Page 72 - PEN eBook July 2023

Design

function is provided and AIF04ZPFC modules can be operated in parallel for systems requiring
greater power levels. A power-fail warning signal is provided, as is an enable output to control
downstream devices like the DC/DC converter.

The next stage is a DC/DC converter that produces a tightly regulated voltage from the approximately
380-V output of the PFC stage. This block (shown in blue) also adds further isolation and control
while reducing the output ripple and noise. The full specification of the output is largely determined
by the requirements of the following HV stage.

The final stage (shown in green) is the HV pulsed DC output that is connected to the patient. This is
often a discrete, board-mounted solution, such as Advanced Energy’s UltraVolt high-power 1/8C to
6C series. These regulated DC/DC converters are designed for HV capacitor-charging applications

that demand fast rise times with controlled voltage overshoot. Devices in the high-power C series
operate from a 24-V input, driven by the output from the blue DC/DC converter stage.

There are several devices available, all with unipolar outputs ranging from 125 to 6 kV at power
levels of 60 W, 125 W or 250 W. The highly accurate outputs have ripple values of <1.0% and a
temperature coefficient of 50 ppm/°C.

A range of factory-configured options is available, including a choice of 5-V or 10-V operation for
control and monitoring, and the header can be replaced by a D-sub connector. A factory-mounted
heatsink and threaded standoffs for PCB mounting are also available.

System control and feedback can be further enhanced by the addition of a Fiber Bragg Grating
Analyzer (FBGA) for accurate temperature monitoring. The latest FBGAs have no moving parts and
employ high-efficiency optical designs that provide excellent wavelength repeatability, resolution,
long-term stability, ultra-low power consumption, sub-millisecond response time and lifetime
calibration.

FLEXIBLE SOLUTIONS

With so many potential configurations for PFA systems, flexibility is key to ensuring that the needs
of the end application are met. Configurable AC/DC power supplies are ideal, as they provide the
medical isolation and leakage currents required, and they can incorporate multiple output modules
to power peripherals and the HV power module. This is especially beneficial during experimental
phases, as the configuration can be changed with nothing more than a screwdriver.

A good example comes from a major medical device company that recently worked with Advanced
Energy to deliver a novel PFA solution that used a non-thermal energy source and proprietary HV
electric fields to overcome the challenges of traditional temperature-based ablation modalities.
This solution required an HV DC/DC power supply to charge a capacitor with a tightly regulated

72 JULY 2023 | www.powerelectronicsnews.com