CN102790594A - Dual-mode automatic gain control circuit working at ultra-low supply voltage - Google Patents
Dual-mode automatic gain control circuit working at ultra-low supply voltage Download PDFInfo
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- CN102790594A CN102790594A CN2011101293928A CN201110129392A CN102790594A CN 102790594 A CN102790594 A CN 102790594A CN 2011101293928 A CN2011101293928 A CN 2011101293928A CN 201110129392 A CN201110129392 A CN 201110129392A CN 102790594 A CN102790594 A CN 102790594A
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Abstract
The invention discloses a dual-mode automatic gain control circuit working at an ultra-low supply voltage. The dual-mode automatic gain control circuit relates to an integrated circuit and comprises a programmable transconductance operational amplifier, an envelope detection circuit, a gain control circuit, an isolation capacitor, an input resistor, a resistor array, an MOS (Metal Oxide Semiconductor) tube equivalent resistor, a comparator and a selector switch. The envelope detection circuit detects a comparison result between an output signal and an inflexion point threshold voltage to decide a working state of the circuit; in an incompressible working state, the selector switch selects a resistance array as a feedback circuit, amplifies a voltage signal at a microphone output end and decreases a degree of distortion of the circuit; in a compressible working state, the dual-mode automatic gain control circuit starts the MOS tube equivalent resistor as the feedback circuit to achieve an automatic gain control of the operational amplifier. The envelope detection circuit achieves different starting time and recovery time, and the gain control circuit achieves an effective utilization of power consumption when sound volumes are in different levels. The dual-mode automatic gain control circuit is used for a hearing aid, a high-precision work and high efficiency for controlling the power consumption of the circuit can be achieved under the ultra-low supply voltage.
Description
Technical field
The present invention relates to the digital deaf-aid microphone and read integrated circuit, and relate to the high-precision integrated circuit of reading that is applicable to the little acoustic-electric of hearing aids system (MEMS) microphone sensor in more detail.
Background technology
Along with little acoustic-electric system (MEMS) continuous advancement in technology, little acoustic-electric hearing aid microphone transducer arises at the historic moment, and it has that volume is little, low in energy consumption, distortion is little and advantage such as noise resisting ability is strong, and its pairing reading circuit becomes the focus of industrial quarters research.
This transducer can equivalence be a comparatively desirable voltage source usually: very little resistance on the desired voltage subject string.But the signal of microphone micro-electro-mechanical sensors output is very faint, and generally only between μ V～mV magnitude, this design to reading circuit has proposed very harsh requirement.The noise level of reading circuit and precision have determined its minimum signal amplitude that can detect; So low noise and high-precision reading circuit are designed in order to realize that reading circuit has high-precision key, especially need under the low-down supply voltage situation at digital deaf-aid.
The simulation automatic gain controlling Design of microphone reading circuit mainly can be divided into analog feedback control amplifier forward direction open-loop gain in the world at present; It is (the reference: Jones of analog feedback control amplifier bias current; Mario Martinez: " a kind of CMOS hearing aids "; Analog integrated circuit and signal processing, 21,163-172 (1999); Bake: ' a kind of low-power consumption monocycle and the control of dicyclo automatic gain ', solid-state circuit, SC-41 (9) to artificial ear; Pp.1983-1996; 2006) and analog feedback control the gate source voltage (reference: Huo Man: " a kind of low noise CMOS automatic gain control ", solid-state circuit, SC-27 (7) of controlled metal-oxide-semiconductor equivalent resistance; Pp.974-981,1992; Jin Shuyong: " a kind of efficient analog front end circuit of inferior 1V digital deaf-aid ", solid-state circuit, SC-41 (4); Pp.876-882,2006.) and the mutual conductance of current-mode FEEDBACK CONTROL metal-oxide-semiconductor (reference: lattice draw the Leix: " low pressure subthreshold value index amplifies and automatic gain control ", circuit; Device and system; Vol.152, No.1, Feb 2005) two kinds of schemes.And above automatic gain control circuit obtains to use widely in simulation hearing aids field.But the former shortcoming is its linearity and can receives the restriction of technology and supply voltage, and is special under the lower situation of supply voltage.The advantage of analog feedback is that its signal has stronger continuity.But the difficult point of analog feedback is the realization of the amplifier output accuracy of low-voltage.Usually the multiplication factor of amplifier has realized comparatively ideal precision under the control of analog feedback, and realizes that in integrated circuit very high precision is extremely difficult, needs complicated compensating circuit or very large power consumption usually.The shortcoming of current-mode feedback system [5] is that amplifier itself does not have negative feedback structure, thereby system is lower to the precision of signal processing.And digital deaf-aid requires reading circuit to have extraordinary reading accuracy, and this has proposed challenge for the design of reading circuit.
