JP2002238088A - Remote control light-receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption at a low cost, without having to externally provide a dedicated power supply control means for a remote control light-receiving circuit. SOLUTION: This remote control light-receiving device for extracting a subcarrier from a remote control signal received by a photodiode 1, integrating the subcarrier, shaping its waveform and outputting the subcarrier, is provided with a detector 7 for detecting the existence/absence of the subcarrier and includes a time control circuit 14 for performing intermittently only detection operation of the carrier, when the detector 7 does not detect the carrier and making the entire device perform normal operation, when the subcarrier is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote control light-receiving device for reducing power consumption during standby.

[0002]

2. Description of the Related Art FIG. 7 shows a block diagram of a conventional remote control light receiving device (remote control light receiving element) 100A. This remote control light receiving device 100A is packaged in a clear mold that transmits infrared light. 1 is a condenser lens for condensing infrared remote control signal light, 2 is a photodiode for receiving the remote control signal light and photoelectrically converting it, 3 is a first amplifier (head AMP) having a large gain, and 4 is a DC light component from the received signal. 5, a second amplifier (2nd AMP), 6 a bandpass filter for extracting a subcarrier from a remote control signal, 8 an integrator for integrating the subcarrier, 9 a comparator for waveform shaping, 10 Is an output circuit, 11
Is an output transistor.

[0003] An infrared command signal arriving from a remote control commander is condensed on a photodiode 2 by a condenser lens 1 and converted into a current signal there. The converted current signal is converted into a voltage signal by the first amplifier 3 and amplified, but the DC component is canceled by the DC light canceling circuit 4. The output signal of the first amplifier 3 is
, And input to the band-pass filter 6, where the sub-carrier is extracted. The extracted subcarrier is input to an integrator 8 and integrated, and further input to a comparator 9 to be shaped. Then, the output transistor 1 is output from the output circuit 10.
1 and is taken into a control circuit (not shown) comprising a microcomputer at the next stage and processed.

[0004]

In such a remote control light receiving device 100A, as a countermeasure for reducing power consumption during standby, a reduction in power supply voltage and a reduction in current consumption are generally adopted. However, in order to further reduce the standby power with only the remote control light receiving device 100A, it is necessary to provide a dedicated power supply means externally and to operate intermittently during standby.

As described above, the conventional remote control light receiving device 100
In order to operate A intermittently, power supply must be intermittently controlled, and a special power supply control means must be provided externally, resulting in an increase in cost.

The remote control light-receiving device 100A has several nA.
Since a very high gain is required to detect the small photocurrent of the above, it is necessary to insert a primary low-pass filter with a resistor and a capacitor in the power supply line in order to remove noise in the power supply line. In such a case, if the power supply is intermittently controlled, a delay time occurs until the voltage reaches a predetermined voltage, and the operation time increases, and the effect of reducing power consumption becomes insufficient.

An object of the present invention is to provide a remote control light-receiving device which can reduce power consumption at low cost without providing a dedicated power supply control means externally.

[0008]

According to a first aspect of the present invention, there is provided a first amplifier for converting a light receiving current of a photodiode for receiving a remote control signal into a voltage and amplifying the current, and amplifying the light by the first amplifier. A second amplifier for further amplifying the output signal, a bandpass filter for extracting a subcarrier from the signal output from the second amplifier, an integrator for integrating the subcarrier output from the bandpass filter, and an output of the integrator. A remote control light-receiving device comprising: a comparator for shaping the waveform of the signal; and an output circuit for amplifying an output of the comparator. A detector for detecting the sub-carrier output from the band-pass filter, and the sub-carrier by the detector. When no carrier is detected, only the sub-carrier detection operation is performed intermittently, and when the sub-carrier is detected, time control for controlling the entire device to operate normally. It was constructed and the road, the provided.

[0009] In a second aspect based on the first aspect, the time control circuit, when the sub-carrier is not detected,
The first amplifier, the second amplifier, the band-pass filter, and the detector are operated intermittently, and the integrator, the comparator, and the output circuit are made inoperative.

[0010] In a third aspect based on the first aspect, the time control circuit, when the sub-carrier is not detected,
The first amplifier, the second amplifier, the bandpass filter, the detector, the integrator, the comparator, and the output circuit are configured to operate intermittently.

In a fourth aspect based on the first, second, or third aspect, the inoperative period of the intermittent operation is set to a shorter time than a signal period excluding a signal indicating the end of the remote control signal. .

In a fifth aspect based on the first, second, or third aspect, the inoperative period of the intermittent operation is defined as a period excluding the signal indicating the head and end of the signal period of the remote control signal. Set a shorter time.

