MX200 V10200V 1A Piezo Driver

Specifications

The MX200 is a complete power supply and highperformance linear amplifier module for driving
piezoelectric actuators. The MX200 can drive stackactuators; standard piezoelectric actuators; two wirebenders; and three-wire piezoelectric benders
requiring a bias voltage. Output currents of up to1 Amp are developed at frequencies up to 100 kHz
with less than 100 uV noise (10Hz to 10kHz). Bipolar
output voltages up to +/-100V are possible with an
external AC coupling capacitor.

InIn+GndEnVsInputs
Neg. Input
Pos. Input
GroundEnableSupplyPeak Current

1 Amp

RMS Current

550 mA, 330 mA, 220 mA

Power Bandwidth

106 kHz (180 Vp-p)

Signal Bandwidth

200 kHz (100nF Load)

Slew Rate

60 V/usGain

20 V/V33 𝑘Ω (In+), 1.6 𝑘Ω (In-)±5 mV
Unlimited

Output Noise<100 uV RMS (10Hz to 10kHz)

Protection

Short-circuit, average current,and under-voltage protection

Quiescent Current

0.3 A (30 mA in Shutdown)

Dimensions

80 x 46 x 40 mm (L x W x H)

Environment

0 to 60C (32 to 140F)
Non-condensing humidity

Weight95 gOperation
The system block diagram is illustrated in Figure 2. A
boost converter generates the high voltage supply andnegative rail. The output voltage range can be set toeither +100V, +150V, or +200V. Configuration options are
discussed in “Configuration”. Bipolar output voltages up
to +/-100V are possible with an external AC coupling
capacitor, refer to “Bipolar Output Voltage”.
The high-voltage amplifier has differential inputs with again of 20 and an input voltage range of 10 V. The
negative input can be connected to ground or to adifferential source. It should not be left floating.
The load is connected between the output and ground.
The bias voltage output is for three wire bimorph benderactuators.

Outputs
HV Output
Bias Voltage
Overload

MX200 V10 Datasheet
Figure 1. Connection diagram+100V, +150V, +200V

Load

46mm

OutVbOvl

Voltage Range

Input Offset

80 mm

InIn+OutVbOvl
EnVsGnd

24V (18V to 36V)

Input Impedance

The MX200 is protected against short-circuit,average current overload, and supply under-voltage.
The MX200 can be used as a stand-alone module ormounted to a base with four M3 screws. The PCB
mounting version (MX200-PCB) is supplied withheaders for direct mounting onto a hostmotherboard.

12345678

Power Supply

1Modified 23/03/2021

current is 1.25 A with a 24 V supply at the full rated power(𝐼𝑎𝑣 = 100 mA).

Enable Overload

Supply Vs
Voltage
Setting

The power supply must be sufficient for the amplifier, arating of at least 1.5 Amps is recommended. Note thatwhen power is first applied or when the amplifier isenabled, full current will be required for a brief period tocharge the storage capacitors.

HV+
BoostConverter-5VVbHV+In+Bimorph
LoadOut

Applications Circuits

20In-+

Load-5V

Input 0-10V+
Figure 2. MX200 Block Diagram+24V

Configuration

200 V Piezo stack driver.

The output voltage range can be set to either +100V,+150V or +200V using the two jumpers LK1 and LK2.
Greater output current is available in the lower voltage
ranges, as described in Table 1. Incorrect jumper
combinations will damage the amplifier.
OutputVoltage
100 V
150 V
200 V

PeakCurrent
1A
1A
1A

InIn+OutVbOvl
EnVs
Gnd

RMSCurrent
550 mA
330 mA
220 mA

AverageCurrent
250 mA
150 mA
100 mA

Input 0-10V++24V

LK1AB
Out

LK2
Out
B
A

InIn+
Out
Vb
Ovl
En
Vs
Gnd+
200 V Bimorph Bender Driver with bias.
Also suitable for benders with +100V and -100V bias.

Table 1. Voltage Range Jumper Settings
Input 0-10V

Output Current
The peak output current is 1 Amp for all voltage ranges
but the maximum continuous RMS current is dependent
on the voltage range, as described in Table 1. The average
positive output current is also useful for calculating power
dissipation and the average supply current. For a sinewave, the average positive output current is equal to𝐼𝑎𝑣 =+++24V

InIn+
Out
VbOvl
EnVs
Gnd

+/-100 V Piezo Driver, see “Bipolar Output Voltage”.

1√2𝐼𝑟𝑚𝑠 = 𝐼𝑝𝑘 .
𝜋𝜋Supply Current

Bias Output for Piezo Bimorphs

The quiescent power for the amplifier and fan isapproximately 8 W. Therefore, the quiescent supply
current at 24 V is 0.3 A. This can be reduced to <30 mA byapplying a logic zero to the Enable pin. The supply current
is related to the average positive output current by

The bias output (Vb) provides a fixed voltage for driving
three-wire piezoelectric benders. The bias voltage isapproximately 5V above the selected voltage range. The
effective capacitance when using bimorph actuators isthe sum of both layers.

