JPH04190456A - Calculation device for power consumption of lsi - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a power consumption calculation device in an LSI, particularly an LSI
The present invention relates to a device that automatically calculates power consumption regarding a predetermined measurement target based on a mask pattern of I.

[Conventional technology]

When designing an LSI, it is very important to consider the power consumption of each circuit that makes up the LSI. As circuits become faster, larger, and smaller, parasitic capacitance of interconnects increases due to an increase in interconnect intersections and a decrease in oxide film thickness. Furthermore, as the scale increases, the through current during transients also increases. As a result, the peak current and average current consumption increase, resulting in a drop in power supply voltage and an increase in the amount of heat generated by the element. Therefore, unless the power consumption of each circuit is sufficiently considered in the design, it may cause malfunction of the LSI.

In addition, in recent years, low power supply voltage LSI and B1-CMO
There is a tendency for LSIs using S to increase, and these LS
When designing I, there is a need to reduce the noise margin more than ever, and consideration of the above-mentioned power consumption has become a more serious issue.

[Problem to be solved by the invention]

Power consumption can be taken into consideration by performing a simulation for each designed cell and calculating the power consumption in that cell. However, it is virtually impossible to rely on humans to perform power consumption simulations each time a cell is designed, given the relatively limited design period and the extremely large scale of the design. It is possible. Furthermore, since information regarding power consumption obtained through such manual operations can only be left as data, there is also the problem that it is impossible to construct design assets that can be effectively used in later designs.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a power consumption calculation device for an LSI that can automatically calculate the power consumption of a designed LSI and store this as a design asset in the form of data. .

[Means to solve the problem]

The present invention provides a power consumption calculation device for an LSI, which includes a circuit that extracts, from a mask pattern of an LSI, circuit connection information indicating connection relationships within the circuit and circuit characteristic information determined in relation to the size of each component of the circuit. A connection characteristic information extraction device inputs circuit parameter information that determines the electrical characteristics of each component of the circuit, and generates a circuit simulation necessary for circuit simulation based on this circuit parameter information, circuit connection information, and circuit characteristic information. A circuit simulation input information creation device that creates input information; a circuit simulator device that performs circuit simulation based on the circuit simulation input information and outputs the result as circuit simulation output information; A power consumption calculation device that calculates power consumption related to a measurement target in the measurement target.

[For production]

According to the power consumption calculation device according to the present invention, the designed LS
Circuit connection information and circuit characteristic information are automatically extracted from the mask pattern I. The circuit simulator automatically performs circuit simulation based on this information and circuit parameter information. The power consumption calculation device automatically calculates power consumption based on the output of this circuit simulator. In this way, the power consumption of the designed LSI can be automatically calculated, and this can also be saved as a design asset in the form of data.

〔Example〕

The present invention will be described below based on illustrated embodiments. FIG. 1 is a block diagram showing the basic configuration of a power consumption calculation device according to an embodiment of the present invention. This device has a function of automatically calculating the power consumption of each cell constituting the LSI based on the designed mask pattern P of the LSI.

The main components of this device are from the mask pattern P.
A circuit connection characteristic information extraction device 1 extracts circuit connection information A and circuit characteristic information B, inputs each of these pieces of information A and B, and circuit parameter information C, and creates circuit simulation input information necessary for circuit simulation. a circuit simulation input information creation device 2 that performs a circuit simulation based on this circuit simulation input information, and a circuit simulator device 3 that performs a circuit simulation and outputs the result as circuit simulation output information E; a power consumption calculation device 4 that calculates power consumption and outputs it as power consumption information F;
It is. Each of these components includes a display device 5.
and an input device 6 are connected. Further, a printer 7, a magnetic disk 8, and a magnetic tape 9 are connected to the power consumption calculation device 4 in order to output power consumption information F.

Each of these components will be described in detail below while explaining its operation.

