CN203720702U - Chopped wave band-gap reference equipment with switched capacitor filter - Google Patents
Chopped wave band-gap reference equipment with switched capacitor filter Download PDFInfo
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- CN203720702U CN203720702U CN201420122754.XU CN201420122754U CN203720702U CN 203720702 U CN203720702 U CN 203720702U CN 201420122754 U CN201420122754 U CN 201420122754U CN 203720702 U CN203720702 U CN 203720702U
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- wave band
- gap reference
- copped wave
- clock signal
- filter
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Abstract
Chopped wave band-gap reference equipment with a switched capacitor filter comprises a chopped wave band-gap reference device. The output end of the chopped wave band-gap reference device is connected with the input end of the switched capacitor filter. The output end of the switched capacitor filter is connected with the input end of an RC filter. The output end of the RC filter is provided with a reference voltage output port. An output voltage adjusting component formed by at least three resistors in a serial-connecting mode is arranged in the chopped wave band-gap reference device. The equipment is further provided with a double-phase overlapping clock device. The input end of the double-phase overlapping clock device is provided with an external clock input port. The double-phase overlapping clock device is provided with at least two clock signal output ends. According to the voltage adjusting component, the mode of a single resistor is changed into the mode that the multiple resistors are connected in series, so that final output voltage is changed to be in an adjustable mode from a fixed mode, influence on reference voltage from detuning voltage is removed by filtering, low-frequency 1/f noise is moved to clock frequency by chopped wave operational amplifying, after filtering, influence from 1/f noise is also greatly lowered, and the stability and the accuracy of reference voltage are improved.
Description
Technical field
The utility model belongs to band-gap reference circuit field, relates in particular to a kind of copped wave band-gap reference equipment of belt switch capacitor filter.
Background technology
As shown in Figure 1, principle is typical band-gap reference circuit of the prior art: it is made up of resistance, transistor, metal-oxide-semiconductor and operational amplifier, and wherein, R1, R2 represent resistance; M1, M2 are generally the PMOS pipe of two same sizes; A1 represents operational amplifier; Q1, Q2 represent pnp transistor, and wherein Q2 is generally made up of n transistor unit arranged side by side, and Q1 is generally a transistor unit.When this band-gap reference circuit is normally worked, amplifier A1 makes its input two ends: X, Y node, is stabilized in approximately equal voltage.Wherein, Vout represents the reference voltage of last output.Because metal-oxide-semiconductor M1, M2 are measure-alike, electric current I 1, I2 equal and opposite in direction, R1 both end voltage size is VBE1-VBE2=VTlnn, thereby obtain electric current I 1=I2=VTlnn/R1, therefore reference voltage V out=VBE2+VTlnn (the R1+R2)/R1=VBE2+ (VTlnn) of output (1+R2/R1).Because at room temperature dVBE/dT ≈-1.5mV/ DEG C, dVT/dT ≈ 0.087mV/ DEG C, in order to obtain zero-temperature coefficient, must make (1+R2/R1) lnn ≈ 17.2.
But existing reference circuit exists many problems, for example, in Fig. 1, the input offset voltage of amplifier can make the reference voltage of output produce certain error.The offset voltage of supposing amplifier is Vos, this impact can be quantified as VBE1-Vos ≈ VBE2+R1 I2, now Vout=VBE2+ (VBE1-VBE2-Vos) (R1+R2)/R1=VBE2+ (VTlnn-Vos) (1+R2/R1), obviously, offset voltage has been exaggerated 1+R2/R1 doubly.The more important thing is that offset voltage itself varies with temperature, thereby increased the temperature coefficient of output voltage, make reference voltage unstable.By above analysis, the noise that can find out amplifier directly appears at output terminal, simultaneously because reference circuit is operated in DC level, and low frequency 1/f noise is large especially for HIGH-FREQUENCY THERMAL NOISE, therefore the 1/f noise of amplifier can significantly reduce the noiseproof feature of reference circuit, has limited the low noise applications of circuit.And under different process environments there is larger difference in the size of device, parameter, therefore be in fact difficult to obtain the reference voltage of zero-temperature coefficient under a room temperature, zero temperature coefficient point even may depart from room temperature far away, due to asymmetry, amplifier can be subject to the impact of input offset voltage, imbalance represents that amplifier is input as zero and its output voltage is non-vanishing, thereby affects stability and the accuracy of reference voltage.
