CN207968443U - A kind of active pull-up and applied to the high-pass filter in MEMS gyroscope - Google Patents
A kind of active pull-up and applied to the high-pass filter in MEMS gyroscope Download PDFInfo
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- CN207968443U CN207968443U CN201820758769.3U CN201820758769U CN207968443U CN 207968443 U CN207968443 U CN 207968443U CN 201820758769 U CN201820758769 U CN 201820758769U CN 207968443 U CN207968443 U CN 207968443U
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- active pull
- operational amplifier
- pmos tube
- nmos tube
- reference voltage
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Abstract
The utility model provides a kind of active pull-up and applied to the high-pass filter in MEMS gyroscope, and the active pull-up includes the first PMOS tube, the second PMOS tube, the first operational amplifier and bias current sources；One end of the bias current sources is grounded, the other end of the bias current sources connects drain electrode and the in-phase input end of first operational amplifier of first PMOS tube, the inverting input of first operational amplifier is suitable for receiving reference voltage, the output end of first operational amplifier connects the grid of the grid and second PMOS tube of first PMOS tube, the one end of the drain electrode of second PMOS tube as the active pull-up, the source electrode of second PMOS tube connect the source electrode of first PMOS tube and as the other end of the active pull-up.Active pull-up provided by the utility model and applied to the high-pass filter in MEMS gyroscope, can accurately determine the resistance value of the active pull-up, improve the stability of the high-pass filter.
Description
Technical field
The utility model is related to wave filter technology field more particularly to a kind of active pull-up and it is applied to MEMS gyroscope
In high-pass filter.
Background technology
High-pass filter is widely used in MEMS (MEMS, Micro Electro Mechanical
System) in the detection circuit of gyroscope or driving circuit.For the high-pass filter in MEMS gyroscope, working frequency one
As in 20kHz or so.In order to reduce phase delay, the stability of gain is improved, the three dB bandwidth of the high-pass filter needs far
Frequency from 20kHz, thus the resistance value of filter resistance usually requires that and reaches up to a hundred megohms in the high-pass filter.It is high in this way
The filter resistance of resistance value needs to occupy great chip area, can generally active metal-oxide-semiconductor circuit be used to realize.
Fig. 1 is a kind of circuit diagram of existing active pull-up, and the active pull-up includes the first PMOS tube MP1, second
PMOS tube MP2 and bias current sources Ib.Wherein, one end ground connection of the bias current sources Ib, the bias current sources Ib's
The other end connects the draining of the first PMOS tube MP1, the grid of the first PMOS tube MP1 and second PMOS tube
The grid of MP2, one end D1 of the second PMOS tube MP2 to drain as the active pull-up, the second PMOS tube MP2's
Source electrode connects the source electrode of the first PMOS tube MP1 and the other end D2 as the active pull-up.The bias current sources Ib
The bias current of a current value very little is provided for the first PMOS tube MP1, the second PMOS tube MP2 is described first
The mirror image of PMOS tube MP1.By the way that the size of the size and the second PMOS tube MP2 of the first PMOS tube MP1 is arranged, can incite somebody to action
The breadth length ratio of the first PMOS tube MP1 is set as N times of the breadth length ratio of the second PMOS tube MP2, to flow through described
The maximum current of two PMOS tube MP2 is defined as N/mono- of the bias current.Since the bias current can be arranged
Very little, and the value of N can be arranged very big, thus the conducting resistance of the second PMOS tube MP2 can be very high, can reach
Up to a hundred megohms of resistance value.
However, in normal operating conditions, the first PMOS tube MP1 works in saturation region, the second PMOS tube MP2
Work in linear zone.With the variation of flow-route and temperature, the conducting resistance of the second PMOS tube MP2 is difficult accurately to go to determine.
The variation of the active pull-up will cause the variation of high-pass filter three dB bandwidth point, and then influence the stability of high-pass filter.
Therefore, those skilled in the art is dedicated to developing a kind of active pull-up that can accurately determine resistance value as answering
Filter resistance for the high-pass filter in MEMS gyroscope.
