CN1042633A - Digital/analogue converter of current model - Google Patents
Digital/analogue converter of current model Download PDFInfo
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- CN1042633A CN1042633A CN 88107500 CN88107500A CN1042633A CN 1042633 A CN1042633 A CN 1042633A CN 88107500 CN88107500 CN 88107500 CN 88107500 A CN88107500 A CN 88107500A CN 1042633 A CN1042633 A CN 1042633A
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Abstract
A kind of digital/analogue converter of current model belongs to integrated circuit (IC) design.The invention provides a kind of total current type D/A, form by N weighting constant current source array and N the switch arrays of often opening.This transducer have high integrated, high-speed, circuit simple, be easy to advantage such as realization, is a kind of practical D/A.
Description
The invention belongs to integrated circuit (IC) design.
The D/A switch technology is along with the development of digital technology and digital computer occurs.Because digital technology and development of computer, particularly microprocessor is advanced by leaps and bounds after 1971, has promoted the Analog signals'digital treatment technology greatly, and therefore the D/A as important interface unit is also developed rapidly.Along with the system integration and single chip integrated needs, high integrated, high-speed and high-precision D/A has crucial meaning.The most important at present and the widest D/A of utilization is that the D/A of R-2R trapezoid resistance network (is seen T.Kamoto, Y.Akazawa and Moshinagawa, " An 8-bit 2-ns monolithic DAC ", IEEE J.Solid-State Circuits, Vol.SC-23, No, PP.142-146,1988.) its circuit is as shown in Figure 1.Wherein, a reference source voltage Vref is fixedlyed connected with resistor network, current switch S
1, S
2, S
3..., Sn is shown in Fig. 1 (b).Determine ground connection or be connected to the input of arithmetic unit by the digital control circuit output signal.If amplifier is that desirable then input point P point is a virtual earth, therefore no matter switch is in arbitrary position of two positions, and the electric current that flows into ladder network is all identical.Each branch current is respectively I/2 like this, I/4, and I/8 ..., I/2, I=Vref/R wherein, the input total current of transferring operational amplifier A can be expressed as:
Is＝Ia
1/2+Ia
2/4+Ia
3/8+…+1a
N/2 （1）
A in the formula
1, a
2, a
3... a
N" 1 " or " 0 " two states is arranged, so the output voltage of amplifier A is:
Vo＝-IsR＝-IR（a
1/2+a
2/2
2+a
3/2
3+…+a
N/2
N） （2）
This R-2R ladder network type D/A has been avoided in weighted resistance network the very big problem that causes of difference between the maximum resistance and minimum resistance, but still has the precision and the conversion speed of this D/A of some factor affecting:
1. because in integrated circuit, be difficult to make very wide temperature range with interior precision resistance, and the conducting resistance of the MOS transistor of using as switching tube must be enough little, otherwise must consider the conducting resistance of MOS switching tube, especially the conducting resistance of MOS switching tube is different with the conventional, electric-resistance temperature coefficient, and certain temperature-compensation circuit must be provided.
2.R-2R ladder network does not have load capacity, promptly can not directly meet load resistance R
LAnd must adopt operational amplifier as cushioning so that the virtual earth load to be provided, increased the complexity of circuit so first, more seriously the conversion speed of D/A is subjected to the influence of amplifier speed, and the switching rate (Slewrate) of general operational amplifier is 1～10
V/ μ s magnitude.
For overcoming the weak point of above-mentioned D/A, the present invention proposes a kind of total current type D/A new departure.Current mode circuit has simple summation, weighting and relatively waits function with current system work, and this brings many convenience for the design of D/A.
The digital/analogue converter of current model that the present invention proposes as shown in Figure 2.Form by constant-current source, current switch, this constant-current source adopts the constant current source array of N weighting, the switch arrays that this current switch adopts N the switch of often opening to constitute, the constant-current source of this N weighting links together respectively with after N switch connected, and constitutes the analog quantity output by digital quantity control.These constant-current sources can constitute the constant-current source to all corresponding digital amount weightings with the PMOS transistor of different breadth length ratios (W/L), also available other device and circuit are realized, make circuit have certain load capacity like this, can directly connect load resistance, and export with voltage, finish the current/voltage conversion, thereby overcome and introduce circuit complexity and the speed that amplifier caused in the common D/A, can overcome the big shortcoming of resistor network discreteness with constant-current source simultaneously, and be easy to temperature-compensating, thereby precision is improved; Constitute switch arrays by N the switch of often opening, its closure is subjected to a respectively
1, a
2... and a
NControl, these switch arrays can be used nmos pass transistor; PMOS transistor and cmos transmission gate constitute, and also available other device and circuit are realized, D/A switch is finished with interior at the one-level gate delay, have improved conversion speed.