Summary of the invention
The objective of the invention is to provide a kind of utmost point low supply voltage bimodulus automatic gain control circuit that works in; The bimodulus automatic gain control reading circuit that can be used for digital deaf-aid; It is on the basis with controlled metal-oxide-semiconductor equivalent resistance ride gain; Under non-compressed state, replace the metal-oxide-semiconductor equivalent resistance, effectively solved the problem of precision under its non-compressed state by electric resistance array; Effectively solved simultaneously power consumption problem of higher under the compressive state.
For achieving the above object, technical solution of the present invention is:
A kind of utmost point low supply voltage bimodulus automatic gain control circuit that works in is used for the 1V working power voltage of hearing aids; It comprises:
The programmable trans-conductance amplifier is used for the amplification to microphone MEMS output signal;
Two inputs of programmable trans-conductance amplifier link to each other with resistance device with two electric capacity that the microphone output links to each other with ground respectively, constitute the high-pass filtering to input signal;
Programmable trans-conductance amplifier output is with two electric resistance array unit that input links to each other, and is used to be formed under the non-compression work state programmable trans-conductance amplifier to the amplification of signal;
Programmable trans-conductance amplifier output is used for the automatic gain control under the compressive state with the metal-oxide-semiconductor equivalent resistance array element that input links to each other;
The selector switch that links to each other with metal-oxide-semiconductor equivalent resistance unit with the electric resistance array unit;
Input is connected the gain control circuit of envelope detected circuit output end and metal-oxide-semiconductor equivalent resistance array grid with output, be used to produce the voltage of automatic gain control;
Input is connected the envelope detected circuit of programmable trans-conductance amplifier output and gain control unit input with output, obtain detecting the energy that the programmable trans-conductance amplifier is exported signal in order to signal is carried out rectification and filtering.
Described bimodulus automatic gain control circuit, its said envelope detected circuit, adopt filter cascade form: form the front-end filtering circuit by 1 in the circuit, 2MOS pipe with capacitor C, it has rectification function concurrently; 4,5,6MOS pipe and capacitor C 1 composition rear end filter circuit.And 1,2, the 6MOS pipe works in sub-threshold region.
Described bimodulus automatic gain control circuit, its said gain control circuit, through amplifier amp1,2 and pipe M1,2 form the adaptation function that two negative feedback loops are realized power consumptions; And put pipe M4 in the control voltage of sub-threshold region, thereby be implemented under the 1V supply voltage reducing of the distortion factor under the automatic gain state of a control to provide one to be applicable to control metal-oxide-semiconductor equivalent resistance unit.
Circuit of the present invention is applicable to very low operation supply voltage (as below, the 1V), for the portable digital hearing aids provides a kind of low-voltage, and low-power consumption and high-precision reading circuit.
Simultaneously, invented gain control circuit accordingly with power consumption adaptation function, when realizing that volume raises gradually, the reducing gradually of its circuit system power consumption.Above circuit still can operate as normal below supply voltage 1V.The present invention proposes and realized automatic ride gain high accuracy and the method for power consumption high efficiency detection signal and circuit module of under low-voltage, working accordingly under non-compression work state.