Invention content
In view of the drawbacks described above of the prior art, the technical problem to be solved by the utility model is to provide one kind can be accurate
The active pull-up for determining resistance value, as the filter resistance applied to the high-pass filter in MEMS gyroscope.
To achieve the above object, the utility model provides a kind of active pull-up, including the first PMOS tube, the 2nd PMOS
Pipe, the first operational amplifier and bias current sources；
One end of the bias current sources is grounded, and the other end of the bias current sources connects the leakage of first PMOS tube
The in-phase input end of pole and first operational amplifier, the inverting input of first operational amplifier, which is suitable for receiving, to be referred to
Voltage, the output end of first operational amplifier connect the grid of the grid and second PMOS tube of first PMOS tube
Pole, one end as the active pull-up of drain electrode of second PMOS tube, the source electrode of second PMOS tube connect described the
The source electrode of one PMOS tube and as the other end of the active pull-up.
In the better embodiment of the utility model, the active pull-up further includes the reference for providing the reference voltage
Voltage source；
The anode of the reference voltage source connects the inverting input of first operational amplifier, the reference voltage source
Negativing ending grounding.
In another better embodiment of the utility model, the breadth length ratio of first PMOS tube is the 2nd PMOS
N times of the breadth length ratio of pipe, wherein N ＞ 1.
Based on same utility model conceive, the utility model also provides another kind active pull-up, including the first NMOS tube,
Second NMOS tube, the first operational amplifier and bias current sources；
The source electrode of first NMOS tube and the source electrode of second NMOS tube ground connection, the grid of first NMOS tube connect
The output end of the grid and first operational amplifier of second NMOS tube is connect, the drain electrode of first NMOS tube connects institute
One end of the in-phase input end and the bias current sources of the first operational amplifier is stated, the reverse phase of first operational amplifier is defeated
Enter end and is suitable for receiving reference voltage, the one end of second NMOS tube to drain as the active pull-up, the bias current
The other end of the other end in source as the active pull-up.
In the better embodiment of the utility model, the active pull-up further includes the reference for providing the reference voltage
Voltage source；
The anode of the reference voltage source connects the inverting input of first operational amplifier, the reference voltage source
Negativing ending grounding.
In another better embodiment of the utility model, the breadth length ratio of first NMOS tube is the 2nd NMOS
N times of the breadth length ratio of pipe, wherein N ＞ 1.
The utility model also provides a kind of high-pass filter applied in MEMS gyroscope, including the first capacitance, second
Capacitance, second operational amplifier and filter resistance, the filter resistance are above-mentioned active pull-up；
One end of first capacitance is the input terminal of the high-pass filter, and the other end of first capacitance connects institute
State the inverting input of one end of the second capacitance, one end of the filter resistance and the second operational amplifier, described
The in-phase input end of two operational amplifiers is grounded, and the output end of the second operational amplifier connects the another of second capacitance
Hold the other end with the filter resistance and as the output end of the high-pass filter.
Active pull-up provided by the utility model, including bias current sources, the first operational amplifier and two metal-oxide-semiconductors,
Wherein, the bias current sources provide bias current to the metal-oxide-semiconductor as benchmark, and as the metal-oxide-semiconductor of mirror image to the biasing
Electric current carries out mirror image.Feedback loop is constituted by using first operational amplifier, ensures metal-oxide-semiconductor and work as benchmark
Linear zone is worked in for the metal-oxide-semiconductor of mirror image, keeps two metal-oxide-semiconductor matchings good, it is thus possible to accurately determine as mirror image
Metal-oxide-semiconductor conduction resistance value.
High-pass filter provided by the utility model applied in MEMS gyroscope, due to being provided using the utility model
Active pull-up as filter resistance, the conduction resistance value of the active pull-up can accurately determine, will not be because of technique and temperature
The variation of degree and change, thus the high-pass filter three dB bandwidth point stablize, improve the steady of the high-pass filter
It is qualitative.
