LR745N3-G Microchip

LR745 High-Input Voltage SMPS Start-up Features Description Accepts inputs from 35 to 450V LR745 is a high input voltage SMPS start-up circuit. Output current limiting LR745 is ideally suited for use with industry standard For PWM ICs with start-up threshold voltage of low-voltage, Pulse-Width Modulation (PWM) ICs hav- 13.9 - 18.0V ing start thresholds of 13.9 to 18.0V. It allows the PWM ICs to be operated from rectified 120 or 240VAC lines, Very low power consumption after start-up and eliminates the use of power resistors often used for this purpose. Applications The internal circuitry of the LR745 allows the PWM ICs Notebook and laptop computers to operate at a V voltage below their start-threshold CC Telecommunication power supplies voltage after start-up. The auxiliary voltage can be less Battery chargers than the start-threshold voltage, which allows for Motor controllers improved efficiency. Current from the high voltage line is drawn only during the start-up period. After start-up, the internal, high-voltage line is disconnected from the IC, thereby reducing the continuous power dissipation to a minimum. 2015 Microchip Technology Inc. DS20005394A-page 1LR745 Package Type GND VOUT VIN VOUT GND VIN GND TO-92 TO-243AA (SOT-89) See Table 2-1 for pin information DS20005394A-page 2 2015 Microchip Technology Inc.