IL4116, IL4117 and IL4118 consist of AlGaAs IRLED optically coupled to a photosensitive zero-cross thyristor network. The thyristor consists of two monolithic thyristors in parallel in reverse. The three semiconductor devices are assembled in a six-pin 300 mil dual-in-line package. High input sensitivity is achieved through the use of emitter follower phototransistors and cascaded thyristor predrivers, resulting in LED trigger currents of less than 1.3 mA (DC).
The IL4116, IL4117, and IL4118 use a zero-crossover voltage detection circuit consisting of two enhanced mosFETs and a photodiode. The suppression voltage of the network is determined by the enhancement voltage of the N-channel fET. The P-channel FET is enabled by a photocurrent source that allows the fet to conduct the main voltage to the N-channel FET. Once the main voltage can make the n channel, it clamps on the base of the phototransistor, disabling the first stage thyristor predrive.
Blocking voltages up to 800 V allow control of off-line voltages up to 240 VAC with a safety factor of more than 2, and are sufficient to control up to 380 VAC. Current handling capacity up to 300 mA RMS continuous 25°C. IL4116, IL4117, IL4118 Separate low-voltage logic from 120 VAC, 240 VAC and 380 VAC lines to control resistive, inductive or capacitive loads including motors, solenoids, high-current thyristors or thyristors and relays. Applications include solid-state relays, industrial controls, office equipment, and consumer appliances
Application program
Direct switching operation:
The IL4116, IL4117, IL4118 isolated switch is mainly suited to control synchronous motors, valves, relays and solenoids. As shows below a basic driving circuit. For resistive load the snubber circuit RS CS can be omitted due to the high static dV/dt characteristic.
Indirect switching operation:
The IL4116, IL4117, IL4118 switch acts here as an isolated driver and thus enables the driving of power thyristors and power triacs by microprocessors. As shows below a basic driving circuit of inductive load. The resister R1 limits the driving current pulse which should not exceed the maximum permissible surge current of the IL4116, IL4117, IL4118. The resister RG is needed only for very sensitive thyristors or triacs from being triggered by noise or the inhibit current.
