Caen ELS LiAM 6005 User Manual page 28

LiAM Description
 Voltage rail fuses;
 Circuit breaker;
Several firmware protections, some of them redundant, are also implemented
and here listed:
 Rails undervoltage protection;
 AC-phase fail;
 Over-temperature;
 Output over-voltage;
 Regulation fault;
 Load fault.
Protection redundancy – i.e. hardware and software – was especially
implemented in order to guarantee a double level of reliability for the specified type
of power supplies.
An overview of all available protections, as well as a brief description of their
behavior, is presented in the following sections.
3.1.1.1 CB – CrowBar
The LiAM module protection against output over-voltage conditions is
guaranteed by a crowbar protection circuit that, as in the case of the over-current
protection one, has a double level of reliability – i.e. both hardware and software.
This protection is hardware-activated when the output voltage crosses a
threshold of about double rating with respect to the maximum output voltage:
that is usually caused by a large di(t)/dt value on a large reactive load.
The crowbar circuit also guarantees dissipation of the residual energy stored in
the load when turning off the power supply output stage from a high current value on
a high inductive load (i.e. 5A on a 100mH magnet).
This protection also activates a galvanically-isolated logic signal that generates
a firmware interrupt on the on-module Digital Signal Processor: when this signal is
activated, the processor sets a flag in the status register that needs to be reset before
re-enabling the channel output again.
V = 130V
CB_TH
LiAM User's Manual
28