DE102004041729A1 - Integrated module for output of output signals e.g. in computing systems, uses level change minimizing function for signals being outputted - Google Patents

Abstract

An integrated module (1) has a number of output terminals for outputting output signals, and an electronic circuit (2) for preparing the signals to be output. Output drivers (3) are used for the signals and a converter circuit receives the signals of the electronic circuit (2) being outputted. The output signals are ascertained through the use of a level change minimizing function for the signals (S0-S7) being outputted, and the output signals (A0-A7) are made ready at the output driver (3). An independent claim is included for a method for outputting output signals at a number of output terminals.

Description

The The invention relates to an integrated module with a plurality of output terminals for Outputting output signals. The invention further relates a method for outputting output signals with a number of output connections.

In Today's computer systems need the interfaces to memory become faster to the transmit increasing amount of data to be stored or read to be able to. Especially, Because DRAM memory devices are manufactured in a very cost-effective technology which can be achieved with the low leakage currents and the has a small number of metal levels, is the driving ability output signals lower at their output terminals than others integrated circuits usual. Due to the low availability area is also the available room for Supply line systems in the integrated memory circuit limited, so that the integrated supply lines due to interference and Noise can be influenced, which in turn drives the driver the integrated memory circuit is reduced.

interfaces Today's DRAM memory circuits are used with clock cycles of operated up to 400 MHz. This operating frequency is for the most part limited by the noise of the output driver. Even simple DRAM memory circuits have up to 32 output drivers, the can switch simultaneously. Two major sources of noise at the output drivers are the noise caused by the synchronous switching and a latch effect. The noise due to the synchronous switching is due to the different number caused by simultaneously switching output drivers.

If For example, all output drivers from a logical one at the same time Turning one to a logical zero results in a large level fluctuation caused in the supply network, causing a much slower Signal level change leads as in a case where only one of the output drivers of a logical one switches to a logical zero. That's what happens to data dependent Noise, which degrades the signal quality.

Also the latch effect affects the Signal quality. The latch effect indicates a different switching speed in a case when a certain logic level during several Clock periods is driven and from this particular level a different level is switched, and a case when a logical one Level only for a clock period is driven. When subsequently to the other level is switched, the signal change takes place depending on the case fast. In the latter case, the potential of the signal level while the first level is not complete have been achieved - in Contrary to the former case - so that the potential of the subsequent reference signal reaches the second signal level earlier and thus the signal change can be performed faster.

The Noise in the supply voltage line leads to significantly deteriorated Data eyes and thus to a significantly deteriorated signal quality.

So far Care has been taken in the design of integrated memory circuits the supply lines and the output drivers as symmetrical as possible similarly build and wire these optimized to the To reduce noise. This will cause the effects described above but not eliminated, only reduced.

It The object of the present invention is an integrated component with several output connections to disposal to provide, in which the outputting of output signals to a reduced Noise leads. It is a further object of the present invention to provide a method for outputting output signals from an integrated component to disposal to make, with the emergence of noise in the integrated module can be reduced and thus a better signal quality of the output signals can be provided.

These The object is achieved by the integrated module according to claim 1 and solved by the method according to claim 5.

Further advantageous embodiments of the invention are specified in the dependent claims.

According to a first aspect of the present invention, there is provided an integrated circuit having a number of output terminals for outputting output signals. The integrated module has an electronic circuit that provides signals to be output. Output drivers are also provided to output the output signals according to the signals to be output. Furthermore, the integrated component comprises a converter circuit which receives the signals to be output from the electronic circuit, the off by applying a level change minimizing function to the signals to be output and providing the output signals to the output drivers for outputting.

Of the integrated module according to the present The invention has the advantage that the applied to the output terminals Signals regarding her Level changes are optimized, that is, the number of level changes opposite to the signal to be output the previously output signal is reduced as possible.

On this way, the noise or fluctuation of the supply voltages be reduced to the supply lines, so that disturbing influences reduces the electronic circuit of the integrated module can be.

It can be provided that depends on the number of times required to output the output signals Level changes at the output terminals either according to a first operating state, the signals to be output unchanged Output signals are output or according to a second operating state the output signals from the signals to be output according to a Flank reduction function are formed. In particular, the Edge reduction function will be an inverter function that provides a specific Part or all of the signals to be output inverted. The second Operating state can be preferably taken when the number of required level change of the output signals in the first operating state would exceed a predetermined number of the output terminals, preferably a predetermined number of the output terminals. In this way, the Edge reduction function can then be applied when the number the level change gets too big, wherein the edge reduction function, the output signals be adjusted so that the number of level changes decreases becomes. This must be done so that the signals to be output information is not affected.

