CN205247253U - Improved generation reference voltage bleeder circuit - Google Patents

Abstract

The utility model discloses an improved generation reference voltage bleeder circuit, add a set of electric capacity in traditional reference voltage bleeder circuit, this group's electric capacity is established ties in each two tunnel difference of organizing the difference comparison reference level that makes perfect relatively between the reference level respectively, form low pass filter with the resistance that corresponds, the reinforcing is to the suppression ability of power supply noise with the ground noise, relatively reference level's synchronous fluctuation of difference has entirely on the same group been guaranteed simultaneously, relatively reference level's stability of full difference has greatly been improved, can the wide application in adc's reference voltage bleeder circuit, especially in the comparator circuit design of high accuracy, performance to the circuit has obvious improvement, the circuit is realized simply, and has a good application prospect.

Description

A kind of modified reference voltage bleeder circuit

Technical field

The utility model relates to the chip design of high-performance analog-digital converter, belongs to semiconductor integrated circuit design field.

Background technology

In recent years, be accompanied by developing rapidly of wireless communication technology and application thereof, high-performance, CMOS technique cheaplyProgressive, bring many opportunities and challenges to the design of analog-digital converter. Analog-digital converter chip is positioned at radio-frequency front-end and numeralBetween signal processor, the conversion of settling signal from analog domain to numeric field, high-performance, low-power consumption and low cost are analog-to-digital conversionThe design object of device chip. And indispensable key modules in analog-digital converter circuit is reference voltage bleeder circuit, it is modulusComparator in converter provides a datum, makes to quantize corresponding digital level, and more high-precision comparator is rightStability and the accuracy requirement of datum are higher. Reference voltage bleeder circuit is to provide stable comparison in essence with reference to electricityFlat, comparator circuit quantizes corresponding bits according to comparing datum, and therefore, the property relationship of reference voltage bleeder circuit arrivesThe correctness of analog-digital converter quantization bit.

The basic structure of traditional reference voltage bleeder circuit, as shown in Figure 1, reference voltage bleeder circuit in essenceA divider in fact, by a fixing voltage difference (Reft_bk-Refb_bk), utilize k series connection substitutional resistance R1,R2 ... R(k-1), R (k) dividing potential drop, produce k-1 datum V<1>, V<2>... V<k-2>, V<k-1>, because modulus turnsParallel operation adopts fully differential circuit to realize, and realizes so the comparison datum while producing quantization bit is also fully differential, obtainsRelatively datum is as follows for k-1 group fully differential:

V<k-1>-V<1>、V<k-2>-V<2>……V<2>-V<k-2>、V<1>-V<k-1>

Because the ability of the inhibition noise of voltage follower Buffer1, Buffer2 is very limited, power supply noise and ground noiseVery large, cause the output voltage Reft_bk of Buffer1 and the output voltage Refb_bk of Buffer2 unstable, there is noise voltage;Power supply noise is more much larger than ground noise simultaneously, causes the noise voltage of Reft_bk more much larger than the noise voltage of Refb_bk, root, datum V<1 known according to circuit theory>, V<2>... V<k-2>, V<k-1>determined by Reft_bk and Refb_bk, soK-1 datum followed power supply noise and ground noise fluctuations, and final k-1 group fully differential comparison datum is also followed power supply and made an uproarSound and ground noise fluctuations, affect the performance of reference voltage bleeder circuit, thereby cause the quantization bit of analog-digital converter to be made mistakes.

Utility model content

The purpose of this utility model is in order to overcome relatively datum of the prior art with power supply noise and ground noiseFluctuation, affects the performance of reference voltage bleeder circuit, thus the problem that causes the quantization bit of analog-digital converter to be made mistakes. This practicalityThe modified reference voltage bleeder circuit of novel proposition, can, under large power supply noise and ground noise situations, reduce greatlyThe relatively noise fluctuations of datum, the inhibition ability of enhancing to power supply noise and ground noise, promotes relatively putting down of datumStability, has avoided analog-digital converter quantization bit to make mistakes, and circuit is realized simple, has a good application prospect.

In order to achieve the above object, the technical scheme that the utility model adopts is:

A kind of modified reference voltage bleeder circuit, is characterized in that: comprise the first voltage follower Buffer1, secondVoltage follower Buffer2, k substitutional resistance R₁、R₂To R_(k-1）、R_(k)(k-1)/2 capacitor C_dec1、C_dec2ExtremelyC_{dec（k-1）/2}, wherein, k >=3, and be odd number,

The positive input of described the first voltage follower Buffer1 meets outside input reference voltage Reft; Described secondThe positive input of voltage follower Buffer2 meets outside input reference voltage Refb;

Described k substitutional resistance R₁、R₂To R_（k-1）、R_(k)Be connected on successively the output of second voltage follower Buffer2And between the output of the first voltage follower Buffer1, relatively datum of k-1 road is drawn in the junction of k substitutional resistanceV₁、V₂To V_k-2、V_k-1, k-1 is compared datum V₁、V₂To V_k-2、V_k-1Form relatively datum of k-1 group fully differentialV_k-1-V₁、V_k-2-V₂To V₂-V_k-2、V₁-V_k-1, wherein-and be minus sign, described (k-1)/2 capacitor C_dec1、C_dec2ExtremelyC_{dec（k-1）/2}Be connected on respectively the two-pass DINSAR of k-1 group fully differential comparison datum relatively between datum.

