Low Cost Small Piezo Amplifier
The EPA-008 is a high voltage linear amplifier with an integral high voltage power supply. It is designed to be small in size and convenient for both bench top experimentation and OEM installation. It utilizes a single 15 VDC power input which can be provided directly, or by using either the 115VAC/60Hz or 100-240VAC/50-60Hz Universal power adapter (provided). It accepts a +/- 10 Vpeak ground referenced input signal and produces a +/- 180 Vpeak ground referenced output drive signal.
It is designed to be used as a high voltage drive source for various piezoelectric actuating devices operated from DC to the low audio frequency range.
Input Power: For bench top experimentation, where minimum setup time and flexibility of amplifier location are advantageous, an AC adapter is provided for DC input power. Two types are offered:
For OEM or permanent installation, a set of screw terminals is provided for DC input (13 to 18VDC) power.
Signal Input: Input to the amplifier is made by connecting wires to the screw terminal connector on the I/O panel at one end of the unit. This is a ground referenced ± 10 Vpeak low voltage input.
High Voltage Output: A ground referenced output from the amplifier appears at the two screw terminals on the I/O panel.
Loads: The EPA-008 is designed for driving piezoelectric actuator loads.
Input and Output Protection: Piezo loads present special problems to electronic drivers. The EPA-008 provides input and output protection to take care of all shorting, turn-on, turn-off, and load generated voltage occurrences which can damage either the amp or your actuator.
Estimating the Current Requirement of a Piezoelectric Actuator
To estimate the peak current requirement of a piezoelectric actuator, solve the appropriate equation:
Ipeak (in Amperes) = 2 π f C Vpeak - (driven with a sine wave)
Ipeak (in Amperes) = 4 f C Vpeak - (driven with a triangle wave)
Ipeak (in Amperes) = C dV / dt - (driven with a square wave)
Where f is the maximum operating frequency in Hertz, C is the capacitance of the piezo device in Farads, dt is the square wave rise time, and Vp is maximum peak drive voltage. The amplifier must be able to supply Vp, lp and f simultaneously.
|Maximum Voltage||± 180 volts peak|
|Maximum Current||± 30 mA peak continuous|
|Output Power||5.4 watts peak|
|Frequency Range||DC to 1.5 KHz|
|Voltage Gain||Fixed: 20X ± 5%|
|Maximum Input Voltage (AC plus DC)||± 10 volts peak|
|Maximum DC Component||± 10 volts DC|
|Input Coupling||DC coupled|
|Input Impedance||10K ohm|
|Output Coupling||DC coupled|
|Output Ripple||typically < 35 mVrms, with input shorted|
|Power Source||+ 13 VDC to +18 VDC, 750 mA|
|Current Draw||400 mA no load; 700 mA full load|
|Circuit Protection||Overload, short circuit and thermal protection|
|Indicators||Green LED "on" indicator|
|Cooling||Internal brushless DC fan|
|Weight||256 g (.56 lb)|
|Dimensions||6.2" (157mm) long x 3.3" (84mm) wide x 1.8" (46mm) high|
Peak Output Voltage vs. Frequency For Various Capacitive Loads
|Steady state sinusoidal waveforms,
Temperature = 25 ° C
EPA-008 Application Diagrams
- Open loop DC drive for positioning
- Open loop AC drive for sound or vibration source
- Closed loop position control
- Wiring the EPA-008 for variable gain
- Powering the EPA-008 from a 24 V DC supply using zenner diodes
- Powering the EPA-008 from a 24 V DC supply using a voltage regulator
- Powering the EPA-008 from a 12 V car battery
- Typical No-Load frequency response