JP2524937B2 - Method for detecting dead battery in infrared remote control unit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a dead battery in various infrared remote control units using a battery as a power source.

[0002]

2. Description of the Related Art Central control unit (microcomputer)
In the infrared remote control unit using, since the battery is used as the power source, the voltage of the power source drops due to long-term use. However, the central control device has a range of normally operating voltage, and a circuit using a low voltage detection IC for resetting the central control device at a constant voltage in order to prevent malfunction when the voltage falls below that voltage range. It is a common practice to set up.

However, in recent years, the number of remote control units equipped with various memory functions such as a learning function, a clock, and a timer is increasing along with the increase in added value. And about the remote control unit equipped with this memory function,
Memory over the contents and suddenly resetting operating at the time of voltage drops will be reset, the stored contents of the timer or the like is lost. Therefore, before resetting the central control unit, a low voltage detection IC that detects that the "battery is almost dead" is required.

That is, in a conventional infrared remote control unit, as shown in FIG. 5, a low voltage detection IC 51 for detecting a battery dead notice and a low voltage for detecting a central control unit reset voltage are provided in front of a central control unit (CPU) 50. A voltage detection IC 52 is provided to monitor the voltage of the battery 53 input to the central control unit 50, and to emit an infrared remote control signal from the central control unit 50 and the liquid crystal display element 5.
5 is configured to be driven.

When the voltage of the battery 53 is 3 V and the operating voltage of the central controller 50 is 2.1 to 3.0 V, for example,
The detection voltage of the first stage of the low voltage detection IC 51 for detecting the battery dead notice is set to 2.3V, and the detection voltage of the second stage of the low voltage detection IC 52 for detecting the central control unit reset voltage is set to 2.1V. Then, when the low voltage detection IC 51 detects the detection voltage (2.3 V) of the first stage, the liquid crystal display element 55
Warns the user that the battery 53 needs to be replaced using
Is used in as the battery 53 is not replaced, which is the second stage of the detection voltage (2.1V) to configure the low-voltage detection knowledge IC52 is to reset the central control unit 50 upon detection.

[0006]

However, according to the above conventional configuration, two low voltage detection ICs are required, which causes a cost increase and the central control circuit normally operates the detection voltage of the first stage. It had to be set at a voltage higher than the possible second-stage detection voltage, and the range of voltage that the remote control unit could normally use was narrowed, resulting in a short battery life. .

The present invention was devised in view of the above problems, and achieves a long battery life, has a small number of high-priced parts, and can be provided at a low cost in an infrared remote control unit. The purpose is to propose a breakage detection method.

[0008]

In order to achieve the above object, a method for detecting a dead battery in an infrared remote control unit according to the present invention is an infrared light emitting element for irradiating a remote control signal and a liquid crystal display for displaying various information. comprising a central control unit in ing to control driving the device, in the infrared remote controller unit driven by a power supply cell comprising batteries, the interrupt terminal of the central control unit, the normal driving voltage of said central control unit The low voltage detection signal for monitoring the power supply voltage of the battery is input through the low voltage detection IC for detecting the dead battery, which is set to the low limit, and the remote control drive signal for the light emitting element is input by the input of the low voltage detection signal. At the same time when the output is interrupted, a liquid crystal display element drive signal is output to the liquid crystal display element to provide a "battery dead notice display", and A reset signal obtained from the low voltage detection signal of the IC through the time delay circuit is input to the reset terminal of the central control unit, and the low voltage detection signal continuously exceeds the time-up time of the time delay circuit. In this case, a reset signal for resetting the memory content of the central control unit is output to prevent the memory content of the central control unit from being reset before the battery is replaced due to the voltage drop of the power supply battery. It is what

[0009]

According to the above method, when the battery is exhausted and the power supply voltage falls below the voltage lower limit when the light emitting element is operating, the low voltage detection I
C outputs a low voltage detection signal to the interrupt terminal of the central control unit, interrupts the output of the remote control drive signal to the light emitting element to restore the voltage of the battery, and prevents the voltage from dropping. At the same time, the liquid crystal is displayed on the liquid crystal display element. The display element drive signal is output to perform the "battery dead notice display". The output of the low voltage detection signal is shorter than the time-up time of the time delay circuit, so that the reset signal does not turn "ON".

