JP2003008941A - Integrated circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an integrated circuit for incorporating a digital signal processor(DSP) or the like that can reduce the noise. SOLUTION: The integrated circuit provided with the DSP and a plurality of processing blocks connected to the DSP is provided with a data transmission line changeover means 180 that sets a data transmission line between processing blocks for selected processing, data transmission line opening means 112, 122, 132, 142, 152 that disconnect picture blocks not connected by data transmission lines 181-189 set by the switching of the data transmission line changeover means 180, and clock supply path cut means 113, 123, 133, 143, 153 that disconnect a clock supply path 171 to processing blocks not connected to the data transmission lines set by the switching by the data transmission line changeover means 180.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated circuit for processing audio data and video data, for example.

[0002]

2. Description of the Related Art Conventionally, a DSP (Digital Signal) has been used as an integrated circuit for processing audio data and video data.
There is an integrated circuit that contains a circuit called Processor) and is applied to various audio equipment and video equipment. This DSP performs various kinds of signal processing on audio data and video data by digital processing. For example, in the case of an DSP for audio, processing for adjusting sound quality, addition of reverberation sound, and surround sound are performed. The audio processing such as the processing of (1) is executed digitally. In the case of a video DSP, video processing such as image quality adjustment is digitally executed.

As an integrated circuit incorporating this DSP,
There is also one having a built-in circuit block that performs data input processing and data output processing. For example, DSP for audio
In the case of an integrated circuit with a built-in circuit, an analog / digital conversion circuit that converts an analog audio signal into digital audio data that can be processed by a DSP, and a digital / analog conversion circuit that converts digital audio data processed by the DSP into an analog audio signal There is also a circuit in which an interface for converting digital audio data in a format handled by a DSP into digital audio data in another format is built in an integrated circuit in which the DSP is configured.

By incorporating many processing blocks in one integrated circuit as described above, the number of integrated circuits mounted on the circuit board of the audio equipment or the video equipment can be reduced correspondingly, and the circuit board of the equipment can be reduced. The configuration can be simplified.

[0005]

By the way, when many processing blocks are integrated in one integrated circuit, an extremely large amount of signal processing is performed in one integrated circuit, which is generated by the integrated circuit. There was a problem that noise increased.
That is, in recent years, the frequency of a clock signal handled by a circuit used for audio data processing or video data processing tends to be high, and unnecessary high frequency noise generated by an integrated circuit is at a level that cannot be ignored. Therefore, when such an integrated circuit is used, there is a problem that it is necessary to take measures such as covering the integrated circuit with a shield case.

Generally, in an integrated circuit including a digital circuit, when it is operated by an input signal having a constant period such as a clock signal, it occurs at the timing of state transition between the high level and the low level of the clock signal. High-frequency noise synchronized with the clock pulse is generated due to large instantaneous current consumption, and there is a problem that the power level of the high-frequency noise increases as the circuit scale increases.

It is an object of the present invention to reduce noise generation in this type of integrated circuit.

[0008]

According to the present invention, in an integrated circuit having a plurality of processing blocks, a data transmission path switching means for setting a data transmission path between processing blocks selected to be processed, Data transmission path opening means for disconnecting a processing block not connected by the data transmission path set by the data transmission path switching means from the data transmission path, and data transmission set by the switching by the data transmission path switching means A clock supply path opening means for disconnecting a clock supply path to a processing block that is not connected by a path is provided.

By doing so, the processing blocks other than the processing block for performing the data processing are separated from the data transmission path and the clock is not supplied in the integrated circuit, so that the data processing operation cannot be executed at all. No
The corresponding processing block does not become a noise source.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing the integrated circuit of this embodiment in terms of its function. In this example, the integrated circuit is configured as an audio signal processing circuit.
To describe the configuration with reference to FIG. 1, the audio signal processing circuit 100, which is an integrated circuit, includes an analog / digital conversion circuit 110, a digital / analog conversion circuit 120, and an input interface circuit 130 as data processing blocks. , Output interface circuit 140
And a digital signal processor (hereinafter referred to as DSP) 150.

The analog / digital conversion circuit 110 converts the analog audio signal obtained at the input terminal 111 to D
This is a processing block for converting into audio data of a format handled by SP150. The digital / analog conversion circuit 120 is a processing block that converts audio data in a format handled by the DSP 150 into an analog audio signal and supplies the analog audio signal to the output terminal 121.

