JPH0581089B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides the following features:
Regarding integrated circuits that connect arbitrary circuit blocks to realize any functional circuit at the user's fingertips, it is possible to realize analog circuits, etc. by preventing erroneous transmission due to a drop in signal level between circuit blocks. The invention relates to integrated circuits.

[Prior Art] Programmable integrated circuits such as PLDs (programmable logic devices), which are configured so that users can realize arbitrary logic circuits at hand, have been known. Among these, we have a European patent for a PLD that can connect multiple circuit blocks arbitrarily using programmable wiring.
There is EP0204034. These PLDs mainly implement logic circuits that handle digital signals.

On the other hand, when a user, i.e., a customer, desires an analog integrated circuit, it is generally designed and manufactured using a fully custom method. A semi-custom analog master slice has been proposed in which a mask pattern for the wiring process is created between circuit blocks according to the customer's wishes, and the final aluminum wiring is performed to realize an arbitrary analog integrated circuit.

[Problems to be Solved by the Invention] However, the integrated circuit according to the above-mentioned conventional technology has the following problems.

(1) PLDs allow users to realize any functional circuit at hand, but when trying to apply them to analog circuits, the voltage drop that occurs in switch elements used in programmable wiring elements, etc. This will cause an error in the analog signal transmitted by the element, and accurate operation cannot be guaranteed.

(2) Full-custom or semi-custom integrated circuits require a great deal of effort and long manufacturing processes to obtain the circuit that the customer needs, although there are differences in degree between the two. The circuit function is already determined when shipped from the factory, and the user cannot change the function of the integrated circuit at hand, resulting in a lack of flexibility.

In programmable integrated circuits, the wiring distance of the programmable wiring elements that interconnect internal circuits and the number of switch elements passing through are uncertain, so signal transmission errors due to voltage drops in wiring elements become a problem. Until now, there has been no proposal for an integrated circuit that allows the user to programmably define any analog functional circuit at hand.

The present invention was devised to solve the above-mentioned problems. It prevents erroneous transmission due to a drop in signal level between circuit blocks, and allows the user to program any functional circuit, including analog circuits, at hand. The purpose is to provide an integrated circuit that can be obtained.

[Means for Solving the Problems] The structure of the integrated circuit of the present invention for achieving the above object is such that, in an integrated circuit comprising a plurality of circuit blocks and programmable wiring elements, at least one circuit block is , comprising at least one analog circuit element and at least one voltage-current exchanger, wherein the voltage output signal of the analog circuit element is converted into a current signal by the voltage-current converter and then connected to the programmable wiring element. Therefore, it is characterized in that it can be connected to the input of any circuit block.

[Function] The present invention is equipped with programmable wiring elements, and realizes a desired analog functional circuit by arbitrarily connecting circuit blocks including one or more circuit blocks each having one or more analog circuit elements by programming. do. At least part of the analog signal exchange between the circuit blocks is performed as a current signal via a voltage-current exchanger, so that even if a voltage drop occurs in wiring elements, the current itself does not change. It uses this effect to accurately transmit signals, making analog programmable integrated circuits possible.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. The integrated circuit of this embodiment has a plurality of input/output pads 2 arranged in a row on the side of a chip 1, a plurality of circuit blocks 3 arranged inside the chip 1, and a plurality of input/output pads 2 A wiring area 4 is formed between the circuit blocks 3 and the circuit blocks 3, and a plurality of programmable wiring elements (not shown) are sewn between them.

The circuit block 3 includes at least one arbitrary circuit element 31 and at least one voltage-current exchanger 32 that converts the voltage output signal of the circuit element 31 into a current signal.
It has one. A plurality of circuit elements 31 and voltage/current exchangers 32 may be provided depending on the circuit function. The output from circuit block 3 is delivered by the above-mentioned current signal.

The programmable wiring elements in the wiring area 4 include, for example, the locations where the wiring of the wiring element intersects with the input/output lines of the input/output pad 2, the locations where the wiring of the wiring element intersects with the input/output lines of the circuit block 3, and the wiring of the wiring element. A programmable switch element is arranged at the location where the circuit blocks intersect with each other, and input/output between arbitrary circuit blocks 3 and arbitrary circuit blocks 3
and any input/output pad 2.

