CN204392194U - A kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function - Google Patents

Abstract

The utility model discloses a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function.This amplifier, comprising: compression module and non-linear conversion module, and two outputs of compression module are connected with two inputs of non-linear conversion module respectively; Compression module comprise PMOS for the first differential input signal to be converted to the first voltage signal with exponential form to the NMOS couple being used for the second differential input signal to be converted to exponential form the second voltage signal; Non-linear conversion module comprises mirror current source for generating current signal according to the first voltage signal of input and the second voltage signal and for according to transform subblock current signal being converted to voltage signal by non-linear transfer function.The differential signal of input for voltage signal with the formal transformation of index, completes compressing and converting, carries out nonlinear function, make output extended transistor be operated in saturation area, while increasing output voltage swing, improves the linearity and common-mode rejection ratio.

Description

A kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function

Technical field

The utility model relates to bio signal process field, particularly relates to a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function.

Background technology

In the middle of daily Wearable portable medical device, in order to meet portability power demands, portability power supply such as button cell is main power supply, but its power supply capacity is limited, be difficult to maintain device running for a long time to become increasingly serious problem, so exacerbate daily body-worn medical detection means low-power consumption requirement.Due to the module that amplifier is the most basic in bio signal front-end collection treatment system, therefore this constraint increases amplifier low-power consumption urgency and necessity, but to reduce a topmost method of power consumption be exactly low-voltage, so low-voltage, low-power consumption and the low frequency required by biomedicine signals self character become a crucial problem demanding prompt solution.

The portable application with minimizing SOC (system on a chip) has increased microelectronics market demands, the especially requirement of biomedical sector product such as hearing aids, cardiac pacemaker, implantable sensor etc.The portability requirements powered battery of system, unfortunately, the development of battery technology is not fast to the speed of requirement on devices, so the problem of low-voltage, low consumption circuit design occurs, and increasingly serious.Log-domain amplifier is that the field-effect transistor (MOS) of work is biased in weak inversion regime, utilizes its logarithmic function to complete the amplifying circuit of amplification.Because metal-oxide-semiconductor is biased in weak inversion regime, its operating voltage is very low, at below 1V; Its operating current is also very little of 100nA level.So just greatly reducing power consumption.

Logarithmic amplifier, first input signal with the formal transformation of exponential function to pointer field, and under normal circumstances, as long as amplifying signal is multiplied by a constant factor, and in pointer field corresponding to adding a constant factor.Then to anti-exponential function, amplifying signal in pointer field is converted in common territory again, while maintenance amplification is linear, achieves amplifying signal.As shown in Figure 1, log-domain amplifier is divided into three parts: compression (Compressor), nonlinear operation (Non-linear Function), expansion (Expander).

Traditional log-domain amplifier implementation, compression branch as shown in Figure 2.Input current signal is converted into voltage signal exponentially through being biased in weak inversion regime metal-oxide-semiconductor, then superposes a constant voltage, then is biased in weak inversion regime metal-oxide-semiconductor through one voltage signal is converted into current signal, just achieves amplification.Current log-domain amplifier, the function that compressed pipe and extension tube realize is a reciprocal function.

In traditional log-domain amplifier, logarithmic amplification does not also have actual adaptable Differential Input.Which greatly enhances noise, reduce the performance of circuit.In addition, because logarithmic amplifier operating current is very low, reduce the carrying capacity of circuit noise, again owing to there is no Differential Input restraint speckle, circuit noise performance is worsened further, makes common-mode rejection ratio lower.Logarithmic amplifier output transistor is biased in weak inversion regime, and its electric current is very low, the amplitude of oscillation of this restriction output current.And carrying out nonlinear operation because logarithmic amplifier needs to be transformed into log-domain, this makes the linear not high of whole amplifier.

Utility model content

The utility model provides a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function, it is by adopting symmetrical Differential Input port, input differential signal respectively through PMOS to NMOS couple, with the formal transformation of index for voltage signal, complete input compressing and converting, carry out unique nonlinear function, make output extended transistor be operated in saturation area, while increasing output voltage swing, improve the linearity and common-mode rejection ratio.

