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Proceedings Paper

Fault-tolerant drive electronics for a Xinetics deformable mirror at GeMS DM0
Author(s): Michael J. Barberio
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Paper Abstract

Gemini South is replacing one of the (3) CILAS DMs with a 349-actuator Xinetics DM in its GeMS MCAO system. Xinetics mirrors operate over a 40-100V dynamic range and require that inter-actuator stroke differences are limited to half-scale; each actuator must be within 30V of its neighbor to prevent mechanical stress and possible face sheet separation. A robust way to implement this protection is to use high power transient voltage suppressors (TVSs) as a 2D-mesh between the amplifiers and mirror, but this has system implications. A sustained clamp condition dissipates significant power in the devices, and if an actuator fails as short (which occurred once with the DM in a thermal chamber), the system is subject to a cascade failure event as multiple outputs drive the shorted actuator through the TVS network. This latter risk is readily resolved by using series fuses to the DM. In this third-generation driver, current sensing and logic inhibit amplifier outputs after a sustained TVS clamp condition or shorted output, and LED indicators show the location. Redundant thermal sensing is used on modular TVS row and column boards. A second 2D-mesh of high impedance resistors after the fuses will hold an unpowered channel to the average voltage of its neighbors, with a negligible influence function. A Failure Modes and Effects Analysis shows significant fault tolerance.

Paper Details

Date Published: 27 July 2016
PDF: 6 pages
Proc. SPIE 9909, Adaptive Optics Systems V, 990985 (27 July 2016); doi: 10.1117/12.2240371
Show Author Affiliations
Michael J. Barberio, Cambridge Innovations (United States)

Published in SPIE Proceedings Vol. 9909:
Adaptive Optics Systems V
Enrico Marchetti; Laird M. Close; Jean-Pierre Véran, Editor(s)

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