Instruments For Testing Your Innovations
Piezo amplifier is ideal for driving high-
Figure 2 and 3 illustrates two examples of TS250 piezo amplifier high-
Figure 1. The TS250 piezo driver amplified signal and drives a piezo transducer.
Figure 2. TS250-
Figure 3. TS250-
The TS250 and the TS200 are both high-
Figure 4. Connect two TS250 in parallel to increase the output current by 2x.
Related Technical Information
Note 1. Piezo element is capacitive which means their power is reactive. The TS250 output current is adjusted for reactive power.
Note 2. Peak resistive current is specified at maximum voltage minus 1V. For ex maple 19V for the TS250-
Some piezoelectric devices are operating only at resonant frequency. An example of these devices is Langevin Ultrasonic Transducers for ultrasonic washing and cleaning applications. At the piezo resonant frequency, these devices’ impedance are actually resistive as opposed to capacitive. These resonant pzt devices often specified operating power rather than voltage. For example, a resonant piezo transducer specified 16 ohm resistance at resonant frequency and the maximum operating power is 32 watts. The TS200 or TS250 ultrasonic amplifier can output up to ~70 watt.
To chose a piezoelectric amplifier, select the TS250/TS200 model that outputs the highest current using Table 1 above. The highest current is calculated by the piezo amp’s maximum voltage divided by the resonant resistance, or the peak resistive output current in Table 1, whichever is the lowest. For example, for a 16 ohm high-
As discussed above, high-
One simple technique to increase piezo driver output current is to make the high-
The TS250 outputs up to 65V. If higher voltage is required, an isolated DC power supply can be used to boost the voltage higher. For example a unipolar piezoelectric actuator needs a DC bias voltage of 100V and a 80Vpp sinewave. The operating swing voltage range is from 60V to 140V. Using an isolated DC power supply in conjunction with the TS250 piezo driver can generate extremely high power (reactive or real) and high current.
As shown in Figure 5, the piezoelectric amplifier driver is connected in series with the DC power supply. Make sure the TS250 driver negative output terminal is connected to ground. The ground connection is common with the function generator ground and the piezo load. Most DC power supplies already have capacitors internal. It is still recommended to add external bypass capacitors, especially for high frequency piezo. You may use multiple capacitors connected in parallel. It is recommend to use low ESR and ESL ceramic capacitors, but a mix of electrolytic, tantalum, and ceramic caps are acceptable. The total capacitance should be large enough such that their impedance is much lower than the pzt load impedance.
For example, if the high-
Other than high current, piezoelectric actuators also require high voltage. Their operating voltage range is generally greater than 10V and can go up to 100V or more. Most signal generator such as those waveform generators are less than 5V, but piezo elements require higher voltage. Therefore a high-
Figure 2. Simple resistive impedance matching increases the piezoelectric driver output current.
Figure 5. Using a piezo amplifier and a DC power supply for high-
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