For reaching this object, the utility model by the following technical solutions:

Based on a Low-voltage Low-power amplifier for log-domain non-linear transfer function, comprising: compression module and non-linear conversion module, two outputs of described compression module are connected with two inputs of described non-linear conversion module respectively; Described compression module comprise PMOS for the first differential input signal to be converted to the first voltage signal with exponential form to the NMOS couple being used for the second differential input signal to be converted to exponential form the second voltage signal; Described first voltage signal and the second voltage signal export respectively by two outputs; Described PMOS forms by two complementary PMOS; Described NMOS forms by two complementary NMOS tube;

Described non-linear conversion module comprises mirror current source for generating current signal according to the first voltage signal of input and the second voltage signal and for according to the transform subblock described current signal being converted to voltage signal by non-linear transfer function.

Wherein, described compression module also comprises the metal-oxide-semiconductor for being biased in wake flow source.

Wherein, described mirror current source front end is also connected with the metal-oxide-semiconductor for described second voltage signal being changed into current signal; Described mirror current source front end is also connected with the metal-oxide-semiconductor for adjusting described current signal.

Wherein, described compression module comprises: PMOS PMOS0, PMOS PMOS1, PMOS PMOS2, NMOS tube NMOS0, NMOS tube NMOS1 and NMOS tube NMOS2; The source electrode access supply voltage of described PMOS PMOS0, the drain electrode of PMOS PMOS0 is connected with the source electrode of the source electrode of PMOS PMOS1, PMOS PMOS2, and the grid of PMOS PMOS0 is connected with the drain electrode of PMOS PMOS2 and accesses reference current; The grid of described PMOS PMOS1 accesses the first differential input signal, and the grid of described PMOS PMOS1 is also connected with the drain electrode of PMOS PMOS1, the grid of NMOS tube NMOS2; The grid access reference voltage of described PMOS PMOS2; The grid of described NMOS tube NMOS1 accesses the second differential input signal, the source electrode of NMOS tube NMOS1 is connected with the source electrode of NMOS tube NMOS2, the drain electrode of NMOS tube NMOS0; The drain electrode of described NMOS tube NMOS1 is connected with the grid of NMOS tube NMOS1; The drain electrode access reference current of described NMOS tube NMOS2 is also connected with the grid of NMOS tube NMOS0; The source ground of described NMOS tube NMOS0.

Wherein, described non-linear conversion module comprises: PMOS PMOS3, PMOS PMOS4, PMOS PMOS5, PMOS PMOS6, NMOS tube NMOS3, NMOS tube NMOS4, NMOS tube NMOS5, NMOS tube NMOS6, NMOS tube NMOS7 and NMOS tube NMOS8; The grid of described PMOS PMOS3 is connected with the grid of the drain electrode of NMOS tube NMOS1, NMOS tube NMOS3, the source electrode access supply voltage of described PMOS PMOS3, the drain electrode of described PMOS PMOS3 is connected with the grid of the drain electrode of NMOS tube NMOS4, NMOS tube NMOS4, the grid of NMOS tube NMOS6; The source electrode of described NMOS tube NMOS4 is connected with the grid of the drain electrode of NMOS tube NMOS5, NMOS tube NMOS5, the grid of NMOS tube NMOS7; The source electrode of NMOS tube NMOS5 is connected with the drain electrode of NMOS tube NMOS3; The source electrode of NMOS tube NMOS6 is connected with the drain electrode of NMOS tube NMOS7; The grid of PMOS PMOS4 is connected with the grid of NMOS tube NMOS2, and the drain electrode of PMOS PMOS4 is connected with the drain electrode of NMOS tube NMOS6, and the source electrode of PMOS PMOS4 is connected with the source electrode of the drain electrode of PMOS PMOS5, PMOS PMOS6; The source electrode access supply voltage of PMOS PMOS5; The grid of PMOS PMOS6 is connected with the grid of the drain electrode of PMOS PMOS6, NMOS tube NMOS8; The drain electrode of described NMOS tube NMOS8 exports the current signal finally obtained; The grid of the source electrode of described NMOS tube NMOS3, the source electrode of NMOS tube NMOS7, PMOS PMOS5, the drain electrode of PMOS PMOS6, the source grounding of NMOS tube NMOS8.

