Wide input voltage is a specialty of this type of DC-DC converter, here’s an app note from ON Semiconductors on SEPIC converters. Link here (PDF)
The single−ended primary−inductor converter (SEPIC) is a type of DC/DC converter that allows the electrical potential (voltage) at its output to be greater than, less than, or equal to that at its input.
Like other DC−DC switch−mode power supply converters, the SEPIC exchanges energy between inductors and capacitors to convert from one voltage to another voltage. Typical applications for a SEPIC regulator are:
• Battery−operated equipment and handheld devices
• NiMH chargers
• LED lighting applications
• DC power supplies having a wide range of input voltages