GENERAL INFORMATION:
The “E” Series of high-voltage,
regulated DC-DC converters addresses the needs
of the precision high-voltage-power-supply
user. Based on the “A” Series,
the “E” Series is designed
and built utilizing state-of-the-art power
conversion topology. These units feature surface
mount technology and encapsulation techniques
providing high reliability and low cost.
DESIGN METHODOLOGY:
The “E” converters utilize a dual-ended forward converter topology with a nominal switch
frequency of <100kHz. A precision reference is provided so the remote control can program the power
supply for a specific voltage. Once input voltage stabilizes, under-voltage lockout is released.
As soon as 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 constant-frequency PWM regulation system controls the MOSFET push-pull power stage, which drives
the high voltage transformer. The power stage is protected from output current overloads or short
circuits via a secondary current limit circuit. High voltage is developed by a multistage multiplier
while feedback voltage is developed and sent to the CTRL circuit to maintain regulation. Multi-stage
internal filters are provided to reduce input current ripple and output voltage ripple.
WIDE INPUT AND OUTPUT RANGE:
The “E” Series has a wide input range of +23 to +30VDC and will maintain full power
output without derating. See Application Note 16 for protection information. The “E” Series
is a non-isolated, unipolar converter. Positive or negative output must be specified. Output voltage
is adjustable from 0 to 1kV, 2kV, 4kV, 6kV, 10kV, or 15kV. As the output voltage is reduced towards
0, the maximum current capability remains unchanged.
OUTPUT VOLTAGE MONITOR
The “E” Series features
a precision-buffered output voltage monitor calibrated to 0.1% accuracy. The
output voltage can be monitored by reading the voltage appearing between pin
4 and Signal Ground Return pin 15. The signal is 0 to +10VDC for 0 to 100%
rated output.
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OUTPUT
CURRENT MONITOR:
The “E” Series features a precision-buffered output current monitor
calibrated to 0.1% accuracy. Current from the high-voltage multiplier can be
monitored by reading the voltage appearing between Output Monitor pin 12 and
Signal Ground Return pin 15.
REMOTE
CONTROL:
The “E” Series is remotely programmed with 0 to +10 VDC to produce
an output voltage. Input may be from a control voltage, a DAC, or from a variable
or fixed resistor. Connections are on the converter for the internal reference,
analog remote adjust and the signal ground. The reference is a precision-buffered
temperature compensated +10VDC. See Figure A & B and Application
Note 1 for more information.
STANDBY
MODE:
The “E” 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 <0.04 mA. All functions other than
the internal reference are shut down. If
the enable pin is connected to a TTL 1, or
at greater voltages up to +32VDC the converter
operates normally.
MECHANICAL:
“E” Series converters are in chassis mountable aluminum cases requiring
a footprint of 25.4 in² and 50.7 in³ of volume. See Application Note
6 for thermal considerations
and for mounting configurations.
ENVIRONMENTAL:
The “E” Series provides full
power and performance operation at case temperatures
from +10 to +45°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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