GENERAL INFORMATION:
The “FL” Series of floating-hot-deck,
low-voltage power supplies offers an integrated
solution for systems requiring LV power & controls
with high-voltage isolation. Combining a highly
isolated, DC-to-DC, multi-output low-voltage
power supply (LVPS) with an advanced isolated
digital & analog I/O topology, the “FL” sub-system
provides both power and controls to floating-hot-deck
circuitry. This solution, when combined with
one or more UV HVPS or other circuitry, can
provide highperformance solutions for applications
such as::
| Floating/Stacked Ion- or E-Beam Biases |
Floating Filament Bias |
| Floating Pulsers & Gated Grids |
Floating Capacitance Meters |
| Floating High Side Current Monitors |
Floating Leakage Testers |
Please contact UltraVolt's
customer service department for an analysis
of your requirements.
DESIGN METHODOLOGY:
The “FL” Series
utilizes
a dual-ended
forward
converter
topology
with a
nominal
switching
frequency
of <100
kHz. Once
input voltage
stabilizes,
under-voltage
lockout
is released.
When the
LVPS enable
is raised
above a
TTL 1,
the converter
begins
to switch.
The soft-start
circuit
brings
the converter
to full
power over
a 1mS period,
reducing
surges
on the
source
supply.
A constantfrequency
PWM regulation
system
with optically
isolated
feed back
controls
the MOSFET
push-pull
power stage,
driving
a highly
isolated
transformer.
This isolated
power ultimately
provides
3 separate
LV floating
outputs
at >80%
efficiency.
The power
stage is
protected
from intermittent
output-current
overloads
or short
circuits
via a primary
current
limit circuit.
The isolated
digital
I/O channel(s)
are optically
transmitted
directly
to the
floating
hot deck
with a
schmitt
trigger
buffer
providing
glitchfree
output
on the
floating
hot deck.
The isolated
analog
I/O channel(s)
are converted
to digital
data and
optically
transmitted
directly
to the
floating
hot deck
for conversion
back to
analog.
COMPATIBILITY:
The “FL” Series
works
directly
with
any
UltraVolt “A” or “C” Series
DC-to-DC
HVPS
from
0
to
62V
through
0
to
35kV
@
0
to
4
watts
through
0
to
20
watts.
By
providing
isolated
power,
TTL
enable/disable,
and
voltage
programming,
UV
HVPS
can
be
floated
or
stacked
on
one
another..
ISOLATED POWER OUTPUTS:
The “15FL12-12W” provides floating
+12VDC @ 1 Amp, -12VDC @ 10 mA, and +5VDC
@ 10 mA from a single ground side +12VDC
input. The “15FL24-24W” provides
floating +24VDC @ 1 Amp, -12VDC @ 10 mA,
and +5VDC @ 10 mA from a single ground side
+24VDC input. The main output is typically
used to drive a floating HVPS, or filament
switching regulator, etc. The -12VDC is for
use with the +DC in providing bias to floated
Op-Amps, DACs & ADCs. The +5 VDC can
run floating micro-controllers or watchdog
reset circuits.
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ISOLATED
CONTROLS: DIGITAL CHANNELS
The “-I/O” option provides isolated digital I/O channel(s) from
the grounded system side to the floating hot deck. The TTL bit is inverted.
The output, a schmitt trigger TTL buffer, sources up to 0.8mA and sinks up
to 13 mA. This bit is typically used to enable/disable a floated UV HVPS. It
can also be used at up to 300kHz to drive a pulser, gate, sample-and-hold multiplexer
or to communicate with a floated micro controller. The “-R/B” option
provides one additional down channel.
ISOLATED CONTROLS:
ANALOG CHANNELS
The “-I/O” option provides isolated
analog I/O channel(s) from the grounded system
side to the floating hot deck. The analog
signal is converted to digital and translated
back to analog at the floating hot deck.
The output is buffered with a source impedance
of 1.5KΩ. This signal is typically
used to remote program a floated UV HVPS.
It can be used at up to 30 Hz to drive an
amplifier, sample-and-hold, or to program
other devices such as a floating filament
regulator. The “-R/B” option
provides one additional down channel.
STANDBY MODE:
All “FL” models feature an LVPS enable/disable function. When the
enable is TTL 0 (< +0.7 VDC +/-0.2 Isink=1mA), the floating LVPS is in standby
mode. All isolated outputs go to 0VDC; input current drops to < 90 mA; and
all functions are shut down except the +5 Volt reference, which is always operational.
If the LVPS enable pin is left unconnected, TTL 1 or at greater voltages up to
+32VDC the converter operates normally.
MECHANICAL:
“FL” Series units are in PCB-mountable plastic cases requiring a
footprint of 8.5 in2 and only 10 in3 of volume. Mounting plates and brackets
are available for chassis mounting. See Application Note
AP-6 for thermal considerations
and for mounting configurations.
ENVIRONMENTAL:
The “FL” Series provides full
power operation at case temperatures from
-20 to +55°C. All units receive a 24-hour
burn-in prior to final testing. Extended
temperature range is available along with
other enhanced capabilities. Please contact
the factory.
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