CN202772866U - Level shifting circuit used for high-voltage applications - Google Patents
Level shifting circuit used for high-voltage applications Download PDFInfo
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- CN202772866U CN202772866U CN 201220335487 CN201220335487U CN202772866U CN 202772866 U CN202772866 U CN 202772866U CN 201220335487 CN201220335487 CN 201220335487 CN 201220335487 U CN201220335487 U CN 201220335487U CN 202772866 U CN202772866 U CN 202772866U
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Abstract
This utility model relates to a level shifting circuit used for high-voltage applications. The circuit comprises the following components of: a current mirror for generating first bias current and second bias current which is in a first ratio with the first bias current; a first level shifter provided with a first input end used for receiving a first input signal and a first output end, wherein the first level shifter is configured to respond to the first bias current to apply first voltage change to the first input signal so as to output a first output signal at the first output end; and a second level shifter which is provided with a second input end used for receiving a second input signal, and a second output end, wherein the second level shifter is configured to respond to the second bias current to apply second voltage change associated with the first voltage change to the second input signal so as to output a second output signal at the second output end.
Description
Technical field
The utility model relates generally to electronic circuit, more specifically, relates to a kind of level shift circuit for high-voltage applications.
Background technology
At present, day by day increase in the demand of electronics industry to high pressure comparator exclusive disjunction amplifier with wider adjustable threshold range.This is because in various application, and in using such as vehicle, the voltage of battery is always higher, for example is 40V.In addition, be starved of following chip, this chip can be monitored via the drain-source voltage of the high-voltage MOS transistor of various types of outsides the electric current of these high-voltage MOS transistors.The drain-source voltage of high-voltage MOS transistor is usually above 3.3V.Therefore, in the situation with higher input and reference voltage, how comparator or operational amplifier can normally and move exactly is very important.
In a kind of possible solution of prior art, used voltage divider, but be arranged in the range of operation of typical CMOS will input with reference voltage.Yet, for example, the random offset noise of voltage divider possibility amplifier comparator exclusive disjunction amplifier, when the contiguous 0V of input voltage, this phenomenon is very serious.And level shift is infeasible in such scheme.
The utility model content
Therefore, need a kind of level shift circuit of degree of precision, so that can operate in the high-voltage applications such as the electronic device of comparator exclusive disjunction amplifier.
In one embodiment, a kind of circuit comprises: current mirror, for generation of the first bias current and the second bias current that becomes the first ratio with described the first bias current; The first level shifter, it has first input end, be used for receiving the first input signal, and has the first output, wherein said the first level shifter is configured to apply the first change in voltage in response to described the first bias current to described the first input signal, in order to export the first output signal at described the first output; And second electrical level shift unit, it has the second input, be used for receiving the second input signal, and has the second output, wherein said second electrical level shift unit is configured to apply the second voltage that is associated with described the first change in voltage to described the second input signal in response to described the second bias current to be changed, in order to export the second output signal at described the second output.
According to an embodiment of the present utility model, described the first level shifter comprises the first resistance, it is coupled between described first input end and described the first output, and described second electrical level shift unit comprises the second resistance, and it is coupled between described the second input and described the second output.
According to an embodiment of the present utility model, the ratio of the resistance of the resistance of described the second resistance and described the first resistance is the inverse of described the first ratio.
According to an embodiment of the present utility model, described circuit comprises the variable current supply, and being used for provides variable current to described current mirror, changes to change described second voltage with respect to described the first change in voltage.
According to an embodiment of the present utility model, described variable current supply comprises: current source, for generation of reference current; And current multiplier, for the described reference current that doubles in response to control signal, so that described variable current to be provided.
According to an embodiment of the present utility model, this circuit also comprises the first overvoltage protector, and it is coupled between described second electrical level shift unit and the described current mirror, and is configured to provide overvoltage protection for described current mirror.
According to an embodiment of the present utility model, described current mirror comprises the first MOS transistor and the second MOS transistor, described the first MOS transistor has first grid, the first drain electrode and the first source electrode, described the second MOS transistor has second grid, the second drain electrode and the second source electrode, wherein said first grid is coupled to described second grid and described the first drain electrode, described the first source electrode and described the second source electrode are coupled to reference voltage line, and described the first drain electrode is coupled to described the first level shifter, so that described the first bias current to be provided at least in part, and described the second drain electrode is coupled to described second electrical level shift unit, so that described the second bias current to be provided.
