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Most laboratory power supplies (PSUs)
offer a fixed maximum voltage and maximum current
capability. Thus, for example, a 35V/20A PSU can supply up
to 700 watts, but its power capability falls in direct
proportion to the output voltage so that when being used at
12V, for example, the maximum power has reduced to 240W.
The alternative approach is to design the PSU to have an
auto-ranging or semi constant power characteristic so that
the current capability rises as the voltage falls. To
achieve this on a high performance laboratory PSU which
operates over a very wide range of voltage and current
including zero power, presents substantial technical
challenges. TTi has developed an
autoranging technology called PowerFlex. Power supplies
using PowerFlex regulation offer a near constant power
output over a limited range. Thus, for example, the QPX1200
can provide 20A at 60V, rising to 50A at 20V. Below 20V the
maximum current remains at 50A. |
