JPH0246133Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a wireless remote control transmitter that uses a battery as a power source and drives a light emitting element such as an infrared LED to transmit a signal.

[Background technology]

FIG. 1 shows a circuit of a conventional general optical beam type wireless remote control transmitter. In the figure, E is a battery, which supplies power supply voltage for operation to each part. Further, A is a signal generation circuit, and key input section B
When there is an input from , it generates a display output signal a ₁ and a signal output signal a ₂ . The display output signal _a1 turns on and off the transistor _Q1 and drives the light emitting element _L1 for displaying operation to blink.
Further, the signal output signal a ₂ turns on and off the transistor Q ₂ and drives the light emitting element L ₂ for signal transmission to blink. Figures 2a to 2c are explanatory diagrams of the operation of the circuit in Figure 1, in which figure a shows the key input to the signal generation circuit A, and figures b and c show the signal generation circuit A when the key input is received. Output signal for the signal
a ₂ and display output signal a ₁ are shown, respectively. A normal light emitting diode is used as the light emitting element _L1 for displaying operation. Furthermore, as the light emitting element _L2 for signal transmission, an infrared light emitting diode, a semiconductor laser, or the like is generally used. If a light emitting element _L2 in the infrared region is used as the light emitting element L2 for signal transmission in this way, even if it emits light, it will not be visible to the naked eye, so it will be necessary to provide an indication using the light emitting element _L1 for operation confirmation. Light emitting element L ₁ for signal transmission
The output signal _a2 for driving the on/off signal is modulated as shown in FIG. 3 in order to improve transmission reliability. FIG. 3a shows the carrier signal (several kilohertz to several MHz) before modulation, and FIG. 3b shows the envelope of the modulated signal. Note that the display output signal _a1 for operation confirmation is also modulated to reduce current consumption.

As described above, the conventional optical wireless remote control transmitter generally uses the battery E as a power source to improve portability. Furthermore, it is necessary to reduce the number, size, weight, etc. of the batteries E to make them as small and light as possible. On the other hand, if you think about the time of use,
It is desirable to increase the light emitting output of the light emitting element _L2 for signal transmission so that it can be used with as non-directional characteristics as possible, and for this purpose it is necessary to increase the voltage and capacity of the battery E. There was a problem that these two demands conflicted with each other. This will be explained using the equivalent circuit diagram shown in FIG. First, the power supply voltage of battery E is V, the forward voltage drop of light emitting element L ₂ for signal transmission is VF, the forward voltage drop of transistor Q ₂ is VCE, and light emitting element L ₂
If the resistance value of the current limiting resistor is R, then the light emitting element
The current IP flowing through _L2 is given by the following equation.

IP=V-(VF+VCE)/R Therefore, the power supply voltage of battery E needs to be set higher than at least the voltage (VF+VCE). However, the light emitting diodes in the infrared region that are commonly used these days have a large light output per current and are high output, but the drawback of these is that the voltage VF is higher than that of conventional products, as shown in Figure 1. In the conventional circuit configuration, it is necessary to increase the electric string voltage V by increasing the number of batteries E, etc. However, this method increases the shape and weight of the transmitter, resulting in a problem of poor portability.

[Purpose of invention]

The present invention has been developed in view of the above-mentioned points, and is intended to enable driving of a light emitting element with a relatively large forward voltage drop in a wireless remote control transmitter that uses a relatively low voltage battery as a power source. The purpose is to

[Disclosure of invention]

The configuration of the present invention will be described below with reference to an illustrated embodiment. As shown in FIG. 5, a wireless remote control transmitter uses a relatively low voltage battery E as a power source and performs signal transmission by blinking the light emitting element _L2 . In the device, a light emitting element L ₁ is provided for operation confirmation that is driven on and off intermittently during signal transmission, and the intermittent drive signal of the light emitting element L ₁ is used as a separate excitation signal input to boost the battery voltage, which is used for signal transmission. The light emitting device of
A booster circuit section G is provided to generate a driving voltage for _L2 . In the embodiment circuit of FIG. 5, parts having the same functions as those of the conventional example circuit of FIG. The characteristic feature of this embodiment is that the display output signal a output from the signal generation circuit A is used as the separately excited signal input of the boost circuit section G consisting of a DC-DC converter, and the output of the boost circuit section G is Light emitting element for signal transmission in
This is to obtain the driving power supply voltage for _L2 .
The booster circuit section G includes a transistor _Q3 that is turned on and off by the display output signal _a1 , a booster oscillation transformer OT through which a primary current flows when the transistor _Q3 is turned on, and a secondary transformer of the oscillation transformer OT. A diode D ₁ that rectifies the output, and a diode D ₁ that rectifies the output.
It has a chiyoke coil L and a capacitor _C1, etc., which smooth the rectified output. diode
D ₂ is for absorbing the back electromotive force of the oscillation transformer OT,
Diode _D3 is a flywheel diode. The display output signal _a1 output from the signal generation circuit A is an intermittent drive signal in order to light up the light emitting element _L1 for operation confirmation with low power consumption as described above. When the transistor Q ₃ is turned on and off by a specific drive signal, an intermittent excitation current flows through the primary side of the oscillation transformer OT. As a result, a voltage is generated on the secondary side of the oscillation transformer OT, but by setting the number of windings on the secondary side to be larger than the primary side, a voltage is generated on the secondary side of the oscillation transformer OT. A voltage higher than the power supply voltage V can be generated. This voltage contains the same alternating current component as the display output signal _a1 , so the chiyoke coil L and capacitor _C1
The voltage is smoothed and supplied as a complete DC voltage to the light emitting element _L2 for signal transmission. As mentioned above, an infrared light emitting diode or a semiconductor laser is used as the light emitting element L ₂ for signal transmission, but the forward voltage drop VF of the light emitting element L ₂ is higher than that of conventional ones. However, since the voltage of capacitor _C1 is boosted higher than the power supply voltage of battery E, a battery with a relatively low power supply voltage can be used as battery E.

[Effect of idea]

The present invention is constructed as described above, and is used in a wireless remote control transmitter that uses a relatively low voltage battery as a power source and transmits signals by blinking a light emitting element. A step-up circuit section is provided which uses an intermittent drive signal of the light-emitting element as a separate excitation signal input to boost the battery voltage and generates a driving voltage of the light-emitting element for signal transmission. Therefore, the intermittent drive signal for driving the light emitting element for operation check with low power consumption can be directly used as a separate excitation signal input for the booster circuit to boost the battery voltage. Even if a relatively low voltage is used to reduce the size and weight of the transmitter, it is possible to obtain a high driving voltage for the light emitting element for signal transmission, which improves portability. This has the effect of making it possible to transmit high-power light while providing a wealth of energy.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of the conventional example, Figures 2 and 3 are waveform diagrams for explaining the operation of the above, Figure 4 is an equivalent circuit diagram for explaining the operation of the above, and Figure 5 is an implementation of the present invention. FIG. 3 is an example circuit diagram. L ₁ and L ₂ are light emitting elements, E is a battery, and G is a booster circuit section.

Claims (1)

[Scope of utility model registration request] In a wireless remote control transmitter that uses a relatively low voltage battery as a power source and transmits signals by driving a light emitting element to blink, a light emitting element is provided for operation confirmation that is driven on and off intermittently during signal transmission, and the light emitting element is turned on and off intermittently during signal transmission. A wireless remote control oscillator comprising a step-up circuit section that receives an intermittent drive signal for the element as a separate excitation signal input, boosts a battery voltage, and generates a drive voltage for the light-emitting element for signal transmission.