Wherein, described non-linear conversion module also comprises PMOS PMOS7, and the drain and gate of described PMOS PMOS7 is connected with the drain electrode of NMOS tube NMOS8; The source electrode access supply voltage of described PMOS PMOS7.

The beneficial effects of the utility model are: by adopting symmetrical Differential Input port, input differential signal respectively through PMOS to NMOS couple, with the formal transformation of index for voltage signal, complete input compressing and converting, carry out unique nonlinear function, make output extended transistor be operated in saturation area, while increasing output voltage swing, improve the linearity and common-mode rejection ratio.

Accompanying drawing explanation

In order to be illustrated more clearly in the technical scheme in the utility model embodiment, be briefly described to the accompanying drawing used required in the description of the utility model embodiment below, apparently, accompanying drawing in the following describes is only embodiments more of the present utility model, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to the content of the utility model embodiment and these accompanying drawings.

Fig. 1 is the schematic diagram of log-domain amplifier.

Fig. 2 is the circuit theory diagrams of existing log-domain amplifier.

Fig. 3 is the circuit theory diagrams of the compression module of a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function provided in the utility model embodiment.

Fig. 4 is a kind of mirror current source of Low-voltage Low-power amplifier based on log-domain non-linear transfer function and the circuit theory diagrams of conversion sub-circuit that provide in the utility model embodiment.

Fig. 5 is the circuit theory diagrams of a kind of Low-voltage Low-power amplifier entirety based on log-domain non-linear transfer function provided in the utility model embodiment.

Fig. 6 is the simulation result schematic diagram of the transient response of a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function provided in the utility model embodiment.

Fig. 7 is the simulation result schematic diagram of the frequency response of a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function provided in the utility model embodiment.

Fig. 8 is the simulation result schematic diagram of the linearity of a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function provided in the utility model embodiment.

Fig. 9 is the simulation result schematic diagram of the DC response of a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function provided in the utility model embodiment.

Embodiment

The technical problem solved for making the utility model, the technical scheme of employing and the technique effect that reaches are clearly, be described in further detail below in conjunction with the technical scheme of accompanying drawing to the utility model embodiment, obviously, described embodiment is only the utility model part embodiment, instead of whole embodiments.Based on the embodiment in the utility model, those skilled in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the utility model protection.

Please refer to Fig. 3 to Fig. 9, it is the simulation result schematic diagram of the circuit theory diagrams of the circuit theory diagrams of the compression module of a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function provided in the utility model embodiment, mirror current source and conversion sub-circuit, overall circuit theory diagrams, the simulation result schematic diagram of transient response, the simulation result schematic diagram of frequency response, the simulation result schematic diagram of the linearity and DC response respectively.The Low-voltage Low-power amplifier based on log-domain non-linear transfer function in the present embodiment, is mainly used in various portable medical device, particularly carries out the medical device detected based on bioelectricity.As shown in the figure, this amplifier, comprising: compression module and non-linear conversion module, and two outputs of described compression module are connected with two inputs of described non-linear conversion module respectively; Described compression module comprise PMOS for the first differential input signal to be converted to the first voltage signal with exponential form to the NMOS couple being used for the second differential input signal to be converted to exponential form the second voltage signal; Described first voltage signal and the second voltage signal export respectively by two outputs; Described PMOS forms by two complementary PMOS; Described NMOS forms by two complementary NMOS tube;

Described non-linear conversion module comprises mirror current source for generating current signal according to the first voltage signal of input and the second voltage signal and for according to the transform subblock described current signal being converted to voltage signal by non-linear transfer function.

Preferably, described compression module also comprises the metal-oxide-semiconductor for being biased in wake flow source.

Preferably, described mirror current source front end is also connected with the metal-oxide-semiconductor for described second voltage signal being changed into current signal; Described mirror current source front end is also connected with the metal-oxide-semiconductor for adjusting described current signal.

