VI BRICK PRM (Pre-Regulator Module): An efficient buck-boost

The VI BRICK PRM shown in Fig. 5 uses a patented ZVS Buck-Boost Regulator control architecture (see Fig. 6) to give high efficiency step-up / step-down voltage regulation. Efficiency is maximized when the output voltage is close to the input voltage. The PRM operates at a typical fixed operating frequency of
1 MHz (1.5 MHz max.). Like VTMs, PRMs may be paralleled to achieve increased output power. A unique feature of the PRM control architecture is that the switching sequence does not change in either buck or boost mode – only the relative duration of phases within an operating cycle need be controlled.

Figure 5 - VI BRICK PRM Click image for larger view

Figure 6 - Simplified PRM schematic Click image for larger view

The PRM provides a regulated output voltage – a ‘factorized bus’ – from an unregulated input source. The combination of the PRM and VTM creates an isolated, regulated DC-DC converter. PRMs can also be used stand alone as non-isolated voltage regulators. The VI BRICK PRM has the following attributes:

• input ranges of 18 – 36 V and 36 – 75 V
• power up to 320 W
• power density up to 416 W/in³
• efficiency up to 97%
• 1.5 MHz switching frequency
• up to 100°C baseplate operation

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