FIGS. 2 and 3 show examples of the configuration of circuit elements constituting the circuit block 3. FIG. The second shows an amplifier circuit that receives output signals from other circuit blocks. This amplifier circuit has an operational amplifier 6, whose non-inverting (+) input terminal is connected to ground ( _GND ) via a resistor R1, and whose inverting (-) input terminal is connected to an input terminal 61. , connected to the output terminal 62 via a resistor _R2 . Third
The figure shows an example of a configuration in which the circuit elements themselves can programmably determine their functions. This circuit element also has an operational amplifier 7 that performs differential amplification, and its non-inverting (+) input terminal is connected to ground GND via a resistor _R3 . Between the inverting (-) input terminal of the operational amplifier 7 and the input terminal 71, there are resistors R ₄ , R ₅ , capacitors C ₁ ,
C ₂ is a programmable switch element S ₁ ,
It is connected in series to S ₂ , S ₃ , and S ₄ and connected in parallel to each other. Further, between the inverting (-) input terminal and the output terminal 72, a transistor Tr ₁ , a resistor R ₆ , and capacitors C ₃ and C ₄ are connected to programmable switch elements S ₅ , S ₆ , S ₇ , and S ₈ , respectively. connected in series and connected in parallel with each other. Each switch element S ₁
~ _S8 is controlled to turn on the necessary points using programming information stored in memory in advance, for example, turns on resistor _R4 or _R5 and transistor _Tr1 , and turns on switch elements _S1 or _S2 and _S5. If you control and choose,
It becomes a logarithmic amplifier circuit. Also, if you turn on switch elements S ₁ or S ₂ and S ₇ or S ₈ and select resistor R ₄ or R ₅ and capacitor C ₃ or C ₄ ,
This circuit element becomes an integrator circuit, and the switch element S ₃
or control S ₄ and S ₆ to turn on capacitor C ₁
Alternatively, by selecting C ₂ and resistor R ₆ , a differentiating circuit can be obtained. Furthermore, if the switch elements S ₁ or S ₂ and S ₆ are turned on and the resistors R ₄ , R ₅ , and R ₆ are selected,
It can be a simple amplifier circuit. The above is an example of the circuit elements, and various other functional circuits such as an A/D converter and a digital circuit can be used as the circuit elements.

FIG. 4 is a circuit diagram of a voltage-current converter,
An example constructed using MOS transistors is shown. In this embodiment, the drain of the MOS transistor 8 is connected to the circuit power supply V _DD , the gate is used as the input terminal V _IN into which the output voltage of the circuit element is input, and the source is used as the output terminal V _OUT of the circuit block. FIG. 5 shows an input/output characteristic diagram of this MOS transistor 8,
If the gate voltage V _G , that is, the input terminal V _IN voltage is constant, even if the drain-source voltage V _DS changes due to the voltage drop of wiring elements, the drain current I _D can be reduced by using the flat part of the characteristic. i.e. output terminal
The output current from V _OUT can be kept constant.

The operation of this embodiment with the above configuration will be described. In this embodiment, inputs and outputs between arbitrary circuit blocks can be arbitrarily connected using programmable wiring elements, so the user can control the functions of the integrated circuit by programming the connection information of the wiring elements. It can be arbitrarily defined at hand. At this time, signals between circuit blocks where voltage drops caused by programmable wiring elements etc. are a problem are:
By transmitting and receiving current signals via a voltage-current exchanger, the signal current is kept constant and accurately transmitted.

FIG. 6 is a block diagram showing another embodiment of the present invention. In this embodiment, a plurality of input/output pads 2 are arranged and arranged on the side of the chip 1, a plurality of circuit blocks 3 and circuit elements 33 are arranged and arranged inside the chip 1, and The area between the input/output pad 2 and the circuit block 3 and the circuit element 33 and the area between the circuit block 3 or the circuit element 33 are used as wiring areas, and a plurality of programmable wiring elements (not shown) are sewn between them. Similar to the first embodiment, the voltage signal generated in the circuit element 31 is converted into a current signal by the voltage-current converter 32 and is transmitted to another circuit block 3 or another circuit element 33 by a programmable wiring element. Connected. On the other hand, the voltage signal generated by the circuit element 33 is connected to another circuit block 3 or another circuit element 33 as it is.

According to the above configuration, for example, when transmitting an analog value to another circuit block, a current signal is used, and when transmitting a digital signal to another circuit block, a voltage signal is used. By converting only the signal into a current signal, it is possible to increase the density of the circuit and maintain the signal propagation characteristics.

Note that when the programmable analog circuit shown in FIG. 3 is employed as a circuit element, even more diverse functions can be defined. In this way, the present invention can be applied in various ways in accordance with the spirit thereof,
Various embodiments are possible.

[Effects of the Invention] As is clear from the above description, the integrated circuit of the present invention enables accurate transmission of signals in any analog functional circuit where signal level reduction due to programmable wiring elements or the like is a problem. It is possible to provide an integrated circuit that can be programmably defined by the user at hand.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
3 is a diagram showing an example of the configuration of circuit elements, FIG. 4 is a diagram showing an example of the configuration of a voltage-current conversion circuit, FIG. 5 is a characteristic diagram of the voltage-current conversion circuit, and FIG. 6 is a diagram showing an example of the configuration of the voltage-current conversion circuit. It is a block diagram which shows another Example. 3...Circuit block, 4...Wiring area (wiring element), 31...Circuit element, 32...Voltage-current converter.

Claims (1)

[Claims] 1. In an integrated circuit comprising a plurality of circuit blocks and programmable wiring elements, at least one circuit block has at least one analog circuit element and at least one voltage-current converter. , an integrated circuit characterized in that the voltage output signal of the analog circuit element is converted into a current signal by the voltage-current exchanger, and then connected to the input of an arbitrary circuit block by the programmable wiring element. .