CN1808445A - IBIS model information reading method, high-speed circuit emulation system and its method - Google Patents

IBIS model information reading method, high-speed circuit emulation system and its method Download PDF

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Publication number
CN1808445A
CN1808445A CN 200510032956 CN200510032956A CN1808445A CN 1808445 A CN1808445 A CN 1808445A CN 200510032956 CN200510032956 CN 200510032956 CN 200510032956 A CN200510032956 A CN 200510032956A CN 1808445 A CN1808445 A CN 1808445A
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China
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rising
drop
negative edge
voltage
draw
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Chinese (zh)
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黄春行
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Huawei Technologies Co Ltd
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Huawei Technologies Co Ltd
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Abstract

The invention discloses a method to read rising edge/falling edge speed information in transducer IBIS model, which comprises: visiting and reading the opposite speed data list and V/I data list in IBIS model; converting the speed information into pull-upper switch coefficient K1 and pull-lower switch coefficient K2 along every time point. It also discloses a high-speed circuit simulation system. This invention lets the simulated result of high-speed circuit accurate and reliable.

Description

IBIS model information read method, high speed circuit analogue system and method thereof
Technical field
The present invention relates to emulation technology, be specifically related to a kind of high speed circuit analogue system and its implementation that can call the rising/negative edge rate information in the device IBIS model.
Background technology
In the high speed circuit design, raising along with system speed and wiring density, SI (Signal Integrity, signal integrity), string is more and more important to the influence of product design around, EMC (electromagneticcompatibility, Electro Magnetic Compatibility) problem, wants in design initial and design process the influence various factors and takes into account, just need adopt the high speed circuit emulation technology to analyze according to the various parameters in the actual physics design.
IBIS (Input/Output Buffer Informational Specification, I/O buffer information standard) is the file of the input, output and the I/O buffering device behavioral trait that are used for describing the IC device, and is used for the interaction of the Circuits System on simulated cushioned device and the pcb board.Particularly, IBIS has described input and output impedance (by the form of I/V curve), rising and the fall time of a buffering device and has drawn with drop-down under the different situations, thereby, the engineering staff can utilize this model to the Circuits System on the pcb board carry out SI, crosstalk, the analysis of EMC and sequential.
It is to adopt the IBIS model that the used device model of high speed circuit analogue system of prior art has quite a few, and this is that characteristic by IBIS model itself is determined.The IBIS model is a kind of behavioral scaling model; it is fast to have simulation velocity; and intellectual property information that can the protection device manufacturer; therefore many high speed circuit emulation tools are all supported calling of IBIS model; wherein; the ADS of Agilen company (Advanced Design System, advanced design system) system uses a kind of very widely design of Simulation instrument.
Fig. 1 is the basic parameter synoptic diagram of IBIS model, the essential information parameter that contains device in the IBIS model, wherein, draw in the A representative/drop-down V/I, B representative rising/negative edge speed, abbreviation rising/negative edge time speed, C represent power supply/ground connection clamp V/I, C cRepresent junction capacity, and comprise encapsulation parasitic parameter (stray inductance L p, dead resistance R pWith stray capacitance C p).Draw wherein/drop-down V/I and power supply/ground connection clamp V/I are that form with tables of data provides the electric current that different voltage is corresponding different.Rising/negative edge speed has two kinds of situations, and a kind of is the ratio that voltage and time directly are provided, and another kind is that the data form with time and voltage provides.A kind of mode in back is a kind of more more accurate than preceding.All these five major parts could intactly constitute the IBIS model, have only and intactly realize the simulation of this five parts characteristic electrical specification of analog device exactly.
Referring to Fig. 2, be depicted as the schematic diagram of the technical scheme of existing ADS system call IBIS model, wherein, port P1 is an input port, port P2 is an output port, element x1, x2, x3, x4, C c, L p, R p, C pDraw in the corresponding respectively IBIS model/drop-down V/I, power supply/ground connection clamp V/I, junction capacity C CWith stray inductance L p, dead resistance R pWith stray capacitance C p, variable element VAR is used for being junction capacity C c, stray inductance L P, dead resistance R PAnd stray capacitance C PAssignment.From the figure as can be seen, this scheme mainly finished on draw/the calling of drop-down V/I, power supply/ground connection clamp V/I, junction capacity and encapsulation parasitic parameter (stray inductance, dead resistance and stray capacitance), and ignored the information of rising/negative edge speed.
Junction capacity, stray inductance, dead resistance and stray capacitance realize fairly simple, can call electric capacity, inductance and resistance in the schematic diagram of ADS system and represent that its capacitance, resistance value and inductance value are the numerical value of stipulating in the IBIS model.
On draw/realization of drop-down V/I, power supply/ground connection clamp V/I comparatively speaking difficulty a bit, the characteristics of these elements are when being in different termination voltages, export different current values, concrete current value is determined by the V/I tables of data in the IBIS file.In order to simulate the function of these elements, need lookup table circuit of design to realize reading to tables of data.Drawing element in the following reference is example, illustrates how to realize drawing calling of tables of data in the IBIS model file, and the call method of remaining tables of data is similarly, only needs the change data file and the voltage of tabling look-up, fully can be with reference to same method design.
On draw the lookup table circuit can be with reference to the circuit of figure 3, this circuit comprises two elements, one is the SDD2P element, another is DAC (Data Access Component) element.These two elements all are that the ADS system provides self, wherein the DAC element can finish on draw data list file visit, numerical value (by attribute iVal1 control) according to access variable (by attribute iVar1 control) is realized the linear interpolation of tables of data is tabled look-up, and the file of visit is determined by file attribute.The access variable of this lookup table circuit is " Vtable ", numerical value is _ v1-_v2 that port (Port) 1 of expression SDD2P and the pressure reduction of port 2 are promptly gone up the termination voltage of drawing-die piece as independent variable, access file is dx4pga_outputl_pullup_typ.cti, promptly deposits the file of V/I tables of data.The independent variable of tabling look-up of the file of V/I tables of data is Vtable, and dependent variable is Itable.The SDD2P element can be realized the visit to the DAC element, attribute I[2 wherein, 0]=dep_data (DAC1.DAC, " Itable ") mA, the electric current of expression element port determined by the DAC1 element, DAC1 with SDD2P port voltage value as independent variable, in the mode of tabling look-up, determine the output current size of port 2, unit is mA.The output current that the electric current of port 2 draws on being exactly.Therefore,, can realize visit, draw element that the characteristic of different electric currents is provided under different termination voltages in the simulation the voltage/current table by the combination of these two elements.
In the ADS system, the DAC element can not directly be visited the IBIS model file, must take out the V/I tables of data in the IBIS model, changes into the CITI document format data then.The data layout of CITI file is as shown below, and the independent variable of form is Vtable, and variable is Itable.
The CITI file content is explained
CITIFILE is version number A.01.01
NAME VI_PULLUP_TYP tables of data title
VAR Vtable MAG 5 name variable data type numbers
DATA Itable data name
The VAR_LIST_BEGIN variable list
5.0
…
1.0
The VAR_LIST_END variable list finishes
The BEGIN data list
2.4
…
2.0
The END data list finishes
But, as a kind of high speed circuit emulation tool commonly used, when the IBIS model calls in existing ADS system in technique scheme, do not realize calling fully to IBIS model five parts, draw on having included only/drop-down V/I, power supply/ground connection clamp V/I, junction capacity and encapsulation parasitic parameter (stray inductance, dead resistance and stray capacitance), and ignored the information of rising/negative edge speed.Because this information is the of paramount importance part of representation signal side information, so the technical scheme of existing ADS system call IBIS model is the signal edge characteristic of analog device exactly, causes the circuit simulation result unreliable.