1.1 × 𝑉𝑜𝑢𝑡 × 𝐼𝑎𝑣 + 8𝐼𝑠 =.
𝑉𝑠
where 𝑉𝑜𝑢𝑡 is the output voltage range, and 𝐼𝑎𝑣 is theaverage output current. Therefore, the maximum supply

Actuators that require a symmetrical bias voltage,e.g. ±100 V can also be driven since this configuration iselectrically identical to the unipolar configuration, e.g. 0V
to 200V.

MX200 V10 Datasheet

2

Modified 23/03/2021

Power Bandwidth
The nominal slew-rate of the MX200 is 60 V/us.
Therefore, the maximum frequency sine-wave is
60 × 106
𝜋𝑉𝐿(𝑝−𝑝)

Peak to Peak Voltage (V)𝑓𝑚𝑎𝑥 =The unloaded power bandwidth for each voltage range islisted in Table 2.
Voltage Range
200 V
150 V
100 V

3uF

10uF

Power Bandwidth
95 kHz127 kHz
190 kHz

1005002310410Frequency (Hz)10Figure 3. Power Bandwidth (200V Range)

With a capacitive load, the power bandwidth is limited bythe output current. The maximum frequency sine wave is
160𝐼𝑎𝑣

10uF

3uF

1uF

300nF 100nF

30nF

140

Peak to Peak Voltage (V)𝑉𝐿(𝑝−𝑝) 𝐶𝐿

where 𝐼𝑎𝑣 is the average current limit, 𝑉𝐿(𝑝−𝑝) is the peakto-peak output voltage, and 𝐶𝐿 is the effective loadcapacitance. The power bandwidth for a range of load
capacitance values is listed in Table 3.

Voltage Range
100 V
150 V200 V
190000 100000
50000
83333
33333
16667
25000
10000
50008333
3333
1667
2500
1000
500833
333
167
250.0
100.0
50.0
83.3
33.3
16.7

120
100
80
60
40
200

2

3

1010Frequency (Hz)451010Figure 4. Power Bandwidth (150V Range)

10uF

3uF

1uF

300nF 100nF30nF

100

Peak to Peak Voltage (V)Load(uF)
0.01
0.03
0.1
0.3
13
103030nF

100nF300nF

150

Table 2. Unloaded power bandwidth𝑓𝑝𝑤𝑟 =1uF

200

Table 3. Power bandwidth (in Hz) with a capacitive load

In the following figures, the maximum peak-to-peakvoltage is plotted against frequency for each voltage
range.

806040200210310410Frequency (Hz)510Figure 5. Power Bandwidth (100V Range)

MX200 V10 Datasheet

3

Modified 23/03/2021

Signal Bandwidth1

The small-signal bandwidth for a range of capacitive loads
is listed in Table 4. The small-signal frequency responses
are plotted in Figure 6.
LF Noise (mV)

LoadCapacitance
10 nF
30 nF
100 nF
300 nF1 uF
3 uF
10 uF
30 uF

0.5Signal
Bandwidth
180 kHz283 kHz275 kHz160 kHz78 kHz
30 kHz8.3 kHz3.0 kHz0-0.5-105

10t (s)

1520Figure 7. Low frequency output noise (0.03 Hz to 10 Hz)

The high frequency noise (10 Hz to 1 MHz) is listed in thetable below versus load capacitance. The total noise from0.03 Hz to 1 MHz is found by summing the RMS values,22that is 𝜎 = √𝜎𝐿𝐹+ 𝜎𝐻𝐹.

Table 4. Small signal bandwidth (-3 dB)

Magnitude (dB)

4030u

30

3u

10u

1u300n 100n 30n 10nLoad
Capacitance
10 nF
30 nF
100 nF
300 nF
1 uF
3 uF
10 uF
30 uF

20100310451010610Phase (deg.)

100

0HFNoise
1.5 mV
2.6 mV
3.5 mV
1.2 mV306 uV
129 uV
100 uV
120 uVTotal
Noise
1.5 mV
2.6 mV
3.5 mV
1.3 mV
470 uV380 uV370 uV380 uV

Table 5. HF Noise (10 Hz to 1 MHz) and total noise-100

The majority of high-frequency noise is due to ripple fromthe boost converter (at 170 kHz). In ultra-low noise
applications, the output bandwidth can be restricted to10 kHz which reduces the noise to less than 100 uV RMS
in the 10 Hz to 1 MHz frequency range. This can beachieved with the RLC filter shown below.