Aforesaid a kind of modified reference voltage bleeder circuit, is characterized in that: described k substitutional resistance R₁、R₂ExtremelyR_(k-1）、R_(k)Resistance be 120 Ω.

Aforesaid a kind of modified reference voltage bleeder circuit, is characterized in that: described (k-1)/2 capacitor C_dec1、C_dec2To C_{dec（k-1）/2}Capacitance from C_dec1To C_{dec（k-1）/2}Reduce successively.

Aforesaid a kind of modified reference voltage bleeder circuit, is characterized in that: described capacitor C_dec1Capacitance be 20pF,Described C_{dec（k-1）/2}Capacitance be 0pF.

The beneficial effects of the utility model are: modified reference voltage bleeder circuit of the present utility model, and in traditional ginsengExamine in voltage branch circuit, add one group of electric capacity, this group electric capacity to be connected on respectively each group of fully differential relatively the two-way of datum is poorPoint relatively, between datum, form low pass filter with corresponding resistance, strengthen the inhibition energy to power supply noise and ground noisePower, ensured the relatively synchronization fluctuate of datum of fully differential on the same group simultaneously, greatly improved relatively datum of fully differentialStability, can be widely used in the reference voltage bleeder circuit of analog-digital converter, particularly at high-precision comparator electricityIn the design of road, the performance of circuit is improved significantly, circuit is realized simple, has a good application prospect.

Brief description of the drawings

Fig. 1 is the circuit theory diagrams of traditional reference voltage bleeder circuit.

Fig. 2 is the circuit theory diagrams of modified reference voltage bleeder circuit of the present utility model.

Detailed description of the invention

Below in conjunction with Figure of description, the utility model is further described.

As shown in Figure 2, the utility model modified reference voltage bleeder circuit, comprise the first voltage follower Buffer1,Second voltage follower Buffer2, k substitutional resistance R₁、R₂To R_（k-1）、R_(k)(k-1)/2 capacitor C_dec1、C_dec2ExtremelyC_{dec（k-1）/2}, wherein, k >=3, and be odd number;

The positive input of described the first voltage follower Buffer1 meets outside input reference voltage Reft; Described secondThe positive input of voltage follower Buffer2 meets outside input reference voltage Refb;

Described k substitutional resistance R₁、R₂To R_（k-1）、R_(k)Be connected on successively the output of second voltage follower Buffer2And between the output of the first voltage follower Buffer1, relatively datum of k-1 road is drawn in the junction of k substitutional resistanceV₁、V₂To V_k-2、V_k-1, k-1 is compared datum V₁、V₂To V_k-2、V_k-1Form relatively datum of k-1 group fully differentialV_k-1-V₁、V_k-2-V₂To V₂-V_k-2、V₁-V_k-1, wherein-and be minus sign, described (k-1)/2 capacitor C_dec1、C_dec2ExtremelyC_{dec（k-1）/2}The two-pass DINSAR that is connected on respectively k-1 group fully differential comparison datum compares between datum, for example V_k-1-V₁And V₁-V_k-1Share capacitor C_dec1。

As shown in Figure 2, capacitor C_dec1Be connected in parallel on relatively datum V of fully differential_k-1-V₁Two-pass DINSAR relatively with reference to electricityFlat V_k-1And V₁Between, meanwhile, substitutional resistance R₁And R_(k)Not only play the effect that dividing potential drop produces comparative level, while and electric capacityC_dec1Form low pass filter, filtering output Refb_bk and the first voltage follower of second voltage follower Buffer2The high-frequency noise fluctuation of the output Reft_bk of Buffer1, has reduced V greatly_k-1On power supply noise V₁On ground noise, withTime ensured V_k-1And V₁Synchronization fluctuate, make relatively datum V of fully differential_k-1-V₁Keep a relatively stable value, itsHis capacitor C_dec2To C_{dec（k-1）/2}Play similar effect, compare the steady of datum thereby improved greatly whole group of fully differentialQualitative.

We know, relatively datum V of k-1 group fully differential_k-1-V₁、V_k-2-V₂To V₂-V_k-2、V₁-V_k-1Be subject to electricitySource noise and ground noise fluctuations that have the greatest impact is V_k-1-V₁And V₁-V_k-1, from circuit theory, capacitor C_dec1Not onlyReduce the relatively noise fluctuations of datum of these two groups of fully differentials, and, V reduced simultaneously_k-2-V₂To V₂-V_k-2, noiseFluctuation, has ensured that the latter's noise fluctuations is less than the former, capacitor C_dec2Reduce V_k-2-V₂To V₂-V_k-2Noise fluctuations, butTo reduce V_k-1-V₁And V₁-V_k-1Noise fluctuations, thereby by (k-1)/2 capacitor C_dec1、C_dec2To C_{dec（k-1）/2}Capacitance from C_dec1To C_{dec（k-1）/2}Reduce successively, the filter effect playing reduces gradually.