Around a receiver the output signals to tell whether the output signals compared to the output Changed signals may be another output terminal of the integrated Be provided in order to output an operating state signal, that indicates the operating state. In this way it can be communicated to a received device whether the signals to be output have been output unchanged as output signals or whether the signals to be output are using the slope reduction function were processed to different output signals from the signals to be output to generate.

• – des Bereitstellens von auszugebenden Signalen, und
• – des Erzeugens der Ausgangssignale durch Anwenden einer Pegelwechselminimierungsfunktion auf die auszugebenden Signale, wobei die Pegelwechselminimierungsfunktion die Anzahl der beim Ausgeben der Ausgangssignale erforderlichen Pegelwechsel minimiert.

In accordance with another aspect of the present invention, a method of outputting outputs at a number of output terminals is provided. The method comprises the steps

• - the provision of signals to be output, and
• Generating the output signals by applying a level change minimizing function to the signals to be output, the level change minimizing function minimizing the number of level changes required in outputting the output signals.

The inventive method has the advantage that the number of simultaneously switching output signals can be reduced. Thereby can the noise and voltage fluctuations on the supply lines of the integrated module are reduced.

According to one embodiment According to the invention, the generation of the output signals can be carried out according to either in a first operating state, the signals to be output as output signals be issued or according to the in a second operating state, the output signals from the output Signals according to a Flank reduction function are formed, wherein the first or second operating state dependent taken by the number of required level changes at the output terminals becomes. At the same time may be dependent a status signal is outputted from the assumed operating state be to a receptions the output signals indicate whether the output signals are unchanged and the output signals or according to the edge reduction function changed have been.

A preferred embodiment The present invention will be described below with reference to the accompanying drawings explained in more detail. It demonstrate:

1 a block diagram of an integrated circuit block according to a preferred embodiment of the invention, and

2 a table of a possible sequence of output signals that are changed according to a level change minimizing function or output unchanged.

In 1 is schematically an integrated component 1 shown, an electronic circuit 2 and output drivers 3 via which output signals are output, with which the integrated module transmits data to external devices or Can transmit blocks. The electronic circuit 2 may be a memory circuit, logic circuit or other type of circuit.

The output drivers 3 preferably have a latch into which the output signals are stored and provided for the period of a data eye to take over from the external device at the output terminals A0 to A7. Before outputting the next output signals, first the output signals are latched to the output drivers 3 taken over and then provided at the outputs A0 to A7.

The electronic circuit 2 provides signals S0 to S7 to be output that represent information to be received from the external device.

The integrated component 1 has a transducer unit 4 which receives the signals S0 to S7 to be output, and outputs signals to the output drivers in response to a level change minimizing function 3 ready. The level change minimizing function serves to change the level required at the output terminals of the integrated circuit to output the information represented by the signals to be output 1 to reduce as much as possible. The converter circuit reads this 4 the state of the latches of the output drivers 3 and compares the respective states with the respective signals to be output. Represents the converter circuit 4 when outputting the signals S0 to S7 to be outputted as output signals to the output drivers, a number of latches in the output drivers 3 change their state, the converter circuit takes 4 a second operating state in which a Flankenreduzierungsfunktion is applied to the output signals S0 to S7. The edge reduction function may be, for example, an inverter function that inverts each or a part of the signals S0 to S7 to be output.

following is assumed by a Flankenreduzierungsfunktion, in the each of the signals to be output inverted output as an output becomes.

For example, the output signals cause more than half of the output drivers 3 must output an output signal at the output terminals, which leads to a level change at the output terminals, so applies the converter circuit 4 the flank reduction function and assumes the second operating state. That is, the second operating state remains occupied until the converter unit 4 determines that the outputting of the output signals generated from the signals S0 to S7 to be output according to the edge reduction function results in a number of level changes of the output signals that is greater than a predetermined number, which is greater than half of the output terminals in the described embodiment , The integrated component 1 also has another output driver 5 to output an operating condition signal BZ. The operating state signal BZ is from the converter unit 4 to the other output driver 5 delivered and indicates the currently assumed operating state. The operating state signal BZ indicates to the external device whether the signals to be output have been outputted as output signals as it is, or whether the signals to be output have been changed according to the edge reduction function. This is necessary so that an external device receiving the output signals A0 to A7 can recognize whether these output signals correspond to the original signals to be output or whether they have been changed. The external device can make a reconversion of the received signals based on the operating state signal BZ.

