KR20030064988A - Infrared remote control receiving system and method for controlling the center frequency of a filter - Google Patents

Abstract

PURPOSE: An infrared remote controller receiving system and a method for controlling a mean frequency of a filter are provided to reduce time required for wafer testing by controlling a mean frequency of a filter without trimming a resistance. CONSTITUTION: A remote control signal is received from a remote controller transmission system through a photodiode(17). The photodiode(17) converts the remote control signal in a light form into a current form. An amplifier(11) amplifies the remote control signal. A variable gain amplifier(12) receives an output of the amplifier(11), amplifies an original signal and a noise signal each with different gains. A filter(13) passes only a carrier frequency component, canceling other component. An automatic gain controller(15) receives an output of the filter(13), and discriminates the original signal and the noise signal so as for the variable gain amplifier(12) to control their gains. A sheath signal of an output of the filter(13) is extracted by a wave shaping circuit(14), A pulse signal corresponding to the remote control signal is generated from the wave shaping circuit(14) and transmitted to a microcomputer(18). The microcomputer(18) receives the pulse signal and performs an operation of a device desired by a user.

Description

INFRARED REMOTE CONTROL RECEIVING SYSTEM AND METHOD FOR CONTROLLING THE CENTER FREQUENCY OF A FILTER}

The present invention relates to an infrared remote control receiving system, and more particularly, to an infrared remote control receiving system capable of adjusting the center frequency of the filter without trimming the resistance.

Recently, a remote control system for remotely controlling a device such as a home appliance using a remote control has been widely used. Such a remote control system can be largely divided into a transmission system and a reception system. The transmission system transmits a remote control signal to the reception system in response to an arbitrary key input, and the reception system receives a remote control signal from the transmission system to operate various devices. Remote control.

The remote control receiver system must adjust the center frequency of the filter according to the transmission frequency of the transmission system. In addition, in the process of assembling the remote control receiver chips having the center frequencies of various filters with the photodiode, a remote control receiver chip having a different center frequency is sometimes accidentally coupled to the photo diode. For this reason, it is necessary to adjust the center frequency of the filter constituting the remote control receiver chip. In the related art, the center frequency of the filter is controlled by including a trimming circuit in the remote control receiver chip as shown in FIG.

1 is a conventional infrared remote control receiver system, which receives a signal from a photodiode 17 and a photodiode 17 for converting an optical signal into an electrical signal, removes noise components, and corresponds to a remote control signal received from a transmission system. A remote control receiving chip 10 for generating a pulse signal, and a microcomputer 18 for receiving and decoding a pulse signal from the remote control receiving chip 10 and performing an operation of a device desired by a user.

The remote control receiving chip 10 receives a signal from the photodiode 17 and amplifies the amplification circuit 11, and a variable gain for receiving the output of the amplifying circuit 11 and amplifying by varying the gain of the original signal and the noise signal. A filter 13 for receiving a signal from the amplifying circuit 12 and the variable gain amplifier circuit 12 and passing only a carrier frequency component, and a waveform shaping circuit for receiving a signal from the filter 13 and extracting an envelope signal. (14), an automatic gain control circuit (15) for receiving the output of the filter (13), separating the original signal from the noise signal, and transmitting it to the variable gain amplifier circuit (12), and an external pin of the remote control receiver chip (10). And a trimming circuit 16 for receiving a high current signal from the filter 13 to adjust the center frequency of the filter 13.

Operation of the conventional infrared remote control receiving system as shown in Figure 1 is as follows.

The remote control signal is received from the remote control transmission system through the photodiode 17. The photodiode 17 functions to convert the remote control signal received in the form of light into the form of current, and the amplification circuit 11 amplifies the remote control signal received through the photodiode 17. The variable gain amplifying circuit 12 receives the output of the amplifying circuit 11 and amplifies the gains of the original signal and the noise signal differently, and the filter 13 passes only the carrier frequency component and removes other components. Function The automatic gain control circuit 15 receives the output of the filter 13 and distinguishes the original signal from the noise signal so as to allow the variable gain amplifier circuit 12 to adjust the gain. The output of the filter 13 is the waveform signal is extracted from the waveform shaping circuit 14, a pulse signal corresponding to the remote control signal is generated and transmitted to the microcomputer 18. The microcomputer 18 receives the pulse signal from the waveform shaping circuit 14 to perform the operation of the device desired by the user. The trimming circuit 16 receives a high current signal from an option pin that is external to the remote control receiver chip 10 and filters the resistors constituting the trimming circuit 16 by fusing or zener zapping. Functions to adjust the center frequency of (13).

The conventional remote control receiver chip 10 adjusts the center frequency of the filter by a fusing or zener zapping method in the wafer test step, and the time taken in this process occupies a substantial portion of the total wafer test time. Also, the center frequency adjusted in the wafer test step can be changed after the chip is packaged.