In addition, existing technical scheme does not realize the automatic processing to the IBIS model, needs the tables of data information in the manual process IBIS file, changes into the CITI document format data then.Because the IBIS model file has comprised 6 V/I forms, and each form correspondence three kinds of patterns, representative value, minimum value and maximal value.Therefore need 18 V/I data files of manual process, very loaded down with trivial details, and make mistakes easily.In addition, the numerical value of package parasitic inductance, dead resistance, stray capacitance and junction capacity also needs hand filling, very trouble.
Therefore being necessary to propose a kind of improved high speed circuit analogue system and method thereof realizes complete the calling fast of IBIS model increased work efficiency and simulated mass.
In the present specification, for making of "/" number as following regulation, all relating to " on draw/drop-down ", " power supply/ground connection ", " rising/negative edge " part represent " or ", all relating to " V/I ", " K/V ", " K1/V " and " K2/V " part are represented corresponding relation, what specialize understands by its meaning that indicates, and other situations are understood according to context.
Summary of the invention
At the deficiency that prior art exists, one object of the present invention is to provide the method for the rising/negative edge rate information in the read converter spare IBIS model, with will rise/the negative edge rate information is converted to the information that the high speed circuit analogue system can be discerned.
Another object of the present invention is to provide a kind of high speed circuit analogue system and method thereof, it is by realizing the calling of rising/negative edge rate information in the IBIS model, exactly the signal edge characteristic of analog device.
Another object of the present invention is to provide a kind of high speed circuit analogue system and method thereof, it is by to the calling of device IBIS model five parts, promptly on draw/drop-down V/I, rising/negative edge speed, power supply/ground connection clamp V/I, junction capacity C cWith encapsulation parasitic parameter (stray inductance L p, dead resistance R pWith stray capacitance C p) the calling of this five parts, realize reliable circuit simulation result.
Another object of the present invention is to the high speed circuit analogue system and the method thereof that provide new, can handle tables of data information in the IBIS file automatically, change into the CITI document format data then, comprise rising/negative edge rate information.Circuit draws on the index automatically/the CITI data file of drop-down V/I, rising/negative edge speed, power supply/ground connection clamp V/I, automatically call appearance value, the encapsulation parasitic parameter of junction capacity, to the automatic processing of IBIS model, and can between representative value, minimum value and three kinds of patterns of maximal value, switch easily.
For achieving the above object, according to an aspect of the present invention, the method of the rising/negative edge rate information in a kind of read converter spare IBIS model is provided, it is characterized in that, comprise: read step, be used for visiting the IBIS model file rising/negative edge speed data table and on draw/drop-down V/I tables of data, switch process is used for rising/negative edge rate information is converted to the last drag switch COEFFICIENT K 1 of each time point of rising/negative edge and the COEFFICIENT K 2 that pulls down switch.
Further, read step comprises: rising/negative edge speed read step, by rising/negative edge speed reading device, rising/negative edge speed data table in the visit IBIS model file, therefrom the voltage V of the rising/negative edge of reading device and the corresponding relation of time, on draw/drop-down V/I read step, by on draw/drop-down V/I reading device, draw/drop-down V/I tables of data in the visit IBIS model, therefrom reading device on draw/the voltage V of drop-down module and the corresponding relation of electric current I; Switch process comprises: rising/negative edge speed data switch process, by rising/negative edge speed data conversion equipment, according to drawing on the voltage V of rising/negative edge and the corresponding relation of time and the device/the voltage V of drop-down module and the corresponding relation of electric current I, calculate device on draw/drop-down module is in the electric current I of each time point of rising/negative edge, and according to drawing on the device/saturation current of drop-down module, calculate respectively device on draw/drop-down module the drag switch COEFFICIENT K 1 and the COEFFICIENT K 2 that pulls down switch on each time point of rising/negative edge, the voltage calculation procedure of tabling look-up, by the voltage calculation element of tabling look-up, according to the voltage V of rising/negative edge and the corresponding relation of time, temporal information according to the IBIS model, calculate the voltage V that tables look-up, and definite limiter voltage range, combination step, pass through composite set, with K1, the K2 and the voltage V that tables look-up make up, obtain rising edge K1/V, K2/V and negative edge K1/V, K2/V, and the CITI file produces step, by CITI file generation device, according to the CITI call format, K1/V table and K2/V that the K1/V and the K2/V of rising edge and negative edge is stored as CITI data file rising edge and negative edge respectively show.
According to a further aspect in the invention, a kind of high speed circuit emulation mode is provided, by calling the IBIS model information of device, realization is to the simulation of device, method comprises and reads switch process and invocation step, it is characterized in that, read switch process and comprise rising/negative edge speed, it comprises: read step, be used for visiting the IBIS model file rising/negative edge speed data table and on draw/drop-down V/I tables of data, switch process, be used for rising/negative edge rate information is converted to the last drag switch COEFFICIENT K 1 of each time point of rising/negative edge and the COEFFICIENT K 2 that pulls down switch, invocation step can realize the simulation to device edge characteristic by calling the drag switch COEFFICIENT K 1 and the COEFFICIENT K 2 that pulls down switch.
Further, read step comprises: rising/negative edge speed read step, by rising/negative edge speed reading device, rising/negative edge speed data table in the visit IBIS model file, therefrom the voltage V of the rising/negative edge of reading device and the corresponding relation of time, on draw/drop-down V/I read step, by on draw/drop-down V/I reading device, draw/drop-down V/I tables of data in the visit IBIS model, therefrom reading device on draw/the voltage V of drop-down module and the corresponding relation of electric current I; Switch process comprises: rising/negative edge speed data switch process, by rising/negative edge speed data conversion equipment, according to drawing on the voltage V of rising/negative edge and the corresponding relation of time and the device/the voltage V of drop-down module and the corresponding relation of electric current I, calculate device on draw/drop-down module is in the electric current I of each time point of rising/negative edge, and according to drawing on the device/saturation current of drop-down module, calculate respectively device on draw/drop-down module the drag switch COEFFICIENT K 1 and the COEFFICIENT K 2 that pulls down switch on each time point of rising/negative edge, the voltage calculation procedure of tabling look-up, by the voltage calculation element of tabling look-up, according to the voltage V of rising/negative edge and the corresponding relation of time, temporal information according to the IBIS model, calculate the voltage V that tables look-up, and definite limiter voltage range, combination step, pass through composite set, with K1, the K2 and the voltage V that tables look-up make up, obtain rising edge K1/V, K2/V and negative edge K1/V, K2/V, and the CITI file produces step, by CITI file generation device, according to the CITI call format, K1/V table and K2/V that the K1/V and the K2/V of rising edge and negative edge is stored as CITI data file rising edge and negative edge respectively show.
Further, reading switch process also comprises: on draw/drop-down V/I data-switching step, draw/drop-down V/I tables of data in the visit IBIS model, and be converted on the CITI data file and draw/drop-down V/I table, and power supply/ground connection clamp V/I data-switching step, power supply/ground connection clamp V/I tables of data in the visit IBIS model, and be converted into CITI data file power supply/ground connection clamp V/I table, invocation step is called the CITI data file, and calls junction capacity and encapsulation parasitic parameter information in the IBIS model.
Further, invocation step comprises: input step by input media, provides a control signal; The shaping step by shaping circuit, receives control signal, and it is carried out the edge shaping, with as the required trigger pip of emulation; The voltage of tabling look-up produces step, by the voltage generation circuit of tabling look-up, and the control signal after the reception shaping, and produce the voltage of tabling look-up; The K/V step of tabling look-up, by the K/V lookup table circuit, with the voltage of tabling look-up as termination voltage, the K1/V of visit rising edge and negative edge table and K2/V table, and export the K1 and the K2 of rising edge and negative edge; The switch step by on-off circuit, receives the rising edge of lookup table circuit output and the K1 and the K2 of negative edge, when VIN signal during by low uprising, and output rising edge K1 or K2, when VIN signal during by high step-down, output negative edge K1 or K2; On draw/the drop-down V/I step of tabling look-up, by on draw/drop-down V/I lookup table circuit, for drawing on the device/drawing/drop-down V/I table on the data file of drop-down module invokes CITI form, on draw/that drop-down V/I lookup table circuit connects load according to the simulation of device is different and produce different termination voltages, draw/drop-down output current on corresponding thereby provide; And multiplying step, to go up drag switch COEFFICIENT K 1 with on draw output current to multiply each other, the COEFFICIENT K that maybe will pull down switch 2 multiplies each other with drop-down output current, analog device at any one time output current under different termination voltages and control signal is with the edge characteristic of simulation with IBIS model corresponding devices.