In a sixth aspect, the first, second, third, fourth, and fourth aspects are provided.
Alternatively, in the fifth invention, the operation period of the intermittent operation is set to a period longer than the maximum non-signal period of the binary data code.

According to a seventh aspect of the present invention, the first, second, third, fourth and fourth
In the fifth or sixth aspect of the present invention, the time control circuit operates the sub-controller even if a predetermined time longer than a signal period indicating the end of the signal period of the remote control signal has elapsed after normal operation of the entire device. When the carrier is not detected, the operation is shifted to the intermittent operation.

[0015]

FIG. 1 is a block diagram of a remote control light receiving device 100 according to one embodiment of the present invention. The remote control light receiving device 100 is packaged in a clear mold that transmits infrared light. 1 is a condensing lens for condensing the infrared remote control signal light, 2 is a photodiode for receiving the remote control signal light and photoelectrically converting it, and 3 is a first with a large gain.
An amplifier, 4 is a DC light canceling circuit for removing a DC light component from a received light signal, 5 is a second amplifier, 6 is a band-pass filter for extracting a subcarrier, 8 is an integrator, 9 is a comparator for waveform shaping, and 10 is An output circuit 11 is an output transistor. The above is the same as the configuration of FIG.

The remote control light receiving apparatus 100 further includes a detector 7 interposed between the band pass filter 6 and the integrator 8 so that the presence or absence of a subcarrier can be detected. Power is supplied to the first amplifier 3, the second amplifier 5, the band-pass filter 6, and the detector 7 via the switch SW1, and the integrator 8, the comparator 9, and the output circuit 1
0 is supplied with power via a switch SW2. 12 is an oscillation circuit, 13 is the oscillation circuit 12
This is a frequency dividing circuit that converts the frequency of the signal oscillated by.

Reference numeral 14 denotes a time control circuit.
Output pulse is input as a timing signal,
Is input as an operation mode switching signal,
The switches SW1 and SW2 are driven. That is, when the detector 7 does not detect the sub-carrier, the time control circuit 14 performs an intermittent operation of turning on the switch SW1 for a predetermined time in a predetermined time cycle and continuously turning off the switch SW2. When the sub-carrier is detected, the switches SW1 and SW2 are turned on continuously, and when the sub-carrier is not detected for a predetermined time or longer, the switch SW1 performs the above-described intermittent operation and switches the switch SW2 to be continuously turned off.

When the remote control signal has not arrived, the sub-carrier is not output from the band-pass filter 6 and the detector 7 cannot detect it, so that the time control circuit 14 is set to the power saving mode. Is done. As a result, the switch SW1 is turned on / off intermittently, and the switch SW2 is turned off continuously. Therefore, at this time, the first amplifier 3, the second amplifier 5, the band-pass filter 6, and the detector 7 are intermittently supplied with power and operate intermittently. Further, no power is supplied to the integrator 8, the comparator 9, and the output circuit 10, and they do not operate.

When a remote control signal arrives in this state, a sub-carrier is output from the band-pass filter 6 when the switch SW1 is turned on, and the detector 7 detects the sub-carrier, so that the time control circuit 14 operates in the normal operation mode. , And the switches SW1 and SW2 are set to the continuous ON state, and the normal operation of receiving and amplifying the incoming remote control signal, integrating the subcarrier, shaping the waveform, and outputting is performed.

Thereafter, when the remote control signal does not arrive for a predetermined time or more, it is detected by the detector 7, the time control circuit 14 returns to the power saving mode, and the switch SW1 is turned on / off intermittently. Switch to switch SW
2 turns off continuously.

As described above, the remote control light-receiving device 100 of the present embodiment only has an operation of intermittently supplying power to a circuit portion necessary for sub-carrier detection in the remote control light-receiving device 100 when no remote control signal has arrived. As a result, power consumption can be reduced at low cost without providing a special power supply control unit outside the remote control light receiving device 100.

FIG. 2 shows a format of a remote control signal established by the Home Appliances Association. The contents of the configuration include a leader corresponding to a marker indicating the head of a signal, and a custom code CO, for identifying a company supplying the product, in a portion sandwiched between a trailer which is a marker indicating the end of the signal.
C1, parity code P for checking erroneous transmission, data code DO for transmitting actual command contents
To Dn are sequentially arranged.

One byte is eight bits, and one bit is determined by a PWM (pulse width modulation) method as shown in FIG.
The determination of 0 "or" 1 "is performed, but the 3T shown in Fig. 3 may be changed to 2T, which differs depending on the specification (manufacturer and product, the same applies hereinafter). <1T <0.5 msec, which is basically set arbitrarily according to the specifications, and is set to 0.4 msec <1
T <0.9 msec is the mainstream. FIG. 4 shows a format of the home appliance association of the leader portion, and only the marker indicating the head is distinguished from the format of “0” or “1” determination in FIG. Since the remote control commander modulates the above 1T basic pulse into a subcarrier of 33 KHz to 40 KHz and transmits it, a subcarrier of 13 to 25 pulses is normally inserted during 1T.

