, and control end receives described first error amplification signal;
Described first detects resistance, and the second termination controls ground, and the voltage on its first end is the first current detection signal.
3. current detection circuit according to claim 1, is characterized in that, described second testing circuit comprises:
4th transistor, its drain electrode is connected with the drain electrode of described power transistor by the 3rd resistance, and source electrode is connected with the source electrode of described power transistor, and grid is also connected with the grid of described power transistor;
Second error amplifier, first input end is connected to the source electrode of described power transistor by a voltage source, second input end is connected to the drain electrode of described power transistor, exports the second error amplification signal, and described second error amplification signal is for controlling described power transistor and the 4th transistor;
3rd error amplifier, first input end is connected to the points of common connection of the 4th resistance and a current source, second input end is connected to the points of common connection of the 5th resistance and another current source, and export the 3rd error amplification signal, described 5th resistance is also connected with described 3rd resistance;
5th transistor, one end is connected to the first input end of described 3rd error amplifier, and the other end is connected to the first end of the second detection resistance, and control end receives described 3rd error amplification signal;
Described second detects resistance, and the second termination controls ground, and the voltage on its first end is the second current detection signal;
Wherein, when described second testing circuit work, described power transistor and described 4th transistor are all operated in variable resistor district.
4. the current detection circuit according to Claims 2 or 3, it is characterized in that, under same gate source voltage, the conducting resistance of described transistor seconds and the 4th transistor and the conducting resistance of described power transistor proportional, and the conducting resistance of described power transistor is less than the conducting resistance of described transistor seconds and the 4th transistor.
5. current detection circuit according to claim 1, is characterized in that, described comparator circuit comprises:
Comparer, first input end receives described first current detection signal, and the second input end receives described first threshold, exports comparison signal;
Described comparison signal is significant level when described first threshold is greater than described first current detection signal.
6. current detection circuit according to claim 5, is characterized in that, described logical circuit is when described clock signal and described comparison signal are significant level, and the testing circuit exported as significant level selects signal.
7. current detection circuit according to claim 6, it is characterized in that, described current detection circuit also comprises the first switch and second switch, in order to work in described first testing circuit access current detection circuit during described first switch conduction, in order to work in described second testing circuit access current detection circuit during described second switch conducting;
Described first switch and described second switch are controlled by described testing circuit and select signal conduction or shutoff, wherein, when described testing circuit selects signal to be significant level, and described second switch conducting, described first switch OFF; When described testing circuit selects signal to be inactive level, described first switch conduction, described second switch turns off.
8. current detection circuit according to claim 7, it is characterized in that, when switching to described second testing circuit work from described first testing circuit, generate the second current detection signal after described second testing circuit postpones predetermined time, described predetermined time is in order to switch the conducting state of described power transistor.
9. current detection circuit according to claim 1, is characterized in that, regulates the width of described clock signal significant level, in order to change the working time of described second testing circuit.
10. a control circuit, is characterized in that, comprising:
Current detection circuit according to any one of claim 1-9.
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| CN107219450A (en) * | 2016-03-22 | 2017-09-29 | 英飞凌科技股份有限公司 | transistor bridge fault test |
| CN108696270A (en) * | 2018-05-24 | 2018-10-23 | 上海艾为电子技术股份有限公司 | A kind of analog switching circuit |
| CN111030640A (en) * | 2019-12-27 | 2020-04-17 | 苏州市新诚氏通讯电子股份有限公司 | Surface-mounted miniature superposed circuit attenuation sheet and preparation method thereof |