Wherein, read switch process and comprise that also index file produces step, produces index file, include index data in the index file, method also comprises the index step, is used to receive the call instruction of calling device, the access index file, and provide index data to calling device.
According to a further aspect in the invention, a kind of high speed circuit analogue system is provided, by calling the IBIS model information of device, realize the simulation of device, system comprises and reads conversion equipment and calling device, it is characterized in that, reading conversion equipment comprises: rising/negative edge speed data conversion equipment, be used for visiting the IBIS model file rising/negative edge speed data table and on draw/drop-down V/I tables of data, rising/negative edge rate information is converted to the last drag switch COEFFICIENT K 1 of each time point of rising/negative edge and the COEFFICIENT K 2 that pulls down switch, thereby calling device can be realized the simulation to device edge characteristic by calling the drag switch COEFFICIENT K 1 and the COEFFICIENT K 2 that pulls down switch.
Further, rising/negative edge speed data conversion equipment comprises: rising/negative edge speed reading device, be used for visiting the rising/negative edge speed data table of the IBIS model file of device, therefrom the voltage V of the rising/negative edge of reading device and the corresponding relation of time; On draw/drop-down V/I reading device, be used for visiting device the IBIS model on draw/drop-down V/I tables of data, therefrom reading device on draw/the voltage V of drop-down module and the corresponding relation of electric current I; The switching coefficient calculation element, respectively with rising/negative edge speed reading device with on draw/drop-down V/I reading device links to each other, be used for according to drawing on the voltage V of the rising/negative edge of device and the corresponding relation of time and the device/the voltage V of drop-down module and the corresponding relation of electric current I, calculate device on draw/drop-down module is in the electric current I of each time point of rising/negative edge, according to drawing on the device/saturation current of drop-down module, calculate respectively device on draw/drop-down module the drag switch COEFFICIENT K 1 and the COEFFICIENT K 2 that pulls down switch on each time point of rising/negative edge; The voltage calculation element of tabling look-up links to each other with rising/negative edge speed data reading device, according to the voltage V of rising/negative edge and the corresponding relation of time, according to the temporal information of IBIS model, calculates the voltage V that tables look-up, and determines a limiter voltage range; Composite set links to each other with the voltage calculation element of tabling look-up with the switching coefficient calculation element, is used for K1, K2 and the voltage V that tables look-up are made up, and obtains rising edge K1/V, K2/V and negative edge K1/V, K2/V; And CITI file generation device, link to each other with composite set, according to the CITI call format, K1/V table and K2/V that the K1/V and the K2/V of rising edge and negative edge is stored as CITI data file rising edge and negative edge respectively show.
Further, rising/negative edge speed data conversion equipment is used for the rising of IBIS model/negative edge speed data table is converted to the K1/V table and the K2/V table of CITI data file rising edge and negative edge, the model data calling device comprises: input media is used to provide a control signal; Shaping circuit links to each other with input media, is used to receive control signal, and it is carried out the edge shaping, with as the required trigger pip of emulation; The voltage generation circuit of tabling look-up links to each other with shaping circuit, is used to receive the control signal after the shaping, and produces the voltage of tabling look-up; The K/V lookup table circuit links to each other with the voltage generation circuit of tabling look-up, and as termination voltage, is used to visit the K1/V table and the K2/V table of rising edge and negative edge with the voltage of tabling look-up, and the K1 and the K2 of output rising edge and negative edge; On-off circuit links to each other with the K/V lookup table circuit, is used to receive the rising edge of lookup table circuit output and the K1 and the K2 of negative edge, when VIN signal during by low uprising, and output rising edge K1 or K2, when VIN signal during by high step-down, output negative edge K1 or K2; On draw/drop-down V/I lookup table circuit, connect with the simulation of device that load is different to possess different termination voltages, be used to device on draw/draw/drop-down V/I table on the data file of drop-down module invokes CITI form, provide to draw/drop-down output current; And multiplier, link to each other with the V/I lookup table circuit with on-off circuit, be used for going up drag switch COEFFICIENT K 1 with on draw output current to multiply each other, the COEFFICIENT K that maybe will pull down switch 2 multiplies each other with drop-down output current, analog device at any one time output current under different termination voltages and control signal is with the edge characteristic of simulation with IBIS model corresponding devices.
The present invention has following beneficial effect.
One, by to the calling of rising/negative edge rate information in the IBIS model, the signal edge characteristic of analog device exactly.
Two,, realized circuit simulation effect accurately and reliably by complete calling to IBIS model five parts.
Three, by the method according to this invention treatment scheme, the information in can automatic processor spare IBIS model produces corresponding C ITI data file and index file.By to the calling of file, the realization system is called automatically to CITI file automatic indexing and passive parameter, has simplified the workload of system call IBIS model information greatly, has greatly improved work efficiency.
Description of drawings
Below in conjunction with accompanying drawing, describe the specific embodiment of the present invention in detail, among the figure:
Figure 1 shows that the basic parameter synoptic diagram of IBIS model;
Figure 2 shows that the schematic diagram of ADS system call IBIS model;
Figure 3 shows that the ADS system on draw the schematic diagram of lookup table circuit;
Figure 4 shows that system principle block scheme of the present invention;
Figure 5 shows that the block scheme of rising/negative edge speed data conversion equipment;
Figure 6 shows that the block scheme of model data calling device;
Figure 7 shows that the schematic diagram of edge shaping circuit;
Figure 8 shows that the voltage waveform view of the control signal of the voltage generation circuit processing front and back of tabling look-up;
Figure 9 shows that the table look-up schematic diagram of voltage generation circuit of high voltage;
Figure 10 shows that the table look-up input/output voltage comparison of wave shape figure of voltage generation circuit of high level;
Figure 11 shows that the schematic diagram of on-off circuit;
Figure 12 shows that the synoptic diagram of three grades of links that form between the data access element of lookup table circuit/passive element, indexing unit and the index file;
Figure 13 shows that the process flow diagram that reads conversion IBIS model data; And
Figure 14 shows that and call the process flow diagram that the IBIS model reads the data after the conversion.
Embodiment
Below be example with the ADS system, the high speed circuit analogue system that proposes according to the present invention and the principle of method thereof are elaborated.
Referring to Fig. 4, be depicted as systematic schematic diagram of the present invention.System comprises and reads conversion equipment 100, calling device 200 and indexing unit 300.
The front is mentioned, and the ADS system realizes that by lookup table circuit the informational needs of tables of data is converted to the CITI form earlier could be by the ADS system call to the reading of the tables of data of IBIS model.Read conversion equipment 100 comprise rising/negative edge speed data conversion equipment 110, on draw/drop-down V/I DTU (Data Transfer unit) 120, power supply/ground connection clamp V/I DTU (Data Transfer unit) 130, passive element parameter reading device 140 and index file generation device 150.
Rising in the IBIS model/negative edge speed data table need convert the component that ADS can discern to.In the present invention, this tables of data is converted into the last drag switch COEFFICIENT K 1 of rising edge/negative edge time and the COEFFICIENT K 2 that pulls down switch.