Further, described compression module comprises: PMOS PMOS0, PMOS PMOS1, PMOS PMOS2, NMOS tube NMOS0, NMOS tube NMOS1 and NMOS tube NMOS2; The source electrode access supply voltage of described PMOS PMOS0, the drain electrode of PMOS PMOS0 is connected with the source electrode of the source electrode of PMOS PMOS1, PMOS PMOS2, and the grid of PMOS PMOS0 is connected with the drain electrode of PMOS PMOS2 and accesses reference current; The grid of described PMOS PMOS1 accesses the first differential input signal, and the grid of described PMOS PMOS1 is also connected with the drain electrode of PMOS PMOS1, the grid of NMOS tube NMOS2; The grid access reference voltage of described PMOS PMOS2; The grid of described NMOS tube NMOS1 accesses the second differential input signal, the source electrode of NMOS tube NMOS1 is connected with the source electrode of NMOS tube NMOS2, the drain electrode of NMOS tube NMOS0; The drain electrode of described NMOS tube NMOS1 is connected with the grid of NMOS tube NMOS1; The drain electrode access reference current of described NMOS tube NMOS2 is also connected with the grid of NMOS tube NMOS0; The source ground of described NMOS tube NMOS0.

The single input port of current compression module, does not have great rejection ability to common-mode signal.Adopt symmetrical Differential Input port in this programme, as shown in Figure 3, it is made up of the PMOS of complementation and nmos pass transistor, and its input inputs from the grid of PMOS and NMOS respectively.PMOS PMOS1 and PMOS PMOS2 forms the input difference pair of PMOS end; NMOS1 and NMOS2 forms the input difference pair of NMOS end; All the other metal-oxide-semiconductors, namely PMOS PMOS0 and NMOS tube NMOS0 each provides the biased of wake flow source.Input differential signal respectively through PMOS to NMOS couple, with the formal transformation of index for voltage signal, i.e. log-domain.

Because all inputs are all operated in weak inversion regime to pipe, according to MOSFET model NMOS voltage-to-current formula be: $I_D=I_S{e}^{\frac{V_{\mathrm{GB}}-V_{\mathrm{TO}}}{n{U}_t}},I_S=2\mathrm{n\β}{U}_t^2,\mathrm{IC}=\frac{I_D}{I_S};$ Wherein I _s, n, β, V _tO, U _t, IC, V _gBrepresentation feature electric current, sub-threshold values slope, current parameters, threshold voltage, electric heating and inversion coefficient respectively.The weak inversion formula of PMOS is just in time corresponding therewith.The input of NMOS and PMOS input are had respectively:

$I_{+}=I_{\mathrm{ref}}{e}^{\frac{V_{+}-V_{-}}{n{U}_t}}$

$I_{-}=I_{\mathrm{ref}}{e}^{\frac{V_{\mathrm{ref}}-V_{-}}{n{U}_t}}$

So have:

$\frac{I_{+}-I_{-}}{I_{+}+I_{-}}=\frac{i_{+}-i_{-}}{I_b}=\frac{\frac{I_{+}}{I_{-}}-1}{\frac{I_{+}}{I_{-}}+1}=\frac{e^{\frac{V_{+}-V_{\mathrm{ref}}}{{\mathrm{nU}}_t}}-1}{e^{\frac{V_{-}-V_{\mathrm{ref}}}{{\mathrm{nU}}_t}}+1}=\tanh \left(\frac{V_{+}-V_{\mathrm{ref}}}{{2\mathrm{nU}}_t}\right)$

$i_{+}-i_{-}=I_b\tanh \left(\frac{V_{+}-V_{\mathrm{ref}}}{{2\mathrm{nU}}_t}\right)$

Input not only realizes the conversion of Differential Input and signal domain, and achieves the difference of the voltage signal after conversionization, i.e. output voltage V+.

