1
Multimedia ICs
High voltage controller for CRT
displays
BA9755S
The BA9755S is an LSI chip with a chopper voltage controller designed to control the anode voltage of multiscan
monitors and other CRTs. There are two internal high-precision power supplies, each with an output voltage preci-
sion of 1%. Using a high-precision voltage detection resistor makes it possible to set anode voltage without adjust-
ment. Other internal components include an output voltage error detector and an overcurrent detector, which detects
overcurrent when the power is turned on.
Applications
CRT displays and HDTV products
Features
1) Internal chopper voltage controller.
2) Two internal high-precision power supplies, each
with an output voltage precision of 1%.
3) Internal output voltage error detector.
4) Internal buffer circuit that directly drives power MOS-
FET for output drive.
Absolute maximum ratings (Ta = 25C)
Recommended operating voltage (Ta = 25C)
Parameter
Symbol
Limits
Unit
Applied voltage 1
V
CC
1
18
1
V
Applied voltage 2
V
CC
2
20
2
V
Power dissipation
Pd
600
1
mW
Operating temperature
Topr
25 ~ + 75
C
Storage temperature
Tstg
55 ~ + 125
C
3 Reduced by 6.0mW for each increase in Ta of 1
C over 25
C.
1 18pin
2 3pin
Parameter
Symbol
Limits
Unit
Applied voltage 1
V
CC
1
11 ~ 13
V
Applied voltage 2
V
CC
2
11 ~ 16
V
Used with condition V
CC
2
V
CC
1
3
Multimedia ICs
BA9755S
Pin No.
Pin name
1
GND
Ground
This is the common ground for the small signal system and the power system, and so requires
a stable ground suitable for common impedance.
2
PWMOUT
PWM wave output
Output is fixed at the low level when the protector circuit or thermal shutdown circuit is activated.
3
PV
CC
Power supply for the power system. Place a decoupling capacitor in proximity to this pin.
4
HDIN
HD pulse input. The input signal should be shorter than the rise time (
s).
5
MMCR
Shifts the phase of the serrated wave. Use a charge resistance higher than 4.7k
.
Internal mono-multi time constant setting.
6
SAWOUT
f
Max
. 80kHz
C = 1500p, f
Max
. 60kHz
C = 2000p
7
AGC
Set capacity according to the linearity of the minimum oscillation frequency and the response
time during frequency change.
AGC time constant setting.
8
ERRIN
Input of the error amplifiers feedback voltage.
9
ERRREF
Input of the error amplifiers feedback voltage.
When this voltage is given a time constant, the IC soft-starts when the power is turned on.
10
ERROUT
Output of the error detection voltage.
11
PON DET
12
ABLIN
Beam protector input. When the protector is activated, the latch locks and PWM output is fixed
at the low level.
13
XRAYIN
X-ray protector input. When the protector is activated, the latch locks and PWM output is fixed
at the low level.
14
XREF
Input of the X-ray protector's reference voltage.
15
VREG6
Reference voltage output (6V). Output variation is guaranteed to be 1% or less (with trimming).
This circuit is completely separate from the 9V system. Output is stopped when the thermal
shutdown circuit is activated. Use a 47
F bypass capacitor.
16
VREG9
Reference voltage output (9V). Output variation is guaranteed to be 1% or less (with trimming).
This circuit is completely separate from the 6V system. Output is stopped when the thermal
shutdown circuit is activated. Use a 10
F bypass capacitor.
17
PROTOUT
Protector output.
Output changes to the high level when the protector circuit or thermal shutdown circuit is activated.
18
Power supply for the signal system.
Place a decoupling capacitor in proximity to this pin.
Function
Serrated wave output. Adjust maximum capacity by changing maximum oscillation frequency.
V
CC
Setting the time constant for the protector output suppression time and input of the beam
protectors reference voltage. This stops the protectors until the system stabilizes. The latch
can be unlocked by raising the voltage of this pin above 4.5V.
f
Max
. 120kHz
C = 1000p, f
Max
. 100kHz
C = 1200p
Pin descriptions
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