Utility model content
For addressing the above problem, a kind of copped wave band-gap reference equipment of belt switch capacitor filter is proposed, technical scheme is as follows.For there is to a basic understanding some aspects of the embodiment disclosing, provide simple summary below.This summary part is not to comment general, neither determine key/critical component or describe the protection domain of these embodiment.Its sole purpose is to present some concepts by simple form, the preamble using this as following detailed description.
A kind of copped wave band-gap reference equipment of belt switch capacitor filter is provided, described equipment comprises copped wave band-gap reference device, the input end of the output terminal connecting valve capacitor filter of described copped wave band-gap reference device, the output terminal of described switching capacity filter connects the input end of RC wave filter, and the output terminal of described RC wave filter is provided with reference voltage delivery outlet; In described copped wave band-gap reference device, be provided with output voltage adjusting part, described voltage adjusting assembly adopts at least three resistance in series; Described equipment also comprises the overlapping clock apparatus of the two-phase for controlling described copped wave band-gap reference device and described switching capacity filter; The input end of the overlapping clock apparatus of described two-phase is provided with external clock input port, and the overlapping clock apparatus of described two-phase is provided with at least two clock signal output terminals, and described clock signal output terminal comprises master clock signal output terminal and secondary clock signal output terminal; Described master clock signal output terminal is exported the clock signal of a pair of phase lag to copped wave band-gap reference device, controls described copped wave band-gap reference device; Described secondary clock signal output terminal is exported the leading clock signal of a pair of phase place to switching capacity filter, controls described switching capacity filter.
On the path of described copped wave band-gap reference device, be connected with operational amplifier, input end, the output terminal of described operational amplifier are all connected with chopping switch, and input two end nodes of described operational amplifier are connected with metal-oxide-semiconductor grid.
Further, described switching capacity filter includes input end, is parallel with two groups of switchgears on described input end, and described switchgear is in series by least two switch modules, between described switch module, is connected with capacitance component.
Further, the overlapping clock apparatus of described two-phase is provided with PORT COM, in described PORT COM, be connected with the transmission assembly periodically overturning between power supply ground for realizing output signal, the connection of described transmission assembly and disconnection are by described clock signal control.
Further, described PORT COM comprises outside input clock port, reverse process input port, supply voltage port and ground voltage port.
Beneficial effect: voltage adjusting assembly fades to multiple resistance by single resistance and connects, make final output voltage adjustable by fixedly becoming, thereby can select different output voltages, reduce the impact of offset voltage on reference voltage by filtering, low frequency 1/f noise is moved clock frequency by chopper amplifier, after filtering, equally greatly reduce the impact of 1/f noise, reduced external environment and changed the impact on reference voltage, thus stability and the accuracy of raising reference voltage.
For above-mentioned and relevant object, one or more embodiment comprise below by the feature that describes in detail and particularly point out in the claims.Explanation below and accompanying drawing describe some illustrative aspects in detail, and its instruction is only some modes in the utilizable variety of way of principle of each embodiment.Other benefit and novel features consider the detailed description along with below by reference to the accompanying drawings and become obviously, and the disclosed embodiments are to comprise being equal to of all these aspects and they.
brief description of the drawings
Below in conjunction with accompanying drawing, the technical program is further described.
Fig. 1 is the schematic diagram of band-gap reference circuit common in prior art;
Fig. 2 is the copped wave band-gap reference equipment schematic diagram of belt switch capacitor filter;
Fig. 3 is the circuit diagram of copped wave band-gap reference device;
Fig. 4 is the circuit diagram of switching capacity filter;
Fig. 5 is the circuit diagram of the overlapping clock apparatus of two-phase;
Fig. 6 is the circuit diagram of RC wave filter.