Description of drawings
Fig. 1 is a kind of utmost point low supply voltage bimodulus automatic gain control circuit sketch map that works in of the present invention.
Main element explanation among the figure:
Programmable trans-conductance amplifier 1 first isolation capacitance 2
Second isolation capacitance, 3 first input resistances 4
Second input resistance, 5 first electric resistance arrays 6
Second electric resistance array, 7 selector switches 8
Metal-oxide-semiconductor equivalent resistance 9 envelope detected circuit 10
Fig. 2 works in the above envelope detected circuit of 1V supply voltage for a kind of working in of the present invention in the utmost point low supply voltage bimodulus automatic gain control circuit;
Fig. 3 works in the above gain control circuit of 1V supply voltage for a kind of working in of the present invention in the utmost point low supply voltage bimodulus automatic gain control circuit.
Embodiment
The present invention has provided a kind of utmost point low supply voltage bimodulus automatic gain control circuit that works in, and is used for the 1V working power voltage of hearing aids; It comprises:
The programmable trans-conductance amplifier is used for the amplification to microphone MEMS output signal;
Two inputs of programmable trans-conductance amplifier link to each other with resistance device with two electric capacity that the microphone output links to each other with ground respectively, constitute the high-pass filtering to input signal;
Programmable trans-conductance amplifier output is with two electric resistance array unit that input links to each other, and is used to be formed under the non-compression work state programmable trans-conductance amplifier to the amplification of signal;
Programmable trans-conductance amplifier output is used for the automatic gain control under the compressive state with the metal-oxide-semiconductor equivalent resistance array element that input links to each other;
The selector switch that links to each other with metal-oxide-semiconductor equivalent resistance unit with the electric resistance array unit;
Input is connected the gain control circuit of envelope detected circuit output end and metal-oxide-semiconductor equivalent resistance array grid with output, be used to produce the voltage of automatic gain control;
Input is connected the envelope detected circuit of programmable trans-conductance amplifier output and gain control unit input with output, obtain detecting the energy that the programmable trans-conductance amplifier is exported signal in order to signal is carried out rectification and filtering.
Wherein the envelope detected circuit can be realized different start-up times and recovery time, makes automatic gain control circuit adapt to the physiological requirements of people's ear to the response of voice signal.
Bimodulus automatic gain control circuit of the present invention is under the condition that volume increases gradually, the gain control circuit that the power consumption of realization own reduces; Provide one to be applicable to control metal-oxide-semiconductor grid simultaneously, be in two output control voltages of high potential, to be implemented under the 1V supply voltage reducing of the distortion factor under the automatic gain state of a control.
A kind of microphone bimodulus automatic gain control circuit, the power consumption high efficiency circuit module and the electric resistance array that work in low supply voltage through employing replace the mode of metal-oxide-semiconductor equivalent resistance to efficiently solve power consumption of the prior art and nonlinear problem.
The present invention carries out high pass by the first, two isolation capacitance and 2～5 pairs of microphone direct current signals of resistance device, and filtering microphone direct current signal is read the microphone small-signal by programmable trans-conductance discharge circuit 1; Comparator 11 compares the envelope signal of envelope detected circuit 10 outputs and with reference to the flex point threshold voltage, its comparative result is confirmed choosing of selector switch 6.The envelope signal that detects programmable trans-conductance amplifiers 1 output signal when envelope detected circuit 10 is less than with reference to the flex point threshold voltage time, and circuit system works in non-compression work state, and selector switch 6 selects first; Two input resistance devices 4; 5 and the first, two electric resistance array 6,7 is as feedback loop.The envelope signal that detects programmable trans-conductance amplifiers 1 output signal when envelope detected circuit 10 is greater than with reference to the flex point threshold voltage time, and circuit system works in compressive state, and selector switch 6 selects metal-oxide-semiconductor equivalent resistances 9 as feedback loop; 12 pairs of envelope signals of gain control circuit are handled and are obtained gain control signal simultaneously, and this gain control signal is controlled the grid voltage of metal-oxide-semiconductor equivalent resistance 9.
