Power Electronics Europe Feb/March 2023

14 POWER DENSITY https://www.allegromicro.com/en Issue 1 2023 Power Electronics Europe www.power-mag.com Power-Thru technology from Allegro MicroSystems, power is transferred to the gate drivers using a fully integrated system-in-package (SiP) gate drive (see Figure 1). The key subcomponents of the Power- Thru technology are two gate drive ICs and a tiny magnetic-based isolation structure that enables efficient power transfer across the boundary from the low-voltage signal to the high-voltage system. At first, this may seem like an ordinary solution. Compared to the wide range of isolated gate drive ICs on the market, the real and significant novelty is located inside the IC: The Power-Thru technology includes a clever and patented circuit design that allows the IC to manage both the gate drive signal and the transfer of energy from the primary IC to the secondary gate driver IC across the magnetic isolation barrier. This novel technology enables the isolation boundary to carry the drive power required to drive both the external FET switch and the gate drive signal data. Because complete electrical isolation is provided by the magnetic coupling, Power-Thru drivers are equally suitable for use in high-side, low-side, and isolated applications. The Power-Thru devices remove the need for a bootstrap circuit or an external Figure 3: The design of an EV on-board charger can be simplified and accelerated using Power-Thru technology from Allegro. Allegro Power-Thru technology can allow an on-board charger design with as few as one power rail per phase. The Allegro AHV85110 isolated gate driver shown in this example is optimized for driving GaN FETs in multiple applications and topologies. (Additional information about the AHV85110 isolated gate driver is available at https://www.allegromicro.com/en/products/motor-drivers/gate-drivers/ahv85110) AHV85110 AHV85110 Vdd Vdd AHV85110 AHV85110 Vdd Vdd AHV85110 Vdd AHV85110 Vdd AHV85110 Vdd AHV85110 Vdd Cbus AHV85110 Vdd AHV85110 Vdd AHV85110 Vdd AHV85110 Vdd Fuse EMI Filter Inrush Protection AC Input 1@ 3 kW AHV85110 EV Charger Totem-Pole PFC AC/DC EV Charger DC/DC Vdd Figure 1: Simplified functional block diagrams of conventional implementation (left) and an implementation enabled by Allegro Power-Thru (right). The Allegro solution reduces system size and component count to deliver benefits that can improve most all aspects of bringing a power product to market. Figure 2: When all phases are considered, dozens of power rails can be required in conventional on-board charger designs.