Maxim MAX13256 H-bridge transformer driver

Maxim has introduced the MAX13256, an H-bridge transformer driver with a wide input-voltage range for isolated power supplies.

It allows engineers to design a highly efficient (up to 90%) isolated DC-DC converter. The device drives a transformer’s primary coil with up to 300 mA from an 8 to 36 V DC supply which can deliver up to 10 W of isolated power.

Users can choose their own transformer winding ratio that defines the output voltage allowing the selection of virtually any isolated output voltage.

This supply range eliminates external voltage regulation and integrated protection features prevent system-level failures. By eliminating 16 discrete components, the driver simplifies BOM complexity and reduces footprint, with high integration in a TDFN package.

Smart grid applications using wired interface communications require isolated power to protect against high-voltage mains that can damage both the installer and power meter’s internal electronics.

The isolated power is typically generated with a transformer and discrete components that increase the solution size and add cost. The device drives the transformer that acts as the additional form of isolation from high-voltage mains.

A smart grid has requirements for input voltage and output power that vary, based on the type of interface used to communicate with the smart meter. The 8 to 36 V input voltage range addresses these power-supply input requirements. It also eliminates external voltage regulation and enables flexible transformer options to satisfy a wide range of power outputs.

The driver also integrates protection features that prevent system-level failures. Adjustable current limiting allows indirect limiting of secondary-side load currents. An overcurrent limit is set by an external resistor over the 215 – 650 mA (typ) range.