The input interface circuit 130 is a processing block for converting digital audio data in a format defined by the IEC60958 standard obtained at the data input terminal 131 into audio data in a format handled by the DSP 150. The output interface circuit 140 is a processing block that converts audio data in a format handled by the DSP 150 into digital audio data in a format defined by the IEC60958 standard and supplies the digital audio data to the data output terminal 141. The IEC60958 standard is a standard for forming digital audio data into a data structure for transmission, and is a standard format of digital audio data input / output from a digital audio data input terminal or an output terminal included in an audio device. is there.

Then, the digital audio data input to the audio signal processing circuit 100 and converted by the analog / digital conversion circuit 110 or the input interface circuit 130 is supplied to the DSP 150, subjected to data processing as necessary, and output from the DSP 150. The digital audio data to be output is supplied to the digital / analog conversion circuit 120 or the output interface circuit 140 and output from the audio signal processing circuit 100. DSP150
If the data processing is not required, the audio data is directly supplied from the analog / digital conversion circuit 110 or the input interface circuit 130 to the digital / analog conversion circuit 120 or the output interface circuit 140 without passing through the DSP 150. And output it.

The data processing state in the audio signal processing circuit 100 and the data supply path are set by the control of the controller 160. A clock generation circuit 170 supplies a clock necessary for each processing block 110 to 150 to perform a processing operation. further,
The power supply circuit 190 supplies power necessary for the processing blocks 110 to 150 to perform processing operations. However, the clock generation circuit 170 and the power supply circuit 190 are provided outside the audio signal processing circuit 100, and a clock and power obtained from the outside are supplied to the processing blocks 110 to 150 in the integrated circuit. There is also.
The clock supplied from the clock generation circuit 170 is, for example, 1 of the sampling frequency of audio data.
The frequency is 28 times or more, and for example, a signal having a frequency of 10 MHz or more is used as the clock signal.

The terminals 111, 121, shown in FIG.
Reference numerals 131 and 141 denote input terminals or output terminals of the audio signal processing circuit 100 which is an integrated circuit, and these terminals are connected to the circuit board of the device. The digital audio data handled by the processing circuit 100 is
It is multi-channel audio data of 2 channels or more, and each processing block of the processing circuit 100 is also configured to be able to process audio data of a plurality of channels, but here, for simplification of description, each processing block is processed. Is connected to only one channel (one system) terminal.

FIG. 2 shows an audio signal processing circuit 1 of this example.
10 is a diagram showing a connection configuration between processing blocks 110 to 150 inside 00. FIG. A data switching unit 180 for setting the connection of the data transmission paths 181 to 185 between the processing blocks 110 to 150 is provided, and switching by the data switching unit 180 is controlled by the controller 160. in this case,
Each processing block 110-150 and data transmission line 181-
The switch 11 for opening the data transmission line
2, 122, 132, 142 and 152 are individually connected.

Further, each processing block 110 to 150 is supplied from the clock generation circuit 170 via the clock supply path 171.
Is supplied with a clock signal. In this case, between each of the processing blocks 110 to 150 and the clock supply path 171,
Clock supply path opening switches 113, 123, 13
3, 143 and 153 are individually connected to each other so that the supply of the clock signal to each processing block can be individually controlled.

Further, from the power supply circuit 190 to the power supply path 1
Power is supplied to each processing block 110 to 150 via 91. In this case, power supply path opening switches 114, 124, 134, 144, and 154 are individually connected between the processing blocks 110 to 150 and the power supply path 191, and the power to each processing block is supplied. The supply can also be controlled individually.

Data transmission line opening switches 112, 122, 132, 1 connected to the data transmission lines 181-185.
42, 152 and clock supply path opening switches 113, 123, 133, 1 connected to the clock supply path 171.
43, 153 and the power supply path opening switches 114, 124, 134, 144, 1 connected to the power supply path 191.
54 is configured to be controlled in conjunction with each other in processing block units in response to a command from the controller 160.

That is, the analog / digital conversion circuit 110
The data transmission path opening switch 112, the clock supply path opening switch 113, and the power supply path opening switch 114, which are connected to each other, are controlled by the control data supplied from the controller 160 via the switch control data supply path 161. At the same time, the connection state or the open state is controlled.

The data transmission path opening switch 122, the clock supply path opening switch 123, and the power supply path opening switch 124 connected to the digital / analog conversion circuit 120 are the switch control data supply path 162 from the controller 160. At the same time, the connection state or the open state is controlled by the control data supplied via.