The device of this embodiment has a function of calculating power consumption for each unit cell configuring an LSI. Therefore, the designer first prepares a mask pattern P for a unit cell whose power consumption is to be calculated, and provides this to the circuit connection characteristic information extraction device 1. The circuit connection characteristic information extraction device 1 extracts circuit connection information A and circuit characteristic information B based on this mask pattern P. Here, circuit connection information A
is information indicating connection relationships within the circuit, and circuit characteristic information B
is information determined in relation to the size of each component of the circuit. Since the mask pattern P is prepared as graphic data, the circuit connection characteristic information extraction device 1 extracts circuit connection information A and circuit characteristic information B from this graphic pattern.
do. For example, as shown in FIG. 2(a), in order to extract circuit connection information A when two graphic patterns corresponding to a diffusion layer and a polysilicon layer are given, first, the logical Performs the work of recognizing elements through calculations. That is, by recognizing the area obtained by ANDing the two graphical operations as the gate and the diffusion layer areas on both sides thereof as the source and drain, this can be recognized as a MOS transistor. By performing phase calculation on this, circuit connection information A as shown in FIG. 2(b) can be obtained. Similarly, as shown in FIG. 3(a), the wiring layer A,
When a graphic pattern corresponding to B, a graphic pattern corresponding to the wiring layer C overlapping this, and a graphic pattern corresponding to the contact are given, the circuit connection information A as shown in FIG. 3(b) is given. can get. On the other hand, the circuit characteristic information B is information determined in relation to the size of each component, and is information such as the size of each element and the parasitic capacitance of wiring. For example, when graphic patterns as shown in FIG. 4(a) are given, the sizes of these figures are extracted, and the parasitic capacitance CXY of the wiring from end point X to end point Y is extracted. That is, as shown in FIG. 4(b), the parasitic capacitance CXY is obtained by multiplying the area S of the wiring layer by the capacitance Co per unit area. It should be noted that the method for extracting the circuit connection information A and the circuit characteristic information B as described above is well known, so a detailed explanation of the specific method will be omitted in this specification.

In this way, the circuit connection information A and the circuit characteristic information B extracted by the circuit connection characteristic information extraction device 1 are provided to the circuit simulation input information creation device 2. At this time, the operator inputs circuit parameter information C from the input device 6. This circuit parameter information C is information that determines the electrical characteristics of each component of the circuit, and specifically includes numerical values such as the thickness of the oxide film and the impurity concentration value in the diffusion layer. In the apparatus of this embodiment, a keyboard is used as the input device 6, and the operator inputs process values when actually manufacturing this LSI as circuit parameter information C from the keyboard. thus,
The circuit simulation input information creation device 2 includes circuit connection information A1 necessary for performing circuit simulation.
Each information of circuit characteristic information B1 and circuit parameter information C1 is given. The circuit simulation input information creation device 2 has a function of creating circuit simulation input information to be provided to the circuit simulator device 3 based on this information. In the device of this embodiment, 5PICE (a circuit simulator developed at the University of California, USA) is used as the circuit simulator device 3, so the circuit simulation input information creation device 2
Circuit simulation input information written in this 5PICE format is created. Note that, in general, the power consumption of a circuit to be measured differs depending on the load circuit connected to the subsequent stage.

Therefore, in the device of this embodiment, n load circuits are prepared in the circuit simulation input information creation device 2, and as shown in FIG. Circuit simulation input information is created with the load circuits 11 to 1n connected as shown in FIG.

The circuit simulation input information created in this way is given to the circuit simulator device 3.

As described above, in the device of this embodiment, 5PICE is used as the circuit simulator device 3, and the circuit simulation input information is written in the 5PICE format. Therefore, the circuit simulator W3 can immediately perform a circuit simulation based on this input information. In this embodiment, n types of circuit simulations are performed with n types of load circuits connected as shown in FIG.

In the circuit simulation performed here, as shown in FIG. 6, the i-th load circuit 1 is added to the circuit 10 to be measured.
This is a simulation to predict what kind of current will flow in the circuit 10 to be measured when a predetermined input signal I is applied with the circuit 10 connected. For example, the seventh
As shown in the figure, the circuit 10 to be measured is an inverter (shown as a combination of MO5I and transistor circuits in the figure), and the load circuit 11 is a two-stage inverter with a parasitic capacitance value Ci (the circuit Let us consider a circuit simulation using a simple model using a circuit consisting of circuits (indicated by symbols). Since the purpose of the simulation is to predict the current flowing in the circuit 10, the ammeter 20 is connected to the circuit 1, for example, as shown in the figure.
0 and the power supply voltage VDD. Of course, the simulation is performed with such an ammeter inserted. In other words, the operator inputs the ammeter 2 to the circuit simulator device 3 from the keyboard or the like.
An instruction is given to perform a simulation with the inserted at this position. As a result, when the circuit simulator device 3 gives the input signal I to the circuit 10, the ammeter 2
Predict what kind of current will flow at 0. for example,
If the circuit simulator device 3 is instructed to give the input signal ■ which rises as shown in FIG. 8, the circuit simulator device 3 outputs, for example, the current waveform flowing through the ammeter 20 as shown in FIG. 9 as the circuit simulation output information E. .

In this embodiment, different output information E is output for each of the n load circuits connected.

