JPH04172720A - D/a converter - Google Patents

Abstract

PURPOSE:To prevent increase in number of input terminals due to multi-channel processing by using a multiplexer so as to select an input terminal to a D/A converter circuit of each channel thereby converting the input signal in a decided timing. CONSTITUTION:A various kind of analog signal is inputted to an input terminal VIN at a timing based on a clock signal fed to a CLK input terminal. Simultaneously, a multiplexer section 30 starts its operation and a various kind of a signal sent in a timing is switched to each channel according to a digital data fed to a DI input terminal at each timing and a different kind of analog signal is fed to each channel. Thus, number of input terminals required for each channel is decreased to one input terminal thereby preventing increase in number of input terminals due to multi-channel processing.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a D/A converter, and particularly to a multiplier type D/A converter suitable for converting analog signals sent serially. .

[Conventional technology]

In general, a multiplication type D/A converter receives an analog signal sent serially as input, converts the analog signal into a value corresponding to a desired setting value input as digital data, and outputs the converted signal to the outside. It is something. Therefore, for example, if the above digital data is 8 bits, the input analog signal is divided by 256 (=2") ladder resistors, and the required tap voltage is taken out by the analog switch controlled by the above digital data and output to the outside. is configured to do so.

FIG. 3 is a block diagram showing the configuration of a conventional multiplication type D/A converter. In the figure, VINI.

VIN2. ..., VINn is an input terminal provided for each channel to receive an analog signal, 11°12,
-, In is the above-mentioned VINI, VIN2. −.

The first . Second.
..., n-th D/A conversion circuit section (hereinafter referred to as DACl, D
AC2-, DACn), vOut 1. vOut
2. -, Voutn is the DAC111, DAC212
, -, an output terminal that outputs an analog signal converted to a desired setting value by DACn 1n, DI is a D1 input terminal for inputting the desired setting value as digital data, and LD is a state in which the digital data can be read into a register. LD input terminal that receives the signal to
LK is the CLK input terminal that receives the clock input for reading the digital data into the register, and 3 is the D
A data line 4 sends a command to operate the DACI 11 when the DAC1 is selected, a data line 4 sends a command to the DAC 212 to operate when the DAC2 is selected, and n+2 connects the DACn when the DACn is selected.
A data line 1 sends a command to operate the digital data to the DACI, DAC2, . . .
This is a data line sent to DACn.

The conventional multiplication type D/A converter is configured as described above, and separately transmits different analog signals to the VINI, VIN2 . ....

VINn, these analog signals are converted to desired set values for each channel, and the converted analog signals are output to output terminals provided for each channel.

[Invention or problem to be solved]

Conventional D/A converters are configured as described above, and as the number of channels increases, the same number of input terminals as the number of channels are required, and at the same time, the same number of input signal lines as the number of channels are required. Since this is necessary, there is a problem in that the number of terminals increases.

This invention was made to solve the above problems, and is a D/A that can prevent an increase in the number of terminals and input signal lines due to an increase in the number of channels.
The purpose is to obtain a converter.

[Means to solve the problem]

In the D/A converter according to the present invention, input terminals existing for each channel are combined into one, a D/A conversion circuit section and a multiplexer section are provided after the input terminal, and this circuit section allows input terminals to be connected to each other. The input signal is distributed to each channel and subjected to D/A conversion, or after D/A conversion, it is distributed to each channel.

In addition, the output of the D/A conversion circuit section must be a value converted to the desired setting value by the D/A conversion circuit section, or a value that does not change.
A signal holding circuit is provided.

[Effect]

In this invention, a desired number of signals to be converted are inputted to the input terminals of the D/A converter at each fixed timing. switch to D/A
After converting or D/A converting the input signal, switching to each channel is performed, so by sending the converted value to the signal holding circuit, it is possible to obtain the desired output signal for each channel. .

〔Example〕 .