The Edge reduction function of the present embodiment is, as mentioned above, preferably an inverter function, all the signals to be output inverted. However, the edge reduction function can also be any any other reversible function with which the signals to be output S0 to S7 are converted into the output signals A0 to A7. Important is that the edge reduction function is chosen to be appropriate is the number of level changes of the output signals when changing of outputting a start date to a next start date. Depending on the type of signals to be output, only a part of the individual signals to be output according to the edge reduction function be inverted.

in the illustrated embodiment only one operating state signal of the size 1 bit is output. It can, however more than two operating states be provided, which is indicated by a plurality of operating state signals can be.

In addition, it may be useful to make a change in the operating state only if the total number of output signals and the operating state signals to a number of level changes causes, which is less than the number of level changes that would take place at an unchanged operating condition, as well the transmission of the operating state signal by the further output driver 5 requires a corresponding output driver power, which is the supply line of the integrated module 1 loaded.

In 2 is a consequence of possible off represented output signals. At the beginning, the first operating state of the converter unit 4 is set, which causes the signals to be output S0 to S7 are output unchanged as output signals. When changing the output of the bit sequence "0-1-0-0-1-0-0-1" to an output date of the bit sequence "0-0-0-1-1-0-1-1", As shown by the arrows, only three level changes of the output signal instead, so that a change of the operating state in the converter unit 4 not performed. If you change to an output date with the bit sequence "0-0-1-0-1-1-0-1", there will be four level changes, which corresponds to half the bits of the output data makes sense, since one could not reduce the number of level changes of the output data and beyond would receive an additional level change of the operating state signal.

If an output signal of the bit sequence "1-0-1-1-0-1-1-0" is to be output, this would result in five level changes as an output signal if the output is unchanged the transducer unit 4 changed, which is indicated by the operating state signal BZ with a logical one. All signals S0 to S7 to be output are inverted accordingly so that the bit sequence "0-1-0-0-1-0-0-1" is now output as the output data, resulting in only three level changes The required level change is reduced from five to four, ie three level changes at the output data and a level change of the operating state signal The operating state now assumed is maintained until the number of level changes in a signal to be reissued would exceed four again would be switched back to the original (first) operating state indicated by the logic zero of the operating state signal.

1

integrated building block

2

electronic circuit

3

output driver

4

converter unit

5

Another output driver

S0 to S7

be issued signals

A0 to A7

output signals

BZ

Mode signal

Claims (10)

Integrated module ( 1 ) with a number of output terminals for outputting output signals, with an electronic circuit ( 2 ), the signals to be output (S0 to S7) provides; with output drivers ( 3 ) for outputting the output signals; with a converter circuit, which outputs the signals of the electronic circuit ( 2 ), which detects output signals by applying a level-change minimizing function to the signals to be output, and outputs (A0 to A7) to the output drivers (FIG. 3 ) for outputting. Integrated module ( 1 ) according to claim 1, wherein the level change minimizing function causes, depending on the number of required when output signals (A0 to A7) level change at the output terminals either according to a first switching state, the output signals as output signals (A0 to A7) are output or according to a second switching state, the output signals from the signals to be output (S0 to S7) are formed according to a Flankenreduzierungsfunktion. Integrated module ( 1 ) according to claim 2, wherein the edge reduction function is an inverter function which inverts a certain part or all of the signals to be output (S0 to S7). Integrated module ( 1 ) according to claim 2 or 3, wherein a further output terminal for outputting an operating condition signal (BZ) is provided which indicates the operating condition. Integrated module ( 1 ) according to one of claims 2 to 4, wherein the converter circuit ( 4 ) assumes the second operating state if the number of required level changes of the output signals (A0 to A7) in the first operating state would exceed a predetermined number of the output terminals. Method for outputting output signals to a Number of output connections, with the following steps: - Provide of signals to be output (S0 to S7); - Generating the output signals (A0 to A7) by applying a level change minimizing function the signals to be output (S0 to S7), wherein the level change minimizing function the number of times required to output the output signals (A0 to A7) Level change minimized. Method according to claim 6, wherein the generation of the output signals (A0 to A7) is carried out either by outputting the output signals (S0 to S7) as output signals (A0 to A7) according to a first operating state or according to a second operating state by output signals (A0 to A7) from the issued Signals (S0 to S7) are formed according to a Flankenreduzierungsfunktion, wherein the first or second operating state is taken depending on the number of required level changes at the output terminals. The method of claim 7, wherein the edge reduction function an inverter function is that a certain part or all of the to be output signals (S0 to S7) inverted. Method according to claim 7 or 8, wherein a status signal is output, which indicates the operating condition. Method according to one of claims 7 to 9, wherein the second Operating state is taken when the number of required Level change of the output signals (A0 to A7) at the first switching state the half would exceed the total number of output ports.