SUMMARY OF THE INVENTION An object of the present invention is to provide an infrared remote control receiver system capable of adjusting the center frequency of a filter without trimming a resistor.

1 is a view showing a conventional infrared remote control receiving system.

2 is a view showing an infrared remote control receiving system according to the present invention.

3 is a block diagram illustrating a filter center frequency control circuit of FIG. 2.

4 is a flowchart illustrating a method of adjusting the center frequency of the infrared remote control receiving system according to the present invention.

<Description of the symbols for the main parts of the drawings>

10: remote control receiver chip 11: amplification circuit

12 variable gain amplifier circuit 13 filter

14: waveform shaping circuit 15: automatic gain control circuit

16: trimming circuit 17: photodiode

18: microcomputer 19: filter center frequency control circuit

20: digital control circuit 21: counter

22: D / A converter 23: memory

24: digital comparator

Infrared remote control receiving system according to the present invention includes a remote control receiving chip for generating a pulse signal corresponding to the remote control signal; And a microcomputer that receives and decodes a pulse signal from the remote controller receiving chip and performs an operation of a device desired by a user. The remote controller receiving chip receives information about a filter center frequency from the microcomputer to obtain a filter center frequency. It characterized in that it comprises a filter center frequency control circuit for adjusting.

The center frequency control circuit includes a counter for receiving a filter output signal and information about the filter center frequency from the microcomputer to calculate a period of the output signal of the filter; A digital control circuit which receives information on the filter center frequency from the microcomputer and controls each block in the filter center frequency adjusting circuit; A digital comparator receiving the output of the counter and comparing it with a predetermined reference value under control of the digital control circuit; A memory for storing an output of a digital comparator under control of the digital control circuit; And a D / A converter which receives an output signal of the memory, converts it into an analog value and generates a center frequency control signal under the control of the digital control circuit.

In addition, the center frequency adjustment method of the infrared remote control system according to the present invention comprises a first step of oscillating a filter; A second step of resetting the counter and calculating a period of the filter output signal; A third step of comparing the calculated period of the filter output signal with a predetermined reference value stored in a comparator; A fourth step of storing the offset in a memory; And a fifth step of controlling the D / A converter based on the offset, and performing a center frequency adjustment signal, repeating steps 2 to 5 if the offset is greater than the tolerance, and centering if the offset is within the tolerance. Characterized in that the frequency adjustment process is terminated.

Hereinafter, an infrared remote control receiving system according to the present invention will be described with reference to the accompanying drawings.

2 is an infrared remote control receiving system according to the present invention, which receives a signal from a photodiode 17 and a photodiode 17 for converting an optical signal into an electrical signal, removes noise components, and receives a remote control signal received from a transmission system. Remote control receiving chip 10 for generating a pulse signal corresponding to the microcomputer 18 for receiving and decoding a pulse signal from the remote control receiving chip 10 and performs the operation of the user's desired device.

The remote control receiving chip 10 receives a signal from the photodiode 17 and amplifies the amplification circuit 11, and a variable gain for receiving the output of the amplifying circuit 11 and amplifying by varying the gain of the original signal and the noise signal. A filter 13 for receiving signals from the amplifying circuit 12 and the variable gain amplifier circuit 12 and passing only carrier frequency components, a waveform shaping circuit 14 for receiving signals from the filter 13 and extracting an envelope signal, An automatic gain control circuit 15 that receives the output of the filter 13, distinguishes the original signal from the noise signal, and transmits it to the variable gain amplifier circuit 12, and receives the output Fout of the filter 13. A filter center frequency control circuit 19 is provided which receives the reference clock Scfin from the computer 18 and generates the center frequency control signal Scfout of the filter 13.

Operation of the infrared remote control receiving system according to the present invention as shown in Figure 2 is as follows.

The remote control signal is received from the remote control transmission system through the photodiode 17. The photodiode 17 functions to convert the remote control signal received in the form of light into the form of current, and the amplification circuit 11 amplifies the remote control signal received through the photodiode 17. The variable gain amplifying circuit 12 receives the output of the amplifying circuit 11 and amplifies the gains of the original signal and the noise signal differently, and the filter 13 passes only the carrier frequency component and removes other components. Function The automatic gain control circuit 15 receives the output of the filter 13 and distinguishes the original signal from the noise signal so as to allow the variable gain amplifier circuit 12 to adjust the gain. The output of the filter 13 is the waveform signal is extracted from the waveform shaping circuit 14, a pulse signal corresponding to the remote control signal is generated and transmitted to the microcomputer 18. The microcomputer 18 receives the pulse signal from the waveform shaping circuit 14 to perform the operation of the device desired by the user.

The center frequency of the filter is adjusted by the filter center frequency adjusting circuit 19. The filter center frequency adjusting circuit 19 measures the period of the output signal Fout of the filter 13, and the period of the measured output signal Fout of the filter 13 and the reference clock (from the microcomputer 18). If there is an error compared to Scfin), adjust the center frequency of the filter.

