
DC-DC converter controller adds adaptive ON time control for higher reliability
Following the BD7F100, the company has added the BD7F200 to cover all applications with a power requirement from 1 W to 10 W, and including two different packaging options.
A newly developed adaptive ON time control method is used to improve load response time (a drawback of conventional isolated power supply ICs), while voltage fluctuation during the load transient is limited to under 200mV at a load current of 1A and rise time of 100us. As a result, load response against instantaneous load current fluctuations is improved, increasing reliability considerably.
A new BD7F100 evaluation kit with six different input and output configurations helps the design of flyback isolated applications with a 24 V input voltage and 5 V output voltage with output current range of 13.8 mA to 800 mA for maximum output power of 4 W.
Conventional solutions use an optocoupler and other components for flyback-type isolated power supply control for the feedback loop but this this generates challenges associated with current consumption and reliability (including circuit scale and product life). The optocoupler-less architecture of the BD7F allows designers to simplify the development of the transformer and to reduce costs.
The power BiCDMOS processes and proprietary advanced analogue technology allow ROHM to detect the secondary side voltage and current from the primary side. This eliminates the need for an optocoupler or tertiary transformer winding and phase compensation network required with conventional configurations, reducing the number of external parts by half which contributes to greater reliability, power savings, and end-product miniaturisation.
The BD7F200 Flyback converter Series up to 10W is sampling now with volume shipments in October. The BD7F100HFN-EVK-001 24V Input 5V Output 5V evaluation kit will be available in the autumn. With its fully controlled supply chain, ROHM can guarantee long-term availability.
