低输入电压驱动小型双路全桥压电马达驱动器

Piezoelectricmotorsareusedindigitalcamerasforautofocus,zoomingandopticalimagestabilization.Theyarerelativelysmall,lightweightandefficient,buttheyalsorequireacomplicateddrivingscheme.Traditionally,thischallengehasbeenmetwiththeuseofseparatecircuits,includingastep-upconverterandanoversizedgenericfull-bridgedriveIC.Theresultinghighcomponentcountandlargeboardspaceareespeciallyproblematicinthedesignofcamerasforevershrinkingcellphones.TheLT®3572solvestheseproblemsbycombiningastep-upregulatorandadualfull-bridgedriverina4mm×4mmQFNpackage.Figure1showsatypicalLT3572Piezomotordrivecircuit.Astep-upconverterisusedtogenerate30VfromalowvoltagepowersourcesuchasaLi-Ionbatteryoranyinputpowersourcewithinthepart’swideinputvoltagerangeof2.7Vto10V.Thehighoutputvoltageofthestep-upconverter,adjustableupto40V,isavailableforthedriversattheVOUTpin.Thedriversoperateinafull-bridgefashion,wheretheOUTAandOUTBpinsarethesamepolarityasthePWMAandPWMBpins,respectively,andtheOUTAandOUTBpinsareinvertedfromPWMAandPWMB,respectively.Thestep-upconverterandbothPiezodrivershavetheirownshutdowncontrol.Figure2showsatypicallayout.TinyDualFull-BridgePiezoMotorDriverOperatesfromLowInputVoltage