描述 Description

The LX1672 is a highly integrated power supply controller IC Key featuring two PWM switching regulator stages with an additional onboard linear regulator driver. The two constant frequency voltage-mode PWM phases can be easily configured as a single Bi-Phase high current output, two independently regulated outputs, or as a DDR memory I/O supply with a tracking DDR termination voltage supply. 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.In bi-phase operation, the high current output utilizes a patented current sharing architecture, called Forced Current Sharing?, to allow accurate current sharing without the use of expensive current sense resistors. This patented approach also gives system designers maximum flexibility with respect to MOSFET supply. Each phase can utilize different supply voltages, for efficient use of available supplies, while programming the ratio of current pulled from each using one of three methods (see application section).The LX1672 incorporates fully programmable soft-start sequencing capabilities. Each output can be configured to come up in any order necessary as required by the application.The LX1672 features an additional Linear Regulator Driver output, which when coupled with an inexpensive MOSFET is capable of supplying up to 5A for I/O, memory, and other supplies surrounding today’s micro-processor designs.Each regulator voltage output is programmed via a simple voltage-divider network. The LX1672, utilizing MOSFET RDS(ON) impedance, monitors maximum current limit conditions, in each PWM phase without the use of expensive current sense resistors.Key Features: Up to Three Independently Regulated Outputs DDR Termination Compliant Bi-phase Current Sharing Outputs As Low As 0.8V Generated From An Internal 1% Reference Multiphase High Current Output Reduces Required Capacitance Integrated High Current MOSFET Drivers 300kHz and 600kHz High Frequency Operation Minimizes External Component Requirements Independent Phase Programmable Soft-Start and Power Sequencing Adjustable Linear Regulator Driver Output No current-sense resistors??ROHS, PB Free-->??ROHS