STMICROELECTRONICS STEVAL-A6986IV3 Evaluation Board, A6986I, Isolated Buck-Boost Converter, Power Management

STEVAL-A6986IV3 is an evaluation board based on ST A6986I. The A6986I is designed for isolated applications and normally implements an buck architecture. The STEVAL-A6986IV3 board adopts an inverting buck-boost topology at the primary side (instead of a standard buck), hence building an is buck-boost (so called from now on). The advantages in using the is buck-boost instead of a buck are mainly: higher deliverable power at the secondary side, optimization of the transformer design. The input voltage is up to 28V. Since the primary side performs an inverting buck boost conversion, the primary output voltage is negative. The secondary side of the board consists of four independent windings, each one intended to provide the supply for a gate driver. The is buck-boost architecture exploits the power capability of the A6986I, delivering up to 60mA for three secondary channels and up to 180mA for the fourth one.

• Designed for is buck-boost topology
• 4V to 28V operating input voltage and selectable isolated voltage pairs: 18V/ - 5V or 15V/ - 8V
• Four isolated outputs with regulated dual voltage
• 60mA typ for the outputs dedicated to high-side drivers
• 180mA typ for the output dedicated to the low side drivers
• Primary output voltage regulation
• Secondary post regulation dedicated to each output with accuracy <±1%
• No optocoupler required, 250KHz operating switching frequency
• Peak and reverse current protections and thermal protection
• Protection against overcurrent and short circuit events at the isolated outputs