In figure, the implication of each Reference numeral is as follows:
1 is copped wave band-gap reference device, and 2 is switching capacity filter, and 3 is RC wave filter, and 4 is the overlapping clock apparatus of two-phase.
Embodiment
The following description and drawings illustrate specific embodiments of the present utility model fully, to enable those skilled in the art to put into practice them.Structure, logic, electric, process and other change that other embodiments can comprise.Embodiment only represents possible variation.Unless explicitly requested, otherwise independent parts and function are optional, and the order of operation can change.The part of some embodiments and feature can be included in or replace part and the feature of other embodiments.The scope of embodiment of the present utility model comprises the gamut of claims, and all obtainable equivalent of claims.In this article, these embodiments of the present utility model can be represented with term " utility model " individually or always, this is only used to conveniently, and if in fact disclose the utility model that exceedes, not that the scope that will automatically limit this application is any single utility model or utility model design.
As shown in Fig. 2～6, the copped wave band-gap reference equipment of belt switch capacitor filter, it comprises copped wave band-gap reference device 1, the output terminal V of this copped wave band-gap reference device 1
out3the input end of connecting valve capacitor filter 2, the output terminal of described switching capacity filter 2 connects the input end of RC wave filter 3, simultaneously, the output terminal of RC wave filter 3 is provided with reference voltage delivery outlet, in described copped wave band-gap reference device 1, be provided with output voltage adjusting part, described voltage adjusting assembly adopts at least three resistance in series, makes output voltage adjustable, the variation that more stable adaptation process environments brings by the series connection of multiple resistance.As shown in Figure 1, what in existing band-gap reference circuit structure, adopt is that single resistance R 2 produces final output, and the reference circuit of this programme adopts the structural equivalents of R21, R22, tri-resistance series connection of R23 in the R2 of traditional benchmark circuit resistance, change the impact on reference voltage thereby can select different output voltages to reduce external environment in the time that process environments changes, to keep accuracy and the stability of reference voltage.
Described equipment is also provided with the overlapping clock apparatus 4 of two-phase, concrete, the input end of the overlapping clock apparatus 4 of described two-phase is provided with external clock input port, and the overlapping clock apparatus 4 of described two-phase is provided with at least two clock signal output terminals, comprises master clock signal output terminal and secondary clock signal output terminal.When actual use, described master clock signal output terminal, exports the clock signal of a pair of phase lag: p1/p1n, to copped wave band-gap reference device 1, controls described copped wave band-gap reference device 1; And described secondary clock signal output terminal is exported the leading clock signal of a pair of phase place: p2/p2n, to described switching capacity filter 2, control described switching capacity filter 2.
Consider the needs that use noise reduction, the voltage signal that first described copped wave band-gap reference device 1 produces an adjustable zero-temperature coefficient is exported to described switching capacity filter 2, described switching capacity filter 2 is sampled and has been eliminated most of burr, the ripple interference of described voltage signal by electric capacity, output to again RC wave filter, finally obtaining one stablizes, the d. c. voltage signal that noise is less, described switching capacity filter 2 can reduce ripple and the burr signal that described copped wave band-gap reference device 1 produces greatly.This programme is at the RC wave filter of an order of output access of described switching capacity filter 2, as shown in Figure 6, ripple and burr signal to output have done further filtering processing, can obtain one and very stablize accurate voltage signal, simultaneously because described switching capacity filter has been done very effectively filtering processing, therefore RC wave filter can adopt less size, only takies compared with small size.By eliminating the impact of offset voltage on reference voltage after filtering, chopper amplifier has reduced the impact of 1/f noise greatly simultaneously, improves stability and the accuracy of reference voltage.
