PDu100 Micro Piezo Driver
|Power Supply||3 V to 5.5 V|
|Max. Unipolar Output||+100V|
|Max. Bipolar Output||+/-100 V|
|RMS Output Current||33 mA|
|Average DC Current||15 mA|
|Power Bandwidth||3.2 kHz|
|Peak Output Current||100 mA|
|Signal Bandwidth||60 kHz (unloaded)|
|Dimensions||11.8 x 12.9 mm (0.46 x 0.51 in)|
|Weight||560 mg (0.018 oz)|
|Input Voltage||Vs/2 +/- 1.8V (Zin = 100k)|
|Input Offset||+/- 100 mV|
|Overload Protection||Thermal and current|
|Noise||70 mV RMS (10uF Load)|
|Environment||-40 to 70 Celsius (-40 to 158 F)
|Quiescent Current||25 mA (1 mA in Shutdown)|
- The PDu100 is the industry’s smallest and lightest driver for piezoelectric actuators. It can be used to drive two-wire piezoelectric actuators and benders up to +/-100 V. It can also drive three-wire piezoelectric benders and stack actuators up to +100 V. Applications include battery powered robotics, piezoelectric motors, and ultra low-power positioning and manipulation systems.
- Key features include:
- +/-100V Output voltage range for piezo actuators and two-wire benders
- +100V Output voltage range for stack actuators
- Bias supply for three-wire bender actuators
- Output current: 15mA
- Supply voltage: 3V to 5.5V
- Dimensions: 12x13mm (0.5x0.5in)
- Mass: 0.5 grams (0.018oz)
The system block diagram is illustrated in Figure 2. A boost converter generates a high-voltage rail to supply a pair of complementary amplifiers. A single output can be used to drive a unipolar load up to +100 V or both amplifiers can be used to produce +/-100 V.
The input is selectable between a unipolar signal biased at half the supply voltage or a bipolar signal. The amplifier gain is 27.5 so a 3.6 Vp-p input will produce a 100 Vp-p output. Both amplifier channels are biased at half the output range (50 V).
The overall system gain is determined by the output configuration. The possible combinations are listed below.
|Output Type||Gain||Input Range||Output Range|
|Unipolar||27.5||0.5 Vs +/- 1.8V||100V|
|Bipolar||55||0.5 Vs +/- 1.8V||+/- 100V|
Both outputs are biased at approximately half the HV bus voltage, e.g. 50 V. The output voltage equations are listed below.
|Output Type||Output Equation|
The maximum average output current is 15 mA. However, for periods less than 100 us an output current of approximately 100 mA is possible. This is useful for achieving small, high-speed step changes in the output voltage.
The output slew-rate of the PDu100 is 1 V/us. Therefore, the maximum frequency sine-wave is
The power bandwidth for each voltage range is listed below
|Voltage Range||Unloaded Power Bandwidth|
|60 V||5.3 kHz|
|70 V||4.5 kHz|
|90 V||3.5 kHz|
|100 V||3.2 kHz|
With a capacitive load, the power bandwidth is limited by the maximum output current. For a sine wave
The average DC current is the average current flowing in either the positive or negative direction. For a sine wave, the average DC current is related to the RMS current by
The power bandwidth for a range of load capacitances and output voltages is listed below.
|Load (uF)||60 V||100 V||+/-100 V|
For a BIPOLAR CAPACITIVE LOAD, the power bandwidth is halved since the voltage range is doubled.
In the following figures, the maximum peak-to-peakvoltage is plotted against frequency for a range of capacitive loads.