Miniaturized Solid-State Battery-Based DC-DC Switched Converter

Designing efficient, compact DC-DC converters for ultra-low power applications (below mW) is challenging, primarily due to significant switching losses. In contrast to switched-capacitor converters, switched-battery converters (SBCs) have recently emerged as a solution capable of maintaining high efficiency even at ultra-low frequencies (in the Hz range), while still achieving reasonable power density. However, initial SBC demonstrations relied on button cell batteries, which limited practical adoption in compact systems. This paper presents the first experimental demonstration of an SBC utilizing a solid-state battery, resulting in a reduced footprint. We achieve a power density of 0.34mW/mm
³
with 95% peak efficiency using a 0.33mm
³
battery while maintaining less than 3.1% output relative ripple without any output capacitor. Furthermore, the paper highlights the favorable scaling laws governing SBCs, suggesting a promising design space for IoT power management.