Further, described non-linear conversion module comprises: PMOS PMOS3, PMOS PMOS4, PMOS PMOS5, PMOS PMOS6, NMOS tube NMOS3, NMOS tube NMOS4, NMOS tube NMOS5, NMOS tube NMOS6, NMOS tube NMOS7 and NMOS tube NMOS8; The grid of described PMOS PMOS3 is connected with the grid of the drain electrode of NMOS tube NMOS1, NMOS tube NMOS3, the source electrode access supply voltage of described PMOS PMOS3, the drain electrode of described PMOS PMOS3 is connected with the grid of the drain electrode of NMOS tube NMOS4, NMOS tube NMOS4, the grid of NMOS tube NMOS6; The source electrode of described NMOS tube NMOS4 is connected with the grid of the drain electrode of NMOS tube NMOS5, NMOS tube NMOS5, the grid of NMOS tube NMOS7; The source electrode of NMOS tube NMOS5 is connected with the drain electrode of NMOS tube NMOS3; The source electrode of NMOS tube NMOS6 is connected with the drain electrode of NMOS tube NMOS7; The grid of PMOS PMOS4 is connected with the grid of NMOS tube NMOS2, and the drain electrode of PMOS PMOS4 is connected with the drain electrode of NMOS tube NMOS6, and the source electrode of PMOS PMOS4 is connected with the source electrode of the drain electrode of PMOS PMOS5, PMOS PMOS6; The source electrode access supply voltage of PMOS PMOS5; The grid of PMOS PMOS6 is connected with the grid of the drain electrode of PMOS PMOS6, NMOS tube NMOS8; The drain electrode of described NMOS tube NMOS8 exports the current signal finally obtained; The grid of the source electrode of described NMOS tube NMOS3, the source electrode of NMOS tube NMOS7, PMOS PMOS5, the drain electrode of PMOS PMOS6, the source grounding of NMOS tube NMOS8.

Further, described non-linear conversion module also comprises PMOS PMOS7, and the drain and gate of described PMOS PMOS7 is connected with the drain electrode of NMOS tube NMOS8; The source electrode access supply voltage of described PMOS PMOS7.

Input signal changes into current signal through PMOS3 pipe, adjusts it to facilitate, and NMOS tube NMOS4-7 forms mirror current source, and NMOS3 is Correctional tube, and it is finely tuned current signal, improves the linearity of amplifier.PMOS PMOS4-PMOS6 constitutes non-linear transfer function, the current signal exported is changed into the voltage signal that can reduce with the NMOS8 pipe being biased in saturation region, complete amplification in mirror current source.

PMOS voltage-to-current formula is:

$I=I_s{\left(\frac{W}{L}\right)}_c{e}^{\frac{-V_{\mathrm{dB}}+V_{\mathrm{TOP}}}{{\mathrm{nU}}_t}}$

Reference current is:

$I_r=I_s{\left(\frac{W}{L}\right)}_b{e}^{\frac{-V_{\mathrm{OB}}+V_{\mathrm{TOP}}}{{\mathrm{nU}}_t}}{e}^{\frac{V_{\mathrm{SB}}}{{\mathrm{nU}}_t}}$

By Fig. 5, obtain according to KCL law:

$I_r+I=I_s{\left(\frac{W}{L}\right)}_a{e}^{\frac{-V_{\mathrm{OB}}+V_{\mathrm{TOP}}}{{\mathrm{nU}}_t}}[1-e^{\frac{V_{\mathrm{SB}}}{{\mathrm{nU}}_t}}]$

${\left(\frac{W}{L}\right)}_b{e}^{\frac{V_{\mathrm{ref}}-V_O}{{\mathrm{nU}}_t}}-{\left(\frac{W}{L}\right)}_c{e}^{\frac{V_{\mathrm{ref}}-V_{\mathrm{dm}}}{{\mathrm{nU}}_t}}=\frac{(1+{\left(\frac{W}{L}\right)}_{a/b})I_r}{I_s}{e}^{-\frac{V_{\mathrm{DD}}+V_{\mathrm{TOP}}-V_{\mathrm{ref}}}{{\mathrm{nU}}_t}}$

Order:

$M=\frac{(1+{\left(\frac{W}{L}\right)}_{a/b})I_r}{I_s}{e}^{-\frac{V_{\mathrm{DD}}+V_{\mathrm{TOP}}-V_{\mathrm{ref}}}{{\mathrm{nU}}_t}}={\left(\frac{W}{L}\right)}_c$

$e^{\frac{V_{\mathrm{dm}}-V_{\mathrm{ref}}}{n{U}_t}}=\frac{{\left(\frac{W}{L}\right)}_{c/b}{e}^{\frac{V_D-V_{\mathrm{ref}}}{n{U}_t}}}{1-\frac{1}{{\left(\frac{W}{L}\right)}_b}{\mathrm{Me}}^{\frac{V_D-V_{\mathrm{ref}}}{n{U}_t}}}$

So:

$\tanh \left(\frac{V_{\mathrm{dm}}-V_{\mathrm{ref}}}{2n{U}_t}\right)={\left(\frac{W}{L}\right)}_{c/d}{e}^{\frac{V_D-V_{\mathrm{ref}}}{n{U}_t}}-\frac{1}{e^{2x}+1}\≈{\left(\frac{W}{L}\right)}_{c/b}{e}^{\frac{V_D-V_{\mathrm{ref}}}{n{U}_t}}$

Owing to exporting:

$I_o=I_s{\left(\frac{W}{L}\right)}_o{e}^{\frac{V_O-V_{\mathrm{TON}}}{n{U}_t}}$

So:

$I_o=\frac{I_s}{I_B}{\left(\frac{W}{L}\right)}_{\frac{\mathrm{ob}}{c}}{e}^{\frac{V_{\mathrm{ref}}-V_{\mathrm{TON}}}{n{U}_t}}(I_1-I_2)$

So its gain amplifier is: $\frac{I_s}{I_B}{\left(\frac{W}{L}\right)}_{\frac{\mathrm{ob}}{c}}{e}^{\frac{V_{\mathrm{ref}}-V_{\mathrm{TON}}}{n{U}_t}}.$

Wherein V _tONrepresent the threshold voltage of NMOS tube; V _tONrepresent grid and the base voltage of metal-oxide-semiconductor; W represents the width of metal-oxide-semiconductor; L represents the length of metal-oxide-semiconductor, I _rrepresent the I in Fig. 5 _oref, I _orepresent the I in Fig. 5 _out.

Through experiment simulation simulation proof, it is feasible and is reliable.

Simulation result is as Fig. 6 to Fig. 9.Fig. 6 is the transient response of amplifier, can find out that its output voltage swing is uA level, instead of nA level this greatly increase output voltage swing.Fig. 7 is frequency response, and 3dB frequency is 500kHz. this is enough to bio signal.The linearity THD of Fig. 8 amplifier is-70.83dB, is less than 0.2%.Fig. 9 is the DC response of amplifier.

In sum: by adopting symmetrical Differential Input port, input differential signal respectively through PMOS to NMOS couple, with the formal transformation of index for voltage signal, complete input compressing and converting, carry out unique nonlinear function, make output extended transistor be operated in saturation area, while increasing output voltage swing, improve the linearity and common-mode rejection ratio.

Below know-why of the present utility model is described in conjunction with specific embodiments.These describe just in order to explain principle of the present utility model, and can not be interpreted as the restriction to the utility model protection range by any way.Based on explanation herein, those skilled in the art does not need to pay performing creative labour can associate other embodiment of the present utility model, and these modes all will fall within protection range of the present utility model.

Claims (6)

1. based on a Low-voltage Low-power amplifier for log-domain non-linear transfer function, it is characterized in that, comprising: compression module and non-linear conversion module, two outputs of described compression module are connected with two inputs of described non-linear conversion module respectively; Described compression module comprise PMOS for the first differential input signal to be converted to the first voltage signal with exponential form to the NMOS couple being used for the second differential input signal to be converted to exponential form the second voltage signal; Described first voltage signal and the second voltage signal export respectively by two outputs; Described PMOS forms by two complementary PMOS; Described NMOS forms by two complementary NMOS tube;

Described non-linear conversion module comprises mirror current source for generating current signal according to the first voltage signal of input and the second voltage signal and for according to the transform subblock described current signal being converted to voltage signal by non-linear transfer function.