The last drag switch COEFFICIENT K 1 and the COEFFICIENT K 2 that pulls down switch be illustrated respectively in certain constantly device on draw output current with drop-down module be saturation current K doubly, 0≤K≤1.So-called saturation current draws on being/and drop-down module is under the state of opening fully, and the size of output current is drawn on promptly/size of current in the drop-down V/I tables of data.In rising edge and high level stage, K1 increases to 1 gradually by 0, and remains to next negative edge and begin, and K2 is reduced to 0 gradually by 1, remains to next negative edge equally and begins.In negative edge and low level stage, K1 is reduced to 0 gradually by 1, and remains to next rising edge, and K2 increases to 1 gradually by 0, remains to next rising edge equally.
Figure 5 shows that the functional-block diagram of rising/negative edge speed data conversion equipment 110.This device comprises:
Rising/negative edge speed reading device 111 is used for visiting the rising/negative edge speed data table of device IBIS model file, therefrom the voltage V of the rising/negative edge of reading device and the corresponding relation of time;
On draw/drop-down V/I reading device 112, be used for visiting device IBIS model on draw/drop-down V/I tables of data, therefrom reading device on draw/the voltage V of drop-down module and the corresponding relation of electric current I;
Switching coefficient calculation element 113, respectively with rising/negative edge speed reading device 111 with on draw/drop-down V/I reading device 112 links to each other, be used for according to drawing on the voltage V of the rising/negative edge of device and the corresponding relation of time and the device/the voltage V of drop-down module and the corresponding relation of electric current I, calculate device on draw/drop-down module is in the electric current I of each time point of rising/negative edge, and according to drawing on the device/saturation current of drop-down module, calculate respectively device on draw/drop-down module the drag switch COEFFICIENT K 1 and the COEFFICIENT K 2 that pulls down switch on each time point of rising/negative edge;
The voltage calculation element 116 of tabling look-up, link to each other with rising/negative edge speed data reading device 111, according to the voltage V of rising/negative edge and the corresponding relation of time, according to the temporal information of IBIS model, calculate the voltage V that tables look-up, and determine a limiter voltage range.This voltage of tabling look-up is sent into the composite set 114 that will describe the back, and this limiter voltage range will be used for the table look-up setting of limiter voltage in the voltage generation circuit of calling device;
Composite set 114 links to each other with the voltage calculation element 116 of tabling look-up with switching coefficient calculation element 113, is used for K1, K2 and the voltage V that tables look-up are made up, and obtains rising edge K1/V, K2/V and negative edge K1/V, K2/V; And
CITI file generation device 115 links to each other with composite set, and according to the CITI call format, K1/V table and K2/V that the K1/V and the K2/V of rising edge and negative edge is stored as CITI data file rising edge and negative edge respectively show.
On draw/drop-down V/I DTU (Data Transfer unit) 120 be used for visiting the IBIS model on draw/drop-down V/I tables of data, and be converted on the CITI data file and draw/drop-down V/I table.
Power supply/ground connection clamp V/I DTU (Data Transfer unit) 130 is used for visiting the power supply/ground connection clamp V/I tables of data of IBIS model, and is converted into CITI data file power supply/ground connection clamp V/I table.
These two devices 120,130 can adopt the used mode of aforementioned prior art.
Passive element parameter reading device 140 is used to visit the IBIS model of device, therefrom reads wherein junction capacity and encapsulation parasitic parameter.
Index file generation device 150 respectively with rising/negative edge speed data conversion equipment 110, on draw/drop-down V/I DTU (Data Transfer unit) 120, power supply/ground connection clamp V/I DTU (Data Transfer unit) 130 and passive element parameter reading device 140 be connected, and is used to produce the index file of a MDF form.Index data in this MDF index file comprises filename and the junction capacity and the encapsulation parasitic parameter of CITI data file, and comprises the limiter voltage range that the voltage calculation element 116 of tabling look-up calculates.
Fig. 6 shows the frame principle figure of model data calling device 200, below in conjunction with Fig. 6, describes the principle that the present invention calls five parts of IBIS model fully in detail.
Model data calling device 200 is used to respond input signal, calls the model data that reads after the conversion, thereby carries out the analogue simulation of device, and it comprises with the lower part.
Input media 210 is used to provide a control signal V In
Shaping circuit 212 links to each other with input media 210, is used to receive control signal V In, and it is carried out the edge shaping, with as the required trigger pip of emulation.
Because control signal is imported by Simulation Engineering teacher, edges of signals may be inconsistent, can't be as effective trigger signals, therefore need to use shaping circuit 212 to unify conversion process, edges of signals is adjusted into consistent with transient state simulation time step-length, to eliminate of the influence of input signal edge to the subsequent conditioning circuit function.Can set, if input voltage more than or equal to 0.5V, then is output as high level 1V, otherwise be 0V.As input V InVoltage is the initial moment of rising edge when surpassing 0.5V, up to V InRising edge finished when voltage was lower than 0.5V, and rising edge K1, K2 work during this period of time.As input V InIt when voltage is lower than 0.5V the initial moment of negative edge, up to V InNegative edge finished when voltage was higher than 0.5V, and negative edge K1, K2 work during this period of time.
Shaping circuit 212 is input as V as shown in Figure 7 In, be output as V Fix, its function has mainly utilized ADS system variable element 2122 and 2,121 two elements of SDD2P element to realize.In certain emulation constantly, if input voltage changes, it is worth more than or equal to 0.5V, and then circuit is exported high level 1V, if input voltage changes, it is worth less than 0.5V, then circuit output low level 0V.The variable of variable element 2122 is set to if (v1＜0.5) then 0 else 1 endif, and this expression is output as 0V, otherwise is 1 when the port one voltage of SDD2P element 2121 during less than 0.5V.Therefore can realize the edge shaping by this circuit, the signal edge is adjusted into consistent, make the follow-up voltage generation circuit of tabling look-up not be subjected to the influence at extraneous input signal edge with transient state simulation time step-length.
The voltage generation circuit of tabling look-up comprises high level voltage generation circuit 214 and the low level voltage generation circuit 216 of tabling look-up of tabling look-up, and links to each other with shaping circuit 212 respectively, is used to receive the control signal V after the shaping Fix, produce high level voltage and the low level voltage of tabling look-up of tabling look-up respectively.
High level voltage generation circuit 214 and the low level temporal information that voltage generation circuit 216 is actually rising edge and negative edge of tabling look-up of tabling look-up converts the information of voltage of tabling look-up to.Figure 8 shows that the voltage oscillogram of the control signal of these two circuit 214 and 216 processing front and back, wherein control signal V FixVoltage waveform be square wave W1, the signal waveform after circuit 214 and 216 is handled is respectively sawtooth wave W1 and W2.The advantage of sawtooth signal is that voltage and time are linear, handles easily.Circuit 214 and 216 receives control signal V simultaneously Fix, for circuit 214, V FixDuring for high level, table look-up voltage output voltage and time are linear, V FixDuring for low level, output voltage is 0, and like this, the output voltage of circuit 214 presents sawtooth wave along the waveform W2 of whole time shaft; Then opposite for circuit 216, V FixDuring for low level, table look-up voltage output voltage and time are linear, V FixDuring for high level, output voltage is 0.By these two sawtooth voltages, can finish the table lookup function of follow-up lookup table circuit.
