Erbe VIO 200 D - Power Supply (High-Voltage Power Supply Unit)

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5 • Circuit Descriptions
Art.-Nr.: 80116-271 04.06
Power supply (high-voltage power supply unit)
The high-voltage power supply unit provides the HF generator with a
DC voltage which may reach 450 V. It depends on the surgical effect
selected and the alternating voltage necessary for this.
The line input voltage is directly rectified using a bridge-connected
rectifier. The AC line voltage of 230 V changes to a DC voltage of ap
-
prox. 320 V; this can be checked between MP3 (ground) and the
holding clips of the fuse holder.
If the power connection is set to 115 V, the bridge circuit becomes a
voltage doubler connection, also producing approx. 320 V.
The input circuit contains two NTC resistors to limit the high charging
current which flows when the unit is switched on. Once the capacitors
of the high-voltage power supply unit are charged, limitation is no
longer necessary. The NTC resistors are therefore jumpered during
activation via the make contacts of relay Rel10.
The resulting DC voltage is chopped by a chopper regulator and sup-
plied to a transformer. The transformer is equipped with two identical
output windings which produce a DC voltage again through rectifica
-
tion. With relay Rel13 these two output windings can be connected ei-
ther in series or in parallel, resulting in two operating ranges for the
power supply unit: in the range up to 250 V the maximum output cur
-
rent is 3.5 A, and in the range up to 450 V 1.75 A max. is possible.
The high-voltage power supply unit is controlled by two analog inputs:
The setpoint voltage is specified at J21 Pin 11. A control voltage of
4.5 V results in a power supply unit output voltage of 450 V. The cur
-
rent limitation is specified at pin 9. Here 5 V corresponds to the max-
imum current of 3.5 A.
Measuring devices are available for both voltage and current. Analog
signaling of the measurement values also takes place at pin 8 (actual
voltage) and pin 6 (actual current) with the same amplification factors.
Two other control inputs are also available: an enable signal (pin 7
5
V -> off), used to switch the high-voltage power supply unit on and
off, and the control for the discharge circuit (pin 1 5 V -> on), used to
discharge the output capacitors.
WARNING! Make sure you observe the safety regulations when using line volt-
age!