According to an embodiment of the present utility model, described circuit also comprises comparator, is used for more described the first output signal and described the second output signal.
According to an embodiment of the present utility model, described circuit also comprises the second overvoltage protector, and it is coupled between described second electrical level shift unit and the described comparator, and is configured to provide overvoltage protection for described comparator.
According to an embodiment of the present utility model, described circuit also comprises operational amplifier, is used for amplifying the voltage difference between described the first output signal and described the second output signal.
By above-mentioned preferred solution, realized a kind of so that high pressure comparator exclusive disjunction amplifier has wider adjustable threshold range and level shift circuit high precision, it mainly depends on the accuracy of reference current or other normative references and the matching degree of current mirror and resistance.
Therefore, in integrated circuit, realized high precision.In addition, in the utility model, only need less high voltage component to realize being higher than the threshold voltage of 3.3V.Alternatively, mainly used the CMOS transistor of 3.3V.Therefore, saved significantly the chip area that integrated circuit expends.In addition, range of application of the present utility model is very extensive.For example, it can be used for the drain-source voltage of the outside high-voltage power MOS transistor of monitoring, can be used for any two end points etc. that its voltage relatively is subjected to the current affects of comparator.And, can operate in the voltage range at whole typical CMOS, the noise of the input of comparator exclusive disjunction amplifier can be by establishment.
Above summarized but not broadly provided the feature of the utility model content.After this supplementary features of the utility model content will described, and it has formed the theme of the utility model claim.It will be appreciated by those skilled in the art that and easily to use disclosed design and embodiment, as the basis of revising or design other structures or process, in order to carry out the purpose identical with the utility model.Those skilled in the art it is also understood that these equivalent structures do not break away from purport of the present utility model and the scope of putting down in writing in the appended claims.
Description of drawings
For more completely understand the disclosure with and advantage, now by reference to the accompanying drawings with reference to following description, wherein:
Fig. 1 shows the block diagram according to the circuit 100 of the first embodiment of the present utility model;
Fig. 2 shows the block diagram according to the circuit 200 of the second embodiment of the present utility model;
Fig. 3 shows the block diagram according to the circuit 300 of the 3rd embodiment of the present utility model; And
Fig. 4 shows the block diagram according to the circuit 400 of the 4th embodiment of the present utility model;
Unless indicate, otherwise the corresponding part of the general expression of the respective markers in the different accompanying drawing and symbol.The drafting accompanying drawing is the parties concerned for the execution mode that is shown clearly in present disclosure, and may not be drawn to scale.In order more to be shown clearly in some execution mode, after Reference numeral, may follow letter, the distortion of its indication same structure, material or process steps.
Embodiment
The below discusses enforcement and the use of embodiment in detail.Yet, should be appreciated that the specific embodiment of discussing only exemplarily illustrates enforcement and uses ad hoc fashion of the present utility model, and unrestricted scope of the present utility model.
Fig. 1 shows the block diagram according to the circuit 100 of the first embodiment of the present utility model.Circuit 100 comprises current mirror 101, has the first level shifter 102 of first input end 104 and the first output 106 and has the second input 105 and the second electrical level shift unit 103 of the second output 107.Circuit 100 is used for changing respectively the level of the first input signal that receives at first input end 104 places and the second input signal that receives at the second input 105 places, in order to export the first output signal that is associated with the first input signal at the first output 106 places, and export the second output signal that is associated with the second input signal at the second output 107 places.By this circuit, the high voltage that receives at the first and second inputs 104,105 places can suitably and exactly be displaced to respectively the adjustable and suitable voltage at the first and second outputs 106,107 places.
As shown in Figure 1, current mirror 101 is configured to produce the first bias current and the second bias current that becomes the first ratio with this first bias current.For example, the second bias current is α times of the first bias current, and wherein α can be predetermined value, such as 1.The first bias current and the second bias current that are produced by current mirror 101 are provided respectively to the first level shifter 102 and second electrical level shift unit 103.
