TDK-Lambda's UK PSU design centre is predicting simplified topologies when GaN FETs and diodes become available.
The centre in Devon has been in the vanguard of advanced resonant topologies, and was the first company to produce an PSU with all-digital control loops without recourse to a large processor - using only an 8bit microcontroller.
Resonant topologies are used to increase efficiency at the expense of higher component count.
"Right now, we are not trying to invent new topologies, we are focussing on devices," marketing director Martin Southam told Electronics Weekly. "With GaN, we might be able to go back to hard-switched [non-resonant] topologies and retain efficiency."
In 2014, the firm expects GaN diodes to become available could offer a lower cost replacement for the SiC diodes currently used in high-performance power factor correction (PFC) circuits, followed by GaN FETs that have better speed, thermal performance and losses compared with the current silicon types.
Combined with conventional PCBs, ceramic substrates are likely to increase power density in open-frame supplies of 400W and upwards.
"This came out of a research project with the University of Sheffield a few years ago," said Southam.
All-software digital loops could have their days numbered as microcontroller makers increasingly adding specialist hardware blocks for power supply control.
"We are working under NDA [non-disclosure agreement] with several device manufacturers to evaluate and optimise the next generation of digital signal controllers. People like TI look to optimise versions for power conversion," said Southam.
Digital control has added control sophistication that would be impossibly expensive in analogue hardware, particularly for supplies feeding widely varying loads.
For example: different control loops switched in for different operating modes, and adjustable conduction angle control in PFCs to boost efficiency at low load.