ZHCS389C June 2011 – December 2022 DRV8662
PRODUCTION DATA
It is useful to understand how the voltage driven onto a piezo actuator relates to the current consumption from the power supply. Modeling a piezo element as a pure capacitor is reasonably accurate. The equation for the current through a capacitor for an applied sinusoid is given by Equation 3:
where f is the frequency of the sinusoid in Hz, C is the capacitance of the piezo load in farads, and VP is the peak voltage. At the power supply (usually a battery), the actuator current is multiplied by the boost-supply ratio and divided by the efficiency of the boost converter as shown by Equation 4.
Substituting typical values for the variables of this equation yields a typical peak current seen by the battery with a sine input as in Equation 5.