The first input end 104 of the first level shifter 102 is configured to receive the first input signal, for example reference signal.The second input 105 of second electrical level shift unit 103 is configured to receive the second input signal, sensing signal for example, and it can be from some obtains on other the equipment, for example the high-voltage power MOS transistor of some outsides to be monitored.Particularly, input signal can be the signal with different level.
Still with reference to figure 1, the first level shifter 102 is configured to apply the first change in voltage to the first input signal that receives at first input end 104 places in response to the first bias current that is provided by current mirror 101, for example, a pressure drop is so that in the first output 106 outputs the first output signal.Second electrical level shift unit 103 is configured to apply second voltage to the second input signal that receives at the second input 105 places in response to the second bias current that is provided by current mirror 101 to be changed, for example, a pressure drop is in order to export the second output signal at the second output 107 places.This second voltage variation is associated with the first change in voltage.For example, the second voltage variation equals the first change in voltage, so that the first output signal at the first output 106 places equals the second output signal at the second output 107 places.
The first level shifter 102 and/or second electrical level shift unit 103 can be comprised of one or more resistance respectively.The ratio of total resistance of total resistance of one or more resistance of second electrical level shift unit 103 and one or more resistance of the first level shifter 102 is the inverse of the first ratio, i.e. 1/ α.Preferably, the first level shifter 102 comprises a resistance, it is coupled between first input end 104 and the first output 106, and second electrical level shift unit 103 comprises another resistance, it is coupled between the second input 105 and the second output 107, and the ratio of the resistance of this another resistance and the resistance of previous resistance is the inverse of the first ratio.
This circuit 100 can be used in comparator exclusive disjunction amplifier, and the supply power voltage of those comparator exclusive disjunction amplifiers for example is equal to or less than 3.3V.Particularly, the first output 106 and the second output 107 can be coupled to respectively the input of comparator exclusive disjunction amplifier.Therefore, even when input voltage is higher than the supply power voltage of comparator or amplifier, circuit 100 can be displaced to input voltage and be lower than its supply power voltage, thereby so that comparator exclusive disjunction amplifier can be normally and accurately operation.
Fig. 2 shows the block diagram according to the circuit 200 of the second embodiment of the present utility model.This circuit 200 comprises the first level shifter, second electrical level shift unit, the first MOS transistor M
1And the second MOS transistor M
2In this embodiment, the first MOS transistor M
1And the second MOS transistor M
2Formed current mirror 201 (shown in the dotted line frame).And the first level shifter comprises the first resistance 202, and it is coupled between first input end 204 and the first output 206, and the second electrical level shift unit comprises the second resistance 203, and it is coupled between the second input 205 and the second output 207.
According to this embodiment, circuit 200 also comprises comparator 210, and it is used for relatively the first output signal and the second output signal.First input end 204 is configured to receive reference signal V
Ref, and the second input 205 is configured to receive sensing signal V
SenseThe first output 206 is configured to export the first output signal V
p, and the second output 207 is configured to export the second output signal V
n
Preferably, circuit 200 also comprises the first overvoltage protector 208, and it is coupled between the second resistance 203 and the current mirror 201, and is configured to provide overvoltage protection for current mirror 201.For example, as the sensing signal V at the second input 205 places
SenseWhen very high, the first overvoltage protector 208 can be shared the major part of sensing signal, and protective current mirror 201 in case its break down.
In addition, circuit 200 can also comprise the second overvoltage protector 209, and it is coupled between resistance 203 and the comparator 210, and is configured to provide overvoltage protection for comparator 210.Be similar to the first overvoltage protector 208, the second overvoltage protectors 209 and can share the major part of sensing signal, and protect comparator 210 in order to avoid it breaks down.For example, the first overvoltage protector 208 and the second overvoltage protector 209 can be respectively MOS transistor.Yet, it will be understood by those of skill in the art that any other form that is fit to that also can consider the first overvoltage protector 208 and the second overvoltage protector 209.
Particularly, current mirror 201 comprises the first MOS transistor M
1With the second MOS transistor M
2, this first MOS transistor M
1Have first grid, the first drain electrode and the first source electrode, this second MOS transistor M
2Have second grid, the second drain electrode and the second source electrode.First grid is coupled to second grid and the first drain electrode.The first source electrode and the second source electrode are coupled to reference voltage line, such as ground connection.The first drain electrode is coupled to the first resistance 202 (R
1), so that the first bias current I to be provided
1, and the second drain electrode is coupled to the second resistance 203 (R via the first overvoltage protector 208
2), so that the second bias current I to be provided
2
In this embodiment, the first bias current I that is provided by current mirror 201
1With the second bias current I
2Between relation as shown in the formula expression:
I
2=α I
1(formula 1)
Wherein, α is the second bias current I
2To the first bias current I
1Ratio, α=1 preferably.
