ROHM BA9755

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 precision of ±1%. Using a high-precision voltage detection resistor makes it possible to set anode voltage without adjustment. 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
•1)Features
Internal chopper voltage controller.
3) Internal output voltage error detector.
4) Internal buffer circuit that directly drives power MOSFET for output drive.
2) Two internal high-precision power supplies, each
with an output voltage precision of ±1%.
•Absolute maximum ratings (Ta = 25°C)
Parameter
Symbol
Limits
Unit
Applied voltage 1
VCC1
18∗1
Applied voltage 2
VCC2
20∗2
V
Pd
600∗1
mW
Operating temperature
Topr
– 25 ~ + 75
°C
Storage temperature
Tstg
– 55 ~ + 125
°C
Power dissipation
∗
∗3
1 18pin
∗
V
2 3pin
Reduced by 6.0mW for each increase in Ta of 1°C over 25°C.
•Recommended operating voltage (Ta = 25°C)
Parameter
Symbol
Limits
Unit
Applied voltage 1
VCC1
11 ~ 13
V
Applied voltage 2
VCC2
11 ~ 16
V
∗ Used with condition
VCC2 ⭌ VCC1
1
Multimedia ICs
BA9755S
•Block diagram
GND
1
PWMOUT
2
GND
Sig VCC
18
VCC
17
PROTOUT
REF
9.0V
16
VREG9
REF
6.0V
15
VREG6
14
XREF
13
XRAYIN
12
ABLIN
11
PONDET
10
ERROUT
Buffer
PVCC
3
HDIN
4
MMCR
5
Power VCC
M. M.
6
SAW
GEN.
AGC
7
AGC
TYPE
ERRIN
8
+
SAWOUT
ERRREF
2
9
–
– +
LATCH
–
+
–
+
START
Multimedia ICs
BA9755S
•Pin descriptions
Pin No.
Pin name
1
GND
2
PWMOUT
Function
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.
PWM wave output
Output is fixed at the low level when the protector circuit or thermal shutdown circuit is activated.
3
PVCC
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 (µs).
5
MMCR
6
SAWOUT
7
AGC
8
ERRIN
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
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.
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
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 47µF 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 10µF bypass capacitor.
17
PROTOUT
18
VCC
Internal mono-multi time constant setting.
Shifts the phase of the serrated wave. Use a charge resistance higher than 4.7kΩ.
Serrated wave output. Adjust maximum capacity by changing maximum oscillation frequency.
fMax. 120kHz→C = 1000p, fMax. 100kHz→C = 1200p
fMax. 80kHz→C = 1500p, fMax. 60kHz→C = 2000p
AGC time constant setting.
Set capacity according to the linearity of the minimum oscillation frequency and the response
time during frequency change.
Input of the error amplifiers feedback voltage.
Input of the X-ray protector's reference voltage.
Protector output.
Output changes to the high level when the protector circuit or thermal shutdown circuit is activated.
Power supply for the signal system.
Place a decoupling capacitor in proximity to this pin.
3
Multimedia ICs
BA9755S
•Input / output circuits
VCC
HDIN
GND
11k
PMWOUT
75k
4
PVCC
75k
1
2
3
37.5k
37.5k
5p
2k
20k
MMCR
SAWOUT
AGC
5
6
7
VCC
VCC
2k
5k
2k
1k
4k
2k
4k Ref 6V
7.5k
330k
50k
22.5k
3.5k
ERRREF
99
30k
ERROUT 10
VCC
VCC
150
13k
1k
ERRIN
8
4
1k
150
2k
Multimedia ICs
BA9755S
PONDET
ABLIN
12
12
11
Ref 6V
VCC
10k
1k
1k
1k
4k
XRAYIN
XREF
13
14
VCC
1k
4k
1k
4k
50k
VCC
VCC
VCC
PROTOUT
1k
1k
20k
17
55
50k
VREG9
ESD16
20
R23
VREG6
50
15
61.335k
74.45k
25k
20k
16
1960
760
960
380
20.01k
25k
10.01k
VCC
18
295
144
590
200
5
Multimedia ICs
BA9755S
•Electrical characteristics (unless otherwise noted, Ta = 25°C, V
CC
Parameter
Supply current
〈 Error amplifier 〉
Symbol
ICC
Min.
