Who Owns Heyday's EIC Accelerator SiC Gate Driver? Allegro

Heyday Integrated Circuits no longer exists as a company. The fabless chip designer from Grasse, on the French Riviera, was bought by Allegro MicroSystems, a Nasdaq-listed US semiconductor maker, on 1 September 2022, according to Allegro's completion announcement and its annual report for the year to March 2023. Twenty-six months earlier it had started Hey3012, an EIC Accelerator pilot project with an EU contribution of €2,437,750 to design an isolated gate driver for silicon carbide (SiC) power transistors. The Commission terminated the project on 20 September 2022, nine months before its planned end, according to CORDIS. In June 2023 Allegro's French subsidiary, as sole shareholder, dissolved Heyday without liquidation, and the company was struck off the Grasse trade register the following month, according to notices in the BODACC and the French company register.

The record is a common one for small European chip designers: EU money took the technology a step further, and a larger, non-European buyer took the company. What it is not is a failure. Allegro now sells the technology under its own brand.

Absorbed Into Allegro

Allegro announced the deal on 31 May 2022, saying it would pay "approximately $19 million in cash" for a company that put an isolated gate driver, an isolated power supply and the passive components into one small package, according to Allegro's announcement, also carried by Stock Titan. Allegro's later 10-K puts the final purchase price at $20,245 thousand, including payments to settle Heyday's debts and other obligations, and reports $19.9 million of cash paid for the acquisition in the fiscal year. The French register records the change of control: in September 2022 Allegro MicroSystems France SAS replaced Joseph Luke Duigan as president of the company, according to the BODACC.

Heyday's own website, heyday-ic.com, now redirects to Allegro's gate driver product pages. Whether the Grasse team still works for Allegro in Grasse is not public.

The Technology: Power and Signal Through One Transformer

A gate driver is the small chip that switches a power transistor on and off. In a typical half-bridge, the driver of the "high-side" transistor floats at the switching voltage and needs its own power, normally supplied by a bootstrap circuit or a separate isolated DC-DC module. Heyday's idea, which it branded Power-Thru, was to send both the switching signal and the drive energy across a single integrated transformer, so that no bootstrap parts and no external isolated supply are needed. Heyday's chief executive Joe Duigan and then chief technology officer Karl Rinne described the approach in 2016 for the company's first product, the HEY1011, a 650V high-side driver for gallium nitride (GaN) transistors, in an article for Electronic Design: they wrote that bootstrap losses become prohibitive at around 500 kHz and above, and that their driver could stay on indefinitely, which bootstrap circuits cannot.

Allegro's 10-K describes the same technology in its accounts as "PowerThru technology that accomplishes gate driver power and signal transmission through an integrated transformer, reducing the size and complexity of the gate drive solution." The same filing calls it a "first-to-market technology" that integrates the isolated DC-DC supply and the isolated gate driver and is "more efficient than competitive solutions that require two chips", a claim Allegro makes for its own product. The archived Heyday website of May 2022 claimed sales of more than 10,000 gate drivers and said its SiC and MOSFET drivers were "pre-series" parts still to be released. The sales figure could not be verified independently.

What the EIC Project Promised

Heyday was selected at the 19 May 2020 cut-off of the EIC Accelerator pilot, the Horizon 2020 Green Deal round, with blended finance (a grant plus EIC equity), according to the European Commission's list of selected companies, which names Heyday as the only beneficiary of the Hey3012 project. CORDIS lists the grant agreement, signed on 23 October 2020, with a start on 1 July 2020, a planned end on 30 June 2023, a total cost of €3,482,500 and an EU contribution of €2,437,750. It is Heyday's only EU-funded project on CORDIS.

The objective on CORDIS set out the plan: having proven Power-Thru on "relatively low power GaN switches", Heyday would design a self-powered isolated gate driver for most SiC switches, start "Hey3012 sales in 2022" in automotive, solar and industrial motors, and aim for 25% of an isolated gate driver market it put at €1.8 billion by 2025. The same text appeared on Heyday's EIC project page.