The operation principle of this circuit is as follows:
The essence of D/A is the corresponding relation of determining between digital quantity and the analog quantity, and its corresponding relation is in binary system:
Io＝Iref（a
1/2
1+a
2/2
2+…+a
N/2
N）
Wherein Io is an analog quantity, and Iref is a reference quantity, a
1, a
2A
NBe digital quantity, in other words in binary system analog quantity to equal with 2 be the digital quantity sum of weight.
As supplied with digital signal a
i=1, by a
iThe respective switch S of control
iClosure, one's own department or unit are exported corresponding electric current I
Ref/ 2
i; Otherwise if a
i=0, then by a
iThe respective switch S of control
iDisconnect, one's own department or unit output current is 0, like this all I
Ref/ 2
i(i=1,2 ... N) constant-current source is through corresponding switch S
iDirectly suing for peace at output in the back, has overcome the needed bidirectional current switch of common D/A switch and " virtual earth " working point, and circuit complexity that causes and power problems.
Brief Description Of Drawings:
Fig. 1 is R-2R ladder network D/A converter (a) and MOS Double-phase switch (b)
Fig. 2 is a current-mode d/a converter circuit diagram of the present invention
Fig. 3 is the circuit diagram of a kind of exemplary embodiments of the present invention
Exemplary embodiments of the present invention as shown in Figure 3, for the MOS digital/analogue converter of current model constitutes full MOS power-type D/A as constant-current source and with the NMOS transmission gate as current switch with the PMOS transistor of different breadth length ratios (W/L).Its operation principle is as follows: when the PMOS transistor is operated in saturation area, promptly satisfy
｜V
GS-V
p｜＜｜V
DS｜ （3）
V wherein
GSBe PMOS transistor gate source voltage, Vp is the transistorized pinch-off voltage of PMOS, V
OSBe the transistorized drain-source voltage of PMOS.The PMOS transistor can be used as constant-current source, and [supposing that the transistor breadth length ratio is (W/L)] promptly has:
Ip＝kp′（W/L）（V
GS-V
P）
2（4）
Connect like this with the parallel connection of PMOS transistor, and with the NMOS current switch, as shown in Figure 3.The PMOS transistor T that utilizes diode to connect
REFReference current is provided, and hypothesis
I
REF＝K
′ P（ (W)/(L) ）
REF（V
GS-V
P）
2＝I
o REF（ (W)/(L) ）
REF（5）
With reference to figure 2, can get output current Iout and be
Select: ((W/L)
i)/((W/L)
REF)=2
-i(i=1,2 ..., N) (7)
Then: I
Out=I
REF((α
1)/2+(α
2)/(2
2)+(α
3)/(2
3)+... + (α
N)/(2
N)) (8)
Load is R
LThe time, output voltage V out is:
V
out= I
outR
L= I
REFR
L( (α
1)/2 + (α
2)/(2
2) + … + (α
N)/(2
N) )（9）
The canonical parameter that present embodiment adopts is supply voltage V
DD=5V, the breadth length ratio (W/L) of NMOS current delivery door
N=10, cut-in voltage V
Tn=0.7V, PMOS current mirror input pipe T
REFBreadth length ratio (W/L)
P=16/1, efferent duct (T
1-T
8) breadth length ratio be respectively 8/1,4/1,2/1,1,1/2,1/4,1/8,1/16(8 figure place/weighted-voltage D/A converter), pinch-off voltage V
P=-1.5V.
Main feature of the present invention:
1. adopt the PMOS constant-current source of weighting to the digital quantity weighting of correspondence, overcome the big shortcoming of You Yu resistor network discreteness, and be easy to carry out the compensation of temperature, improved Zhuan and changed precision;
2. the characteristics of sharp You electric current summation are passed through one-level NMOS current switch Zai output Zhi and are connect summation, overcome the caused circuit complexity of bidirectional current switch and the power problems of common D/A;
3. You Yu adopts weighting constant-current source and current switch thereof, make this circuit have certain load capacity, introduce process complexity and the speed that the operation amplifier device Zao of institute becomes thereby overcome common D/A Zhong, make this full MOS digital/analogue converter of current model have higher switching rate.