FIG. 3 is a block diagram illustrating the filter center frequency adjusting circuit of FIG. 2. The output signal Fout of the filter 13 and the reference clock Scfin are received from the microcomputer 18 to calculate a period of the output signal of the filter. Receive a reference clock Scfin from the counter 21 and the microcomputer 18 to receive the outputs of the digital control circuit 20 and the counter 21 for controlling each block in the filter center frequency adjustment circuit 19. The digital comparator 24 which compares with a predetermined reference value under the control of the digital control circuit 20, the memory for storing the output of the digital comparator 24 under the control of the digital control circuit 20, the digital control circuit 20 A D / A converter 22 for receiving the output signal of the memory 23 under control and converting it into an analog value to generate the center frequency control signal Scout is provided.

The operation of the filter center frequency adjustment circuit shown in FIG. 3 will be described below.

The reference clock Scfin is received from the microcomputer 18 as the information on the center frequency of the filter and used as the reference clock of the digital control circuit 20 and the counter 21. The counter 21 receives the output signal Fout of the filter 13 and calculates the period of the output signal of the filter using the reference clock Scfin received from the microcomputer 18. The digital comparator 24 compares the period of the output signal calculated by the counter 21 with a reference value stored in a memory device (not shown) such as a read only memory (ROM) provided in the digital comparator 24. The digital control circuit 20 stores the difference (offset) between the two data in a memory 23 composed of a flip-flop or the like, and controls the D / A converter 22 based on the offset to control the center frequency adjustment signal Scout. Generates.

4 is a flowchart illustrating a method of adjusting the center frequency of the infrared remote control receiving system according to the present invention.

Hereinafter, a method of adjusting the center frequency of the infrared remote control receiving system according to the present invention will be described with reference to FIG. 4.

When power is supplied to the remote control receiving chip 10, the filter 13 oscillates (S1). The counter 21 is reset and the period of the output signal of the filter 13 is calculated (S2). The period of the calculated output signal of the filter is compared with a predetermined reference value stored in the comparator (S3). The difference (offset) between the two data is stored in a memory 23 composed of flip flops or the like (S4). The D / A converter is controlled and the center frequency is adjusted based on the offset (S5). If the offset is greater than the tolerance, the steps S2 to S5 are repeated. If the offset is within the tolerance, the center frequency adjustment process is completed.

However, when the remote control receiver chip 10 is applied to a system having various filter center frequencies, there may be two ways to adjust the filter center frequency.

First, there is a method of making the reference clock input from the microcomputer 18 to the remote control receiving chip 10 constant and changing the reference value in the digital comparator 24.

Second, there is a method of changing the reference clock input from the microcomputer 18 to the remote control receiving chip 10 while keeping the reference value in the digital comparator 24 constant.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

As described above, according to the infrared remote control receiving system according to the present invention, since the center frequency of the filter can be adjusted without trimming the resistance, the time required for wafer testing can be reduced, and various kinds of center frequencies are different. Errors in the assembly phase due to the presence of the remote control receiver system can be eliminated. In addition, the adjustment of the center frequency by the infrared remote control receiving system according to the present invention is more reliable than the conventional method.

Claims (5)

A remote control receiver chip for generating a pulse signal corresponding to the remote control signal; And It is provided with a microcomputer for receiving and decoding a pulse signal from the remote control receiving chip and performs the operation of the device desired by the user, The remote control receiving chip is an infrared remote control receiving system comprising a filter center frequency control circuit for adjusting the filter center frequency by receiving information on the filter center frequency from the microcomputer. The method of claim 1, wherein the center frequency control circuit A counter for receiving a filter output signal and information about the filter center frequency from the microcomputer to calculate a period of the output signal of the filter; A digital control circuit which receives information on the filter center frequency from the microcomputer and controls each block in the filter center frequency adjusting circuit; A digital comparator receiving the output of the counter and comparing it with a predetermined reference value under control of the digital control circuit; A memory for storing an output of a digital comparator under control of the digital control circuit; And And a D / A converter for receiving an output signal from the memory, converting the signal into an analog value, and generating a center frequency control signal under the control of the digital control circuit. The method of claim 1 or 2, wherein the information on the filter center frequency is Infrared remote control receiving system, characterized in that the reference clock. The infrared remote control receiving system according to claim 1 or 2, wherein the memory comprises a flip-flop. A first step of oscillating the filter; A second step of resetting the counter and calculating a period of the filter output signal; A third step of comparing the calculated period of the filter output signal with a predetermined reference value stored in a comparator; A fourth step of storing the offset in a memory; And Controlling a D / A converter based on the offset to obtain a center frequency control signal; And repeating steps 2 to 5 if the offset is greater than the tolerance, and terminating the center frequency adjusting process if the offset is within the tolerance.