This circuit is owing to adopt first under non-compression work state; Two input resistances 4; 5 and the first, two electric resistance array 6, but the mode of 7 replacement metal-oxide-semiconductor equivalent resistances 9 has realized that high-precision wheat wind signal is read under the low supply voltage; Through analog feedback, the mode of control metal-oxide-semiconductor equivalent resistance 9 grids has realized the automatic gain control under the low supply voltage simultaneously.
Fig. 1 describes the exemplary bimodulus automatic gain control circuit of implementing according to the present invention.The bimodulus automatic gain control circuit is divided into following components; Comprise: programmable trans-conductance amplifier (1), first and second electric capacity that programmable trans-conductance amplifier (1) first and second input is linked to each other with ground with the microphone output respectively and input resistance device (2～5), cross-over connection second electric resistance array (7), cross-over connection in first electric resistance array (6) of programmable trans-conductance amplifier (1) first input end and second output, cross-over connection in programmable trans-conductance amplifier (1) second input and first output connect respectively in the metal-oxide-semiconductor equivalent resistance (9) of programmable trans-conductance amplifier (1) input and output, cross-over connection in selector switch (6), output and the input of the first, two electric resistance array unit (4) and metal-oxide-semiconductor equivalent resistance (9) gain control circuit (12) input and programmable trans-conductance amplifier (1) output envelope detected circuit (10), connect envelope detected circuit (10) output and metal-oxide-semiconductor equivalent resistance (9) grid gain control circuit (12), be connected in the comparator (11) between envelope detected circuit (10) output and the selector switch (6).
In practical application, consider that the output signal of programmable trans-conductance amplifier carries out envelope detected (with reference to accompanying drawing 2) by the envelope detected circuit to it under lower supply voltage and the lower power consumption.Consider this envelope detected circuit working at the low supply voltage state, this envelope detected circuit adopts filter cascade form, and 1,2, the 6MOS pipe works in sub-threshold region 13.By 1, the 2MOS pipe is formed the front-end filtering circuit with capacitor C, and it has rectification function concurrently; 4,5,6MOS pipe and capacitor C 1 composition rear end filter circuit.Because the cut-off frequency of design front-end filtering circuit is filter circuit much smaller than the rear end.When filter was imported in large-signal, this filter time constant (compression time) was:
Subsequently, when the large-signal input becomes the small-signal input, 4,5,6MOS manages shutoff, then by rear end filter circuit this filter time constant of decision (recovery time) is:
Can know that by above-mentioned theory the envelope detected circuit can be realized different startups and recovery time. circuit has following function simultaneously: under the situation that promptly input signal is big more, output voltage V
OutThen more little.
Be in following time of operating state of non-compression of volume and compression at circuit system, the output signal of envelope detected circuit is handled (with reference to accompanying drawing 3) by gain control circuit.The output signal V of envelope detected circuit
PDPerhaps compress knee voltage V
THThe input signal of gain control circuit for this reason, V
1And V
2Be the control signal of output, V
CIt is index gain controlling adjustment end.
Amplifier amp1,2 with pipe M1,2 form two negative feedback loops; Because resistance R 1 equates with R2, makes pipe M1 like this, M2 and M5; The source-drain voltage of M6 accurately equates, promotes the mirror image precision of electric current, thereby increases substantially the input resistance of gain control circuit; Therefore, the output voltage V of envelope detected circuit
PDOr knee voltage V
THCan directly be added to the input of gain control circuit and can not produce decay.
The equivalent input resistance of efficient gain control circuit is:
R
in＝A*[r
5//(R
1+r
1)]
Wherein A is the negative feedback loop open-loop gain that amplifier amp1 and pipe M1 form, r1, and 5 is M1,5 drain impedance.
