Description:The EPA-104 is a high voltage (±200 Vp), high current (±200 mA), and high frequency
(DC to 250 KHz) amplifier designed to drive higher capacitive (low impedance) loads, such as low voltage stacks, at
moderate frequencies; or lower capacitive loads, such as ultrasonic devices, at high frequencies.
The ability of an amplifier to drive a piezoelectric device statically is determined by its voltage capability and stability.
Its ability to drive a piezo device dynamically is determined by the capacitance of the actuator, the voltage to which
it must be driven, and the number of times it must be charged and discharged per second. These establish the current,
voltage, and frequency requirements of the amplifier.
Low electrical noise, low distortion: The EPA-104 is made with a high quality Apex ® High Voltage
Hybrid Operational Amplifier, and utilizes high regulation linear power supplies. It is housed in a heavy high
conductivity aluminum case which provides an excellent shield from external electromagnetic interference.
Input and Output Protection: Piezo loads present special problems to electronic drivers.
Piezo Systems amplifiers provide heavy input and output protection to take care of all shorting, turn-on, turn-off, and load
generated voltage occurrences which can damage either the amplifier or your actuator.
Manual Bias Controls (voltage polarity and DC offset): Useful for making manual adjustments of drive
voltage to verify piezoelectric actuator static motion, for static settings, or for applying DC bias to dynamically driven
piezo actuators such as piezoelectric stacks.
Input Control (via analog signal to the BNC input connector): Accepts up to ± 10 V signal waveforms
from external signal generators, computer controllers, or feedback networks from DC to rated frequency. The combined
AC plus DC offset voltage is adjustable from zero to the rated voltage.
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 piezoelectric 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.
SPECIFICATIONSValues to be used as guidelines.
± 200 volts peak
± 200 mA peak
40 watts peak
DC to 250 KHz
Into 1 K ohm resistive load: Flat, DC to 300 KHz; 3db roll-off,
400 KHz; Into capacative load: see chart below.
Variable gain, adjustable from 0 to 20X
-.083° per KHz, typical
Slew Rate (no load)
380 volts / µsecond
Maximum Input Voltage
± 10 volts peak
Maximum DC Component
± 10 volts DC
Direct DC coupling only
Variable DC Offset
Normally zero volts. Adjustable to ± 200 volts peak
Capable of driving any load within the voltage and current
limitations of the amplifier
Output Noise (300 KHz bandwidth)
2 mvrms with input shorted
AC Power Source
User settable: 100-130 VAC, 50/60 Hz; or 200-250 VAC, 50/60 Hz
Overload, short circuit and thermal protection.
Front Panel Controls
Gain adjust; DC Polarity selector (+, 0, -); DC offset adjust
Rear Panel Controls
On/off switch; Line voltage selector
BNC for Input (ground referenced); safety shrouded banana jacks for
high voltage output terminals (ground referenced)
6.4 kg (14 lbs)
12" (305mm) long x 12" (305mm) deep x 5" (127mm) high
PEAK VOLTAGE DELIVERED TO CAPACATIVE LOAD AT PEAK CURRENT RATING versus
Steady state sinusoidal waveforms,
Temperature = 25 ° C