SU966858A1 - Device for switching-on light emitting diode - Google Patents

Description

(S) DEVICE FOR SWITCHING ON LED

R

The invention relates to the field of pulsed technology and can be used in optoelectronic switches, generators, triggers, analog-digital converters.

A device for turning on a LED is known, which contains a source of electrical signals connected to the LED through a capacitor, shunted by a resistor 1.

However, in the known device, the energy consumption from the source of electrical signals is significant.

A device for switching on an LED containing a series of connected electrical signal sources, a correction stage, a current amplifier in whose output circuit an LED 23 is connected is known. However, the control signals in the device are generated without rigid (synchronous) communication with LED switching processes and therefore it does not may be optimal over a wide range of conditions for LEDs with different static and dynamic characteristics.

The purpose of the invention is to increase the speed of the inclusion of LEDs, regardless of their static and dynamic characteristics.

To do this, a device for switching an LED containing a current amplifier, the output of which is connected to the anode of the LED, the cathode of which is connected to the common bus, a source of electrical signals, a photodiode optically connected to the LED, an input of the current amplifier connected to the cathode of the photodiode, the anode of which is connected to the common bus.

Claims (2)

FIG. Figure 1 shows the electrical circuit of the device for turning on the LED; in fig. 2 is a phase diagram of the LED switching. 396 According to FIG. 1 LED 1 is energized by current amplifier 2 using 3 electrical signals coming from a source through a circuit with a resistor C. Amplifier 2 is powered by constant voltage source 5. A photodiode 6 is inserted into the negative feedback circuit enclosing the amplifier 2, optically coupled to the LED 1. The amplifier 2, the light cathode, the diode 1 and the photodiode 6 anode are connected to the zero potential bus. The device works as follows. In the initial electrical state SRI LED 1 is off; its operating point is fixed at position M (Fig. 2). When the control current is applied, Of the excitation current of the OgQ35 LED due to amplifier 2 increases dramatically and forces the barrier capacitance of LED 1 to charge. covering amplifier-2 is inactive. As soon as the operating point of the LED reaches the steep branch of the current-voltage characteristic, its conduction current increases, a photocurrent F appears in the negative feedback circuit, and the excitation current of the Bojg LED decreases sharply. At the end of the activation process, the operating point of the LED 1 is fixed at position N (Fig. 2) at a small excitation current. Thus, the photodiode 6 accurately monitors the process of turning on the LED 1 and automatically reduces the level of the excitation current of the LED in the final process. . At the stage of turning off the LED T, the input current DT changes direction. Only at first, the current of the negative feedback through the channel with the photodiode 6) is small. Fast enough, however, the current s ..,. and with it the current Of, decreases, and turning off the LED 1 is forced by a significant current Dgcj35 (Fig. 2). Thus, this device allows for fast switching of the LED, it is not associated with significant power consumption during long-term formation of the optical signal. The use of this device will dramatically improve the performance of optoelectronic switches, generators, triggers, analog-to-digital converters. In multichannel devices, faster transmission of information via optical channels makes it possible to significantly (2-5 times) reduce the required number of such channels. The invention includes a device for switching on an LED containing a current amplifier, the output of which is connected to the anode of an LED, the cathode of which is connected to a common bus, a source of electrical signals, in order to increase the speed of switching on LEDs regardless of their static and dynamic characteristics , a photodiode optically coupled to the LED is inserted, the input of the current amplifier is connected to a source of electrical signals and to the cathode of the photodiode, the anode of which is connected to the common bus. .: Sources of information taken into account in the examination 1. For the German Federal Republic If 260363, cl. H 03 H 7/1, 1978. 2. AsatanI K., Kimura T. Linearization of LED noulinearity by predistortions - IEEE - Trans, 1978, V. SC - 13, No. 1, p. 133-138 (prototype). 1 ho3f 2