When non-compression work state, envelope voltage signal V
PDValue is greater than knee voltage V
TH, this moment V
THDirectly be added to the input of gain control circuit.The electric current that M1, M2 flow through is:
The feedback loop of forming through amp3 and M4. makes the node voltage between R3 and R4 remain Vc, because R3 and R4 are equal, so two output voltage values are respectively
V
1，2＝V
C±V
X
Since R3,4, and R1,2, equate, so the differential mode voltage of control circuit is output as
V
X＝I
control·R
3＝V
TH-V
LH
When the compression work state, envelope voltage signal V
PDLess than knee voltage signal V
TH, the envelope voltage signal can substitute input that the knee voltage signal is added to gain control circuit and made the output V of control circuit this moment
1And V
2Differential mode voltage V
XReduce, thereby reduce amplifier's gain.This moment M1; 2,3 quiescent current reduces than the operating current under the non-compressed state (like formula (4)) suc as formula shown in (7) to some extent; Increase along with input signal amplitude; The electric current of efficient gain control circuit will further reduce, and when volume reached maximum, gain control circuit institute power consumed was reduced to 1/10th under the non-compression work state approximately.
Because the signal bandwidth that gain control circuit is handled approaches DC level, amp1, the value of 2,3 bias current can satisfy bandwidth demand about 100nA.And consider the stability problem of power consumption and feedback control loop, I
ControlDesign load be 3.5 μ A.
In order to reduce the non-linear of metal-oxide-semiconductor equivalent resistance; Two output voltage V 1 of gain control circuit; 2 need as far as possible near supply voltage, therefore place sub-threshold region keeping enough big mutual conductance pipe M4, thereby make the feedback loop of amp3 and M4. composition obtain enough loop gains.On the other hand, receive the influence of power supply noise in order to prevent MRC resistance, Vdd is produced by LDO power management module in the sheet, guarantees that further the systematic distortion degree is in enough little scope.
Aspect circuit stability, the secondary amplifier closed loop stability of gain control circuit is by 1,2, the bias current setting of 3amp, and miller capacitance C and resistance r keep. and bias current need be set at:
I
Control, worstcaseBe 1,2,3,4,5, the minimum current value that leak in 6MOS pipe source.
1,2,5,6MOS pipe and amp1,2 form another loop, by capacitor C 1 it are carried out zero compensation, and its dominant pole of compensation back does
G wherein
M-amp1Be the mutual conductance of amp1, and
G wherein
m, r
O2Be respectively the mutual conductance and the output resistance of 2MOS pipe.
More than be the description that microphone of the present invention is worked in the execution mode of 1V supply voltage bimodulus automatic gain control circuit, to one skilled in the art, some advantage that has obtained this circuit is conspicuous.Also should be appreciated that in scope of the present invention and spirit and can carry out various changes, modification and alternative embodiment, all be included in the scope of claims protection of the present invention.
Claims (3)
1. one kind works in utmost point low supply voltage bimodulus automatic gain control circuit, is used for the 1V working power voltage of hearing aids; It is characterized in that, comprising:
The programmable trans-conductance amplifier is used for the amplification to microphone MEMS output signal;
Two inputs of programmable trans-conductance amplifier link to each other with resistance device with two electric capacity that the microphone output links to each other with ground respectively, constitute the high-pass filtering to input signal;
Programmable trans-conductance amplifier output is with two electric resistance array unit that input links to each other, and is used to be formed under the non-compression work state programmable trans-conductance amplifier to the amplification of signal;
Programmable trans-conductance amplifier output is used for the automatic gain control under the compressive state with the metal-oxide-semiconductor equivalent resistance array element that input links to each other;
The selector switch that links to each other with metal-oxide-semiconductor equivalent resistance unit with the electric resistance array unit;
Input is connected the gain control circuit of envelope detected circuit output end and metal-oxide-semiconductor equivalent resistance array grid with output, be used to produce the voltage of automatic gain control;
Input is connected the envelope detected circuit of programmable trans-conductance amplifier output and gain control unit input with output, obtain detecting the energy that the programmable trans-conductance amplifier is exported signal in order to signal is carried out rectification and filtering.
