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High Voltage generator
MAMMOMAT Balance
SPB7-115.840.01 Page 33 of 62
Siemens AG
Troubleshooting Guide
Rev.02 10.04
Medical Solutions
High Voltage generator
Description
High Voltage generator has positive polarity with respect to ground to supply X-ray tube with
grounded cathode.
A
HV CABLE
HV GENERATOR
25khz
VDC IN
F
E
E
D
F
O
R
W
A
R
D
V
d
c
I
N
P
U
T
C
O
M
P
E
N
S
A
T
I
O
N
50khz
BRIDGE
E7
E8
X
R
A
Y
T
U
B
E
E3
E4
TP11
TP1
CHOPPER
50khz PWM
CURRENT FEEDBACK
10ohm
-
1V=100mA
+
1V=10mA
R16
100ohm
K
+
-
FILAMENT CIRCUIT
NOT SHOWN
KV0
KV0
KV1
KV2
TP2
C
O
N
T
R
O
L
L
E
R
E5
E6
E1
P
W
M
KV FEEDBACK
CONTROL VOLTAGE
TP5
EXPOSURE TIME
TP7
DAC
KV3
KV4
KV5
KV6
KV7
KV7
INVON
X RAY PB
CPU
TP6
50khz
E?
High voltage is set by the CPU through an 8-bit opto-coupled bus IC6/IC7/IC8.
Ground return of opto-couplers is directly connected to x-ray pushbutton by means of dead man
function for maximum continuous safety.
Releasing x-ray pushbutton high voltage and x-ray emission stops immediately.
Output bridge is supplied by PWM power supply with current limit capability.
Anode current overload results in kV output limitation.
If not overloaded, kV output is independent of anode loading and overshoot free.
kV waveform at 20 kV and 35 kV measured on TP1
NOTICE
NOTICE