In some optional embodiments, as shown in Figure 3, on the path of described copped wave band-gap reference device 1, be connected with operational amplifier, input end, the output terminal of operational amplifier are all connected with chopping switch, and input two end nodes of operational amplifier are connected with metal-oxide-semiconductor grid.Like this, metal-oxide-semiconductor M1 tube grid connects constant bias voltage, so that steady current to be provided, make the circuit shown in Fig. 3 can be in normal operating conditions, obviously metal-oxide-semiconductor M1 is equivalent to the start-up circuit in normal tape gap reference circuit, greatly simplify start-up circuit design, saved area, and more reliable and more stable.Meanwhile, operational amplifier input, output have added respectively chopping switch, and thus, switch on and off is controlled by clock signal p1, p1n, and p1, p1n are the contrary clock signal of a pair of frequency same phase.Circuit X, Y node are connected to two amplifier input metal-oxide-semiconductor grids in turn.Therefore the direct current signal on circuit is moved chopping switch clock frequency after inputting by amplifier, then by moving back again direct current frequency range after output chopping switch.Corresponding with it, the offset voltage of amplifier and low frequency 1/f noise have only passed through the conversion of output chopping switch, finally move chopping switch frequency, then by the filtering of rear class wave filter.Chopping switch frequency is higher, the frequency that the noise signals such as ripple are moved is higher, require lowlyer for the design of filter of rear class, but circuit bandwidth and signal have restricted switch clock frequency Time Created, and therefore the selection of last frequency need consider that many aspects make compromise.
In some optional embodiments, described switching capacity filter 3 includes input end, is parallel with two groups of switchgears on this input end, and switchgear is in series by least two switch modules, meanwhile, between described switch module, is connected with capacitance component.Specifically, as shown in Figure 4, be the circuit diagram of switching capacity filter, p2, p2n are the contrary clock signal of a pair of frequency same phase, control the break-make of 4 K switch 1～K4.When p2 is high level, p2n while being low level, K switch 1, K4 closure, K2, K3 disconnect.Capacitor C 1 is to input signal sampling, and capacitor C 2 is transferred to C3 at the signal of previous moment sampling.Equally, when p2 is low level, p2n while being high level, K switch 1, K4 disconnect, K switch 2, K3 closure.Capacitor C 2 is to input signal sampling, and capacitor C 1 is transferred to C3 at the signal of previous moment sampling, and capacitor C 3 is linked output always.And, because described switching capacity filter 3 is that the output voltage of described copped wave band-gap reference device 1 is carried out to sampling filter, therefore its switch clock frequency should be identical with copped wave clock frequency, can obtain a stable voltage signal in order to sample, filter clock phase place should be ahead of copped wave clock phase slightly simultaneously.Like this, switching capacity can not be subject to the impact of chopping switch upset, and can sample to a voltage signal stable, that establish.
In some optional embodiments, the overlapping clock apparatus 4 of described two-phase is provided with PORT COM, is connected with clock signal control transmission assembly in this PORT COM.The break-make of clock signal control transmission assembly, makes output signal periodically upset between power supply ground.Described PORT COM comprises outside input clock port, reverse process input port, supply voltage port, ground voltage port.In conjunction with Fig. 5, clk is outside input clock, and clkn is that clk passes through the signal after phase inverter, and vcc represents supply voltage, and vss represents ground voltage.Like this, by the break-make of clock signal control transmission gate, make output signal periodically upset between power supply ground.Even if therefore the clock signal amplitude of input is unstable, the clock signal that circuit still can stable output.Like this, the clock signal of output is applied to copped wave band-gap reference device and switch-capacitor filtering circuit, and obviously p2/p2n phase place is ahead of p1/p1n phase place, meets design requirement.The phase inverter that connects in addition output clock can adopt larger size to strengthen its driving force, reduces clock rise and fall time delay.
In some optional embodiments, described PORT COM comprises outside input clock port, reverse process input port, supply voltage port, ground voltage port.
Those skilled in the art it is also understood that various illustrative box, module, circuit and the algorithm steps described in conjunction with embodiment herein all can be embodied as electronic hardware, computer software or its combination.For the interchangeability between hardware and software is clearly described, above various illustrative parts, frame, module, circuit and step are all carried out usually describing around its function.Be embodied as hardware or be embodied as software as for this function, depend on specific application and the design constraint that whole system is applied.Those skilled in the art can, for each application-specific, realize described function in flexible mode, still, thisly realize decision-making and should not be construed as and deviate from protection domain of the present disclosure.