Be in operation, as reference signal V
RefBe higher than the first MOS transistor M
1Gate source voltage V
GSThe time, the first MOS transistor M
1Conducting.Subsequently, the first bias current I
1And the second bias current I
2, i.e. α I
1, provided respectively to the first resistance 202 and the second resistance 203 by current mirror 201.
On the other hand, in this embodiment, provided the resistance (R of the first resistance 202 by following formula
1) and the resistance (R of the second resistance 203
2) between relation:
R
2=R
1/ α (formula 2)
This means that the ratio of the resistance of the resistance of the second resistance 203 and the first resistance 202 is second bias current I
2With the first bias current I
1Between the inverse of ratio.
According to above-mentioned two equatioies, can summarize following the first bias current I
1, the second bias current I
2, the resistance of the first resistance 202 and the second resistance 203 resistance between relation:
I
1R
1=I
2R
2(formula 3)
Therefore, in this embodiment, the second voltage that the first change in voltage on the first resistance 202 equals on the second resistance 203 changes.
With reference to figure 2, by receive reference signal V at first input end 204 places
RefWith receive sensing signal V at the second input 205 places
Sense, provide to the first and second output voltage V of the input of comparator 210
pAnd V
n, can be derived as:
V
p=V
Ref-I
1R
1(formula 4)
V
n=V
Sense-I
2R
2(formula 5)
According to equation 3 to 5, respectively to reference signal V
RefWith sensing signal V
SenseApply an identical level shift, this can be so that reference signal V
RefWith sensing signal V
SenseBe reduced within the scope of moving of comparator 210.
By equation 3, can followingly obtain the first and second output voltage V that in formula 4 and 5, provide
pAnd V
nBetween poor:
V
p-V
n=V
Ref-I
1R
1-(V
Sense-I
2R
2)=V
Ref-V
Sense(formula 6)
Comparator 210 will be according to the first and second output voltage V
pAnd V
nAnd operate.For example, work as V
nBe higher than V
pThe time, the output of comparator 210 will be overturn.Therefore, according to formula 6, should be appreciated that by circuit 200 that comparator 210 can be used for monitoring sensing signal V
Sense, its can be for example from the high-voltage MOS transistor of dissimilar outsides and can be far above 3.3V.For example, as the V that satisfies condition
Sense＞V
RefThe time, with the alarm signal of output for the high-voltage MOS transistor of monitored outside, because can observe at this moment the upset of the output of comparator 210.
In other words, by the specific configuration of this circuit 200, work as V
Sense＞V
RefThe time, the output of comparator 210 will be overturn, even V
SenseFar above 3.3V, i.e. the maximum of comparator running voltage.
Therefore, by above-mentioned configuration, realized a kind of high pressure comparator.In addition, by selecting the resistance that is fit to of the first resistance 202 and the second resistance 203, and two bias currents are set correspondingly, namely via changing change in voltage, comparator can have wider threshold range, and this is favourable for different application scenarios.
In addition, can based on real application scenarios, for example need monitored high-pressure MOS parts to carry out reference signal V
RefSelection, and the technical staff can regulate this reference signal V simply according to different application scenarioss
Ref
As reference signal V
RefBe lower than the first MOS transistor M
1Gate source voltage V
GSThe time, circuit 200 still can operate.In this case, the first MOS transistor M
1Close, do not have electric current to pass through the first MOS transistor M
1With the second MOS transistor M
2, and the first MOS transistor M
1With the second MOS transistor M
2Bias current so V will be provided
p=V
Ref, V
n=V
SenseComparator 210 will be based on V
pAnd V
n(that is, V
RefAnd V
Sense) and operate.Therefore, this circuit 200 also can so that comparator than the input signal of low voltage.
