PDm200 Hih Performance Piezo Driver The PDm200 is a complete hih-performance power supply and linear amplifier module for drivin piezoelectric actuators. The output voltae rane can be switched between bipolar or unipolar modes with a rane of 100V, 150V, or. Up to ±400 V can be achieved in the brided confiuration. In the unipolar mode, the neative output rane is fixed at -30V for use with stack actuators. The PDm200 can drive stack actuators; standard piezoelectric actuators; two wire benders; and three-wire piezoelectric benders requirin a bias voltae. Compatible Actuators Stack Actuators Plates and Tubes Two Wire Benders Three Wire Benders 100V, 120V, 150V, up to ± up to ± 0 to with bias ± 100V with ± 100V bias The PDm200 is suited to a wide rane of applications includin: Electro-optics, ultrasound, vibration control, nanopositionin systems, and piezoelectric motors. The PDm200 is protected aainst current overload and excessive temperature. The PDm200 can be used as a stand-alone module or mounted to a base with four M2.5 threaded spacers. The PCB mountin version (PDm200-PCB) is supplied with headers for direct mountin onto a host motherboard. Power Supply Max Unipolar Output Max Bipolar Output Peak Output Current RMS Output Current Power Bandwidth Sinal Bandwidth Slew Rate Dimensions Weiht Gain Impedance Offset Overload Noise Environment Quiescent Current en nd s en Enable Sinal nd Ground Positive Supply Neative Supply Specifications ± 12 V to 34 V -30V to 200 V ± 200 V (±400 V bride mode) 300 ma 100 ma (±100 V Output) 63 khz (3.9 nf load, 100 Vp-p) 200 khz 20 V/us 71 x 38 mm 50 20 V/V 200 kω ±10 mv Any Thermal and current overload protection <1 mv RMS (1uF ) -40 to 60 C (-40 to 140 F) Non-condensin humidity 100 ma (7.5 ma in Shutdown) 71 mm PDm200 nd nd Fiure 1. Connection diaram 38 mm Outputs Low Noise Output Hih Speed Output Ground Bias Voltae
Operation The system block diaram is illustrated in Fiure 2. A power converter enerates a unipolar or bipolar supply. The output voltae rane is controlled by the voltae selector jumpers. The amplifier has a ain of 20 and an input voltae rane of ±10 V. The load is connected directly to the hih-speed output () or throuh a filter () which reduces the noise and bandwidth. In most applications, the output is recommended. When the amplifier is confiured for operation, a bias supply is enabled for bimorph bender applications. Supply Enable Voltae Selector Boost Converter Bias Voltae 200 V *With a sinle supply, the neative output voltae rane is reduced from -30 V to -20 V. In bipolar output mode, the correct positions for the L1 and L2 jumpers are listed in below in Table 2. In the ±200 V mode, a 220 Ω resistor is recommended in series with the output. See the section on Stability for more details. Output Voltae Max Min ±12 to ±14 V Power Supply Voltae ±15 to ±17 V 24 V to 30V 30 V to 34 200 V -200 V D,H D,H 150 V -150 V D,H C,G D,H C,G 100 V -100 V B,F A,F B,F A,F Table 2. Bipolar jumper confiuration The PDm200 can also be used in lower voltae applications; however, the output current may be reduced. The correspondin low-voltae jumper positions are listed below. H Output Voltae Max Min Power Supply Voltae ±12 to ±14 V 12 V to 15 V 20 H Filter 80 V -30 V A,E 80 V 0 V D,E 60 V -60 V D,H Table 3. Low voltae jumper confiurations Confiuration The PDm200 is confiurable to suit a wide rane of power supply and output voltae ranes. The output voltae rane is selected by two jumpers marked L1 and L2, each of which has four possible positions marked by the letters a to d and e to h. In unipolar output mode, the neative output rane is fixed at -30 V and the jumper L2 is always in the E position. The correct position for the L1 jumper is listed below for different power supply voltaes. Output Max Min Fiure 2. PDm200 Block Diaram ±12 to ±14 Power Supply Voltae ±15 to ±17 24V* to 30 30V* to 34 200 V -30 V D D 150 V -30 V D C D C 120 V -30 V C B C B 100 V -30 V B A B A Table 1. Unipolar jumper confiuration (L2 = E) Output Current The peak output current is approximately 300 ma and the maximum averae output current is approximately I av = 0.375 V s V out 0.01, where V s is the differential supply voltae e.. 30V, and V out is the differential output voltae rane e.. 400 V. The averae DC current is the averae current flowin in either the positive or neative direction. For a sine wave, the averae current is related to RMS current by I av = 2 π I rms. The PDm200 calculator can be used to estimate the maximum input and output current for a iven supply voltae and output voltae rane. Some common values are tabulated below. Voltae Rane RMS Current Averae Current -30 V, 150 V 118 ma 53 ma -30 V, 200 V 87 ma 39 ma -100 V, 100 V 102 ma 46 ma -200 V, 200 V 40 ma 18 ma Table 4. Averae output current for ±15V supply