Claims (3)
1, a kind of digital/analogue converter of current model, it is characterized in that being formed by constant-current source, mains switch, said current source is the constant current source array of N weighting, said current switch is N the switch arrays that the switch of often opening constitutes, the constant-current source of this N weighting links together respectively with after this N switch is connected, and constitutes the analog quantity output by digital quantity control.
2, a kind of described D/A of claim 1 of pressing is characterized in that this constant-current source adopts the PMOS transistor of different breadth length ratios (W/L), and this current switch adopts nmos switch pipe.
3, a kind of by the described D/A of claim 1, it is characterized in that said current switch adopts cmos transmission gate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88107500 CN1042633A (en) | 1988-11-10 | 1988-11-10 | Digital/analogue converter of current model |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88107500 CN1042633A (en) | 1988-11-10 | 1988-11-10 | Digital/analogue converter of current model |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1042633A true CN1042633A (en) | 1990-05-30 |
Family
ID=4834674
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 88107500 Pending CN1042633A (en) | 1988-11-10 | 1988-11-10 | Digital/analogue converter of current model |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1042633A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1053775C (en) * | 1995-02-14 | 2000-06-21 | 联华电子股份有限公司 | Digital analoge converter |
| CN1320765C (en) * | 2002-10-10 | 2007-06-06 | 威盛电子股份有限公司 | Convertor for simplifying control logic/complementary current source power supply structure |
| CN102780483A (en) * | 2011-05-13 | 2012-11-14 | 英特尔移动通信有限责任公司 | RF DAC with configurable DAC mixer interface and configurable mixer |
| CN101795136B (en) * | 2010-02-05 | 2013-02-13 | 电子科技大学 | Digital-to-analog conversion circuit |
| CN101694843B (en) * | 2009-10-21 | 2015-04-22 | 无锡思泰迪半导体有限公司 | Unbalanced design method of high-position current source unit of current rudder-type digital-to-analog converter |
| CN105429506A (en) * | 2015-12-10 | 2016-03-23 | 北京理工大学 | Multilevel piezoelectric ceramics driving circuit and driving control method thereof |
| CN106093631A (en) * | 2016-06-03 | 2016-11-09 | 温州大学 | A kind of Testing System for Electronic Equipment possessing location recognition and IP establishing method |
-
1988
- 1988-11-10 CN CN 88107500 patent/CN1042633A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1053775C (en) * | 1995-02-14 | 2000-06-21 | 联华电子股份有限公司 | Digital analoge converter |
| CN1320765C (en) * | 2002-10-10 | 2007-06-06 | 威盛电子股份有限公司 | Convertor for simplifying control logic/complementary current source power supply structure |
| CN101694843B (en) * | 2009-10-21 | 2015-04-22 | 无锡思泰迪半导体有限公司 | Unbalanced design method of high-position current source unit of current rudder-type digital-to-analog converter |
| CN101795136B (en) * | 2010-02-05 | 2013-02-13 | 电子科技大学 | Digital-to-analog conversion circuit |
| CN102780483A (en) * | 2011-05-13 | 2012-11-14 | 英特尔移动通信有限责任公司 | RF DAC with configurable DAC mixer interface and configurable mixer |
| CN102780483B (en) * | 2011-05-13 | 2015-08-12 | 英特尔移动通信有限责任公司 | With the radio frequency digital to analog converter of configurable digital to analog converter mixer interface and configurable mixer |
| CN105429506A (en) * | 2015-12-10 | 2016-03-23 | 北京理工大学 | Multilevel piezoelectric ceramics driving circuit and driving control method thereof |
| CN105429506B (en) * | 2015-12-10 | 2018-06-15 | 北京理工大学 | More level driver circuit for piezoelectric ceramics and its drive control method |
| CN106093631A (en) * | 2016-06-03 | 2016-11-09 | 温州大学 | A kind of Testing System for Electronic Equipment possessing location recognition and IP establishing method |
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