Fig. 3 shows the block diagram according to the circuit 300 of the 3rd embodiment of the present utility model.This circuit 300 comprises the first level shifter, second electrical level shift unit, the first MOS transistor M
3And the second MOS transistor M
4In this embodiment, the first MOS transistor M
3And the second MOS transistor M
4Formed current mirror 301 (shown in the dotted line frame).And the first level shifter comprises the first resistance 302, and it is coupled between first input end 304 and the first output 306, and the second electrical level shift unit comprises the second resistance 303, and it is coupled between the second input 305 and the second output 307.
According to this embodiment, circuit 300 also comprises comparator 310, and it is used for relatively the first output signal and the second output signal.First input end 304 is configured to receive reference signal V
Ref, and the second input 305 is configured to receive sensing signal V
SenseThe first output 306 is configured to export the first output signal V
p, and the second output 307 is configured to export the second output signal V
n
Preferably, circuit 300 also comprises the first overvoltage protector 308, and it is coupled between the second resistance 303 and the current mirror 301, and is configured to provide overvoltage protection for current mirror 301.For example, as the sensing signal V at the second input 305 places
SenseWhen very high, the first overvoltage protector 308 can be shared the major part of sensing signal, and protective current mirror 301 in case its break down.
In addition, circuit 300 can also comprise the second overvoltage protector 309, and it is coupled between resistance 303 and the comparator 310, and is configured to provide overvoltage protection for comparator 310.Be similar to the first overvoltage protector 308, the second overvoltage protectors 309 and can share the major part of sensing signal, and protect comparator 310 in order to avoid it breaks down.For example, the first overvoltage protector 308 and the second overvoltage protector 309 can be respectively MOS transistor.Yet, it will be understood by those of skill in the art that any other form that is fit to that also can consider the first overvoltage protector 308 and the second overvoltage protector 309.
As shown in Figure 3, circuit 300 also comprises variable current supply 311, is used for variable current I
5Provide to current mirror 301, change with the second voltage that changes with respect to the first change in voltage on the first resistance 302 on the second resistance 303.Therefore, even at reference signal V
RefWith sensing signal V
SenseUnder the mutual different situations, the first output signal V
pAlso can equal the second output signal V
n
According to this embodiment, variable current supply 311 can for example comprise current source 312 and current multiplier 313.
Subsequently, reference current I
RefBe provided to current multiplier 313, it will be in response to control signal with the factor K reference current that doubles, thereby variable current I is provided
5Therefore, can obtain following relation:
I
5=K * I
Ref=K * V
BG/ R (formula 7)
Yet, it will be understood by those of skill in the art that other mechanism that are fit to that can produce variable current also are suitable for this circuit.
Particularly, current mirror 301 comprises the first MOS transistor M
3With the second MOS transistor M
4, this first MOS transistor M
3Have first grid, the first drain electrode and the first source electrode, this second MOS transistor M
4Have second grid, the second drain electrode and the second source electrode.First grid is coupled to second grid and the first drain electrode.The first source electrode and the second source electrode are coupled to reference voltage line, such as ground connection.The first drain electrode is coupled to the first resistance 302 (R
3), so that the first bias current I to be provided at least in part
3, and the second drain electrode is coupled to the second resistance 303 (R via the first overvoltage protector 308
4), so that the second bias current I to be provided
4
In this embodiment, the first bias current I that is provided by current mirror 301
3With the second bias current I
4Between relation as shown in the formula expression:
I
4=α I
3(formula 8)
Wherein, α is the second bias current I
4To the first bias current I
3Ratio, α=1 preferably.
Be in operation, as reference signal V
RefWith I
5R
3And (that is, V
Ref+ I
5* R
3) be higher than the first MOS transistor M
3Gate source voltage V
GSThe time, the first MOS transistor M
1Conducting.Subsequently, produce respectively the first bias current I by current mirror 301
3And the second bias current I
4, i.e. α I
3At this, the second bias current I
4It is the electric current that flows through the second resistance 303.
As shown in Figure 3, the first bias current I that is produced by current mirror 301
3Comprise variable current I
5With the electric current that flows through the first resistance 302 (be I
6).That is, I
3=I
5+ I
6
Therefore, based on formula 8, can obtain
I
4＝α(I
5+I
6)
Therefore, I
6=I
4/ α-I
5(formula 9)
On the other hand, in this embodiment, provided the resistance (R of the first resistance 302 by following formula
3) and the resistance (R of the second resistance 303
4) between relation:
R
4=R
3/ α (formula 10)
This means that the ratio of the resistance of the resistance of the second resistance 303 and the first resistance 302 is second bias current I
4With the first bias current I
3Between the inverse of ratio.