The technique effect of the design of the utility model, concrete structure and generation is made furtherly below with reference to attached drawing
It is bright, to be fully understood from the purpose of this utility model, feature and effect.
Description of the drawings
Fig. 1 is a kind of circuit diagram of existing active pull-up；
Fig. 2 is a kind of circuit diagram of the active pull-up of embodiment of the utility model；
Fig. 3 is the circuit diagram of the active pull-up of the utility model another kind embodiment；
Fig. 4 is the circuit diagram of the high-pass filter being applied in MEMS gyroscope of the utility model embodiment.
Specific implementation mode
Just as described in the background art, the high-pass filter in MEMS gyroscope uses active pull-up as filtered electrical
Resistance, but the first PMOS tube MP1 as benchmark works in saturation region, and the second PMOS tube MP2 as mirror image works in linear zone,
It is difficult accurately to go to determine to lead to the conducting resistance of the second PMOS tube MP2.Based on this, the utility model provides a kind of active electrical
Resistance is still to constitute current-mirror structure using bias current sources and two metal-oxide-semiconductors, but the utility model also uses operational amplifier
Feedback loop is constituted, so that the conducting of the metal-oxide-semiconductor as benchmark is controlled voltage constant, ensures the metal-oxide-semiconductor as benchmark and conduct
The metal-oxide-semiconductor of mirror image works in linear zone, keeps two metal-oxide-semiconductor matchings good.Since the current-mirror structure may be used
PMOS tube constitute, can also use NMOS tube constitute, correspondingly, the active pull-up also have there are two types of structure, the utility model
The active pull-up of two kinds of different structures is described in detail in the examples below.
Embodiment 1
The present embodiment provides a kind of active pull-up, Fig. 2 is the circuit diagram of the active pull-up, and the active pull-up includes the
One PMOS tube MP1, the second PMOS tube MP2, the first operational amplifier A mp1 and bias current sources Ib.
Specifically, one end ground connection of the bias current sources Ib, the other end connection described the of the bias current sources Ib
The drain electrode of one PMOS tube MP1 and the in-phase input end of the first operational amplifier A mp1, the first operational amplifier A mp1
Inverting input be suitable for receive reference voltage Vref, the first operational amplifier A mp1 output end connection described first
The grid of the grid of PMOS tube MP1 and the second PMOS tube MP2, the drain electrode of the second PMOS tube MP2 is as described active
The source electrode of one end D1 of resistance, the second PMOS tube MP2 connect the source electrode of the first PMOS tube MP1 and as described active
The other end D2 of resistance.
In the present embodiment, the first PMOS tube MP1 and the second PMOS tube MP2 constitutes current-mirror structure, described
Bias current sources Ib provides bias current to the first PMOS tube MP1.By be arranged the first PMOS tube MP1 size and
The size of the second PMOS tube MP2 can set the breadth length ratio of the first PMOS tube MP1 to the second PMOS tube MP2
N times of breadth length ratio, the maximum current to flow through the second PMOS tube MP2 be defined as the N of the bias current/
One.Further, the value of N can be more than 1.
The first operational amplifier A mp1 constitutes feedback loop, and the feedback loop ensures first PMOS tube
The drain voltage of MP1 and the reference voltage Vref are of substantially equal.By the way that the voltage value of the reference voltage Vref is arranged, can protect
It demonstrate,proves the first PMOS tube MP1 and works in linear zone.Due to the first PMOS tube MP1 and the equal works of the second PMOS tube MP2
Make in linear zone, matching is good, thus the resistance value of the second PMOS tube MP2 can accurately be set.
Further, the reference voltage Vref can be provided by the reference voltage source for being integrated in chip interior, can also be by
The reference voltage source of chip exterior provides.In the present embodiment, the active pull-up further includes the ginseng for providing the reference voltage
Examine voltage source VREF.The anode of the reference voltage source VREF connects the inverting input of the first operational amplifier A mp1,
The negativing ending grounding of the reference voltage source VREF.