In the present embodiment, the time from the leader excluding the trailer to the last byte and 1T and 3T are used.
Focusing on the pulse widths determined by 0 "and" 1 ", the intermittent operation of turning on the switch SW1 only in the time period from the reader excluding the trailer to the last byte, where the subcarrier can be always detected when the remote controller command signal is input. As a result, the current consumption can be significantly reduced.

FIG. 5 is a timing chart of the command signal, the detection output of the detector 7, and the operation of the switches SW1 and SW2. The command signal represents the same code three times for one commonly used command. it represents a state of transmitting at intervals of T _4. When the command signal has not been input, the switch SW1 is turned on for a time T ₁ for each interval of time T _2, to confirm the command signal presence at that time T _1. In FIG. 5, the input of the command signal is confirmed when the switch SW1 is turned on for the third time. Command data is 0.4 msec to 0.9 msec, with a subcarrier signal of several tens of pulses per bit.
A burst signal having a pulse width of is transmitted in a bundle of several tens of bits, and in FIG. 5, detection is started from the signal of the eighth bit.

The output of the detector 7 which has detected the input of the command signal is input to the time control circuit 14, whereby the mode becomes the normal mode, and the switch SW1 is continuously turned on.
The switch SW2 is switched on continuously.

[0027] When the continuation of the input state of the command signal is continued by monitoring the detection output of the detector 7 at the time control circuit 14, which interrupted the input time preset T ₃ or more command signals, time The control circuit 14 returns to the power saving mode, sets the switch SW1 to the intermittent operation, sets the switch SW2 to the continuous off state, and enters a standby state for the next command input. The time T ₃ is set longer than the period of the trailer is a marker indicating the end of the remote control signal, when transmitting a plurality of times the same code for a command as above, the interval time T ₄ , T ₃ > T ₄ is set. Thus, the period _{T 4} switches SW1, SW2 will not be restored.

The power reduction rate is the ratio of the time _{T 1} and _{T 2} in FIG. 5, and the power consumption of the circuit portion 3 to 10 which is controlled by the switches SW1, SW2 of FIG. 1, and the constantly operating state Oscillator circuit 12, frequency divider 13, time control circuit 1
4 is determined by the power consumption.

FIG. 6 is a diagram for explaining the time setting of the on-time of the intermittent operation T ₁ and time interval T ₂ of the switch SW1 when a 4-byte data of the data from the first byte to the fourth byte, 1T = At the time of 600 μsec. Time setting of the on time of the switch SW1 T _1, it is necessary to set the time width data and the leader can always detected, the maximum no-signal period of the data in the present embodiment is 3T (Fig. 3), Mu maximum leader code Signal period is 4
T (FIGS. 4 and 6), so here 4T (= 2.
4 msec) (T ₁
> 4T). As described above, the ON time T ₁ is T ₁ > 4T, and the ON time T ₁ when the time width during which seven subcarriers of 38 KHz enter seven pulses is 2.6 msec.

[0030] On the other hand, the time setting of the interval of the switch SW1 time _{T 2} must be set to be smaller than the 4-byte data code time width Ta obtained by adding a leader in the shortest time _(T 2 <Ta). The 4-byte data becomes the shortest when all the data is "0". At this time, the leader code (0.6 msec x 12 = 7.2 mse)
The time width Ta to which c) is added is Ta = (0.6 msec × 2 × 4 bytes × 8 bits) +7.2 msec = 45.6 msec.

Here, the amount of reduction in the current consumption during the intermittent operation when T ₂ = 44 msec is set as the time when T ₂ <Ta is satisfied is calculated. The current consumption of the circuit portions 3, 5 to 7 whose power supply is controlled by the switch SW1 is 420 μA, and the current consumption of the circuits 8 to 10 whose power supply is controlled by the switch SW2 is 200 μA. First,
The average value I1 of the current consumption of the circuit portions 3, 5 to 7 related to the switch SW1 during the intermittent operation is I1 = 420 × (2.6 / 44) = 24.82 μA. In addition, the oscillation circuit 12 which always operates, the frequency dividing circuit 1
3 and the time control circuit 14 has an average current value of 16 μA when the circuit is designed by the CMOS process, and the total sum Ia of the current consumption during the intermittent operation is as follows: Ia = 24.82 + 16 = 40.82 μA. The current consumption of the conventional circuit shown in FIG.
As compared with the case described above, the current consumption during the intermittent operation can be reduced to about 7%, and a great reduction effect can be obtained.

