Synchronous dc-dc converters provide excellent performance in automotive applications

STMicroelectronics has introduced step-down and isolated buck synchronous dc-dc converters which improve performance and ease integration in automotive applications. 

The A6983 series consists of six non-isolated step-down converters in versions optimized either for low power consumption or low noise. The A6983I is an isolated buck converter. Featuring on-chip compensation circuitry, these highly integrated converters need minimal external components for functions such as filtering and feedback. The A6983I additionally needs a transformer for its isolated operation. 

The non-isolated A6983 series offers a choice of a fixed 3.3 V or 5.0 V output, or an adjustable output over a range from 0.85 V to the input voltage. The isolated A6983I allows for primary output-voltage adjustment, with the secondary voltage determined by the transformer turns ratio.

The non-isolated A6983 converters can supply a load current of up to 3 A, and achieve 88% efficiency at full load. The low-consumption A6983C variants are optimized for light-load operation at high efficiency and with low output ripple, to minimize drain on the vehicle battery in applications that remain active when parked. 

The low-noise A6983N variants operate at a constant switching frequency and minimize output ripple across the load range, making them ideal for noise-sensitive applications such as the power supply to the audio system. 

The A6983I is a 10 W-rated isolated buck converter: it performs primary-side regulation to eliminate the need for an optocoupler. Ideal for use as an isolated gate driver for IGBTs or silicon carbide (SiC) MOSFETs  in traction inverters and on-board chargers, this converter allows accurate adjustment of the primary output voltage. The transformer turns ratio determines the secondary voltage.