The data transmission path opening switch 132, the clock supply path opening switch 133, and the power supply path opening switch 134 connected to the input interface circuit 130 connect the switch control data supply path 163 from the controller 160. The control data supplied via the control means simultaneously controls the connection state or the open state.

The data transmission path opening switch 142, the clock supply path opening switch 143, and the power supply path opening switch 144 connected to the output interface circuit 140 connect the switch control data supply path 164 from the controller 160. The control data supplied via the control means simultaneously controls the connection state or the open state.

The data transmission path opening switch 152, the clock supply path opening switch 153, and the power supply path opening switch 154 connected to the DSP 150 are supplied from the controller 160 via the switch control data supply path 165. The control data simultaneously controls the connection state or the open state. The data transmission path 185 connected to the DSP 150 is actually the DSP 1
A transmission line for data input to 50 and a transmission line for data output from the DSP 150 are prepared, but the data transmission line opening switch 152 is in the connected state for data input and data output at the same time. Alternatively, it is controlled to an open state.

The controller 160 includes a processing circuit 100.
An external control means (not shown) supplies a command for setting the processing state in the processing circuit 100. Based on this command, the controller 160 sets the processing state in the internal processing blocks and the data transmission state between the processing blocks. Regarding the data transmission state, the data switching unit 180
It is set by controlling the connection of the data transmission paths 181 to 185.

For example, when the analog audio signal obtained at the terminal 111 is input and the processed analog audio signal is output at the terminal 121, the data transmission line 1 connected to the analog / digital conversion circuit 110 is used.
81 is connected to the data transmission line 185 connected to the DSP 150 by the data switching unit 180 to input audio data to the DSP 150, and further connected to the DSP 150 as a transmission line for outputting the data processed by the DSP 150. The data transmission line 185 is connected to the data transmission line 182 connected to the digital / analog conversion circuit 120 by the data switching unit 180.

At this time, the switch control data supply path 16
Control data to be supplied to each switch via 1, 162, 163, 164, and 165 include switches 112, 113, which are connected to the analog / digital conversion circuit 110.
114, switches 122, 123, 124 connected to the digital / analog conversion circuit 120, and DSP 150.
The switches 152, 153, 154 connected to the switch control data supply paths 161, 162, 165
The control data is supplied via the respective terminals and is set to the connected state. Then, the switches 132, 133, 134, 142, 1 connected to the other processing blocks 130, 140
43 and 144, the switch control data supply path 1
The control data supplied via 63 and 164 are set to the open state.

By doing so, the data switching unit 18
By switching the data transmission path at 0, the input path to the DSP 150 and the output path from the DSP 150 are set, and the processing of the audio data input to the processing circuit 100 is properly executed and output. At this time, the clock and the power are supplied to the processing blocks 110, 120, and 150 that execute the processing in the processing circuit 100, respectively, by the setting of the clock supply path opening switch and the power supply path opening switch described above. It operates by using the supplied power and clock, and the data processing is correctly performed in each processing block 110, 120, 150.

At this time, in the input interface section 130 and the output interface section 140, which are processing blocks that do not require data processing, since the data transmission line opening switches 132 and 142 are set to the open state, There is no data supply through the transmission line and the clock supply line opening switches 133 and 143 are opened.
Also, since the power supply path opening switches 134 and 144 are set to the open state, neither the clock signal nor the power is supplied. Therefore, the input interface unit 13
0 and the output interface unit 140 do not operate at all,
No noise is generated due to the operation of these processing blocks 130 and 140. Therefore, the noise generated by the audio signal processing circuit 100 of this example can be reduced accordingly. In particular, high-frequency noise synchronized with a clock pulse, which is noise generated by a momentary large current consumption that occurs at the timing of state transition between a high level and a low level of a clock signal, is generated from a non-operating processing block. And the noise level can be effectively reduced.

FIG. 3 shows an audio signal processing circuit 1 of this example.
It is the figure which showed the example of the noise level which 00 emits. Figure 3
In A, only the processing block that performs data processing in the audio signal processing circuit 100 is connected to the data transmission path, and then the power supply and the clock are supplied only to the processing block to determine the noise level when the operation is performed. This is an example of measurement. FIG. 3B is an example in which all the processing blocks in the audio signal processing circuit 100 are connected to the data transmission path, and then the power level and the clock are supplied to all the processing blocks to measure the noise level when they are operated. Is. As can be seen by comparing FIGS. 3A and 3B, it is found that the noise level is lower when the processing circuit 100 of the present example shown in FIG. It is understood that there is.