FIG. 6 shows an example in which the code length of data is 4 bytes from the first byte to the fourth byte as described above. The reduction effect varies depending on the number of bytes and the setting time of the reader. I do. In addition, since the setting of the code length differs depending on the specifications, the optimum T ₁ ,
T ₂ is present, but these set time corresponding to the technically possible in an easy change of the time control circuit.

It should be noted, deformed in the fourth byte of the code length of the time from the first byte also excluding the leader not the time width Ta of FIG. 6 trailer only, the interval of the switch SW1 time T ₂ to T _{2 <Ta} set, can be set to _{T 1} which is on-time of the switch SW1 to _T 1> 3T (provided that when the data code in Figure 3).

When set as described above, a sufficient effect of reducing power consumption can be achieved even in the specification of FIG. 6 which uses a code having an extremely long no-signal period. In this embodiment, the data code “1” is changed to 1
The contents changed from T to-3T to specifications and 1T pair 2T is also effective against (lower part of FIG. 6), setting time T ₁ of the this case is as short as T _1> 2T, the effect of reducing the current consumption Is more increased.

In still another embodiment, the switches SW1 and SW2 of FIG. 1 are commonly used, that is, shared by one switch, and the integrator 8, the comparator 9, and the output circuit 10 can also be operated intermittently. In this case, there is an advantage that the time control circuit can be simplified, but the effect of reducing the current consumption is slightly reduced as compared with the above case.

[0036]

As described above, according to the present invention, a sufficient effect of reducing power consumption can be obtained even in the conventional remote control format and code length. Also, since the present invention processes all the intermittent operations in the remote control light receiving device, it does not require any external control, does not need to provide a dedicated power supply control means for the remote control light receiving device, and consumes power at low cost. Can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a remote control light receiving device according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a format of an infrared remote controller.

FIG. 3 is a timing chart of a data code.

FIG. 4 is a timing chart of a leader code.

FIG. 5 is a timing chart of the operation of the remote control light receiving device of FIG. 1;

FIG. 6 is a waveform diagram for explaining the operation when the data length is 4 bytes.

FIG. 7 is a block diagram of a conventional remote control light receiving device.

[Explanation of symbols]

100, 100A: remote control light receiving device 1: condensing lens, 2: photodiode, 3: first amplifier, 4: DC light canceling circuit, 5: second amplifier, 6:
Bandpass filter, 7: detector, 8: integrator, 9: comparator, 10: output circuit, 11: output transistor, 1
2: Oscillator circuit, 13: frequency divider circuit, 14: time control circuit.

Claims (7)

[Claims] A first amplifier for converting a light-receiving current of a photodiode for receiving a remote control signal into a voltage and amplifying the voltage;
A second amplifier for further amplifying the signal amplified by the amplifier,
A band-pass filter for extracting a sub-carrier from the signal output from the second amplifier, an integrator for integrating the sub-carrier output from the band-pass filter, a comparator for shaping the output of the integrator, and a comparator A remote control light-receiving device comprising: an output circuit that amplifies an output of the sub-carrier; a detector that detects the sub-carrier output from the band-pass filter; and an operation of detecting the sub-carrier when the sub-carrier is not detected by the detector. A remote control light-receiving device, comprising: a time control circuit for controlling the whole device to operate normally when the subcarrier is detected only intermittently. 2. The time control circuit intermittently operates the first amplifier, the second amplifier, the bandpass filter and the detector when the subcarrier is not detected, and operates the integrator and the comparator. 2. The remote control light receiving device according to claim 1, wherein the remote controller and the output circuit are disabled. 3. The time control circuit, when the sub-carrier is not detected, the first amplifier, the second amplifier, the band-pass filter, the detector, the integrator, the comparator, and the output circuit. The remote control light receiving device according to claim 1, wherein the remote control light receiving device is operated intermittently. 4. The remote controller according to claim 1, wherein an inoperative period of the intermittent operation is set to a shorter time than a signal period excluding a signal indicating the end of the remote control signal. Light receiving device. 5. The non-operating period of the intermittent operation is set to a shorter time than a period excluding a signal indicating a head and an end of a signal period of a remote control signal. Or the remote control light-receiving device according to 3. 6. The intermittent operation according to claim 1, wherein the operation period is set to a period longer than a maximum non-signal period of a binary data code. Remote control light receiving device. 7. The time control circuit detects the subcarrier even if a predetermined time longer than a signal period indicating the end of the signal period of the remote control signal has elapsed after normal operation of the entire apparatus. 7. The remote control light receiving device according to claim 1, wherein said intermittent operation is performed when not performed.