LX1671 Datasheet | Microsemi

I N T E G R A T E D P R O D U C T S Multiple Output Load SHARE™ PWM P RODUCTION D ATA S HEET DESCRIPTION KEY Features . Microsemi . C OM The LX1671 is a highly integrated power supply controller IC featuring ..net three PWM switching regulator stages with an additional onboard linear regulator driver. Two of the constant frequency voltage-mode PWM phases can be easily configured for a single Bi-Phase high current output or two independently regulated outputs. Each phase incorporates a fully programmable soft-start sequence. This versatility yields either three or four independently regulated outputs with full power sequencing capability giving system designers the ultimate flexibility in power supply design. In Bi-Phase operation, the high current (>30A) output can utilize different supply rails allowing Forced Current Sharing† from different sources. Power loss and noise, due to the ESR of the input capacitors, are minimized by operating each PWM output 180° out of phase. This architecture also minimizes capacitor requirements while maximizing regulator response. The additional outputs are capable of supplying up to 5A (Linear Regulator Driver) and 15A (Switching Regulator) for I/O, memory, termination, and other supplies surrounding today’s microprocessor designs. Each PWM regulator output is programmed via a simple voltage-divider network. The LX1671, utilizing MOSFET RDS(ON) impedance, monitors current limit conditions, in each PWM phase, without the use of expensive current sense resistors. The LX1671 was designed to give design engineers maximum flexibility with respect to the MOSFET supply. Each phase can utilize different supply voltages for efficient use of available supply rails. Additionally, when two phases are configured in Bi-Phase output, the Load SHARETM topology can be programmed via inductor ESR selection. There are three other methods that can also be used with Load SHARETM. These other methods are presented in the...