The high level shown in Figure 9 voltage generation circuit 214 of tabling look-up, the low level voltage generation circuit 216 of tabling look-up can be applied mechanically this circuit fully, as long as will import V FIX_PAnd V FIX_NSignal turns upside down and gets final product.The function of this circuit 214 mainly realizes by ideal current source 2141, switch 2142,2143, electric capacity 2144, resistance 2145 and the limiter 2146 of ADS system, is input as V Fix_pAnd V Fix_n, these two signal correspondences be V FixSignal and V FixInversion signal, be output as V Ctr1, the initial voltage of node 2147 is set to 0.The principle of work of this circuit is, as input V Fix_pVoltage during less than 0.49V, the resistance of switch 2142 is 1G ohm, presents off-state, and the resistance of switch 2143 is 1m ohm, presents conducting state, electric capacity 2144 discharges by switch 2143.As input V Fix_pVoltage during greater than 0.5V, the resistance of switch 2142 is 1m ohm, presents conducting state, and the resistance of switch 2143 is 1G ohm, presents off-state, ideal current source 2141 charges by 2142 pairs of electric capacity 2144 of switch.The electric current and voltage formula of electric capacity is U = 1 C ∫ idt , U is a voltage, and C is a capacitor's capacity, and i is an electric current.The electric current of ideal current source 2141 remains unchanged, so when charging, the voltage of electric capacity 2144 increases progressively in time and increases progressively, in the time of discharge, circuit is short-circuit condition, the emptying soon of the electric weight of electric capacity 2144, so voltage reduces to 0 soon.
Figure 10 shows the table look-up input signal V of potential circuit 214 of high level Fix_pWith the output signal V behind process limiter 2146 amplitude limits CtrlComparison of wave shape.Can see output signal V Ctr1Waveform be a kind of sawtooth wave, its voltage swing is restricted.Table look-up voltage and limiter voltage is determined according to the time information of voltage that rising/negative edge speed data table is comprised of IBIS model by the aforesaid voltage calculation element 116 of tabling look-up that reads in the conversion equipment 100.Limiter 2146 voltage limit of will tabling look-up can guarantee that within the specific limits this voltage can not exceed the scope of tables of data, guarantees the correctness of tabling look-up.
The K/V lookup table circuit, comprise rising edge K1/V lookup table circuit 218, rising edge K2/V lookup table circuit 220, link to each other with the high level voltage generation circuit 214 of tabling look-up respectively, table look-up voltage as termination voltage with high level, be used to visit rising edge K1/V table and K2/V table, and the K1 and the K2 of output rising edge; Also comprise negative edge K1/V lookup table circuit 224 and negative edge K2/V lookup table circuit 226, link to each other with the low level voltage generation circuit 216 of tabling look-up respectively, table look-up voltage as termination voltage with low level, be used to visit negative edge K1/V table and K2/V table, and the K1 and the K2 of output negative edge.
Since there are K1, the K2 of rising edge and negative edge simultaneously, therefore need be according to control signal V InRequirement switch, export rational K1, K2.Work as V InSignal is during by low uprising, and circuit need switch to rising edge K1, K2 from negative edge K1, K2; Work as V InSignal is during by high step-down, and circuit need switch to negative edge K1, K2 from rising edge K1, K2.This handoff functionality is realized by an on-off circuit 128.
On-off circuit 228 links to each other with rising edge K1/V lookup table circuit 218, rising edge K2/V lookup table circuit 220, negative edge K1/V lookup table circuit 224 and negative edge K2/V lookup table circuit 226 respectively, and its effect is to work as V Fix_pDuring for high level, switch switches to rising edge K1, K2 passage, and promptly the output channel of rising edge K1/V and K2/V lookup table circuit is exported rising edge K1 or K2; Work as V Fix_pDuring for low level, switch switches to negative edge K1, K2 passage, output negative edge K1 or K2.Can guarantee like this has correct K1, K2 component in moment corresponding, i.e. the output channel of negative edge K1/V and K2/V lookup table circuit.
Figure 11 shows that the schematic diagram of on-off circuit 228.The function of this circuit mainly realizes by ADS system variable element 2281 and SDD4P element 2282.As shown in the figure, work as V Fix_pVoltage was less than 0.5 o'clock, and K1, K2 get the switching coefficient K of negative edge Up2, work as V Fix_pVoltage was defaulted as high level this moment constantly more than or equal to 0.5 o'clock.Variable is set to i (v1＜0.5) then_v2else_v3endif in the variable element 2281, is connected to V at the port one place of SDD4P element 2282 Fix_pSignal is at the switching coefficient K of port 2 places connection negative edge Up2, corresponding 1: 1 component of voltage is at the switching coefficient K of port 3 places connection rising edge Up1, corresponding 1: 1 component of voltage is in the current component I[4 of port 4,0]=k/50, and connect 50 ohm load 2283.This special on-off circuit 228 just can be finished the switching of rising edge K1 and K2 and negative edge K1 and K2, obtains final switching coefficient K at port 4 UpComprise K1 or K2 after the switching.
On draw and be connected load difference with drop-down V/I lookup table circuit 234,236 with the device of simulation and possess different termination voltages, be used to device on draw/draw/drop-down V/I table on the data file of drop-down module invokes CITI form, provide to draw/drop-down output current, draw on the analog device/drop-down V/I characteristic.
Power supply clamp V/I lookup table circuit 238 and ground connection clamp V/I lookup table circuit 240 link to each other with ground connection with power supply respectively, are used to call the data file power supply clamp V/I table and the ground connection clamp V/I table of CITI form, the power supply of analog device and ground connection clamp V/I characteristic.
Multiplier, comprise first multiplier 230, with on-off circuit 228 with on draw V/I lookup table circuit 234 to link to each other, be used for last drag switch COEFFICIENT K 1 with on draw output current to multiply each other, the output current of last drawing-die piece time in office under different termination voltages and control signal of output device.And comprise second multiplier 232, with on-off circuit 228 with on draw V/I lookup table circuit 236 to link to each other, the COEFFICIENT K 2 that is used for pulling down switch multiplies each other the output current of drop-down module time in office under different termination voltages and control signal of output device with drop-down output current.These two multipliers 230 and 232 K1 or K2 according to on-off circuit 228 output optionally work, thereby make output signal can simulate edge characteristic with described IBIS model corresponding devices.
Draw in the IBIS model/drop-down V/I, power supply/ground connection clamp V/I, junction capacity be consistent with the implementation method of encapsulation parasitic parameter (stray inductance, dead resistance and stray capacitance) with existing technology.Junction capacity C wherein c, stray inductance L p, dead resistance R pWith stray capacitance C pBe respectively to utilize the principle shown in the schematic diagram of ADS directly to call electric capacity, inductance and resistance to realize that its capacitance, resistance value and inductance value can adopt the numerical value of stipulating in the IBIS model.Lookup table circuit above-mentioned comprises the element that two ADS systems carry respectively, and one is the SDD2P element, and another is DAC (Data AccessComponent) element.Effect by these two elements realizes the table lookup function to the tables of data of CITI form, specifically can be with reference to Fig. 3.
Return Fig. 4.Calling device 200 provides index by an indexing unit 300 when calling model information, thereby obtains the information that will call rapidly.Indexing unit 300 comprises index file memory storage 310, be used to store the index file that aforesaid index file generation device 150 produces, and data access element 320, be used to visit described index file, read filename and the described junction capacity and the encapsulation parasitic parameter of CITI data file wherein, and deliver to various lookup table circuits.Data access element 320 specifically can adopt the DAC element that carries in the ADS system, and as the control inlet of visit MDF index file, the MDF index file leaves in the index file memory storage 310.Lookup table circuit just can directly be visited according to the filename of the CITI data file that obtains and be called corresponding C ITI data file.
Below with dead resistance R pWith on draw V/I lookup table circuit 234 to be example, the mode of model data calling device 200 by the 300 realization data calls of model data indexing unit be described.The parameter of passive element should correctly be provided with in the circuit of model data calling device 200, to the dead resistance R of encapsulation p, R=file{DAC1, " RP " }, wherein DAC1 is the data access element 320 of index MDF file, RP is the variable name of dead resistance correspondence in the MDF file.Passive element for other also can adopt similar mode.The setting of the DAC element of lookup table circuit, more than draw V/I lookup table circuit 234 to be example, being set to of DAC element 2341, File=file{DAC1, " VT_PULLUP " }, wherein DAC1 is the data access element 320 of index MDF file, and VT_PULLUP is the variable name of the title correspondence of lookup table circuit 234 in the MDF file.For other lookup table circuit also can adopt with mode.
