Two drive circuits for separately excited piezoelectric loudspeakers and piezoelectric vibrating plates

Separately excited piezoelectric amplifiers and piezoelectric diaphragms vibrate by applying AC voltage between the two terminals of the product. Taking the standard driving circuit example as an example, there are two methods, (1) using transistor circuits and (2) driving directly through a microcomputer.

(1) When using a transistor circuit

Examples of driving circuits for piezoelectric speakers and piezoelectric vibrating plates (separately excited type) using transistor circuits

The greater the voltage value applied to V, the greater the sound pressure of the piezoelectric sound element. Therefore, it is widely used when the power supply (voltage) can be ensured to be higher than the driving voltage of the microcomputer.

For the circuit components in the figure, add the following:

Rp in the diagram is essential to release the charge stored in the piezoelectric sound-generating element, so be sure to use it. Rs is for volume adjustment, please use it when needed.

When protecting the IC from the reverse voltage of the piezoelectric sounding element, the transistor becomes a buffer, but for the protection of the transistor itself, if necessary, please also consider using a Zener diode in parallel with the piezoelectric sounding element and Rp.

FETs can also be used instead of transistors.

(2) When driven directly by microcomputer

Example of driving circuit for piezoelectric loudspeaker and piezoelectric diaphragm (separately excited type) when driven directly by microcomputer

Electronic sound components have high impedance and are voltage driven, so they can be driven directly by ICs.

For the circuit components in the figure, add the following:

In order to protect the IC from damage by the reverse voltage of the piezoelectric sound element, if necessary, please also consider using a Zener diode in parallel with the piezoelectric sound element.

Please adopt a circuit design that avoids applying DC voltage to piezoelectric sound components for a long time.