The "battery dead notice display" of the liquid crystal display element allows the user to confirm that the capacity of the battery has diminished, and avoids the disappearance of the memory of the central control unit by replacing the battery. be able to.

Further, after the “battery dead notice display” of the liquid crystal display element, if the user uses the battery for a longer period without replacing the battery, the power supply voltage of the battery continuously becomes 2.1 V or less, which is low. continuously low voltage detection signal output of the voltage sensing IC is turned "oN" state, the reset signal from said time delay circuit when the time-up time T was Yue example of time-delay circuit is output, the reset terminal of the central control unit "ON" to reset the contents of the memory.

Therefore, by replacing the battery in accordance with the "battery dead notice display" of the liquid crystal display element, the power supply voltage can be maintained within an appropriate range, and the memory of the central control unit will not be erased. .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a remote control unit equipped with a battery dead detection device for carrying out the battery dead detection method for an infrared remote control unit according to the present invention will be described below with reference to FIG.

In the drawing, reference numeral 1 is a central control unit composed of a microcomputer, which controls and drives an infrared light emitting element 2 for emitting a remote control signal and a liquid crystal display element 3 for displaying various information. The central control unit 1 is driven by a power supply battery 4 composed of, for example, two 1.5 V dry batteries (3 V), and has a low voltage for battery exhaustion detection set to 2.1 V with respect to the interrupt terminal P1. The low voltage detection signal S1 is input through the detection IC5, and the low voltage detection IC5 is input to the reset terminal P2.
The low voltage detection signal S1 is input through the time delay circuit 6.

As shown in FIG. 2, the time delay circuit 6 is composed of a resistor R and a capacitor C,
Outputs a reset signal S2 with respect to the reset terminal P2 when the low voltage detection signal S1 has passed continuously constant time T set in advance, are then <br/> the arrangement to reset the central control unit 1.

Next, the operation of the battery dead detecting device will be described with reference to FIG.
This will be described with reference to the timing chart of FIG. In the process of using the remote control unit configured as described above, the voltage of the battery 4 decreases as the light emitting element 2 emits light. However, if the voltage is higher than 2.1 V, the infrared signal from the light emitting element 2 is normally generated. The light emission operation of S3 is performed.

When the battery 4 is used up for a long period of time and the power supply voltage of the battery 4 becomes 2.1 V or less when the light emitting element 2 is operated, the low voltage detection IC 5 centrally controls the low voltage detection signal S1. Output to the interrupt terminal P1 of the device 1. When the input of the interrupt terminal P1 is "ON", the central control unit 1 interrupts the output of the remote control drive signal S4 to the light emitting element 2 to prevent further voltage drop of the battery 4, and at the same time, displays a liquid crystal display on the liquid crystal display element 3. The element drive signal S5 is output and the "battery dead notice display" is performed.

When the power supply voltage of the battery 4 is restored (exceeds 2.1 V) by stopping the driving of the light emitting element 2 and stopping the use of the remote control unit, the low voltage detection IC
5 turns off the output of the low voltage detection signal S1. Since the "OFF" operation of the output of the low voltage detection signal S1 is performed in a shorter time than the time-up time T of the time delay circuit 6, the output from the time delay circuit 6 maintains the "OFF" state and the central control is performed. The reset terminal P2 of the device 1 is "OFF"
Since it is in the state, the memory contents of the central control unit 1 are not reset.

Then, the user can confirm that the capacity of the battery 5 has diminished by the "battery dead notice display" of the liquid crystal display element 3, and the battery 4 can be replaced accordingly to replace the central control unit 1 It is possible to avoid the disappearance of memory.