According to the first change in voltage V on equation 9 and 10, the first resistance 302
1Be:
V
1=I
6R
3=(I
4/ α-I
5) α R
4=I
4R
4-I
5α R
4(formula 11)
And the second voltage on the second resistance 303 changes V
2Be:
V
2=I
4R
4(formula 12)
Still with reference to figure 3, based on equation 11 and 12, by receive reference signal V at first input end 304 places
RefWith receive sensing signal V at the second input 305 places
Sense, provide to the first and second output voltage V of the input of comparator 310
pAnd V
n, can be derived as:
V
p=V
Ref-V
1=V
Ref-I
4R
4+ I
5α R
4(formula 13)
V
n=V
Sense-V
2=V
Sense-I
4R
4(formula 14)
According to equation 13 to 14, respectively to reference signal V
RefWith sensing signal V
SenseApply level shift, this can cause reference signal V
RefWith sensing signal V
SenseBe reduced within the scope of moving of comparator 310.
Can followingly obtain the first and second output voltage V that in formula 13 and 14, provide
pAnd V
nBetween poor:
V
p-V
n=V
Ref-I
4R
4+ I
5α R
4-V
Sense+ I
4R
4=V
Ref-V
Sense+ I
5α R
4(formula 15)
Because I
5=K * I
Ref=K * V
BG/ R, equation 15 can further be expressed as:
V
p-V
n=V
Ref-V
Sense+ KV
BG/ R * α R
4=V
Ref-V
Sense+ KV
BG/ R * R
3(formula 16)
Based on this threshold value, comparator 310 can be used for monitoring sensing signal V
Sense, its can be for example from the high-voltage MOS transistor of dissimilar outsides and can be far above 3.3V.For example, as the V that satisfies condition
Sense-V
Ref＞K * V
BG/ R * R
3The time, with the alarm signal of output for the high-voltage MOS transistor of monitored outside, because can observe at this moment the upset of the output of comparator 310.
In other words, by the specific configuration of this circuit 300, work as V
Sense＞V
Ref+ K * V
BG/ R * R
3The time, the output of comparator 310 will be overturn, even V
SenseFar above 3.3V, i.e. the maximum of comparator running voltage.
In addition, according to different application scenarioss, can be for example by changing electric current I via different factor K is set
5Or regulate simply this threshold value by the resistance that is fit to of selecting the first resistance 302 and the second resistance 302.
As reference signal V
RefWith I
5R
3And (that is, V
Ref+ I
5* R
3) be lower than the first MOS transistor M
3Gate source voltage V
GSThe time, circuit 300 still can operate.In this case, the first MOS transistor M
3Close, do not have electric current to pass through the first MOS transistor M
3With the second MOS transistor M
4, and the first MOS transistor M
3With the second MOS transistor M
4Bias current so V will be provided
p=V
Ref+ I
5* R
3, V
n=V
SenseComparator 310 will be based on V
pAnd V
n(that is, V
Ref+ I
5* R
3And V
Sense) and operate.Therefore, this circuit 300 also can so that comparator than the input signal of low voltage.And in this case, threshold value is still V
Ref-V
Sense+ KV
BG/ R * R
3
Fig. 4 shows the block diagram according to the circuit 400 of the 4th embodiment of the present utility model.This circuit 400 comprises the first level shifter, second electrical level shift unit, the first MOS transistor M
5And the second MOS transistor M
6In this embodiment, the first MOS transistor M
5And the second MOS transistor M
6Formed current mirror 401 (shown in the dotted line frame).And the first level shifter comprises the first resistance 402, and it is coupled between first input end 404 and the first output 406, and the second electrical level shift unit comprises the second resistance 403, and it is coupled between the second input 405 and the second output 407.And current source 410 is coupled to the second input 405, to provide bias current and the voltage at the second input 405 places that are used for stretching, forms thus loop.
