Synchronous buck converter with PMBus single-phase FCCM operation

The Texas Instruments TPS546E25W device is a highly integrated, buck Converter with D-CAP4 control topology for fast transient response. All programmable parameters can be configured via the PMBus interface and stored in NVM as new default values, thereby minimising the external component count. Pin-strap options provide for configuration as primary or secondary, stack position and stack number, DCM (single phase only) or FCCM, overcurrent limit, fault response, internal or external feedback resistor, output voltage selection or range, switching frequency, and compensation.

The PMBus interface with 1MHz clock support provides a convenient, standardised digital interface for configuration as well as telemetry of key parameters, including output voltage, output current, and internal die temperature. Response to fault conditions can be set to restart, latch off, or ignore, depending on the system's needs. Two, three, and four of the devices can be interconnected to provide up to 50A on a single output.

The TPS546E25W offers an option to overdrive the internal 4.5V LDO with an external 5V supply through the VDRV and VCC pins, thereby improving efficiency, reducing power dissipation, and enabling start-up with a lower input voltage.

The TPS546E25W is a lead-free device and is RoHS compliant without exemption.