2. a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function according to claim 1, is characterized in that, described compression module also comprises the metal-oxide-semiconductor for being biased in wake flow source.

3. a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function according to claim 1, is characterized in that, described mirror current source front end is also connected with the metal-oxide-semiconductor for described second voltage signal being changed into current signal; Described mirror current source front end is also connected with the metal-oxide-semiconductor for adjusting described current signal.

4. a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function according to claim 2, it is characterized in that, described compression module comprises: PMOS PMOS0, PMOS PMOS1, PMOS PMOS2, NMOS tube NMOS0, NMOS tube NMOS1 and NMOS tube NMOS2; The source electrode access supply voltage of described PMOS PMOS0, the drain electrode of PMOS PMOS0 is connected with the source electrode of the source electrode of PMOS PMOS1, PMOS PMOS2, and the grid of PMOS PMOS0 is connected with the drain electrode of PMOS PMOS2 and accesses reference current; The grid of described PMOS PMOS1 accesses the first differential input signal, and the grid of described PMOS PMOS1 is also connected with the drain electrode of PMOS PMOS1, the grid of NMOS tube NMOS2; The grid access reference voltage of described PMOS PMOS2; The grid of described NMOS tube NMOS1 accesses the second differential input signal, the source electrode of NMOS tube NMOS1 is connected with the source electrode of NMOS tube NMOS2, the drain electrode of NMOS tube NMOS0; The drain electrode of described NMOS tube NMOS1 is connected with the grid of NMOS tube NMOS1; The drain electrode access reference current of described NMOS tube NMOS2 is also connected with the grid of NMOS tube NMOS0; The source ground of described NMOS tube NMOS0.

5. a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function according to claim 4, it is characterized in that, described non-linear conversion module comprises: PMOS PMOS3, PMOS PMOS4, PMOS PMOS5, PMOS PMOS6, NMOS tube NMOS3, NMOS tube NMOS4, NMOS tube NMOS5, NMOS tube NMOS6, NMOS tube NMOS7 and NMOS tube NMOS8; The grid of described PMOS PMOS3 is connected with the grid of the drain electrode of NMOS tube NMOS1, NMOS tube NMOS3, the source electrode access supply voltage of described PMOS PMOS3, the drain electrode of described PMOS PMOS3 is connected with the grid of the drain electrode of NMOS tube NMOS4, NMOS tube NMOS4, the grid of NMOS tube NMOS6; The source electrode of described NMOS tube NMOS4 is connected with the grid of the drain electrode of NMOS tube NMOS5, NMOS tube NMOS5, the grid of NMOS tube NMOS7; The source electrode of NMOS tube NMOS5 is connected with the drain electrode of NMOS tube NMOS3; The source electrode of NMOS tube NMOS6 is connected with the drain electrode of NMOS tube NMOS7; The grid of PMOS PMOS4 is connected with the grid of NMOS tube NMOS2, and the drain electrode of PMOS PMOS4 is connected with the drain electrode of NMOS tube NMOS6, and the source electrode of PMOS PMOS4 is connected with the source electrode of the drain electrode of PMOS PMOS5, PMOS PMOS6; The source electrode access supply voltage of PMOS PMOS5; The grid of PMOS PMOS6 is connected with the grid of the drain electrode of PMOS PMOS6, NMOS tube NMOS8; The drain electrode of described NMOS tube NMOS8 exports the current signal finally obtained; The grid of the source electrode of described NMOS tube NMOS3, the source electrode of NMOS tube NMOS7, PMOS PMOS5, the drain electrode of PMOS PMOS6, the source grounding of NMOS tube NMOS8.

6. a kind of Low-voltage Low-power amplifier based on log-domain non-linear transfer function according to claim 5, it is characterized in that, described non-linear conversion module also comprises PMOS PMOS7, and the drain and gate of described PMOS PMOS7 is connected with the drain electrode of NMOS tube NMOS8; The source electrode access supply voltage of described PMOS PMOS7.