When the user uses the battery 5 for a longer period after the "battery dead notice display" of the liquid crystal display element 3, the power supply voltage of the battery 4 continuously falls below 2.1V. If the output of the low voltage detection signal S1 of the low voltage detection IC 5 is continuously turned on and the time-up time T of the time delay circuit 6 is exceeded, the time delay circuit 6
Outputs a reset signal S2, and the reset terminal P2 of the central control unit 1 turns "ON". The reset signal S2 resets the memory contents of the central control unit 1.

As described above, by exchanging the battery 4 according to the "battery dead notice display" of the liquid crystal display element 3, the power supply voltage can be maintained within an appropriate range, and the memory of the central control unit 1 disappears. It won't let you.

FIG. 4 is a graph comparing the battery lives of the battery dead detection method of the present invention and the conventional method. The detection voltage of the low voltage detection IC 5 shown in the above embodiment is 2.1.
V, and the detection voltage of the first stage by the conventional detection method is 2.3V, so if the battery width used by the method of the present invention is V1 and the battery width used by the conventional method is V2, then V1 / V2 = ( 3.0-2.1) / (3.0-2.3)
= 1.29, which means that the battery can be used in a voltage range 1.29 times that of the conventional method, but the actual battery life decreases as the voltage decreases, and the arrow A The battery voltage is 2.3 because it draws a curve like
Assuming that the time to drop to V is t1 and the time to drop to 2.1V is t2, t2 / t1 = 1.5 to 2, which is actually 1.5 to 2 times as long as that of the conventional method. You can

[0023]

As described above, the method for detecting a dead battery in the infrared remote control unit according to the present invention utilizes the drop in the battery voltage when the remote control unit is activated, as described above.
The battery dead warning function and the reset function to prevent malfunction of the central control unit can be configured by a time delay circuit consisting of a resistor and a capacitor, so the device can be provided at low cost and the use of a battery as a power source It has features such that the possible battery voltage width can be widened and the life can be greatly improved, and the effect obtained by implementing the present invention is extremely large.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a remote control unit equipped with a battery dead detection device for carrying out a battery dead detection method for an infrared remote control unit according to the present invention.

FIG. 2 is a circuit diagram showing an embodiment of the delay circuit.

FIG. 3 is a timing chart showing the operation of each part of the apparatus.

FIG. 4 is a graph comparing the lifespan of a battery according to the battery dead detection method of the present invention and a conventional method.

FIG. 5 is a block diagram of a battery exhaustion detecting device for implementing a battery exhaustion detecting method in a conventional infrared remote control unit.

[Explanation of symbols]

 1 Central Control Unit 2 Light Emitting Element 3 Liquid Crystal Display Element 4 Power Battery 5 Low Voltage Detection IC 6 Time Delay Circuit

Claims (1)

(57) [Claims] 1. A infrared which comprises a central control unit in ing to drive and control the liquid crystal display device for displaying an infrared light emitting element and various kinds of information is irradiated with the remote control signal, driven by a power supply cell comprising batteries In the remote control unit, the power supply voltage of the battery is monitored with respect to the interrupt terminal of the central control unit via a low voltage detection IC for detecting the dead battery set to a low limit of the normal drive voltage of the central control unit. By inputting a low voltage detection signal, the remote control drive signal output to the light emitting element is interrupted by the input of the low voltage detection signal, and at the same time, the liquid crystal display element drive signal is output to the liquid crystal display element to provide a "battery dead notice display". At the same time, the reset signal obtained by the low voltage detection signal of the low voltage detection IC through the time delay circuit is input to the reset terminal of the central control unit. Then, when the low voltage detection signal continuously exceeds the time-up time of the time delay circuit, a reset signal for resetting the memory contents of the central control unit is output, and the voltage of the power supply battery is lowered, thereby A method for detecting battery exhaustion in an infrared remote control unit, characterized in that the content of the memory of the central control unit is prevented from being reset before replacement.