Dead resistance R PData access element 320 to indexing unit sends call instruction, and MDF index file in the data access element 320 access index file storage devices 310 therefrom reads dead resistance R PValue, be dead resistance R with this value then pAssignment.On draw V/I lookup table circuit 234 to call when drawing the V/I tables of data, DAC element 2341 in circuit data access element 320 in indexing unit sends call instruction, DAC element visit MDF index file, draw the filename of V/I table to send to DAC element 2341 on the CITI data file with correspondence, DAC element 2341 calls corresponding output current according to drawing the V/I table in the visit of this document name according to its termination voltage.Lookup table circuit for other also adopts similar mode.
Can see, form three grades of link structures between the data access element 320 of the passive element of calling device 200 or lookup table circuit and indexing unit 300 and the MDF index file in the index file memory storage 310.This three grades of link structures have been shown among Figure 12, wherein, the parameters of data access element 320 is provided with as follows: the File=MDF index file name, can be defined as IBIS filename _ model name _ all.mdf, Type=Discrete, Interp Mode=Index Lookup, the value of iVall can be 0, change between 1,2, respectively corresponding TYP, MIN, three kinds of simulation models of MAX.
By three grades of such links, can realize automatically equally also realizing to representative value the switching between maximal value and the minimum value pattern to the visit of relevant CITI file, junction capacity, encapsulation parasitic parameter and limiter voltage.
Figure 13 is the process flow diagram that reads conversion IBIS model data.This flow process comprises the steps:
Opening steps S401 opens the IBIS model file of device.
Rising/negative edge speed data switch process S410, by rising/negative edge speed data conversion equipment 110, visit in the described IBIS model file described rising/negative edge speed data table and on draw/drop-down V/I tables of data, rising/negative edge rate information is converted to the last drag switch COEFFICIENT K 1 of each time point of rising/negative edge and the COEFFICIENT K 2 that pulls down switch, specifically comprises:
Read step S411, by rising/negative edge speed reading device 111, visit the rising/negative edge speed data table in the IBIS model file of described device, therefrom read the voltage V of rising/negative edge of described device and the corresponding relation of time, by on draw/drop-down V/I reading device 112, visit in the IBIS model of described device on draw/drop-down V/I tables of data, therefrom read described device on draw/the voltage V of drop-down module and the corresponding relation of electric current I;
Switching coefficient calculation procedure S412, by switching coefficient calculation element 113, according to drawing on the voltage V of the rising/negative edge of described device and the corresponding relation of time and the described device/the voltage V of drop-down module and the corresponding relation of electric current I, calculate described device on draw/drop-down module is in the electric current I of each time point of rising/negative edge, according to drawing on the described device/saturation current of drop-down module, calculate respectively device on draw/drop-down module the drag switch COEFFICIENT K 1 and the COEFFICIENT K 2 that pulls down switch on each time point of rising/negative edge;
The voltage calculation procedure of tabling look-up S415 utilizes the voltage calculation element 116 of tabling look-up, and according to the voltage V of described rising/negative edge and the corresponding relation of time, according to the temporal information of described IBIS model, calculates the voltage V that tables look-up, and determines a limiter voltage range.
Combination step S413 utilizes composite set 114, and the voltage V that tables look-up that K1, K2 and the voltage calculation element 116 of tabling look-up are calculated makes up, and obtains rising edge K1/V, K2/V and negative edge K1/V, K2/V; And
The CITI file produces step S414, utilizes CITI file generation device 115, and according to the CITI call format, K1/V table and K2/V that the K1/V and the K2/V of rising edge and negative edge is stored as CITI data file rising edge and negative edge respectively show;
On draw/drop-down V/I data-switching step S420, by on draw/drop-down V/I DTU (Data Transfer unit) 120, with draw in the IBIS model/drop-down V/I tables of data is converted to the CITI form.Specifically comprise:
Read step S421 draws/drop-down V/I tables of data in the visit IBIS model; And
Switch process S422 is converted to the data that read on the CITI data file and draws/drop-down V/I table.
And power supply/ground connection clamp V/I data-switching step S430, by power supply/ground connection clamp V/I DTU (Data Transfer unit) 130, power supply in the IBIS model/clamp V/I tables of data is converted to the CITI form.Specifically comprise:
Read step S431, the power supply/ground connection clamp V/I tables of data in the visit IBIS model; And
Switch process S432 is converted to CITI data file power supply/ground connection clamp V/I table with the data that read.
Passive element parameter read step S440, by passive element parameter reading device 140, visit IBIS model reads wherein junction capacity and encapsulation parasitic parameter.
In above-mentioned rising/negative edge speed data switch process S410, because the last drag switch COEFFICIENT K 1 of rising edge and negative edge is different, need separately deposit, the COEFFICIENT K that pulls down switch 2 also is so, therefore need deposit 4 CITI data files.In last drawing/drop-down V/I data-switching step 420, need deposit and draw V/I and two CITI data files of drop-down V/I.In power supply/ground connection clamp V/I data-switching step 430, need deposit power supply clamp V/I and two CITI data files of ground connection clamp V/I.Therefore for a kind of pattern, need 8 CITI data files to deposit different tables of data, the IBIS model has comprised three kinds of patterns, and representative value, maximal value and minimum value always have 24 CITI data files.For junction capacity and encapsulation parasitic parameter, three kinds of patterns will have 12 device parameters.
Like this, by software processes, an IBIS model will produce 24 CITI data files and 12 device parameters automatically.Continuation is referring to Figure 12, in order to realize that automatically each element to the automatic index of these 24 CITI data files and calling automatically of 12 passive parameters, also need produce a MDF index file, IBIS filename _ model name _ all.mdf.This produces step S450 by rope phase file and realizes.
Index file produces step S450, by index file generation device 150, produce a MDF index file, include index data in the MDF index file, these index datas comprise filename and the junction capacity and the encapsulation parasitic parameter of CITI data file, also are included in the limiter voltage range that is produced by the voltage calculation element 116 of tabling look-up among the voltage calculation procedure S415 that tables look-up.The data that write in the MDF index file are discharged by row.Different row are represented TYP (typical case), MIN (minimum) and the relevant data of MAX (maximum) pattern.
By above step, can utilize software program to finish the data of the IBIS model of device are handled automatically.
Figure 14 is the process flow diagram that calls the model data after the conversion.Invocation step specifically comprises the steps.
Input step S510 by input media 210, provides a control signal;
Shaping step S520 by shaping circuit 212, receives described control signal, and it is carried out the edge shaping, with as the required trigger pip of emulation;
The voltage of tabling look-up produces step S530, by the voltage generation circuit of tabling look-up, control signal after the reception shaping, and produce the voltage of tabling look-up, the described voltage generation circuit of tabling look-up comprises high level voltage generation circuit 214 and the low level voltage generation circuit 216 of tabling look-up of tabling look-up, and produces high level voltage and the low level voltage of tabling look-up of tabling look-up respectively;
The K/V step S540 that tables look-up by K/V lookup table circuit 118,120,124 and 126, as termination voltage, visits the K1/V table and the K2/V table of described rising edge and negative edge with the voltage of tabling look-up, and exports the K1 and the K2 of rising edge and negative edge;
Switch step S550 by on-off circuit 228, receives described lookup table circuit 118,120,124 and the rising edge of 126 outputs and the K1 and the K2 of negative edge, when VIN signal during by low uprising, output rising edge K1 or K2, when VIN signal during by high step-down, output negative edge K1 or K2;
On draw/the drop-down V/I step S560 that tables look-up, by on draw and drop-down V/I lookup table circuit 234,236, call for the last drawing-die piece of device on the data file of CITI form and draw the V/I table, be the drop-down V/I table of the data file of the drop-down module invokes CITI form of device, draw on described/drop-down V/I lookup table circuit is different according to the simulation connected mode of described device and the different termination voltages that possess draw/drop-down output current thereby provide;
Multiplying step S570, utilize first multiplier 230 will go up drag switch COEFFICIENT K 1 with on draw output current to multiply each other, or utilize will pull down switch COEFFICIENT K 2 of second multiplier 232 to multiply each other with drop-down output current, the voltage and current of the control signal of a time in office of exporting described device under different termination voltages is with the edge characteristic of simulation with described IBIS model corresponding devices.