Described k substitutional resistance R₁、R₂To R_（k-1）、R_(k)Value principle be to ensure datum driving force require andPower consumption requirement, if resistance value is too little, causes reference voltage bleeder circuit electric current too large, and power consumption can not meet the demands; Resistance valueIf too large, cause datum driving force too little, reference voltage is unstable; Comprehensive above-mentioned two index requests, resistance valueNeed to do a compromise, preferably 120 Ω.

Described (k-1)/2 capacitor C_dec1、C_dec2To C_{dec（k-1）/2}Value principle be that chip area requires and datumStability requirement. If capacitance is too large, cause chip area too large, exceed designing requirement; If capacitance is too little, cause ginsengExamine level fluctuation too large; Comprehensive above-mentioned two index requests, capacitance need to be done a compromise. Due to C_dec1、C_dec2ExtremelyC_{dec（k-1）/2}The filter effect playing reduces gradually, and electric capacity value is selected to reduce gradually, wherein, and capacitor C_dec11 capacitance is excellentElect 20pF as, capacitor C_{dec（k-1）/2}Capacitance be preferably 0pF.

Based on above-mentioned principle, traditional reference voltage bleeder circuit and modified reference voltage bleeder circuit are carried out to emulation,The binding inductance modeling 0.8nH of power line, the binding inductance modeling 0.2nH of ground wire, substitutional resistance value 120 Ω, electric capacity valueC_dec1=20pF，C_{dec（k-1）/2}Get 0pF, relatively relatively datum V of its fully differential_k-1-V₁Fluctuation voltage and equivalence are to comparingDevice input error voltage, fully differential is datum V relatively_k-1-V₁Fluctuation voltage, in traditional circuit, be 90.06mV, thisIn the improved circuit of utility model, be reduced to 3.14mV. Fluctuation voltage equivalence is to comparator input terminal error voltage, in traditionIn circuit, be 23.5mV, the error voltage in improvement circuit of the present utility model is reduced to 1mV.

In sum, modified reference voltage bleeder circuit of the present utility model, at traditional reference voltage bleeder circuitIn add one group of electric capacity, this group electric capacity is connected on respectively the relatively relatively datum of two-pass DINSAR of datum of each group of fully differentialBetween, form low pass filter with corresponding resistance, strengthen the inhibition ability to power supply noise and ground noise, ensured same simultaneouslyThe relatively synchronization fluctuate of datum of group fully differential, has greatly improved the relatively stability of datum of fully differential, can be extensiveBe applied in the reference voltage bleeder circuit of analog-digital converter, particularly in high-precision comparator circuit design, to circuitPerformance improve significantly, circuit is realized simple, has a good application prospect.

More than show and described general principle of the present utility model, principal character and advantage. The technical staff of the industryShould understand, the utility model is not restricted to the described embodiments, and the just explanation of describing in above-described embodiment and description originallyThe principle of utility model, is not departing under the prerequisite of the utility model spirit and scope, and the utility model also has various variationsAnd improvement, these changes and improvements all fall within the scope of claimed the utility model. The claimed scope of the utility modelDefined by appending claims and equivalent thereof.

Claims (4)

1. a modified reference voltage bleeder circuit, is characterized in that: comprise the first voltage follower Buffer1, the second electricityPress follower Buffer2, k substitutional resistance R₁、R₂To R_(k-1）、R_(k)(k-1)/2 capacitor C_dec1、C_dec2To C_{dec（k-1）/2}，Wherein, k >=3, and be odd number,

The positive input of described the first voltage follower Buffer1 meets outside input reference voltage Reft; Described second voltageThe positive input of follower Buffer2 meets outside input reference voltage Refb;

Described k substitutional resistance R₁、R₂To R_（k-1）、R_(k)Be connected on successively the output and of second voltage follower Buffer2Between the output of one voltage follower Buffer1, relatively datum V of k-1 road is drawn in the junction of k substitutional resistance₁、V₂To V_k-2、V_k-1, k-1 is compared datum V₁、V₂To V_k-2、V_k-1Form relatively datum V of k-1 group fully differential_k-1-V₁、V_k-2-V₂To V₂-V_k-2、V₁-V_k-1, wherein-and be minus sign, described (k-1)/2 capacitor C_dec1、C_dec2To C_{dec（k-1）/2}PointBe not connected on the two-pass DINSAR of k-1 group fully differential comparison datum relatively between datum.

2. a kind of modified reference voltage bleeder circuit according to claim 1, is characterized in that: described k equivalent electricityResistance R₁、R₂To R_(k-1）、R_(k)Resistance be 120 Ω.

3. a kind of modified reference voltage bleeder circuit according to claim 1, is characterized in that: described (k-1)/2Capacitor C_dec1、C_dec2To C_{dec（k-1）/2}Capacitance from C_dec1To C_{dec（k-1）/2}Reduce successively.

4. according to a kind of modified reference voltage bleeder circuit described in claim 1 or 3, it is characterized in that: described capacitor C_dec1Capacitance be 20pF, described C_{dec（k-1）/2}Capacitance be 0pF.