- 8 models from 0 to 62 Volts through 0 to 6kV
- 20 or 30 watts of output power
- Maximum Iout capability down to 0 Volts
- Maximum Iout during charge/rise time
- Indefinite output short-circuit protection
- Very fast rise with very low overshoot
- Output voltage and current monitors
- >400,000 hour MTBF @65oC
- Fixed-frequency, low-stored-energy design
- UL, CUL, IEC-60950-1, and Demko Recognized
GENERAL INFORMATION:
The "C" Series of high-voltage
regulated DC-DC converters are designed for
fast rise-time/charging applications utilizing
state-of-the-art power conversion topology.
Surfacemount technology and encapsulation techniques
provide high reliability and low cost. See
Application Note 10 for more charging information.
DESIGN METHODOLOGY:
The "C" converters
utilize
a dual-ended
forward
converter
topology
with a
nominal
switching
frequency
of <100kHz.
A precision
reference
is provided
so the
remote
control
can program
the power
supply
for a specific
voltage.
A soft-start
circuit
brings
the converter
to full
power over
a 1ms period,
reducing
surges
on the
source
supply.
A constant-frequency
PWM regulation
system
controls
the MOSFET
push-pull
power stage
and high-voltage
transformer.
The power
stage is
protected
from output
current
overloads
or short
circuits
via a secondary
current
limit circuit.
This current
limit is
optimized
for low-impedance
capacitor
charging.
The high
voltage
developed
in the
multistage
multiplier
generates
feedback
voltage,
which is
sent to
the CTRL
circuit
to maintain
regulation.
The AC
feedback
networks
are configured
for maximum
speed of
rise with
little
or no overshoot
into capacitive
loads.
WIDE INPUT VOLTAGE
RANGE:
The "C" Series is designed for full DC power operation at up to 92%
efficiency. A wide input range of +23 to +30VDC maintains full output
power. The derated input range is +9 to +32VDC. See Application
Note 16 for
protection
information.
WIDE OUTPUT RANGE:
The "C" Series is a non-isolated, unipolar converter. Positive or
negative output must be specified. Output voltage is adjustable from 0
to 62, 125, 250, 500, 1kV, 2kV, 4kV or
6kV. As the output voltage is reduced towards 0, the maximum current
capability remains unchanged.
OUTPUT VOLTAGE & CURRENT
MONITORS:
The "C" Series features a 100:1
voltage monitor. Units 2kV or higher have
a 100 MegΩ/1.1 MegΩ divider;
units below 2kV use a 10 MegΩ/102k
divider. The monitor output impedance is
calibrated for use with a 10 MegΩ input
impedance meter. Overall accuracy is ±2.0%
with a temperature coefficient of ±200
ppm per oC. The voltage monitor is output
on pin 9 and referenced to Signal Ground
pin 5.
Current from the high-voltage multiplier can be monitored by reading the voltage
appearing between Output Monitor pin 3 and Signal Ground pin 5. See Application
Note 13.
REMOTE CONTROL:
The "C" Series is remotely programmed with 0 to +5VDC to produce
an output voltage. Input may be from a control voltage, a DAC, or from a variable
or fixed resistor. On a negative output converter the programming logic of
the remote adjust would be inverted, i.e.: +5 to 0VDC. Connections are on the
converter for the internal reference, analog remote adjust and the signal ground.
The reference is +5.0VDC, temperature compensated with a 464Ω output
impedance. See Figure E and
Application Note 1 for more information.
ENABLE/DISABLE:
The "C" converters also have
an enable function. When the enable is TTL
0 (<+0.7V Isink=1mA) the converter is
in a standby mode and input current is reduced
to <30mA. All functions other than the
internal reference are shut down. If the
enable pin is left unconnected, TTL 1, or
at greater voltages up to +32VDC the converter
will initiate soft-start before beginning
to operate normally. The open-circuit output
voltage from the enable pin is <+5VDC.
In the inhibit mode 1mA will have to be sunk
for proper shutdown.
MECHANICAL:
"C" Series converters are in PCB-mountable plastic cases requiring
a footprint of 5.5 in² and only 4.3 in³ of volume. Mounting plates and brackets
are available for chassis mounting. This series is also available in an RF-tight
metal PCB/chassis mount package. See Application Note 6 for thermal considerations
and mounting configurations. All models are available with optional, six-sided,
wrap-around Mu-Metal Shielding.
ENVIRONMENTAL:
The "C" Series provides full
power operation at case temperatures from
-40 to +65°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.