When the data processing in the DSP 150 is not necessary, the data switching section 180 is used to set the data transmission path from the processing block that performs the input processing to the processing block that directly performs the output processing, and the DSP 150 is set. The connected switches 152, 153 and 154 may also be opened so that the data supply to the DSP 150 is eliminated and the clock signal and power are not supplied to the DSP 150. For example, I input from the terminal 131
EC60958 standard digital audio data
The IEC6 does not perform data processing by the SP150 and outputs the analog audio signal from the terminal 121, or processes the analog audio signal input from the terminal 111 by the DSP150.
It is also possible to perform processing such that the digital audio data of 0958 standard is output from the terminal 141. In these cases, there is no data supply to the DSP 150 and the DS
Since the clock signal and power are not supplied to P150, D
The SP 150 does not generate noise, and the noise generated by the audio signal processing circuit 100 can be reduced accordingly.

In the above description, the data transmission path opening switch, the clock supply path opening switch, and the power supply path opening switch connected to the respective processing blocks are controlled simultaneously, Although the connection state or the open state is set, only one of the switches may be controlled. For example, the power supply path opening switch may not be provided, and the power may be constantly supplied to all processing blocks. Even if the power supply is always supplied in this way, the clock signal is not supplied to the inactive processing block by the switch for opening the clock supply path so that the processing block does not operate substantially and noise is generated accordingly. Can be prevented.

Further, the switches for opening the data transmission lines connected to the data transmission lines 181 to 185 are omitted, and only the switching on the side of the data switching unit 180 is performed to switch the data transmission lines 181 to 185. The data transmission state may be controlled. However, the data switching unit 180
Even if the data transmission line is not connected at 1, the signal whose level has dropped may leak depending on the signal state at that time, and as shown in FIG. 2, the switches 112, 122, 122 for opening the data transmission line, By arranging 132, 142, and 152 immediately before the data input / output units of the respective processing blocks 110 to 150, it becomes possible to more completely prevent the data supply, and the noise reduction effect is great.

In the above-described embodiment, processing blocks 110 and 120 that perform input conversion and output conversion of analog audio signals, and processing blocks 130 and 140 that perform input conversion and output conversion of audio data of the IEC609558 standard, Although the integrated circuit as the audio signal processing circuit provided with the DSP 150 is used, the audio signal processing circuit may be provided with other processing blocks. Further, it is also possible to provide only one processing block for performing input processing and one processing block for performing output processing.

Further, as long as it is an integrated circuit in which a plurality of internal processing blocks are selectively used, it can be applied to a circuit other than the integrated circuit for processing an audio signal. For example, as shown in FIG. 4, it may be applied to an integrated circuit configured as the video signal processing circuit 200. That is, as the data processing block, for example, the analog video input terminal 21
Analog to convert the video signal obtained in 1 to digital
Digital conversion circuit 210 and analog video output terminal 2
21. A digital / analog conversion circuit 220 for analog-converting the video data to be output from the output terminal 21, and an input for converting the MPEG-system video data obtained at the data input terminal 231 into digital video data in the format handled by the processing circuit 200. Interface circuit 230
And an output interface circuit 240 for converting digital video data in a format handled by the processing circuit 200 into MPEG video data, and a DSP 250 for performing predetermined data processing on the video data.

Under the control of the controller 260, the internal data processing state and the setting of the data transmission path are controlled, and the data switching section 280 for switching the data transmission path.
Equipped with. In addition, the clock generation circuit 270 and the power supply circuit 2
90, and a clock signal and a power supply are supplied to each processing block.

Here, as in the case of the audio signal processing circuit 100 shown in FIG. 2, in the case of the video signal processing circuit 200 shown in FIG.
A data transmission line opening switch is individually provided between 10, 220, 230, 240, 250 and the data transmission line,
A switch for opening the clock supply path is also provided individually for the clock supply path, and a switch for opening the power supply path is also provided individually for the power supply path. By controlling according to the operating state, it becomes possible to reduce the noise level of the video signal processing circuit 200 as in the case of the audio signal processing circuit 100 described above.