| CN112187267A (en) * | 2019-07-01 | 2021-01-05 | 圣邦微电子（北京）股份有限公司 | Current sampling circuit and control method thereof |
| JP2021532600A (en) * | 2018-07-31 | 2021-11-25 | テキサス インスツルメンツ インコーポレイテッド | Power transistor coupled to multiple sensing transistors |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11252909A (en) * | 1998-02-27 | 1999-09-17 | Hitachi Ltd | Current detecting circuit |
| TW469363B (en) * | 1998-10-30 | 2001-12-21 | Volterra Semiconductor Corp | Current measuring techniques |
| CN1922496A (en) * | 2004-03-03 | 2007-02-28 | 罗姆股份有限公司 | Current detecting circuit, load drive, and storage |
| US7915870B2 (en) * | 2005-09-09 | 2011-03-29 | Semiconductor Components Industries, Llc | Method of forming a current sense circuit and structure therefor |
| CN103743945A (en) * | 2014-01-17 | 2014-04-23 | 大连泰思曼科技有限公司 | Circuit and method for detecting load current of high-voltage pulse power supply |
| CN103809007A (en) * | 2012-11-13 | 2014-05-21 | 中兴通讯股份有限公司 | Device and method for inductive current sampling of bridge-free PFC circuit |
| JP5585481B2 (en) * | 2011-02-10 | 2014-09-10 | 株式会社デンソー | Semiconductor device |
| EP2786158A1 (en) * | 2011-11-30 | 2014-10-08 | Valeo Etudes Electroniques | System for measuring a load current and for diagnosing an absence of load or an overload |
| CN104181370A (en) * | 2013-05-23 | 2014-12-03 | 海洋王（东莞）照明科技有限公司 | Load current detection circuit and detection device |
| CN104300792A (en) * | 2014-04-22 | 2015-01-21 | 上海华力微电子有限公司 | A current detection circuit and an electric current loop control circuit comprising the current detection circuit |
| CN104597310A (en) * | 2014-01-31 | 2015-05-06 | 成都芯源***有限公司 | Switch converter, current simulation circuit thereof, current detection circuit and method |
| CN104883162A (en) * | 2014-02-27 | 2015-09-02 | 快捷半导体(苏州)有限公司 | Overcurrent detection circuit and method, load switch and portable device |
-
2015
- 2015-10-19 CN CN201510675379.0A patent/CN105242190B/en active Active
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11252909A (en) * | 1998-02-27 | 1999-09-17 | Hitachi Ltd | Current detecting circuit |
| TW469363B (en) * | 1998-10-30 | 2001-12-21 | Volterra Semiconductor Corp | Current measuring techniques |
| CN1922496A (en) * | 2004-03-03 | 2007-02-28 | 罗姆股份有限公司 | Current detecting circuit, load drive, and storage |
| US7915870B2 (en) * | 2005-09-09 | 2011-03-29 | Semiconductor Components Industries, Llc | Method of forming a current sense circuit and structure therefor |
| JP5585481B2 (en) * | 2011-02-10 | 2014-09-10 | 株式会社デンソー | Semiconductor device |
| EP2786158A1 (en) * | 2011-11-30 | 2014-10-08 | Valeo Etudes Electroniques | System for measuring a load current and for diagnosing an absence of load or an overload |
| CN103809007A (en) * | 2012-11-13 | 2014-05-21 | 中兴通讯股份有限公司 | Device and method for inductive current sampling of bridge-free PFC circuit |
| CN104181370A (en) * | 2013-05-23 | 2014-12-03 | 海洋王（东莞）照明科技有限公司 | Load current detection circuit and detection device |
| CN103743945A (en) * | 2014-01-17 | 2014-04-23 | 大连泰思曼科技有限公司 | Circuit and method for detecting load current of high-voltage pulse power supply |
| CN104597310A (en) * | 2014-01-31 | 2015-05-06 | 成都芯源***有限公司 | Switch converter, current simulation circuit thereof, current detection circuit and method |
| CN104883162A (en) * | 2014-02-27 | 2015-09-02 | 快捷半导体(苏州)有限公司 | Overcurrent detection circuit and method, load switch and portable device |
| CN104300792A (en) * | 2014-04-22 | 2015-01-21 | 上海华力微电子有限公司 | A current detection circuit and an electric current loop control circuit comprising the current detection circuit |
Non-Patent Citations (3)
| Title |
|---|
| CHI YAT LEUNG ET AL.: "An Integrated CMOS Current-Sensing Circuit for Low-Voltage Current-Mode Buck Regulator", 《IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS—II: EXPRESS BRIEFS》 * |
| 刘布民 等: "低功耗无损电流检测技术的分析与设计", 《电子科技大学学报》 * |
| 百度文库: "《门控时钟》", 10 April 2014 * |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107219450A (en) * | 2016-03-22 | 2017-09-29 | 英飞凌科技股份有限公司 | transistor bridge fault test |
| CN107219450B (en) * | 2016-03-22 | 2020-01-10 | 英飞凌科技股份有限公司 | Transistor bridge fault testing |
| US10746806B2 (en) | 2016-03-22 | 2020-08-18 | Infineon Technologies Ag | Transistor bridge failure test |
| US11686781B2 (en) | 2016-03-22 | 2023-06-27 | Infineon Technologies Ag | Transistor bridge failure test |
| CN106787717A (en) * | 2016-12-12 | 2017-05-31 | 深圳市派捷电子科技有限公司 | A kind of four line programmable power supply circuits |
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| JP2021532600A (en) * | 2018-07-31 | 2021-11-25 | テキサス インスツルメンツ インコーポレイテッド | Power transistor coupled to multiple sensing transistors |
| CN112187267A (en) * | 2019-07-01 | 2021-01-05 | 圣邦微电子（北京）股份有限公司 | Current sampling circuit and control method thereof |
| CN112187267B (en) * | 2019-07-01 | 2022-09-16 | 江阴圣邦微电子制造有限公司 | Current sampling circuit and control method thereof |
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