UC3702

The UC3702 Quad Relay Driver is intended to drive up to four relays from ogic inputs using an unregulated relay voltage supply. The relays are riven from the Bus supply in a power efficient PWM converter fashion. he relay coil is used as the inductive element. (See the application's section oncerning the relay selection.) VBUS must be higher then the rated elay voltage. Short circuit protection is provided on chip with periodic retry.

The UC3702 requires a +5V logic supply as a reference. Two external resistors rogram the effective relay voltage and a capacitor sets the nominal perating frequency. Internal Schottky diodes eliminate the need for any xternal power components.

In typical applications, the UC3702 grants the user the flexibility to choose he most cost effective relay without the added burden of generating a separate elay supply voltage. The UC3702 will even function with a poorly egulated supply VBUS, containing significant 100Hz or 120Hz ripple.