Power supply/ground connection clamp V/I step S580 that tables look-up, utilize power supply clamp V/I lookup table circuit 238 and ground connection clamp V/I lookup table circuit 240 respectively, call the data file power supply clamp V/I table and the ground connection clamp V/I table of CITI form, the power supply of analog device and ground connection clamp V/I characteristic.
Passive element parameter call step S590 is by calling junction capacity and the encapsulation parasitic parameter value in the MDF file, the relevant parameter of analog device.
By above step, can utilize software program to finish the data of the IBIS model of device are called automatically, thereby realize device simulation.
By above-described technical scheme, the present invention has realized calling rising/negative edge rate information in the IBIS model, the signal edge characteristic of analog device has realized complete the calling to IBIS model five partial parameters exactly, thereby can obtain circuit simulation effect accurately and reliably.
Utilize method treatment scheme of the present invention, can produce corresponding C ITI data file and index file by the information in the software automatic processor spare IBIS model.By to the calling of file, the system that can realize is to the calling automatically of CITI file automatic indexing and passive parameter, thereby simplified the workload of system call IBIS model information, improved work efficiency.
IBIS model described in the literary composition is all output model, for input model, realize more simply,, can use for reference the call method of output model fully because input model has only comprised power supply/ground connection clamp V/I tables of data information and junction capacity and encapsulation parasitic parameter information.
The above is the preferred embodiments of the present invention only, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within the claim scope of the present invention.

Claims (10)

1. the method for the rising in the read converter spare IBIS model/negative edge rate information is characterized in that, comprising:
Read step, visit in the described IBIS model file rising/negative edge speed data table and on draw/drop-down V/I tables of data,
Switch process is converted to the last drag switch COEFFICIENT K 1 of each time point of rising/negative edge and the COEFFICIENT K 2 that pulls down switch with rising/negative edge rate information.
2. method according to claim 1 is characterized in that:
Described read step comprises:
Rising/negative edge speed read step by rising/negative edge speed reading device, is visited the rising/negative edge speed data table in the described IBIS model file, therefrom reads the voltage V of rising/negative edge of described device and the corresponding relation of time,
On draw/drop-down V/I read step, by on draw/drop-down V/I reading device, visit in the described IBIS model on draw/drop-down V/I tables of data, therefrom read described device on draw/the voltage V of drop-down module and the corresponding relation of electric current I;
Described switch process comprises:
Rise/fall is along the speed data switch process; By rise/fall along the speed data conversion equipment; According to drawing on the voltage V on described rise/fall edge and the corresponding relation of time and the described device/the voltage V of drop-down module and the corresponding relation of electric current I; Calculate described device on draw/drop-down module is in the electric current I of each time point on rise/fall edge; And according to drawing on the described device/saturation current of drop-down module; Calculate respectively device on draw/drop-down module is in the upper drag switch COEFFICIENT K 1 of each time point on rise/fall edge and the COEFFICIENT K 2 that pulls down switch
The voltage calculation procedure of tabling look-up by the voltage calculation element of tabling look-up, according to the voltage V of described rising/negative edge and the corresponding relation of time, according to the temporal information of described IBIS model, calculates the voltage V that tables look-up, and determines a limiter voltage range,
Combination step by composite set, makes up K1, K2 and the described voltage V that tables look-up, and obtains rising edge K1/V, K2/V and negative edge K1/V, K2/V, and
The CITI file produces step, and by CITI file generation device, according to the CITI call format, K1/V table and K2/V that the K1/V and the K2/V of rising edge and negative edge is stored as CITI data file rising edge and negative edge respectively show.
3. high speed circuit emulation mode by calling the IBIS model information of device, realizes the simulation to described device, and described method comprises and reads switch process and invocation step, it is characterized in that the described switch process that reads comprises rising/negative edge speed, and it comprises:
Read step, be used for visiting described IBIS model file rising/negative edge speed data table and on draw/drop-down V/I tables of data,
Switch process is used for rising/negative edge rate information is converted to the last drag switch COEFFICIENT K 1 of each time point of rising/negative edge and the COEFFICIENT K 2 that pulls down switch,
Described invocation step can realize the simulation to described device edge characteristic by calling the described drag switch COEFFICIENT K 1 and the COEFFICIENT K 2 that pulls down switch of going up.
4. method according to claim 3 is characterized in that:
Described read step comprises:
Rising/negative edge speed read step by rising/negative edge speed reading device, is visited the rising/negative edge speed data table in the described IBIS model file, therefrom reads the voltage V of rising/negative edge of described device and the corresponding relation of time,
On draw/drop-down V/I read step, by on draw/drop-down V/I reading device, visit in the described IBIS model on draw/drop-down V/I tables of data, therefrom read described device on draw/the voltage V of drop-down module and the corresponding relation of electric current I;
Described switch process comprises:
Rise/fall is along the speed data switch process; By rise/fall along the speed data conversion equipment; According to drawing on the voltage V on described rise/fall edge and the corresponding relation of time and the described device/the voltage V of drop-down module and the corresponding relation of electric current I; Calculate described device on draw/drop-down module is in the electric current I of each time point on rise/fall edge; And according to drawing on the described device/saturation current of drop-down module; Calculate respectively device on draw/drop-down module is in the upper drag switch COEFFICIENT K 1 of each time point on rise/fall edge and the COEFFICIENT K 2 that pulls down switch
The voltage calculation procedure of tabling look-up by the voltage calculation element of tabling look-up, according to the voltage V of described rising/negative edge and the corresponding relation of time, according to the temporal information of described IBIS model, calculates the voltage V that tables look-up, and determines a limiter voltage range,
Combination step by composite set, makes up K1, K2 and the described voltage V that tables look-up, and obtains rising edge K1/V, K2/V and negative edge K1/V, K2/V, and
The CITI file produces step, and by CITI file generation device, according to the CITI call format, K1/V table and K2/V that the K1/V and the K2/V of rising edge and negative edge is stored as CITI data file rising edge and negative edge respectively show.
5. method according to claim 4 is characterized in that, the described switch process that reads also comprises:
On draw/drop-down V/I data-switching step, draw/drop-down V/I tables of data on visiting in the described IBIS model, and be converted on the CITI data file and draw/drop-down V/I table, and
Power supply/ground connection clamp V/I data-switching step, the power supply/ground connection clamp V/I tables of data in the visit IBIS model, and be converted into CITI data file power supply/ground connection clamp V/I table,
Described invocation step is called described CITI data file, and calls junction capacity and encapsulation parasitic parameter information in the described IBIS model.
