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Semi-Custom Drive Amplifier Solutions
Deformable mirrors have a wide range of drive requirements. The numerous permutations of channel count, drive voltage, drive current and frequency response mean that a semi-custom drive amplifier solution is often the best way to meet an individual requirement.
Starpoint offers a range of configuration options
built around a portfolio of proven design elements. This
combines demonstrated performance with the ability to meet
one-off customer requirements.
The drive amplifier systems were Starpoint's first product offering.
They use technology licenced from the University of Durham,
and provide a mature design with a proven record of
reliable operation.
The systems have a simple, opto-isolated differential parallel data interface, a standard DAC format, and a user-specified high voltage amplifier stage. The enclosures are 19" sub-racks. Channel counts are typically between 100 and 250, but much larger configurations can be provided.
All the drive systems consist of a single Common Digital Interface card, a variable number of Common DAC cards for the desired channel count, and a number of high voltage amplifier cards, whose characteristics will be set to match the requirements of the deformable mirror to be driven. The high voltage amplifier stage is typically a semi-custom variant derived from one of a number of existing design blocks.
The spec. sheet presented here is given as an example
of an available configuration. The Digital Interface Card
and the DAC Card remain the same for all configurations,
the High Voltage Amplifier Card will vary from system to system.
The enclosure size will vary with channel count.
| Common Digital Interface Card | ||
| Data Format | 16-bit Parallel Data; Data Strobe; Frame Sync. | |
| Electrical Format | RS-422 compatible; differential; opto-isolated. | |
| Data Transfer Rate | 4 × 106 samples / second | |
| Board Form Factor | Eurocard; 6U, 4HP (0.8") wide | |
| Common D-to-A Converter Card | ||
| No. of DAC channels per board | 32 | |
| DAC Resolution | 13 bits | |
| Board Form Factor | Eurocard; 6U, 4HP (0.8") wide | |
| High Voltage Amplifier Board | ||
| No. of HV channels per board | 30 | |
| Output Voltage Range | -215V to +215V | |
| Output Drive Current (max.) | 4mA | |
| Signal Bandwidth | 1kHz @ -3dB corner | |
| Actuator Load Capacitance | 6 nF | |
| Quiescent Power (max.) | 1.4W / channel | |
| HV Amplifier Board Form Factor | Eurocard; 6U, 10HP (2.0") wide | |
| System Characteristics | ||
| No. of drive channels in system | 228 | |
| No. of HV Amplifier boards in system | 8 | |
| Enclosure Dimensions | 2 × 6U, 19" sub-racks. | |
The system listed here is of the type in use on the NAOMI
common-user adaptive optics facility on the
4.2m William Herschel Telescope (right),
where it has operated since the summer of 2000.
(Photo courtesy of the Isaac Newton Group of Telescopes, La Palma.)
© 2004 Starpoint Adaptive Optics Limited