2. bimodulus automatic gain control circuit according to claim 1 is characterized in that, said envelope detected circuit adopts filter cascade form: form the front-end filtering circuit by 1 in the circuit, 2MOS pipe with capacitor C, it has rectification function concurrently; 4,5,6MOS pipe and capacitor C 1 composition rear end filter circuit.And 1,2, the 6MOS pipe works in sub-threshold region.
3. bimodulus automatic gain control circuit according to claim 1 is characterized in that, said gain control circuit, through amplifier amp1,2 and pipe M1,2 form the adaptation function that two negative feedback loops are realized power consumptions; And put pipe M4 in the control voltage of sub-threshold region, thereby be implemented under the 1V supply voltage reducing of the distortion factor under the automatic gain state of a control to provide one to be applicable to control metal-oxide-semiconductor equivalent resistance unit.
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| CN201110129392.8A CN102790594B (en) | 2011-05-18 | 2011-05-18 | Dual-mode automatic gain control circuit working at ultra-low supply voltage |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103050119A (en) * | 2012-12-30 | 2013-04-17 | 安徽科大讯飞信息科技股份有限公司 | Self-adaptive detection method for synchronism of lamplight/motor and sound |
| CN104183241A (en) * | 2013-05-28 | 2014-12-03 | 无锡华润矽科微电子有限公司 | Control circuit and method for improving volume adjustment of audio signal |
| CN105305990A (en) * | 2015-12-09 | 2016-02-03 | 北京中科汉天下电子技术有限公司 | Power control circuit of power amplifier |
| CN112968684A (en) * | 2021-02-08 | 2021-06-15 | 西安理工大学 | Broadband programmable gain amplifier based on transconductance switching technology |
Citations (1)
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| CN101102097A (en) * | 2006-07-07 | 2008-01-09 | 美国凹凸微系有限公司 | Fixed gain amplifier for automatic gain control and variable gain amplifier |
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2011
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101102097A (en) * | 2006-07-07 | 2008-01-09 | 美国凹凸微系有限公司 | Fixed gain amplifier for automatic gain control and variable gain amplifier |
Non-Patent Citations (1)
| Title |
|---|
| SUNYOUNG KIM ELT.: "An Energy-Efficient Analog Front-End Circuit for a Sub-1-V Digital Hearing Aid Chip", 《IEEE JOURNAL OF SOLID-STATE CIRCUITS》, vol. 41, no. 4, 30 April 2006 (2006-04-30) * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103050119A (en) * | 2012-12-30 | 2013-04-17 | 安徽科大讯飞信息科技股份有限公司 | Self-adaptive detection method for synchronism of lamplight/motor and sound |
| CN104183241A (en) * | 2013-05-28 | 2014-12-03 | 无锡华润矽科微电子有限公司 | Control circuit and method for improving volume adjustment of audio signal |
| CN104183241B (en) * | 2013-05-28 | 2017-09-29 | 无锡华润矽科微电子有限公司 | Improve the control circuit and method of audio signal volume regulation |
| CN105305990A (en) * | 2015-12-09 | 2016-02-03 | 北京中科汉天下电子技术有限公司 | Power control circuit of power amplifier |
| CN105305990B (en) * | 2015-12-09 | 2018-02-09 | 北京中科汉天下电子技术有限公司 | A kind of power control circuit of power amplifier |
| CN112968684A (en) * | 2021-02-08 | 2021-06-15 | 西安理工大学 | Broadband programmable gain amplifier based on transconductance switching technology |
| CN112968684B (en) * | 2021-02-08 | 2024-04-05 | 西安理工大学 | Broadband programmable gain amplifier based on transconductance switching technology |
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