Unitrode UC3702
The UC3702 Quad Relay Driver is intended to drive up to four relays from logic inputs using an unregulated relay voltage supply. The relays are driven from the Bus supply in a power efficient PWM converter fashion. The relay coil is used as the inductive element.| Part No. | UC3702 |
|---|---|
| Datasheet | UC3702 Download |
| Manufacturer |  Unitrode |
| Description | Quad PWM Relay Driver |
| Buy | Stock & Price |
FEATURES
● Maintains Constant Average Relay Voltage With Varying Supply Voltages● VBUS Voltages up to 42.5V
● Up to 50mA per Relay
● Integrated Schottky Flyback Diodes
● Individual Relay Control Inputs
● Short Circuit Protection
● User Selectable Operating Center Frequency and Relay Voltage
● Global Reset
DESCRIPTION
The relay coil is used as the inductive element. (See the application's section concerning the relay selection.) VBUS must be higher then the rated relay voltage. Short circuit protection is provided on chip with periodic retry. The UC3702 requires a +5V logic supply as a reference. Two external resistors program the effective relay voltage and a capacitor sets the nominal operating frequency. Internal Schottky diodes eliminate the need for any external power components. In typical applications, the UC3702 grants the user the flexibility to choose the most cost effective relay without the added burden of generating a separate relay supply voltage. The UC3702 will even function with a poorly regulated supply VBUS, containing significant 100Hz or 120Hz ripple.