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a multiplication type D/A converter according to an embodiment of the present invention, which includes a D/A conversion circuit section and output terminals Vout 1. Vout 2. The Voutn register section is exactly the same as the above conventional device.

vIN is an input terminal for inputting an analog signal to be converted; 30 is a multiplexer unit for distributing the analog signal input through the input terminal to the D/A converter provided for each channel; 41, 42, . . . , 4n is D/
This is a signal holding circuit section for storing and holding the analog signal converted to a desired value by the A converter.

In the multiplication type D/A converter configured as described above, first, various analog signals are input to the input terminal at timings based on the clock signal input to the CLK input terminal. At the same time, the multiplexer section also starts operating, switching the various signals sent at a certain timing to each channel according to the digital data sent to the DI input terminal at each timing, and converting each channel into a different analog signal. send.

The analog signal sent in this manner is then sent to a D/A conversion circuit section provided for each channel, and is converted into a desired set value according to the digital data. Each converted analog signal is sent to a signal holding circuit provided at the output of the D/A conversion circuit to prevent the converted value from changing.

In this way, according to this embodiment, a desired number of analog signals to be converted to the multiplication type D/A converter are serially inputted to the input terminals at certain fixed timings. , the input terminal is switched to the D/A conversion circuit of each channel using a multiplexer at fixed timings, and after converting to the desired circuit, the converted value is sent to the signal holding circuit, so that By reducing the number of input terminals that should be present to one, it is possible to prevent an increase in the number of input terminals due to multichannelization, and it is possible to significantly reduce the number of bins. Further, there is no need to provide a large number of analog signal lines, and the circuit can be prevented from becoming complicated.

In the above embodiment, the same operation can be expected by providing a D/A conversion circuit section for each channel or by providing this D/A conversion circuit section immediately after the input terminal.

FIG. 2 shows another embodiment of the present invention in which only one input terminal is provided. In the embodiment of FIG. 1, the D/A conversion circuit section provided for each channel is placed immediately after the input terminal. Furthermore, the number of circuits is one. According to this Figure 2,
Since the D/A conversion circuit shown in FIG. 1 can be combined into one, the circuit configuration becomes simple.

In addition, in each of the above embodiments, only a multiplication type D/A converter has been explained, or a normal D/A converter whose input signal is digital.
The present invention can also be applied to the A converter, and the same effects as in the above embodiment can be achieved.

〔Effect of the invention〕

As described above, according to the D/A converter according to the present invention,
Input the desired number of input signals that you want to convert at each fixed timing into the input terminals, and use the multiplexer to convert the input signals to the D of each channel at each fixed timing.
The input signal can be converted by switching to a /A conversion circuit, or the input signal can be converted by a D/A conversion circuit, and the output can then be distributed to each channel by a multiplexer, and the converted value can be sent to the signal holding circuit. The number of input terminals provided for each channel can be reduced to one, which prevents an increase in the number of input terminals due to multichannelization, and enables a significant reduction in the number of bins.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing another embodiment of the invention, and FIG. 3 is a block diagram showing a conventional multiplication type D/A converter. . In the figure, VIN, VINI, VIN2. .... VINn is an input terminal, 11.12. -, In is a D/A conversion circuit section, 41, 42 . ..., 4n is a holding circuit, Vo
u t 1. Vout 2. ..., Voutn is an output terminal section, 1 is a digital data line sent to the D/A conversion circuit to convert the input analog signal into a desired value, 2 is a channel select line for operating the multiplexer section, 3 is a channel select line that operates DAC1, 4 is a channel select line that operates DAC2, n
+2 is a channel select line that operates DACn. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) One input terminal that receives an input signal, and performs D/A conversion after passing the input signal to many channels, or performs D/A conversion of the input signal and then passing it to many channels. A D/A converter comprising a D/A conversion circuit section, a multiplexer section, and a plurality of signal holding circuit sections that store and hold signals output from the circuit section.