—
Input bias current
IB
—
—
0
10
50
±3
Typ.
13
= 12V)
Max.
21
Unit
mA
Conditions
– 45
– 250
nA
S8, 9a, 9b, 9c = 2 ; Vs8, 9 = 0V
; IB8 (IB9) = V8 (V9) × 10 – 5
±1
0.2
10.5
60
±5
±5
mV
V
V
dB
mA
S9b, 9c = 3 ; VIO = V10 × 10 – 2
S9a, 9c = 2 ; Vs9 = 6V
S9a, 9c = 2 ; Vs9 = 4V
f = 1kHz, guaranteed performance
S10 = 2 ; Vs10 = 12V, 0V
S6 = 2
Input offset voltage
Output voltage, Low
Output voltage, High
Open loop gain
Maximum output current
〈 Protector 〉
Input bias current
VIO
VOL
VOH
Av
IOM
IB
—
0
Input offset voltage
VIO
—
±1
Common mode input voltage
VICR
0
—
10
V
Verify: pin 17 = LO when Vs11 (Vs12 = Vs11 + 0.5V) = 0, 10V
Verify: pin 17 = LO when Vs13 (Vs14 = Vs13 + 0.5V) = 0, 10V
Output voltage, High
Output voltage, Low
〈 PWM amplifier 〉
Output voltage, High level
Output voltage, Low level
Rise time
Fall time
VOH
VOL
10.0
—
11.0
1.0
—
2.0
V
V
S17 = 2 ; Vs12 = 5V ; Is17 = – 50µA
S17 = 2 ; Is17 = 3mA
VOH
VOL
Tr
Td
9.5
—
—
—
10.5
1
—
—
—
2
60
40
V
V
ns
ns
S2 = 2 ; Is2 = – 100mA
S2 = 2 ; Vs8 = 3V ; Is2 = 100mA
Guaranteed performance
Guaranteed performance
Minimum pulse width
TMin.
0.5
—
1.3
µs
S4 = 2 ; Vs8 = 0V ; SG4 = p1 (f = 90kHz) ; threshold = 5V
〈 Hd input pin 〉
Input voltage, High level
Input voltage, Low level
Input current, High level
Input current, Low level
〈 Monomulti 〉
VIH
VIL
IOH
IOL
4.0
—
—
—
—
—
285
0
Vcc
1.5
420
–1
V
V
µA
µA
Verify oscillation of SAW GEN. S4 = 2 ; Vs8 = 0V ; SG4 = p1
Verify oscillation of SAW GEN. S4 = 2 ; Vs8 = 0V ; SG4 = p1
Vs4 = 12V
—
Delay time
Tdl
0.3
0.5
0.8
µs
S4 = 2 ; Vs8 = 0V ; SG4 = p1
; (R = 4.7kΩ, C = 0pF)∗1
〈 SAW GEN 〉
Output level, High
Output level, Low
HOS
LOS
8.0
0
9.0
0.15
10.0
0.35
V
V
HI level of S4 = 2 ; SG4 = p1 ; 6pin output wave form
LO level of S4 = 2 ; SG4 = p1 ; 6pin output wave form
Output frequency characteritic
FSAW
150
200
—
kHz
〈 Reference voltage source 1 〉
Output voltage
Maximum output current
Output voltage
temperature characteristics
VREF9
IRMax.
8.91
10
9.0
—
9.09
—
V
mA
S15 = 2 ; Is = 10mA ;
TVREF
– 0.7
—
0.7
%
Ta = – 25°C ~ + 75°C
VREF6
IRMax.
5.94
10
6.0
—
6.06
—
V
mA
S15 = 2 ; Is = 10mA ;
TVREF
– 0.7
—
0.7
%
Ta = – 25°C ~ + 75°C
Tdow
100
—
—
deg
〈 Reference voltage source 2 〉
Output voltage
Max. output current
Output voltage
temp. characteristics
Thermal shutdown
0.5
—
—
±7
– 50
nA
Vs11, 12, 13, 14 = 0V
±5
mV
Verify: pin 17 = LO→HI when Vs12 = 6.005V→5.995V
Verify: pin 17 = LO→HI when Vs13 = 5.995V→6.005V
∗1 Time between rise of pin 4 input waveform and rise of pin 2 output waveform
6
S4 = 2, SG4 = input frequency 1 dB lower than
HI level of pin 6 output waveform when SG4 = p2
—
—
—
Multimedia ICs
BA9755S
•Measurement circuit
VCC
A
15mA
IS17
V
1
15mA
IS16
IS15
1
1
2
S17
2
S16
+
17
V
6V
5V
7V
6V
VS14
VS13
VS12
VS11
A
A
A
A
14
13
12
11
A
V
A
A
18
2
S10
2
S15
V
+
Is10
1
16
15
10
REF
6.0V
–
+
–
REF
9.0V
+
Sig VCC
LATCH
+
START
–
SAW GEN.