-200
310451010610Frequency (Hz)Figure 6. Small signal frequency response

Noise

MX200

The output noise contains a low frequency component(0.03 Hz to 10 Hz) that is independent of the load
capacitance; and a high frequency component (10 Hz to1 MHz) that is inversely related to the load capacitance.

𝑅𝐶𝐿Note that many manufacturers quote only the AC noise
measured by a multimeter (20 Hz to 100 kHz) which isusually a gross underestimate.

Figure 8. Output noise filter

The noise is measured with an SR560 low-noise amplifier(Gain = 1000), oscilloscope, and Agilent 34461A
Voltmeter. The low-frequency noise is plotted in Figure 7.
The RMS value is 360 uV with a peak-to-peak voltage of
1.8 mV.

MX200 V10 Datasheet

𝐿The required inductance and resistance is𝐿=41
4𝜋 2 𝑓𝑐2 𝐶𝐿and𝑅 = 1.4√𝐿/𝐶𝐿

Modified 23/03/2021

where 𝑓𝑐 is the cut-off frequency (10 kHz) and 𝐶𝐿 is theload capacitance. The inductor should be rated for atleast 1 A with a self-resonance frequency of greater than1 MHz.

If the load is not capacitive at the operating frequency,
the impedance of C1 should be less than 1% of the load
impedance 𝑍𝑝 , that is,
𝐶1 >A first-order resistive filter can also be effective, although
it must be rated for the expected RMS current. The
required value is

𝑅=The resistor R1 sets the AC coupling frequency 𝑓𝑎𝑐 , whichis recommended to be 1 Hz. The value of R1 is12𝜋𝑓𝑐 𝐶𝐿

𝑅1 =The MX200 is protected against short-circuit and average
current overload. The module is also disabled when theinput supply voltage is less than 12 V. Current overload
conditions are signalled by +5 V on the Overload pin.

Bridge Configuration
The output voltage range can be doubled to ±200 V bydriving the load in a bridged configuration as shown inFigure 9. In this configuration, the output voltage isThe amplifier can be shutdown manually by pulling theEnable pin low with an open-collector, or open-drain
circuit. The Enable pin normally floats at 6.2V and should
not be driven directly.

𝑉𝑜𝑢𝑡 = 40(𝑉𝑖𝑛 − 5)That is, a 0V to 10V input produces ±200V at the load.
Zero volts across the load occurs when the input voltage
is +5V. However, note that the absolute voltage of eachterminal is still +100V.

Bipolar Output Voltage
Bipolar output voltages can be achieved by adding an
external AC coupling capacitor, as shown in the diagram
below. This approach creates a high-pass filter with a cutoff frequency of 1 Hz. i.e., frequencies below 1 Hz will bestrongly attenuated.

The power bandwidth for this configuration can becalculated by considering only one amplifier and doubling
the effective capacitance.

Up to +/-100V can be obtained using the 200V range, or+/-75V using the 150V range, or +/-50V using the 100Vrange.

Vin = 5V ± 5V

Input 0-10V

R1++Cp+24V

12𝜋𝑓𝑎𝑐 𝐶12The power rating of R1 should be greater than 𝑉𝑟𝑚𝑠
/𝑅1,
where 𝑉𝑟𝑚𝑠 is the RMS voltage across the load.

Overload Protection / Shutdown

C1100
2𝜋𝑓|𝑍𝑝 |+24V

InIn+OutVbOvl
EnVs
Gnd±200V+/-100 V Piezo Driver, using an external capacitor C1and resistor R1.

++10V

C1 should be rated for at least the full output voltage ofthe amplifier. For example, to achieve +/-100V using the200V configuration, a 250V rated capacitor is required.
The capacitance of C1 should be large enough to ensure
the series voltage drop is less than 1% of the output
voltage. Film capacitors are preferred but electrolytic
capacitors are also suitable.

InIn+OutVbOvl
EnVs
Gnd+24V

InIn+OutVbOvl
EnVsGndFigure 9. Bridge configuration achieving ±200V

If the load is a piezo or capacitor, 𝐶1 > 100 × 𝐶𝑝 .

MX200 V10 Datasheet

5

Modified 23/03/2021

Safety
This device produces hazardous potentials and should be
used by suitably qualified
personnel. Do not operate thedevice when there are exposedconductors.
Parts of the circuit may store
charge so precautions must also
be taken when the device is not powered.

Dimensions
The mounting posts accept M3 screws. For the PCB
mounting version (MX200-PCB), a schematic andfootprint library is available for Altium Designer. Refer tothe online product details.

Contact / Support
info@piezodrive.com

Revision History
Date
23/03/21
21/01/21
16/01/21

Rev
R4
R3
R2By
KB
KB
KB

Changes
Added bipolar output info
Updated figure styleTemp range updated

Figure 10. Dimensions (mm)MX200 V10 Datasheet

6Modified 23/03/2021