According to this embodiment, circuit 400 also comprises operational amplifier 409, and it is used for amplifying the voltage difference between the first output signal and the second output signal.First input end 404 is configured to receive the first input signal, for example reference signal V
Ref, and the second input 405 is configured to receive the second input signal, for example sensing signal V
SenseThe first output 406 is configured to export the first output signal V
n, and the second output 407 is configured to export the second output signal V
p
Preferably, circuit 400 also comprises the first overvoltage protector 408, and it is coupled between the second resistance 403 and the current mirror 401, and is configured to provide overvoltage protection for current mirror 401 and operational amplifier 409.For example, as the sensing signal V at the second input 405 places
SenseWhen very high, the first overvoltage protector 408 can be shared the major part of sensing signal, and protective current mirror 401 and operational amplifier 409 in case its break down.For example, the first overvoltage protector 408 can be MOS transistor.Yet, it will be understood by those of skill in the art that any other form that is fit to that can realize similar effect that also can consider the first overvoltage protector 408.
Particularly, current mirror 401 comprises the first MOS transistor M
5With the second MOS transistor M
6, this first MOS transistor M
5Have first grid, the first drain electrode and the first source electrode, this second MOS transistor M
6Have second grid, the second drain electrode and the second source electrode.First grid is coupled to second grid and the first drain electrode.The first source electrode and the second source electrode are coupled to reference voltage line, such as ground connection.The first drain electrode is coupled to the first resistance 402 (R
5), so that the first bias current I to be provided
7, and the second drain electrode is coupled to the second resistance 403 (R via the first overvoltage protector 408
6), so that the second bias current I to be provided
8
Similar with described in reference Fig. 2, the first bias current I that is provided by current mirror 401
7With the second bias current I
8Between relation as shown in the formula expression:
I
8=α I
7(formula 17)
Wherein, α is the second bias current I
8To the first bias current I
7Ratio, α=1 preferably.
Be in operation, as reference signal V
RefBe higher than the first MOS transistor M
5Gate source voltage V
GSThe time, the first MOS transistor M
5Conducting.Subsequently, the first bias current I
7And the second bias current I
8, i.e. α I
7, provided respectively to the first resistance 402 and the second resistance 403 by current mirror 401.
And also similar with described in reference Fig. 2 provided the resistance (R of the first resistance 402 by following formula
5) and the resistance (R of the second resistance 403
6) between relation:
R
6=R
5/ α (formula 18)
Therefore, described similar with reference Fig. 2, in this embodiment, the second voltage that the first change in voltage on the first resistance 402 equals on the second resistance 403 changes.Therefore, respectively to reference signal V
RefWith sensing signal V
SenseApply an identical level shift, this can be so that reference signal V
RefWith sensing signal V
SenseBe reduced within the scope of moving of operational amplifier 409.
By above-mentioned configuration, similar with the described embodiment of reference Fig. 2, the first and second output voltage V
nWith V
pBetween difference be:
V
n-V
p=V
Ref-I
7R
5-(V
Sense-I
8R
6)=V
Ref-V
Sense(formula 19)
This just means, the first and second output voltage V
nWith V
pBetween difference equal reference signal V
RefWith sensing signal V
SenseBetween poor.
Therefore, even reference signal V
RefAnd/or sensing signal V
SenseFar above 3.3V, i.e. the maximum of operational amplifier 409 running voltage, operational amplifier 409 still can be according to reference signal V
RefWith sensing signal V
SenseAnd operate.Thus, realized a kind of operational amplifier that can amplify the input signal of high pressure.In addition, according to this embodiment, between the input and output of operational amplifier 409, coupled miller capacitance 411.Based on the Miller effect (Miller Effect), this miller capacitance 411 can have less electric capacity, and this can reduce chip area significantly.
In addition, by selecting the resistance that is fit to of the first resistance 402 and the second resistance 403, and two bias currents are set correspondingly, operational amplifier can have wider threshold range by changing change in voltage, and this is favourable for different application scenarioss.