The power consumption calculation device 4 is a device that calculates power consumption based on such circuit simulation output information E. In this embodiment, the power consumption calculation device 4 calculates three elements: power consumption, average current consumption, and peak current.
It has a function of calculating based on output information E as shown in FIG. 9 and outputting it as power consumption information F. Each operation is performed as follows.

(1) Power consumption Based on the graph shown in FIG. 9, power consumption P is calculated using the following formula.

P-(Σ l i (t) l・V DD) Δ
T/T where vDD is the power supply voltage of this circuit, and T is the time required for measurement. Since current flows in the CMO 3 only during the transient period up to time T, calculations are performed on events that occur during this transient period.

(2) Average current consumption Based on the graph shown in FIG. 9, the average current consumption l is calculated by the following formula.

i-ΔT/T·Σ l i (t) l Here, ΔT is the time step size in the circuit simulator device 3, and T is the time required for measurement, as described above.

(3) The maximum value of the peak current absolute value 1i(t)l is determined from the graph shown in FIG. 9, and is set as the peak current 11IIax.

The above is the result when an input signal I that rises as shown in FIG. 8 is applied, or similarly, the result when an input signal I that falls is applied is also obtained.

Then, the power consumption in the inverter 10 is obtained by adding both results.

In this way, the power consumption for each of the n load circuits connected can be determined. The result is displayed on the display device 5 and also output as power consumption information F to the printer. This power consumption information F is preferably output in the form of a table or a graph. In addition, this power consumption information F can be saved as a magnetic disk 8 or magnetic tape 9, and previously designed information can be left as a design asset in the form of data, making it possible to utilize it in future designs. become.

Although the present invention has been described above based on an illustrated embodiment, the present invention is not limited to this embodiment only.
In addition to this, it can be implemented in various other ways. For example, the four blocks 1 to 4 shown in FIG. 1 can be realized by a single computer, or can be realized by multiple computers as separate devices. Further, in the above embodiment, the circuit simulator device 3
Although an example using 5PICE is shown as an example, any other circuit simulator device may be used. In short, in the present invention, circuit simulation input information suitable for the format of the circuit simulator device 3 may be created by the circuit simulation input information creation device W2.

〔Effect of the invention〕

As described above, the power consumption calculation device according to the present invention automatically extracts circuit connection information and circuit characteristic information from a designed LSI mask pattern, and calculates the circuit based on this information and circuit parameter information. The designed L
Power consumption for SI can be automatically calculated, and this can be saved as a design asset in the form of data.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of a power consumption calculation device according to an embodiment of the present invention, and FIGS. 2 and 3 are diagrams illustrating the extraction work of circuit connection information A in the device shown in FIG. 1. , FIG. 4 is a diagram explaining the extraction work of circuit characteristic information B in the apparatus shown in FIG. 1, FIG. 5 is a diagram showing an example of circuit simulation input information created by the apparatus shown in FIG. 6 is a diagram showing the principle of circuit simulation performed on the information shown in FIG. 5, FIG. 7 is a diagram showing an example of a circuit to be processed by the apparatus shown in FIG. 1, and FIG. 7 is a diagram showing input signals used in circuit simulation for the circuit shown in FIG. 7, and FIG. 9 is a diagram showing an example of the result of circuit simulation for the circuit shown in FIG. DESCRIPTION OF SYMBOLS 1... Circuit connection characteristic information extraction device, 2... Circuit simulation input information creation device, 3... Circuit simulator device, 4... Power consumption calculation device, 5... Display device, 6... Input device, 7... Printer, 8
...Magnetic disk, 9...Magnetic tape, 10...
Circuits to be measured, 11 to 1n...load circuits. Patent applicant Dai Nippon Printing Co., Ltd. Applicant agent Patent attorney Hiroshi Shimura Figure 1 (a) (b) Mouth diffusion layer (a) (b) Figure 3 (a) (b) Figure 5

Claims (1)

[Claims] A circuit connection characteristic information extraction device that extracts circuit connection information indicating connection relationships within a circuit and circuit characteristic information determined in relation to the size of each component of the circuit from an LSI mask pattern. and input circuit parameter information that determines the electrical characteristics of each component of the circuit, and generate circuit simulation input information necessary for circuit simulation based on this circuit parameter information, the circuit connection information, and the circuit characteristic information. a circuit simulation input information creation device that creates circuit simulation input information; a circuit simulator device that performs circuit simulation based on the circuit simulation input information and outputs the result as circuit simulation output information;
A power consumption calculation device in an LSI, comprising: a power consumption calculation device that calculates power consumption regarding a measurement target in an SI.