Further, in the above-mentioned embodiment, although the physical structure of the integrated circuit is not particularly explained, the IC
Alternatively, the configurations of various integrated circuits that are put into practical use as LSIs can be applied.

[0040]

According to the present invention, in the integrated circuit, the processing blocks other than the processing block for performing the data processing are separated from the data transmission path and the clock is not supplied, so that the data processing operation is not executed at all. Therefore, the corresponding processing block does not become a noise source. Therefore, it is possible to reduce the noise level generated by the integrated circuit, and it is possible to reduce the cost required for the noise countermeasure of the device in which the integrated circuit is incorporated.

In this case, since the power supply path to the processing block which is not connected by the data transmission path set by the switching by the data transmission path switching means is disconnected, the processing block which does not require the data processing operation is formed. The operation of will be stopped more completely, and it will be possible to prevent the noise generation from the processing block which is not operated completely.

Further, by applying the integrated circuit of the present invention to an integrated circuit for performing audio data processing or video data processing, it is possible to effectively reduce noise generated by audio equipment or video equipment.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a configuration example according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an internal connection configuration example according to an embodiment of the present invention.

3A is a waveform diagram showing an example of a noise level, and FIG.
Is an example of the case where the process according to the embodiment of the present invention is executed, and FIG. 3B is an example of the case where the process of the present invention is not executed.

FIG. 4 is a functional block diagram showing a configuration example according to another embodiment of the present invention.

[Explanation of symbols]

100 ... Audio signal processing circuit, 110 ... Analog /
Digital conversion circuit, 111 ... Analog audio signal input terminal, 112 ... Data transmission path opening switch, 113
... switch for opening clock supply path, 114 ... switch for opening power supply path, 120 ... digital / analog conversion circuit, 121 ... analog audio signal output terminal, 122
... data transmission path opening switch, 123 ... clock supply path opening switch, 124 ... power supply path opening switch, 130 ... input interface circuit, 131 ... data input terminal, 132 ... data transmission path opening switch,
133 ... Clock supply path opening switch, 134 ... Power supply path opening switch, 140 ... Output interface circuit, 141 ... Data output terminal, 142 ... Data transmission path opening switch, 143 ... Clock supply path opening switch, 144 ... switch for opening power supply path, 150 ... digital signal processor (DSP), 152 ... switch for opening data transmission path, 153 ... switch for opening clock supply path, 154 ... switch for opening power supply path, 160
... controller, 161-165 ... switch control data supply path, 170 ... clock generation circuit, 171 ... clock supply path, 180 ... data switching section, 181-185 ... data transmission path, 190 ... power supply circuit, 191 ... power supply path, Two
00 ... Video signal processing circuit, 210 ... Analog / digital conversion circuit, 211 ... Analog video signal input terminal, 2
20 ... Digital / analog conversion circuit, 221 ... Analog video signal output terminal, 230 ... Input interface circuit, 231 ... Data input terminal, 240 ... Output interface circuit, 241 ... Data output terminal, 250 ... Digital signal processor (DSP) 260 ... Controller, 270 ... Clock generation circuit, 280 ... Data switching unit, 290 ... Power supply circuit

Claims (4)

[Claims] 1. One or a plurality of input processing blocks that perform input processing of data, a data processing block that performs predetermined processing on data that is input processed by the input processing block, and data that is input processed by the input processing block. Alternatively, a data transmission path is set between one or a plurality of output processing blocks that perform output processing of the data processed by the data processing block and a processing block selected to perform the processing of each of the processing blocks. A data transmission path switching means, a data transmission path opening means for disconnecting a processing block which is not connected by the data transmission path set by the switching in the data transmission path switching means from the data transmission path, and the data transmission path switching means Open the clock supply path to disconnect the clock supply path to the processing block that is not connected by the data transmission path set by Integrated circuits and means. 2. The integrated circuit according to claim 1, further comprising a power supply path opening means for disconnecting a power supply path to a processing block which is not connected by the data transmission path set by the data transmission path switching means. Integrated circuit with. 3. The integrated circuit according to claim 1, wherein the input processing block and the output processing block are blocks that perform input processing and output processing of audio data, and the data processing block is a predetermined block for audio data. An integrated circuit that is a block that performs the process of. 4. The integrated circuit according to claim 1, wherein the input processing block and the output processing block are blocks that perform input processing and output processing of video data,
The data processing block is an integrated circuit that is a block that performs a predetermined process on video data.