Supply Current The maximum supply current is 0.5 A at full load. For a partial load, the supply current is I in = P in V s, where the required input power is P in = 1.33 V out (0.01 I av ), where V out is the differential output voltae rane and I av is the averae output current. Application Notes The amplifier input V in should not be left floatin as it will drift towards a supply rail. However, the input can be left floatin if a 1 kω resistor is connected from V in to round. This input impedance is now 1 kω. Example Applications -1.5V to 7.5V 12V -12V ±10V 0V - 10V 16V -16V 30V 150 V Piezo stack driver ±200 V Piezo driver (*see Stability ) 200 V Three-wire bender driver with bias -30V to 150V *220Ω ±200 V 0V to to 0V Heat Dissipation With a capacitive load, the majority of input power is dissipated as by the amplifier. The worst-case power dissipation is approximately 15 W. The quiescent heat dissipation can be calculated from the equation for P in in Supply Current. Note that when usin the /- output rane, the quiescent power dissipation is always >5 W so forced air coolin is always required, as discussed below. The thermal impedance of the PDm200 from junction to ambient is approximately 10 /W in still conditions. An air-flow of 100 LFM or reater is required when more than 5 W is dissipated continuously. The PDm200 will shut down when the heat-sink reaches 70 Power Bandwidth With a capacitive load, the power bandwidth is limited by the averae output current. The maximum frequency sine wave is f pwr = I av V L(p p) (C L 3.9nF) The power bandwidth for a rane of load capacitance values is listed below. Peak to Peak Voltae (uf) 100 V 200 V 300 V 400 V 0.01 55395 14029 6715 3237 0.03 22714 5752 2753 1327 0.1 7411 1877 898 433 0.3 2534 642 307 148 1 767 194 93 45 3 256 65 31 15 10 77.0 19.5 9.3 4.5 30 25.7 6.5 3.1 1.5 Table 5. Power bandwidth for a capacitive load In the followin fiures, the maximum peak-to-peak voltae is plotted aainst frequency for a rane of capacitive loads. ±5V 24V ±100V ±100 V Piezo driver
Peak to Peak Voltae (V) Peak to Peak Voltae (V) Peak to Peak Voltae (V) 120 100 10uF 30uF 1uF 3uF 3uF 1uF 1uF 300nF 300n 100nF 100n 30nF not possible, the full-rane power bandwidth should be de-rated by 50% for the ±200 V rane. 80 60 40 20 0 10 0 10 1 10 2 10 3 10 4 200 150 100 50 500 Frequency (Hz) Fiure 3. 100 V rane power bandwidth 10uF 30uF 1uF 3uF 3uF 1uF 1uF 300nF 300n 100nF 100n 30nF 0 10 0 10 1 10 2 10 3 10 4 Frequency (Hz) Fiure 4. 200 V rane power bandwidth Sinal Bandwidth With a load capacitance reater than 100 nf, the small sinal bandwidth is f bw = 1 63 C L. With a load capacitance less than 100 nf, the small sinal bandwidth is approximately 200 khz. The bandwidth of the low noise output () is approximately one quarter of the hih speed output, that is, f bw = 1 233 C L. The small sinal bandwidth for a rane of capacitive loads is listed in Table 6. Capacitance Hih Speed Bandwidth Low Noise Bandwidth 10 nf 200 khz 200 khz 30 nf 200 khz 140 khz 100 nf 158 khz 42 khz 300 nf 52 khz 14 khz 1 uf 15 khz 4.2 khz 3 uf 5.2 khz 1.4 khz 10 uf 1.5 khz 430 Hz 30 uf 530 Hz 140 Hz Table 6. Small sinal bandwidth 400 300 200 30uF 10uF 1uF 3uF 3uF 1uF 1uF 300nF300n 100nF 100n 30nF Noise The output of the PDm200 contains a small amount of switchin noise from the boost converter and random noise from the hih-voltae amplifier. With a ±15 V supply and ±100 V output rane, the RMS noise is listed in Table 7. 100 0 10 0 10 1 10 2 10 3 Frequency (Hz) Fiure 5. 400 V rane power bandwidth The power bandwidth is primarily related to the averae current limit as described above. However, when operatin at full rane, e.. ±200 V, with the minimum supply voltae, e.. ±15 V, the power supply droop can distort the top of a sinal. This effect can be reduced by increasin the supply voltae. If this is Cap Hih Speed Output Low Noise Output 10 nf 4.1 mv* 4.1 mv* 100 nf 1.3 mv* 1.3 mv* 1 uf 1.3 mv 0.72 mv 10 uf 0.42 mv 0.30 mv Table 7. RMS noise For applications requirin low noise, a 220Ω resistor can be placed in series with the load capacitance. This will reduce the noise by approximately a factor of three.
