JP2901428B2 - Integrated circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated circuit having a function of outputting a logical signal containing information to be transmitted by processing an input signal.

[0002]

2. Description of the Related Art FIG. 4 is a block circuit diagram showing an example of such an integrated circuit. This integrated circuit has an input terminal 1 to which an input signal is applied as shown in a waveform diagram (a) of FIG. 5 which is intermittent according to information to be transmitted by a signal of a constant frequency, and a detection circuit 3 for detecting the input signal. And a waveform shaping circuit 4 which shapes the output waveform of the detection circuit 3 and outputs it to the output terminal 2 as a logic signal containing the information as shown in the waveform diagram (b) of FIG. , A preamplifier of a remote control receiving unit for general AV equipment.

[0003] In such an integrated circuit, the following methods are used as a method for discriminating the difference between those having similar characteristics and functions, or for preventing them from being mixed with each other. Is used.

That is, one method is to change the terminal arrangement and the package. As another method, as shown in the plan view of the package shown in FIG. 6, a pair of check terminals t1 and t2 and a certain value of a resistor R are formed between the terminals, and the difference between the terminals is identified by the resistance value. Is the way.

[0005]

Among the above-described methods for preventing the mixing of similar integrated circuits and identifying the difference between the integrated circuits, the former method has a disadvantage that the terminal arrangement and the package are difficult to use for the user. . Also, the latter check terminal may be provided only with extra terminals, but otherwise, a new terminal must be provided, which is very uneconomical.

[0006]

According to the present invention, a time constant circuit is inserted between an output circuit for outputting a logic signal and an output terminal, and the time constant is changed. The differences between the integrated circuits are identified.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a block circuit diagram of one embodiment of the present invention. In FIG. 1, an input signal in which a continuous signal of a constant frequency is intermittently transmitted according to predetermined information as shown in FIG. This input signal is detected by the detection circuit 3 to generate a detection output, and is applied to the next waveform shaping circuit 4. The output of the waveform shaping circuit 4 is a time constant provided between the waveform shaping circuit 4 and the output terminal 2. The signal is output to the output terminal 2 via the circuit 5. Thus, the time constant of the time constant circuit 5 is changed according to the difference between similar integrated circuits.

For example, when the time constant of the time constant circuit 5 is the minimum value, the waveform is a rectangular wave having no original distortion as shown in FIG. 3B, and as shown in FIG. The waveform becomes dull as shown in FIG. 3), and becomes a dull waveform as shown in FIG. Therefore, the difference between similar integrated circuits can be identified by determining the difference between the waveforms.

As a discriminating means, for example, a sample and hold circuit 6 as shown in the block circuit diagram of FIG. 2 is used, and by comparing the voltages held at timings T1, T2, T3 and T4 shown in FIG. As a result, differences between integrated circuits can be identified.

Although the above example describes a preamplifier integrated circuit of a remote control circuit receiving section, the present invention is not limited to this, and outputs a logic signal by a certain signal processing.
It goes without saying that the present invention can be applied to a -D converter and the like.

[0011]

As described above, in the present invention, the time constant circuit is provided in the logic signal output section, and the time constant of this time constant circuit is set to a different time constant in a different integrated circuit. The discrimination has the effect that the difference between the integrated circuits can be easily identified.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of one embodiment of the present invention.

FIG. 2 is a block circuit diagram of a sample and hold circuit according to the embodiment of FIG.

FIG. 3 is a waveform chart for explaining the operation of the embodiment of FIG. 1;

FIG. 4 is a block circuit diagram showing a preamplifier of a remote control receiving unit of a general AV device.

FIG. 5 is a waveform diagram showing an input signal and an output signal of the circuit of FIG.

FIG. 6 is a plan view of an integrated circuit package with a resistor for distinguishing between similar integrated circuits.

[Explanation of symbols]

 1 input terminal 2 output terminal 3 detection circuit 4 waveform shaping circuit 5 time constant circuit 6 sample hold circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01R 31/28-31/3193 H01L 21/822 H01L 27/04

Claims (1)

(57) [Claims] An integrated circuit that outputs a logic signal to an output terminal by processing a signal input to an input terminal, wherein a similar output signal is output between a final output circuit that outputs the logic signal and the output terminal. An integrated circuit, comprising a time constant circuit for identifying a difference.