| US 7,550,897 B2 | ||
| Electronic drive system for a droplet spray generation device | ||
| Anthony Hailes, Hertfordshire (United Kingdom) | ||
| Assigned to The Technology Partnership PLC, Melbourn, Hertfordshire (United Kingdom) | ||
| Appl. No. 11/547,806 PCT Filed Apr. 06, 2005, PCT No. PCT/GB2005/001317 § 371(c)(1), (2), (4) Date Oct. 06, 2006, PCT Pub. No. WO2005/097348, PCT Pub. Date Oct. 20, 2005. |
||
| Prior Publication US 2007/0176958 A1, Aug. 02, 2007 | ||
| Int. Cl. H01L 41/09 (2006.01); H02N 2/06 (2006.01) | ||
| U.S. Cl. 310—317 [310/316.03] | 7 Claims |
| 1. An electronic drive system for a droplet spray generation device of the type having a droplet generator including a perforate
membrane driven by a piezoelectric transducer, the electronic drive system comprising:
a drive circuit including a programmable micro-controller and a power supply for converting, in use, a battery supply voltage
to power the device,
a power amplifier connected to receive electric power from the power supply and supply a drive signal to the piezoelectric
generator in use, the power amplifier comprising a resonant bridge circuit; and
wherein the micro-controller is connected to the power amplifier and outputs, in use, a pair of signals in anti-phase to the
resonant bridge circuit to control the operation of the power amplifier, including the drive signal operating frequency at
substantially its resonant frequency,
and wherein the micro-controller is arranged
to measure the current provided to the power amplifier by the power supply at a plurality of different input frequencies,
to determine, as the resonant frequency of the droplet generator, the frequency of such different input frequencies at which
the maximum power is consumed by the amplifier, and
to set the drive signal operating frequency at the resonant frequency.
|