Embodiment 2
The present embodiment provides a kind of active pull-up, Fig. 3 is the circuit diagram of the active pull-up, and the active pull-up includes the
One NMOS tube MN1, the second NMOS tube MN2, the first operational amplifier A mp1 and bias current sources Ib.
Specifically, the source electrode of the source electrode of the first NMOS tube MN1 and the second NMOS tube MN2 are grounded, and described first
The grid of NMOS tube MN1 connects the output end of the grid and the first operational amplifier A mp1 of the second NMOS tube MN2, institute
The drain electrode for stating the first NMOS tube MN1 connects the in-phase input end of the first operational amplifier A mp1 and the bias current sources Ib
One end, the inverting input of the first operational amplifier A mp1 is suitable for receiving reference voltage Vref, second NMOS tube
One end D1 of the drain electrode of MN2 as the active pull-up, the other end of the bias current sources Ib is as the active pull-up
Other end D2.
In the present embodiment, the first NMOS tube MN1 and the second NMOS tube MN2 constitutes current-mirror structure, described
Bias current sources Ib provides bias current to the first NMOS tube MN1.By be arranged the first NMOS tube MN1 size and
The size of the second NMOS tube MN2 can set the breadth length ratio of the first NMOS tube MN1 to the second NMOS tube MN2
N times of breadth length ratio, the maximum current to flow through the second NMOS tube MN2 be defined as the N of the bias current/
One.Further, the value of N can be more than 1.
The first operational amplifier A mp1 constitutes feedback loop, and the feedback loop ensures first NMOS tube
The drain voltage of MN1 and the reference voltage Vref are of substantially equal.By the way that the voltage value of the reference voltage Vref is arranged, can protect
It demonstrate,proves the first NMOS tube MN1 and works in linear zone.Due to the first NMOS tube MN1 and the equal works of the second NMOS tube MN2
Make in linear zone, matching is good, thus the resistance value of the second NMOS tube MN2 can accurately be set.
Further, the reference voltage Vref can be provided by the reference voltage source for being integrated in chip interior, can also be by
The reference voltage source of chip exterior provides.In the present embodiment, the active pull-up further includes the ginseng for providing the reference voltage
Examine voltage source VREF.The anode of the reference voltage source VREF connects the inverting input of the first operational amplifier A mp1,
The negativing ending grounding of the reference voltage source VREF.
Embodiment 3
The present embodiment provides a kind of high-pass filters applied in MEMS gyroscope, and Fig. 4 is the high-pass filter
Circuit diagram.The high-pass filter includes the first capacitance C1, the second capacitance C2, second operational amplifier Amp2 and filter resistance
R1, wherein the filter resistance R1 is the active pull-up that embodiment 1 provides or the active pull-up that embodiment 2 provides.The filter
One end of wave resistance R1 is one end of the active pull-up, and the other end of the filter resistance R1 is the another of the active pull-up
End.
Specifically, one end of the first capacitance C1 is the input terminal of the high-pass filter, the first capacitance C1's
The other end connects one end of the second capacitance C2, one end of the filter resistance R1 and the second operational amplifier Amp2
Inverting input, the second operational amplifier Amp2 in-phase input end ground connection, the second operational amplifier Amp2's
Output end connects the other end of the second capacitance C2 and the other end of the filter resistance R1 and as the high-pass filter
Output end.
High-pass filter provided in this embodiment applied in MEMS gyroscope, due to using embodiment 1 or implementation
As filter resistance, the conduction resistance value of the active pull-up can accurately determine the active pull-up that example 2 provides, will not be because of work
The variation of skill and temperature and change, thus the high-pass filter three dB bandwidth point stablize, improve the high-pass filtering
The stability of device.
The preferred embodiment of the utility model described in detail above.It should be appreciated that the ordinary skill people of this field
Member according to the present utility model can conceive without creative work makes many modifications and variations.Therefore, all this technology necks
Technical staff passes through logic analysis, reasoning or limited reality on the basis of existing technology according to the design of the utility model in domain
Available technical solution is tested, it all should be in the protection domain being defined in the patent claims.
