R.V.R. Elettronica PJ300M, Руководство пользователя, Страница: 25 / 34

PJ300M
19 / 28 User Manual Rev. 7.0 - 25/07/03
8. Theory of Operation
The figure 8.1 shows the block diagram of PJ300M. The blocks are described in the
present chapter:
Figure 8.1
8.1 Power supply section
The power supply section of the PJ300M is composed by the mains transformer, the
soft start card and the switching mode power supply.
The mains transformer includes a primary winding with selectable input for
100,120,220 or 240 V ac supply and three secondary windings: A) 30-0-30 V, B) 16-
0-16 V and C) 0-36V. The A) output is used to drive the switching mode power
supply, B) is connected to the alarms card, and the output C) supplies the soft-start
circuit.
The soft start board is intended to eliminate the current spikes that could be drained
by the transformer when when the amplifier is switched on. This is achieved using a
high power resistor that is momentarily included by a relay to load the secondary
circuit of the transformer.
The RF module is supplied at 50 V by the switching mode power supply.
The alarms card includes a rectifying and stabilizing circuit to provide the ±15V needed
by the electronics.