Claims (5)
1. the copped wave band-gap reference equipment of a belt switch capacitor filter, it is characterized in that, described equipment comprises, copped wave band-gap reference device, the input end of the output terminal connecting valve capacitor filter of described copped wave band-gap reference device, the output terminal of described switching capacity filter connects the input end of RC wave filter, and the output terminal of described RC wave filter is provided with reference voltage delivery outlet;
In described copped wave band-gap reference device, be provided with output voltage adjusting part, described voltage adjusting assembly adopts at least three resistance in series;
Described equipment also comprises the overlapping clock apparatus of the two-phase for controlling described copped wave band-gap reference device and described switching capacity filter;
The input end of the overlapping clock apparatus of described two-phase is provided with external clock input port, and the overlapping clock apparatus of described two-phase is provided with at least two clock signal output terminals, and described clock signal output terminal comprises master clock signal output terminal and secondary clock signal output terminal;
Described master clock signal output terminal is exported the clock signal of a pair of phase lag to copped wave band-gap reference device, controls described copped wave band-gap reference device;
Described secondary clock signal output terminal is exported the leading clock signal of a pair of phase place to switching capacity filter, controls described switching capacity filter.
2. the copped wave band-gap reference equipment of belt switch capacitor filter according to claim 1, it is characterized in that, on the path of described copped wave band-gap reference device, be connected with operational amplifier, input end, the output terminal of described operational amplifier are all connected with chopping switch, and input two end nodes of described operational amplifier are connected with metal-oxide-semiconductor grid.
3. the copped wave band-gap reference equipment of belt switch capacitor filter according to claim 1, it is characterized in that, described switching capacity filter includes input end, on described input end, be parallel with two groups of switchgears, described switchgear is in series by least two switch modules, between described switch module, is connected with capacitance component.
4. the copped wave band-gap reference equipment of belt switch capacitor filter according to claim 1, it is characterized in that, the overlapping clock apparatus of described two-phase is provided with PORT COM, in described PORT COM, be connected with the transmission assembly periodically overturning between power supply ground for realizing output signal, the connection of described transmission assembly and disconnection are by described clock signal control.
5. the copped wave band-gap reference equipment of belt switch capacitor filter according to claim 4, is characterized in that, described PORT COM comprises outside input clock port, reverse process input port, supply voltage port and ground voltage port.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420122754.XU CN203720702U (en) | 2014-03-18 | 2014-03-18 | Chopped wave band-gap reference equipment with switched capacitor filter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420122754.XU CN203720702U (en) | 2014-03-18 | 2014-03-18 | Chopped wave band-gap reference equipment with switched capacitor filter |
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| CN203720702U true CN203720702U (en) | 2014-07-16 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104375546A (en) * | 2014-03-18 | 2015-02-25 | 苏州芯动科技有限公司 | Chopped wave band-gap reference device with switched-capacitor filter |
| CN104682928A (en) * | 2015-03-12 | 2015-06-03 | 中国科学院微电子研究所 | CMOS programmable chopping oscillator circuit integrated on chip |
| CN114815947A (en) * | 2021-01-27 | 2022-07-29 | 中国科学院微电子研究所 | Band gap reference circuit |
-
2014
- 2014-03-18 CN CN201420122754.XU patent/CN203720702U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104375546A (en) * | 2014-03-18 | 2015-02-25 | 苏州芯动科技有限公司 | Chopped wave band-gap reference device with switched-capacitor filter |
| CN104682928A (en) * | 2015-03-12 | 2015-06-03 | 中国科学院微电子研究所 | CMOS programmable chopping oscillator circuit integrated on chip |
| CN104682928B (en) * | 2015-03-12 | 2017-07-18 | 中国科学院微电子研究所 | Integrated CMOS may be programmed copped wave pierce circuit on piece |
| CN114815947A (en) * | 2021-01-27 | 2022-07-29 | 中国科学院微电子研究所 | Band gap reference circuit |
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Granted publication date: 20140716 Termination date: 20160318 |
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| CF01 | Termination of patent right due to non-payment of annual fee |