Following the BD7F100, the company is now expanding the series with the new BD7F200, covering all applications with a power range of 1W to 10W and offering two different package options. In addition, ROHM is introducing an evaluation kit for the BD7F100, which simplifies the design of isolated flyback transformer applications.
Isolation is almost always incorporated into electronic equipment to provide protection against shocks and damage. In this respect, numerous applications such as energy meters, industrial programmable logic controllers (PLCs), industrial fieldbuses, industrial automation, and gate drivers for insulated-gate bipolar transistors (IGBTs) and SiC MOSFETs require isolated DC/DC converters. These devices provide galvanic isolation, improve protection, and increase noise immunity in systems. They enable the creation of multiple output voltage rails and dual-polarity (positive and negative) rails. High-voltage, high-power industrial applications (such as energy storage systems and solar inverters, which are experiencing increasing adoption rates) are no exception, as they demand even greater reliability due to harsher temperature conditions and the need for long-term continuous operation.
Conventional solutions use an optocoupler and other components to control the isolated flyback power supply in the feedback loop. However, this creates problems related to current consumption and reliability (such as circuit size and product lifespan). The BD7F series, with its optocoupler-free architecture, allows designers to simplify transformer development and reduce costs.
It reduces the number of external components by nearly half by eliminating the need for an optocoupler and a phase compensation network, thus offering greater energy savings, reliability, and miniaturization. Furthermore, it uses a new adaptive method for ON-time control that improves load response time (a drawback of conventional isolated power supply ICs), while voltage fluctuation during load transients is limited to less than 200mV, further enhancing reliability. It also incorporates additional protection features.
With the aim of providing greater support to designers during the device evaluation phase, and therefore in the application design phase, ROHM also presents a new evaluation kit BD7F100HFN-EVK-001, which includes the BD7F100HFN and incorporates 6 different input and output configurations.
Samples and the evaluation board will be available for purchase. This board allows for designs with an input voltage of 24V and an output voltage of 5V, with a current range of 13.8mA to 800mA and a maximum output power of 4W.
Availability
BD7F100 Series Flyback Converters up to 5W
Availability: current
BD7F200 Series Flyback Converters up to 10W
Availability: current (samples), October 2016 (OEM quantities)
BD7F100HFN-EVK-001 24V input and 5V output (max. 800mA)
Availability: Autumn 2016
Key Features
1. High-Reliability Isolation
The BD7F series of isolated power supply control ICs is optimized for industrial equipment requiring long-term continuous operation under extreme conditions. The use of advanced power BiCDMOS processes and advanced analog technology allows ROHM to detect voltage on the secondary side and current on the primary side. This eliminates the need for the optocoupler or tertiary transformer winding required in conventional configurations, thus reducing the number of external components by half. This helps to increase reliability, save energy, and miniaturize the final product.
2. Improved Load Response Characteristics Through Adaptive ON-Time Control.
On-time control, commonly used in control ICs for isolated power supplies, is applied to minimize output voltage fluctuations caused by sudden changes in load current.
ROHM's new adaptive ON-time control method limits output voltage fluctuations to as little as 200mV, 65% less than conventional solutions (for a load current of 1A and a rise time of 100µs). This results in improved load response to instantaneous load current fluctuations, significantly increasing reliability.
3. Optional evaluation card for easy performance verification.
In addition to the control ICs, an evaluation card (BD7F100HFN-EVK-001) is available, which integrates the BD7F100HFN-LB to facilitate the evaluation of the isolated power supply's performance (24V input, 5V/800mA output). Furthermore, ROHM Semiconductor GmbH is preparing six versions of the CE-certified evaluation card (BD7F100HFN-EVK-30x) for release in October 2016.