6. method according to claim 5 is characterized in that, described invocation step comprises:
Input step by input media, provides a control signal;
The shaping step by shaping circuit, receives described control signal, and it is carried out the edge shaping, with as the required trigger pip of emulation;
The voltage of tabling look-up produces step, by the voltage generation circuit of tabling look-up, and the control signal after the reception shaping, and produce the voltage of tabling look-up;
The K/V step of tabling look-up by the K/V lookup table circuit, as termination voltage, is visited the K1/V table and the K2/V table of described rising edge and negative edge with the described voltage of tabling look-up, and is exported the K1 and the K2 of rising edge and negative edge;
The switch step by on-off circuit, receives the rising edge of described lookup table circuit output and the K1 and the K2 of negative edge, when VIN signal during by low uprising, and output rising edge K1 or K2, when VIN signal during by high step-down, output negative edge K1 or K2;
On draw/the drop-down V/I step of tabling look-up, by on draw/drop-down V/I lookup table circuit, for drawing on the described device/drawing/drop-down V/I table on the data file of drop-down module invokes CITI form, draw on described/that drop-down V/I lookup table circuit connects load according to the simulation of described device is different and produce different termination voltages, draw/drop-down output current on corresponding thereby provide; And
The multiplying step, with described go up drag switch COEFFICIENT K 1 with described on draw output current to multiply each other, or the described COEFFICIENT K 2 of pulling down switch multiplied each other with described drop-down output current, simulate described device at any one time output current under different termination voltages and control signal, with the edge characteristic of simulation with described IBIS model corresponding devices.
7. according to each described method among the claim 3-6, it is characterized in that the described switch process that reads comprises that also index file produces step, produces index file, includes index data in the described index file,
Described method also comprises the index step, is used to receive the call instruction of described calling device, visits described index file, and provides described index data to described calling device.
8. the high speed circuit analogue system by calling the IBIS model information of device, realizes the simulation of described device, and described system comprises and reads conversion equipment and calling device, it is characterized in that the described conversion equipment that reads comprises:
Rising/negative edge speed data conversion equipment, be used for visiting described IBIS model file described rising/negative edge speed data table and on draw/drop-down V/I tables of data, rising/negative edge rate information is converted to the last drag switch COEFFICIENT K 1 of each time point of rising/negative edge and the COEFFICIENT K 2 that pulls down switch, thereby described calling device can be realized the simulation to described device edge characteristic by calling the described drag switch COEFFICIENT K 1 and the COEFFICIENT K 2 that pulls down switch of going up.
9. system according to claim 8 is characterized in that, described rising/negative edge speed data conversion equipment comprises:
Rising/negative edge speed reading device is used for visiting the rising/negative edge speed data table of the IBIS model file of described device, therefrom reads the voltage V of rising/negative edge of described device and the corresponding relation of time;
On draw/drop-down V/I reading device, be used for visiting described device the IBIS model on draw/drop-down V/I tables of data, therefrom read described device on draw/the voltage V of drop-down module and the corresponding relation of electric current I;
The switching coefficient calculation element, respectively with described rising/negative edge speed reading device with described on draw/drop-down V/I reading device links to each other, be used for according to drawing on the voltage V of the rising/negative edge of described device and the corresponding relation of time and the described device/the voltage V of drop-down module and the corresponding relation of electric current I, calculate described device on draw/drop-down module is in the electric current I of each time point of rising/negative edge, according to drawing on the described device/saturation current of drop-down module, calculate respectively device on draw/drop-down module the drag switch COEFFICIENT K 1 and the COEFFICIENT K 2 that pulls down switch on each time point of rising/negative edge;
The voltage calculation element of tabling look-up, link to each other with described rising/negative edge speed data reading device, according to the voltage V of described rising/negative edge and the corresponding relation of time, according to the temporal information of described IBIS model, calculate the voltage V that tables look-up, and determine a limiter voltage range;
Composite set links to each other with the described voltage calculation element of tabling look-up with described switching coefficient calculation element, is used for K1, K2 and the described voltage V that tables look-up are made up, and obtains rising edge K1/V, K2/V and negative edge K1/V, K2/V; And
CITI file generation device links to each other with composite set, and according to the CITI call format, K1/V table and K2/V that the K1/V and the K2/V of rising edge and negative edge is stored as CITI data file rising edge and negative edge respectively show.
10. system according to claim 9, it is characterized in that, described rising/negative edge speed data conversion equipment is used for the rising of described IBIS model/negative edge speed data table is converted to the K1/V table and the K2/V table of CITI data file rising edge and negative edge, and described model data calling device comprises:
Input media is used to provide a control signal;
Shaping circuit links to each other with described input media, is used to receive described control signal, and it is carried out the edge shaping, with as the required trigger pip of emulation;
The voltage generation circuit of tabling look-up links to each other with described shaping circuit, is used to receive the control signal after the shaping, and produces the voltage of tabling look-up;
The K/V lookup table circuit links to each other with the described voltage generation circuit of tabling look-up, and as termination voltage, is used to visit the K1/V table and the K2/V table of described rising edge and negative edge with the described voltage of tabling look-up, and the K1 and the K2 of output rising edge and negative edge;
On-off circuit links to each other with described K/V lookup table circuit, is used to receive the rising edge of described lookup table circuit output and the K1 and the K2 of negative edge, when VIN signal during by low uprising, and output rising edge K1 or K2, when VIN signal during by high step-down, output negative edge K1 or K2;
On draw/drop-down V/I lookup table circuit, connect with the simulation of described device that load is different to possess different termination voltages, be used to described device on draw/draw/drop-down V/I table on the data file of drop-down module invokes CITI form, provide to draw/drop-down output current; And
Multiplier, link to each other with described V/I lookup table circuit with described on-off circuit, be used for described go up drag switch COEFFICIENT K 1 with described on draw output current to multiply each other, or the described COEFFICIENT K 2 of pulling down switch multiplied each other with described drop-down output current, simulate described device at any one time output current under different termination voltages and control signal, with the edge characteristic of simulation with described IBIS model corresponding devices.
CN 200510032956 2005-01-21 2005-01-21 IBIS model information reading method, high-speed circuit emulation system and its method Pending CN1808445A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101221587B (en) * 2007-01-09 2011-06-22 昆山杰得微电子有限公司 Method for reconstructing ground clamp curve and electric power clamp curve of chip IBIS model
CN102254073A (en) * 2011-08-03 2011-11-23 西安电子科技大学 IBIS (Input/Output Buffer Information Specification) model reconstructing method
WO2012000342A1 (en) * 2010-07-02 2012-01-05 中兴通讯股份有限公司 Method and system for validating input/output buffer information specification (ibis) model
CN103308846A (en) * 2013-05-07 2013-09-18 南京邮电大学 Method and device for detecting functional performance of integrated chip based on model identification
US9460250B1 (en) * 2012-07-30 2016-10-04 Cadence Design Systems, Inc. System, method, and computer program product for input/output buffer modeling
CN114266150A (en) * 2021-12-16 2022-04-01 电子科技大学 Frequency multiplier joint simulation method based on mdf file

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101221587B (en) * 2007-01-09 2011-06-22 昆山杰得微电子有限公司 Method for reconstructing ground clamp curve and electric power clamp curve of chip IBIS model
WO2012000342A1 (en) * 2010-07-02 2012-01-05 中兴通讯股份有限公司 Method and system for validating input/output buffer information specification (ibis) model
CN102314532A (en) * 2010-07-02 2012-01-11 中兴通讯股份有限公司 IBIS (Input/Output Buffer Information Specification) model verification method and system
CN102314532B (en) * 2010-07-02 2015-06-03 中兴通讯股份有限公司 IBIS (Input/Output Buffer Information Specification) model verification method and system
CN102254073A (en) * 2011-08-03 2011-11-23 西安电子科技大学 IBIS (Input/Output Buffer Information Specification) model reconstructing method
US9460250B1 (en) * 2012-07-30 2016-10-04 Cadence Design Systems, Inc. System, method, and computer program product for input/output buffer modeling
CN103308846A (en) * 2013-05-07 2013-09-18 南京邮电大学 Method and device for detecting functional performance of integrated chip based on model identification
CN103308846B (en) * 2013-05-07 2015-07-08 南京邮电大学 Method and device for detecting functional performance of integrated chip based on model identification
CN114266150A (en) * 2021-12-16 2022-04-01 电子科技大学 Frequency multiplier joint simulation method based on mdf file

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