SRT X-BAND RADAR SYSTEMS
FUNCTIONAL DESCRIPTION
304202P003 3.4 Rev. C
− 50 VDC (VMOD)
− HVON from Gate Array of SRT Control Board
− LPA (Long Pulse Adjustment), MPA (Medium Pulse Adjustment) and
SPA (Short Pulse Adjustment) from Gate Array of SRT Control Board
− HVSTOP from SRT MOS board.
The H.V.P.S. starts functioning when the signal, output from the
COMPARATOR, is active; the signal is active when:
− the signal HVON, from the Gate Array of SRT Control Board, is LOW;
this signal is forced to high, inactive, when:
o 3 min. period isn’t yet passed since TXRX has been turned on
o TXRX is in standby mode
o safety switch or interlock is open.
o +15V is ≤ 14V or ≥ 16V
o VFil (6.3V) is ≤ 5V or ≥ 7V
− input voltage supply is over 40 VDC
− the signal HVSTOP is Low, which disables the functioning of the circuit
when the +15 ISO voltage is absent.
− the HVPS Generator Circuit generates the correct high voltage value.
When the high voltage is generated, the COMPARATOR sends to the Gate
Array of the SRT_Control board the signal HVOK and the red LED DL3
(HVOK), mounted on the SRT_Power lights-up.
The VMOD is applied to the primary of the HVPS TRANSFORMER which,
driven by the MOSFET, generates as output the required high voltage (700 V).
The Mosfet enabling is controlled by a circuit, which, also protects the
MOSFET, itself.
The circuit is composed by the blocks COMPARATOR, POTENTIOMETER and
FLYBACK CONTROLLER. When the COMPARATOR recognizes HVON signal
to be low, enables the FLYBACK CONTROLLER that in turn enables
transformer Mosfet output; in the feedback loop another comparator assures
that high voltage value is stable and correct. This action is performed by
potentiometers and LPA, MPA and SPA signals. In this way, it is possible to
control the Magnetron output power.
HVPS unit generates an additional 150 V voltage for a neon lamp performance
monitor, for future use.
3.2.1.4 SRT_Mos Board
Two configurations are available one for 12 KW and one for 25 KW, the number
of MOSFET transistor switched differ in these two versions.
Basically the SRT_Mos board (Chapter 9, Figure 9.1.16) performs the following
main function: High Voltage Pulses generation for Magnetron.
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