Miniaturized Arbitrary Waveform Generator for Micropumps with Piezoelectric Actuators

Inhalt:
Microdosing systems with micropumps have multiple applications in the biomedical field, e.g., drug delivery or implants. Many of these applications pose challenging restrictions in terms of system size, which is why micropumps are attractive. However, not only the microfluidic actuator itself, but also its driving unit needs to be miniaturized whilst preserving optimal performance. In the case of piezoelectric micro diaphragm pumps the performance strongly depends on the piezoelectric actuator and its driving signal in terms of signal form, frequency, and voltage amplitudes. We introduce a pump driver with custom signal generation to meet the requirements of the micropump while remaining small with an outline of 22x11.5 mm². This driver features a combined boost and boost-buck converter where the necessary Pulse-Width Mod-ulation (PWM) is controlled by a microcontroller. The chip receives feedback from the high and low voltage generation to calculate the necessary PWM outputs and reach its target wave points. Frequency, waveform, as well as positive and negative peak voltages can be changed by user input. In this work, the signal generation from five Printed Circuit Boards (PCB) were measured, to demonstrate the capability of the system. Measurements with two wave forms include negative peak voltages from -10 V to -60 V and positive peak voltages from 50 V to 110 V with frequencies of up to 600 Hz. The miniaturized circuitry design enables flexibility for applications that require miniaturization. The flexible wave form generation enables to minimize the mechanical stress on the bending actuator and allows to optimize dosing precision and pressure generation.