The only periodic report, covering 1 July 2021 to 30 June 2023, says Heyday completed its technical work packages 2 and 3 and produced "the first batch of prototypes HEY3012", and that "electrical testing validates the basic working of the Hey3012". It adds that further improvements and testing "fall outside of the scope of the project due to the acquisition of the beneficiary by Allegro Microsystems", and that new circuit designs were "being reworked into patent applications", according to the CORDIS reporting page. No Hey3012 patent application by Heyday or Allegro could be identified for this article.

1. Self-powered isolated gate driver for SiC switchesDeliveredFirst prototype batch built and electrically tested, per the periodic report.
2. Project run to 30 June 2023PartlyTerminated on 20 September 2022 after the sale to Allegro.
3. Hey3012 sales from 2022Not achievedNo Hey3012 was sold; Allegro's SiC Power-Thru driver, the AHV85311, is still listed as pre-release.
4. 25% of the isolated gate driver marketNot achievedNo market share figure has been published by Heyday or Allegro.

What Happened to the SiC Driver

Allegro launched its first Power-Thru product, the AHV85110 for GaN transistors, in July 2023, claiming up to a 50% smaller footprint and a 40% efficiency gain against competing parts, according to Components101 and itismagazine, which quoted Allegro's Vijay Mangtani crediting the Heyday acquisition. The AHV85110 and AHV85111 are the two isolated gate drivers on Allegro's gate driver page.

The SiC part, the market Hey3012 was funded for, came later. In November 2024 Allegro presented the AHV85311, "a high-power isolated gate driver designed to accelerate the development of Silicon Carbide (SiC)-based power electronics", at Electronica, according to its press release. In January 2026 it added an AHV85003/AHV85043 chipset for 800V SiC systems in AI data centres and electric vehicles, calling the AHV85311 its "flagship" integrated solution, according to Power Electronics News and Electropages. On 15 October 2026 the AHV85311 product page still read: "This is a pre-release product, engineering samples available upon request." Whether the AHV85311 descends directly from the Hey3012 prototypes is not stated by Allegro; its 10-K booked $1.6 million of in-process research and development from Heyday, described as "efforts to expand the power capability of these gate drivers for wide-bandgap semiconductor technology".

The Money

The French company's filed accounts show small revenues that peaked at €795,477 in 2019, the year before the award, and fell to €289,748 in 2020 and €66,238 in 2021, according to annual accounts ratios published by the INPI on data.economie.gouv.fr and the 2021 figures shown by the French company register. The operating result (EBIT) was a loss of €419,547 in 2020 and €792,525 in 2021, while the net result was a profit in both years (€98,218 and €256,725); the accounts data do not show which items made up the difference. Heyday's team also worked from Ireland and the UK, so the French accounts may not cover the whole business; no accounts of other group entities were found.

Before the award Heyday had raised €2 million of private funding, according to CORDIS; its website named a business angel, Garry Tomlins, among its advisers. Investors in individual rounds were not published. The registered share capital rose from €16,050 in 2015 to €20,000 in 2017 and stood at €20,250.80 in September 2022, according to BODACC notices.

Why It Matters for Europe

SiC and GaN power chips decide how much energy is lost in electric car chargers, solar inverters and data centre power supplies, and the EU treats them as strategic. The European Chips Act, in force since 21 September 2023, aims to "ensure the resilience of supply chains" and lists SiC device and wafer projects among the plants approved for state aid, according to the Commission. In May 2024 the Commission approved €2 billion of Italian aid for STMicroelectronics' SiC plant in Catania, with competition commissioner Margrethe Vestager saying it would "ensure our access to a reliable source of power-efficient chips used for example in electric vehicles and charging stations", as reported by Euronews.

Heyday's story shows the other side of that policy. The EU co-funded a French design for the chip that drives these transistors, and two years later the intellectual property belonged to a company based in Manchester, New Hampshire, the dateline of Allegro's announcements. That outcome is legal and common, and it gave Heyday's backers an exit, but the Power-Thru technology is no longer a European-owned asset.

The Verdict

This article is based on public records and published statements, linked throughout. Allegro MicroSystems and the EIC were not asked for comment.