LS7317 Datasheet | LSI

FEATURES : - Inputs/Outputs for selecting and displaying 5 speed/power levels Electronically latched inputs with dome switch patibility - Separate Boost input for full-speed/power selection - Separate Pulse input for periodic on/off cycle selection - +6V Operation (VDD - VSS) - LS7317 (DIP); LS7317-S (SOIC) -See Figure 1Applications: - Consumer Appliances such as Blenders, Range Hoods, Fans, etc. - Lamp Dimmer for control of high-voltage lamps and electronic-transformer coupled low-voltage lamps such as Halogen Lamps. DESCRIPTION : The LS7317 is a MOS circuit for controlling the speed of an AC motor. Five inputs, PL1/ through PL5/ are provided to select five speed/power levels between 40% and 96% of full power. A BOOST/ input is provided to override any selected power level with a jump to 99% of full power. A PULSE/ input provides for periodic two seconds on, two seconds off auto-pulse cycle for one minute. All these inputs require momentary activation which can very conveniently be produced by push-button dome or leaf switches. When a logic low is applied through such a push-button switch to any of the speed inputs or the Pulse input, the input bees .. active and switches state to bee an output for driving an external LED and display the selected speed level. A TRIG/ output is also turned on to drive the trigger input of a triac in series with the motor and control its speed by controlling the firing angle of the triac. Phase synchronization of the external AC and the triac trigger is made with an internal PLL, with the AC signal being applied to the SYNC input of the LS7317. An OFF/ input is provided for turning the motor off with a momentary push-button switch. The LS7317 can also be used as a Lamp Dimmer providing 5 selectable intensity levels as indicated in the application schematic shown in Figure 5. The LOAD can be either a high voltage lamp or the input to an electronic-transformer coupling to a low-voltage lamp. In the Lamp Dimmer application, the Pulse/...