Auto-regenerative shielding was a type of deflector shield used by the Hierarchy on their survey vessels.
In 2378, Lieutenant Commander Tuvok, while piloting a class 2 shuttle with Lieutenant Tom Paris, noted that Zet and Nar's starship had auto-regenerative shielding. Paris was glad that they had the element of surprise on their side. When the Hierarchy ship was under phaser attack from both the shuttle and Delta Flyer II, it was quickly apparent to the Hierarchy crew that the ships shield generator wasn't going to hold for very long. (VOY: "Renaissance Man")