For applications requirin extremely low noise, a larer resistance can be used to reduce the effective bandwidth, which is approximately f bw = 1 2πRC L where C L is the load capacitance. The recommended bandwidth is low-noise applications is 100 Hz. The noise measurements were performed with the input shorted. The noise may increase when sinificant current is drawn from the output due to ripple from the boost converter. *For load capacitances of 100nF or smaller, a 220Ω resistor is recommended in series with the load. Stability In the ±200 V rane, oscillation can occur with some load capacitances when the output voltae is very close to the neative rail ( -190V). This problem can be eliminated by placin a 220Ω resistor in series with the load capacitance as shown in the example applications. Alternatively, a 330pF 25V 0603 capacitor can be soldered on top of R14 which reduces the bandwidth to approximately 3 khz and will avoid oscillation. This capacitor can be installed before delivery if necessary. Note that PDm200 modules produced before July 2014 required a minimum load capacitance of 3.9 nf for stability. After July, 2014, this load capacitance was included on the PCB (C33). However, it can be removed in applications that require maximum performance with load capacitances in the 5 nf to 30 nf rane. If the capacitor is removed, the cable lenth and inductance should be minimized to avoid oscillation. 0V - 10V 30V 200 V Three-wire bender driver with bias 0V to to 0V Enable / Shutdown The Enable pin is a hih impedance sinal that floats 5V above the neative supply rail. It can be pulled to the neative supply rail to disable the amplifier. The voltae on this pin can also be monitored to check the status of the amplifier. Any monitorin circuit should have an input impedance of reater than 200 kω. A hih level voltae on the enable pin indicates a normal status while a low level indicates a thermal shutdown. The recommended enable circuits for unipolar and bipolar supplies are shown below. Any small sinal transistors are suitable, e.. BC817 and BC807. Fiure 6. Enable circuit for unipolar supply ( is rounded) Bias Output The bias output () provides a fixed 200 V output for drivin 200 V three-wire actuators like benders that require a bias voltae. Actuators that require a ±100 V bias can also be driven in this confiuration as this is electrically identical. The bias output can sink or source an averae current of 10 ma. However, there is no protection so care must be taken not to exceed the current limit. If more than 10 ma is required, the primary output of a second PDm200 can be used to enerate the bias. Fiure 7. Enable circuit for bipolar supply Overload Protection The PDm200 is protected aainst over-current and thermal overload. If the PCB temperature exceeds 70 the amplifier will be disabled until the temperature reduces.
Bride Confiuration The output voltae rane can be doubled by drivin the load in a brided confiuration as shown below. Both amplifiers should be confiured for ± operation. 4k7 ±10V 4k7 16V -16V 100Ω 16V -16V 100Ω ±400 V Piezo driver The power bandwidth for this confiuration can be calculated by considerin only one amplifier and doublin the effective capacitance. Fiure 8. Dimensions (mm) Safety This device produces hazardous potentials and should be used by suitably qualified personnel. Do not operate the device when there are exposed conductors. Parts of the circuit will store chare so precautions must also be taken when the device is not powered Dimensions The mountin posts accept an M2.5 screw. For the PCB mountin version (PDm200-PCB), a schematic and footprint library is available for Altium Desiner, contact info@piezodrive.com to receive the file. Warranty PDm200 devices are tested prior to delivery. There is no warranty period. Contact / Support info@piezodrive.com