In addition, can based on real application scenarios, for example need monitored high-pressure MOS parts to carry out reference signal V
RefSelection, and the technical staff can regulate this reference signal V simply according to different application scenarioss
Ref
As reference signal V
RefBe lower than the first MOS transistor M
5Gate source voltage V
GSThe time, circuit 400 still can operate.In this case, the first MOS transistor M
5Close, do not have electric current to pass through the first MOS transistor M
5With the second MOS transistor M
6, and the first MOS transistor M
5With the second MOS transistor M
6Bias current so V will be provided
n=V
Ref, V
p=V
Sense Operational amplifier 409 will be based on V
nAnd V
p(that is, V
RefAnd V
Sense) and operate.Therefore, this circuit 400 also can be so that operational amplifier amplifies the input signal of low-voltage.
Those skilled in the art will be understood that easily that also materials and methods can change, and still be within the scope of the present utility model simultaneously.It will also be appreciated that except the concrete context that is provided to show execution mode, the utility model provides multiple applicable inventive concept.Therefore, claims are intended to these processes, machine, goods, composition, device, method or step are included within its scope.
Claims (10)
1. circuit comprises:
Current mirror is for generation of the first bias current and the second bias current that becomes the first ratio with described the first bias current;
The first level shifter, it has first input end, be used for receiving the first input signal, and has the first output, wherein said the first level shifter is configured to apply the first change in voltage in response to described the first bias current to described the first input signal, in order to export the first output signal at described the first output; And
The second electrical level shift unit, it has the second input, be used for receiving the second input signal, and has the second output, wherein said second electrical level shift unit is configured to apply the second voltage that is associated with described the first change in voltage to described the second input signal in response to described the second bias current to be changed, in order to export the second output signal at described the second output.
2. circuit according to claim 1, wherein, described the first level shifter comprises the first resistance, it is coupled between described first input end and described the first output, and described second electrical level shift unit comprises the second resistance, and it is coupled between described the second input and described the second output.
3. circuit according to claim 2, wherein, the ratio of the resistance of the resistance of described the second resistance and described the first resistance is the inverse of described the first ratio.
4. circuit according to claim 1, wherein, described circuit comprises the variable current supply, being used for provides variable current to described current mirror, changes to change described second voltage with respect to described the first change in voltage.
5. circuit according to claim 4, wherein said variable current supply comprises:
Current source is for generation of reference current; And
Current multiplier is for the described reference current that doubles in response to control signal, so that described variable current to be provided.
6. circuit according to claim 1 also comprises:
The first overvoltage protector, it is coupled between described second electrical level shift unit and the described current mirror, and is configured to provide overvoltage protection for described current mirror.
7. according to claim 5 or 6 described circuit, wherein, described current mirror comprises the first MOS transistor and the second MOS transistor, described the first MOS transistor has first grid, the first drain electrode and the first source electrode, described the second MOS transistor has second grid, the second drain electrode and the second source electrode, wherein said first grid is coupled to described second grid and described the first drain electrode, described the first source electrode and described the second source electrode are coupled to reference voltage line, and described the first drain electrode is coupled to described the first level shifter, so that described the first bias current to be provided at least in part, and described the second drain electrode is coupled to described second electrical level shift unit, so that described the second bias current to be provided.
8. circuit according to claim 1 also comprises comparator, is used for more described the first output signal and described the second output signal.
9. circuit according to claim 8 also comprises the second overvoltage protector, and it is coupled between described second electrical level shift unit and the described comparator, and is configured to provide overvoltage protection for described comparator.
10. circuit according to claim 1 also comprises operational amplifier, is used for amplifying the voltage difference between described the first output signal and described the second output signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220335487 CN202772866U (en) | 2012-07-05 | 2012-07-05 | Level shifting circuit used for high-voltage applications |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220335487 CN202772866U (en) | 2012-07-05 | 2012-07-05 | Level shifting circuit used for high-voltage applications |
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| Publication Number | Publication Date |
|---|---|
| CN202772866U true CN202772866U (en) | 2013-03-06 |
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ID=47779407
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103532538A (en) * | 2012-07-05 | 2014-01-22 | 意法半导体研发（上海）有限公司 | Level shift circuit used for high-voltage application |
-
2012
- 2012-07-05 CN CN 201220335487 patent/CN202772866U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103532538A (en) * | 2012-07-05 | 2014-01-22 | 意法半导体研发（上海）有限公司 | Level shift circuit used for high-voltage application |
| CN103532538B (en) * | 2012-07-05 | 2017-11-03 | 意法半导体研发（上海）有限公司 | A kind of level shift circuit for high-voltage applications |
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