Claims (7)
1. a kind of active pull-up, which is characterized in that including the first PMOS tube, the second PMOS tube, the first operational amplifier and partially
Set current source；
One end of the bias current sources is grounded, the other ends of the bias current sources connect first PMOS tube drain electrode and
The in-phase input end of first operational amplifier, the inverting input of first operational amplifier are suitable for receiving with reference to electricity
Pressure, the output end of first operational amplifier connect the grid of the grid and second PMOS tube of first PMOS tube,
The one end of the drain electrode of second PMOS tube as the active pull-up, the source electrode connection described first of second PMOS tube
The source electrode of PMOS tube and as the other end of the active pull-up.
2. a kind of active pull-up as described in claim 1, which is characterized in that further include the reference electricity for providing the reference voltage
Potential source；
The anode of the reference voltage source connects the inverting input of first operational amplifier, and the reference voltage source is born
End ground connection.
3. a kind of active pull-up as claimed in claim 1 or 2, which is characterized in that the breadth length ratio of first PMOS tube is institute
State the breadth length ratio of the second PMOS tube N times, wherein N ＞ 1.
4. a kind of active pull-up, which is characterized in that including the first NMOS tube, the second NMOS tube, the first operational amplifier and partially
Set current source；
The source electrode of first NMOS tube and the source electrode of second NMOS tube ground connection, the grid of first NMOS tube connect institute
State the output end of the grid and first operational amplifier of the second NMOS tube, the drain electrode connection of first NMOS tube described the
One end of the in-phase input end of one operational amplifier and the bias current sources, the inverting input of first operational amplifier
Suitable for receiving reference voltage, one end as the active pull-up of drain electrode of second NMOS tube, the bias current sources
The other end of the other end as the active pull-up.
5. a kind of active pull-up as claimed in claim 4, which is characterized in that further include the reference electricity for providing the reference voltage
Potential source；
The anode of the reference voltage source connects the inverting input of first operational amplifier, and the reference voltage source is born
End ground connection.
6. a kind of active pull-up as described in claim 4 or 5, which is characterized in that the breadth length ratio of first NMOS tube is institute
State the breadth length ratio of the second NMOS tube N times, wherein N ＞ 1.
7. a kind of high-pass filter applied in MEMS gyroscope, which is characterized in that including the first capacitance, the second capacitance, the
Two operational amplifiers and filter resistance, the filter resistance are claim 1 to 6 any one of them active pull-up；
One end of first capacitance is the input terminal of the high-pass filter, the other end connection described the of first capacitance
The inverting input of one end of two capacitances, one end of the filter resistance and the second operational amplifier, second fortune
Calculate the in-phase input end ground connection of amplifier, the output end of the second operational amplifier connect second capacitance the other end and
The other end of the filter resistance and as the output end of the high-pass filter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820758769.3U CN207968443U (en) | 2018-05-21 | 2018-05-21 | A kind of active pull-up and applied to the high-pass filter in MEMS gyroscope |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820758769.3U CN207968443U (en) | 2018-05-21 | 2018-05-21 | A kind of active pull-up and applied to the high-pass filter in MEMS gyroscope |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207968443U true CN207968443U (en) | 2018-10-12 |
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ID=63727842
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820758769.3U Active CN207968443U (en) | 2018-05-21 | 2018-05-21 | A kind of active pull-up and applied to the high-pass filter in MEMS gyroscope |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN207968443U (en) |
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2018
- 2018-05-21 CN CN201820758769.3U patent/CN207968443U/en active Active
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Address after: 312030 Building 5, intelligent innovation center, 487 Kebei Avenue, Keqiao Economic and Technological Development Zone, Keqiao District, Shaoxing City, Zhejiang Province Patentee after: Shendi semiconductor (Shaoxing) Co.,Ltd. Address before: Room 208, podium building, No.1 building, 3000 Longdong Avenue, Pudong New Area pilot Free Trade Zone, Shanghai, 201203 Patentee before: Senodia Technologies (Shanghai) Co.,Ltd. |
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