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AmpArray[32]
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Applications: • Deformable mirror drive • MEMS/NEMS device drive & test The AmpArray[32]™ is a simple 32-channel amplifier unit capable of driving adaptive mirrors with actuator load capacitances in the 10pF – 10nF range, at the frequencies typically required to correct atmospheric turbulence. It contains no internal digital-to- analogue converters, and is intended to be |
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This analogue in–analogue out configuration was created to allow a deformable mirror to be controlled directly from high-level data acquisition and instrument control software, without requiring additional device driver software. The AmpArray[32] would typically be driven by a PC multi-channel DAC card supported by the user's preferred high-level software. The input specification matches the output characteristics of many popular DAC cards offered with the leading instrument control software packages. |
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This simple yet versatile device comes in a compact enclosure and requires only a single +5V dc power supply input. It offers a convenient and economical way to control a variety of modern MEMS-based and bimorph deformable mirrors. A variety of output options can be offered as semi-custom drive solutions. |
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| System Characteristics | ||
| Number of amplifier channels | 32 | |
| Amplifier Gain | +19 ± 5% | |
| Input Characteristics | ||
| Input Voltage Range | 0V to +10V | |
| Input Impedance | 10kΩ | |
| Output Characteristics | ||
| Output Voltage Range | 0V to +190V | |
| Output Drive Current Limit | 45μA ± 40% | |
| Small Signal Bandwidth | 4kHz @ -3dB corner | |
| Slew Time with Capacitive Load (2.2nF load, 100V step) |
3.9ms typ. (10% to 90% of step) | |
| Physical Characteristics | ||
| Enclosure Dimensions | 126mm(D) × 106mm(W) × 34mm(H) | |
| Power In | +5V dc regulated, @ 0.2A | |
The AmpArray[32] has a unipolar output range, but it can also be used to drive mirrors requiring a bipolar drive signal. Application Note 1 explains how.
The 32-channel AmpArray[32] is matched to the channel
count of popular DAC cards, and can be used to
drive a wide range of deformable mirror sizes.
Several of the compact
AmpArray[32] units can be combined to form higher channel-count
drive systems. The image to the left shows a 128-channel
configuration formed from four AmpArray[32] units.
The maximum channel count
is typically limited by the DAC I/O capacity of the host computer.
Each amplifier channel's current limit is set to a nominal 50µA. There is a ± 40% spread in this value. The current limit is a safety feature of the amplifier, it is not the normal operating mode. The amplifier should be operated in the linear regime, not the current-limited regime.
The plot below shows the large signal step response for a low capacitance load (15pF) and for a high capacitance load (2.2nF). These values are typical of MEMS mirrors and bimorph mirrors, respectively. A 100V pk–pk square wave is applied, the voltage swing is between +20V and +120V.
For the 15pF load, the rise and fall times are about 80µs, determined
by the 4kHz low pass filter. For the 2.2nF load, the large signal
step response is quasi-linear, with a 3.4ms rise time and a 2.5ms
fall time, determined by the current limit. There is a 2V overshoot
on exit from the current limited mode.
| System Connectors: | ||
| Signal Input Connector: | 44-way HD22 (density-and-a-half) 'D'-type socket. | |
| HV Output Connector: | 37-way HD20 'D'-type socket. | |
| Power Supply Connector: | 0.1" pin miniature power jack. (Power supply is included). |
Pin assignment on the input (44-way) and output (37-way) 'D'-type connectors:
| Input Connector: 44-way | Output Connector: 37-way | ||||
| Pin No. | Signal | Pin No. | Signal | ||
| 1 | IN31 | 1 | GND | ||
| 2 | GND | 2 | HV1 | ||
| 3 | IN26 | 3 | HV3 | ||
| 4 | IN24 | 4 | HV5 | ||
| 5 | IN22 | 5 | HV7 | ||
| 6 | GND | 6 | HV8 | ||
| 7 | IN17 | 7 | HV10 | ||
| 8 | IN15 | 8 | HV12 | ||
| 9 | IN13 | 9 | HV14 | ||
| 10 | GND | 10 | GND | ||
| 11 | IN8 | 11 | HV17 | ||
| 12 | IN6 | 12 | HV19 | ||
| 13 | IN4 | 13 | HV21 | ||
| 14 | GND | 14 | HV23 | ||
| 15 | GND | 15 | HV24 | ||
| 16 | GND | 16 | HV26 | ||
| 17 | IN29 | 17 | HV28 | ||
| 18 | IN27 | 18 | HV30 | ||
| 19 | IN25 | 19 | GND | ||
| 20 | GND | 20 | HV0 | ||
| 21 | IN20 | 21 | HV2 | ||
| 22 | IN18 | 22 | HV4 | ||
| 23 | IN16 | 23 | HV6 | ||
| 24 | GND | 24 | GND | ||
| 25 | IN11 | 25 | HV9 | ||
| 26 | IN9 | 26 | HV11 | ||
| 27 | IN7 | 27 | HV13 | ||
| 28 | GND | 28 | HV15 | ||
| 29 | IN2 | 29 | HV16 | ||
| 30 | IN0 | 30 | HV18 | ||
| 31 | IN30 | 31 | HV20 | ||
| 32 | IN28 | 32 | HV22 | ||
| 33 | GND | 33 | GND | ||
| 34 | IN23 | 34 | HV25 | ||
| 35 | IN21 | 35 | HV27 | ||
| 36 | IN19 | 36 | HV29 | ||
| 37 | GND | 37 | HV31 | ||
| 38 | IN14 | ||||
| 39 | IN12 | ||||
| 40 | IN10 | ||||
| 41 | GND | ||||
| 42 | IN5 | ||||
| 43 | IN3 | ||||
| 44 | IN1 | ||||
© 2002–2011 Starpoint Adaptive Optics Limited