AGC TYPE
GND
–+
M. M.
Power VCC
1
2
3
9V
4
5
6
7
8
9
4.7k
S2
V 1
2
1S2
V
1
VS4
4V
A
1200p
S4
2
SG4
V
2
S6
1
V
V
VS6 4V
1µ
Universal
counter
Universal
Peak
counter voltmeter
V
V
2
2
1 100k 100k 1
S9a
S8
S9c
50
50
1 2 3
S9b
VS8
3
5V
5k
2 1
VS9
Fig. 1
SG4 input pulse
p1
4.0V
1.5V
5µs
11µs
p2
4.0V
1.5V
5µs
33µs
7
Multimedia ICs
BA9755S
•Application example
PROT OUT
VCC 12V
+
+
+
18
17
16
15
14
13
12
11
10
–
–
+
+
Sig VCC
REF
6.0V
REF
9.0V
LATCH
+
START
–
– +
Power VCC
GND
1
SAW GEN.
AGC TYPE
M. M.
Buffer
2
3
4
5
6
7
8
9
+
12V
+B
Hd
HRC
Hd pulse
Fig. 2
8
Anode Voltage
FBT
Multimedia ICs
BA9755S
4
3
2
1
0
50
100
150
200
250
1.3
12
PWM Min. PULSE WIDTH : TMin. (µs)
5
LOW LEVEL OUTPUT VOLTAGE : VOL (V)
HIGH LEVEL OUTPUT VOLTAGE : VOH (V)
•Electrical characteristic curves
11
10
9
8
7
0
– 50
OUTPUT CURRENT : IO (mA)
– 150
– 200
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
– 50
– 250
OUTPUT CURRENT : IO (mA)
Fig. 3 PWM HIGH output voltage vs.
output current
Fig. 4 PWM LOW output voltage vs.
output current
9.08
6.08
9.06
0.7
0.6
0.5
0.4
0.3
0.2
OUTPUT VOLTAGE : VREF9 (V)
6.10
6.06
6.04
6.02
6.00
5.98
5.96
5.94
5.92
0.1
– 50
– 25
0
+ 25
+ 50
+ 75 + 100
TEMPERATURE : Ta (°C)
Fig. 6 PWM minimum delay time vs.
temperature
0
+ 25
+ 50
+ 75 + 100
Fig. 5 PWM minimum pulse width vs.
temperature
0.9
0.8
– 25
TEMPERATURE : Ta (°C)
1.0
OUTPUT VOLTAGE : VREF 6 (V)
PWM Min. DELAY TIME : Tdl (µs)
– 100
1.2
9.04
9.02
9.00
8.98
8.96
8.94
8.92
8.90
– 50
– 25
0
+ 25
+ 50
+ 75 + 100
– 50
– 25
0
+ 25
+ 50
+ 75 + 100
TEMPERATURE : Ta (°C)
TEMPERATURE : Ta (°C)
Fig. 7 Output voltage
(6V reference voltage) vs.
temperature
Fig. 8 Output voltage
(9V reference voltage) vs.
temperature
SAW OUT HIGH PEAK LEVEL : HOS (V)
9.6
9.4
9.2
9.0
8.8
8.6
8.4
8.2
8.0
7.8
10
20
30
50 70 100
200 300
FREQUENCY : f (kHz)
Fig. 9 SAW H peak vs.
frequency
9
Multimedia ICs
BA9755S
•External dimensions (Units: mm)
19.4 ± 0.3
10
1
9
3.4 ± 0.2
0.51Min.
3.95 ± 0.3
6.5 ± 0.3
18
7.62
0.3 ± 0.1
1.778
0.5 ± 0.1
SDIP18
10
0° ~ 15°