A 40 nm integrated cryo-CMOS 120 MHz switching power converter for power management at 4 K aiming large-scale quantum computers

Abstract

Quantum computers require a complex cryogenic electrical interface to avoid the wiring bottleneck between the cryogenic qubits and the room-temperature controllers. Such cryogenic electronics are typically supplied through long cables that introduce significant resistive and thermal losses, hindering efficiency and scalability. To circumvent this hurdle, this work presents a fully integrated cryo-CMOS synchronous buck converter operating at 4 K that enables the use of a high-voltage low-current supply to reduce resistive losses in the cables. Implemented in 40 nm CMOS, the converter targets a 7 V input, a 1.1 V output, and load currents of 100-300 mA, while achieving 63% efficiency by exploiting the cryogenic behavior of active and passive CMOS devices. These results pave the way for the power-management systems required in the cryo-CMOS SoC controlling future large-scale quantum computers.