High efficiency Piezoelectric Transformer Driver in BCD6-20V technology, generating up to positive or negative 1700V output voltage, from 1V input supply

An integrated controller in BCD6 technology for piezoelectric transformer (PT) is presented. The controller, which includes both the driving and the control circuitry to maximize the space saving, can be used to implement small and compact dc-dc converters with high step-up ratios (depending on the PT) onboard of portable electronic devices. The chip can be supplied from 0.9 V to 3.3 V and allows the PT to be always driven in under zero voltage switching condition without requiring a precise matching between the inductor and the transformer characteristics. An adaptive feedback locks the proper switching frequency according with output power and temperature variations. Experimental results on a piezoelectric transformer dc-dc converter prototype are given