CN200976567Y - Multiplier based single terminal local oscillation inputted MOS frequency mixer - Google Patents

Abstract

The utility model discloses a local oscillator input MOS mixer, which is based on a single-ended multiplier, comprising a MOS pair tube (M1 and M2), a MOS pair tube (M3 and M4), a MOS pair tube (M5 and M6) and constant current source (I00); with the application of a new linear amplifier used to improve the feed-forward amplifier, the linearity is improved; the adoption of single-ended local oscillator input eliminates the phase shift produced by the opposite phase of the vibration signal steps to avoid the phase shift due to the imprecise and phase noise.

Description

MOS frequency mixer based on the single-ended local oscillator input of multiplier

Technical field

The utility model relates to a kind of frequency mixer, particularly a kind of MOS frequency mixer of importing based on the single-ended local oscillator of multiplier.

Background technology

Frequency mixer is widely used in the frequency exchange of carrier signal in the Modern Communication System.In radio-frequency transmitter, the performance of down-conversion mixer has a strong impact on the performance of system and the system performance requirement to other functional circuit.Along with wireless telecommunications system constantly develops, low pressure, low-power consumption have also been proposed the frequency mixer as one of core of wireless telecommunications radio-frequency front-end, noise-reduction coefficient and the requirement that improves the linearity.At present, the raising of metal-oxide-semiconductor cut-off frequency and at the employing of the special process of radio frequency integrated circuit makes CMOS technology can realize high performance radio frequency integrated circuit.Frequency mixer in the communication system is normally based on the active Gilbert current switching mode frequency mixer of CMOS technology.But this general Gilbert frequency mixer needs higher direct voltage, and simultaneously, the restriction of voltage is unfavorable for the raising of mixer linearity degree.Therefore, need carry out the improvement of low-voltage and high linearity aspect at this frequency mixer.

The utility model content

For solving the problems of the technologies described above, the utility model provides a kind of MOS frequency mixer of importing based on the single-ended local oscillator of multiplier.

The technical scheme that the utility model solves the problems of the technologies described above is: be made up of metal-oxide-semiconductor M1～M6 and constant-current source Ioo, current output signal io1 links to each other with the drain electrode of M2 and M3, and current output signal io2 links to each other with the drain electrode of M1 and M4, the source-coupled of M1 and M2 is by constant-current source Ioo ground connection, the grid of M1 is connected to the drain electrode of source electrode and the M5 of M3, and the grid of M2 then is connected to the drain electrode of source electrode and the M6 of M4; The source electrode of M3 links to each other with the drain electrode of M5, and M3 and M5 are with the series system cascade, and the source electrode of M4 links to each other with the drain electrode of M6, M4 and M6 same with the series system cascade; The direct ground connection of the source-coupled of M5 and M6.

Advantage of the present utility model: 1) adopt the feed-forward amplifier that improves the linearity of amplifier degree in the design of circuit, the linearity is good; 2) do not need to use Ba Lun that local oscillation signal is carried out single both-end conversion, Ba Lun takies very big area usually, helps simplifying circuit and reduces chip area; 3) adopt single-ended local oscillator input, saved the step that produces the opposite local oscillation signal of phase place by phase shift, avoided the phase noise that produces because of the phase shift inaccuracy, relaxed designing requirement greatly.

The utility model is described in further detail below in conjunction with accompanying drawing.

Description of drawings

Fig. 1 is based on the MOS frequency mixer of the single-ended local oscillator input of multiplier

Embodiment

Referring to Fig. 1, to form by two-stage circuit based on the MOS frequency mixer that the single-ended local oscillator of multiplier is imported, the common source that promptly is biased in steady job point is to the transconductance stage of pipe M5 and M6 formation with by big local oscillation signal switch driven level M1, M2 and M3, M4.Transconductance stage is responsible for the conversion of radiofrequency signal to pipe M5 and M6, with the radio-frequency voltage conversion of signals of input is current signal, changed the gate source voltage of M3 and M4 thus, because pipe M5 and M6 are worked in saturation condition, then also changed simultaneously the gate source voltage of M1 and M2, equivalence is a small signal input.And the bigger local oscillation signal of amplitude is imported from the source end of M1 and M2 with current system, makes its mutual conductance generating period variation.The radiofrequency signal of input has been modulated in the periodicity mutual conductance of M1 and M2, finishes the mixing function.It is as follows to derive:

$\∂I_{D3}=2K\frac{W_3}{L_3}(V_{\mathrm{GS}3}-V_T)\∂V_{\mathrm{GS}3}---\left(1\right)$

$\∂V_{\mathrm{GS}3}=\frac{{\∂I}_{D3}}{2K\frac{W_3}{L_3}(V_{\mathrm{GS}3}-V_T)}=\frac{\frac{1}{2}{i}_{\mathrm{rj}}}{2K\frac{W_3}{L_3}(V_{\mathrm{GS}3}-V_T)}---\left(2\right)$

i _od＝2i _o1 (5)

As can be known, suitable adjusting M1 and the grid width of M3, and bias current, the i.e. gain of adjustable circuit.

Claims (1)

1, a kind of MOS frequency mixer of importing based on the single-ended local oscillator of multiplier, it is characterized in that: (M1～M6) and constant-current source (Ioo) are formed by metal-oxide-semiconductor, current output signal (io1) links to each other with the drain electrode of metal-oxide-semiconductor (M2) and (M3), and current output signal (io2) links to each other with the drain electrode of (M4) with (M1), the source-coupled of metal-oxide-semiconductor (M1 and M2) is by constant-current source (Ioo) ground connection, the grid of metal-oxide-semiconductor (M1) is connected to the drain electrode of the source electrode and the metal-oxide-semiconductor (M5) of metal-oxide-semiconductor (M3), and the grid of metal-oxide-semiconductor (M2) then is connected to the drain electrode of the source electrode and the metal-oxide-semiconductor (M6) of metal-oxide-semiconductor (M4); The source electrode of metal-oxide-semiconductor (M3) links to each other with the drain electrode of metal-oxide-semiconductor (M5), and metal-oxide-semiconductor (M3) and metal-oxide-semiconductor (M5) are with the series system cascade, and the source electrode of metal-oxide-semiconductor (M4) links to each other with the drain electrode of metal-oxide-semiconductor (M6), metal-oxide-semiconductor (M4) and (M6) same with the series system cascade; Metal-oxide-semiconductor (M5) and the direct ground connection of source-coupled (M6).

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