University of California San Diego and French lab CEA-Leti have got together to create a novel high-voltage drive for electrostatic and piezoelectric actuators in mini-drones, describing the technique at ISSCC in San Francisco this week.

ISSCC25 paper 20.9 UsanDiago LETI

The aim is to deliver tens of miliwatts at tens of volts and ten of hertz into a highly capacitive load, all from a 3 – 5V battery, using compact lightweight electronics.

The designers rulled out switched capacitor or inductive boost converters due to the size of their capacitors or inductors, so what was left?

The answer in this case was flying batteries:  18 small (1704 SMD) solid-state cells instead of one large cell, switched in various series-parallel combinations to deliver various voltages – allowing the actuators to be driven smoothly.

This arrangement generated up to 56.1V when driving a 400nF load “at a few Hz”, according to the team, and a 2nF load was driven at 20Hz for over 50 hours from a 1.8g battery.

On the 0.18μm control and current switching IC, each of the 18 power cells gets four switching transistors and their necessary level-shifters.

Each power cell also functions like a bootstrap capacitor to provide the power rail for the level-shifters.

“Micro-drones and micro-robots already require a battery, and so it costs us next to nothing to use a solid-state battery, split it up into smaller pieces, and dynamically rearrange the small pieces to generate the voltages we need,” said UC San Diego’s Professor Patrick Mercier. “This is the smallest and lightest way we could think of to generate the high voltages needed to run these sorts of systems.”

ISSCC 2025

Paper 20.9 University of California, San Diego, CEA-Léti, Grenoble.
An autonomous and lightweight microactuator driving system using flying solid-state batteries