Philips TDA4861 User Manual
INTEGRATED CIRCUITS
DATA SH EET
TDA4861
Vertical deflection power amplifier
for monitors
Product specification
Supersedes data of March 1992
File under Integrated Circuits, IC02
1997 Jan 20
Philips Semiconductors Product specification
Vertical deflection power amplifier for
TDA4861
monitors
FEATURES
• Vertical pre-amplifier with differential inputs
• Powerless vertical shift
• Flyback voltage generation suitable for two operating
modes (doubling the supply voltage or external supply
for the short flyback time, this achieves a minimum of
power dissipation)
• Vertical output stage with thermal and SOAR protection
• High deflection frequency up to 140 Hz
• High linear sawtooth signal amplification
• Possibility of guarding the deflection
• Voltage stabilizer.
QUICK REFERENCE DATA
Measurements referenced to substrate (pin 6).
SYMBOL PARAMETER MIN. TYP. MAX. UNIT
V
P1
V
P2
V
P3
I
P1
I
P2
V
I
I
5(p-p)
T
amb
supply voltage (pin 1) 9 − 30 V
supply voltage (pin 4) 9 − 60 V
flyback supply voltage (pin 8) 9 − 60 V
supply current (pin 1) −−10 mA
supply quiescent current (pin 4) − 9 − mA
input voltage (pins 2 and 3) 1.6 − VP1− 0.5 V
deflection output current (peak-to-peak value; pin 5) −−2.8 A
operating ambient temperature −20 − +75 °C
GENERAL DESCRIPTION
The TDA4861 is a vertical power amplifier for differential
input signals suitable for colour monitor/TV systems with
deflection frequencies up to 140 Hz.
ORDERING INFORMATION
TYPE
NUMBER
NAME DESCRIPTION VERSION
PACKAGE
TDA4861 SIL9P plastic single in-line power package; 9 leads SOT131-2
1997 Jan 20 2
Philips Semiconductors Product specification
Vertical deflection power amplifier for
monitors
BLOCK DIAGRAM
handbook, full pagewidth
TDA4861
VOLTAGE
STABILIZER
VERTICAL
DRIVER
DIFFERENTIAL
INPUT
AMPLIFIER
THERMAL AND
SOAR
PROTECTION
VERTICAL
OUTPUT
FLYBACK
DRIVER
FLYBACK
GENERATOR
TDA4861
PULSE
CIRCUIT
V
P1
+
8.8 V
470
150 kΩ
from TDA4850
V-shift
Assumed values:
I
= 1.42A.
yoke
R
= 4.17 Ω +7%+∆R(T) =6.12 Ω.
yoke
L
= 5.25 mH.
yoke
R1= 1.0 Ω±1%.
T
=65°C.
amb
T
= 105 °C.
j(max)
T
=75°C.
yoke
P
= 1.2 W.
yoke
PIC= 1.8 W.
P
= 3.0 W.
tot
t
= typically 250 µs.
pFLB
Attention: the heatsink of the IC must be isolated against ground (it is connected to pin 6).
µF
1 MΩ
1.8 kΩ
1.8 kΩ
BAX13
270 Ω
R1
1 Ω
V-OUT SUB FLB
V
P2
5.6 Ω
0.1 µF
yoke
−
8.1 V
470 µF
V
N
470 µF
4.3 Ω
87654321 9
V
+
52 V
P3
10 kΩ
R
PCO
PCO
MHA612
Fig.1 Block diagram and application circuit with flyback supply voltage VP3 from an external source.
Deflection frequency range from 50 to 100 Hz.
1997 Jan 20 3
Philips Semiconductors Product specification
Vertical deflection power amplifier for
monitors
PINNING
SYMBOL PIN DESCRIPTION
V
P1
INP1 2 input 1 of differential input amplifier
INP2 3 input 2 of differential input amplifier
V
P2
V-OUT 5 vertical output
SUB 6 substrate
FLB 7 flyback generator output
V
P3
PCO 9 pulse circuit output
1 supply voltage 1
supply voltage 2 for vertical output
4
stage
8 flyback supply voltage 3
handbook, halfpage
V
1
P1
INP1
2
INP2
3
V
4
P2
V-OUT
5
TDA4861
SUB
6
7
FLB
V
8
P3
9
PCO
MEH360
Fig.2 Pin configuration.
TDA4861
FUNCTIONAL DESCRIPTION
Differential input amplifier
The differential sawtooth input signal (coming from a ramp
output of the TDA4850 for example) is fed to the input at
pins 2 and 3. The non-inverted signal is attached to pin 3.
The vertical feedback signal is superimposed on the
inverted input signal on pin 2.
Vertical shift is applied at the inputs in a power-less way
(see Fig.1).
Flyback generator
Signals for the flyback generator and the pulse circuit are
generated in the flyback driver stage. The flyback output
consists of a Darlington transistor and a flyback diode.
The flyback generator can operate in two modes:
1. An external supply voltage is applied for the short
flyback time, thus the power dissipation is minimum
(see Fig.1).
2. The flyback voltage is generated by doubling the
supply voltage (see Fig.5). The 100 µF capacitor C2
connected between pins 4 and 7 is charged up to V
P1
during scan, using the external diode and the resistor
R2. The cathode of the capacitor C2 is connected to
the positive rail during flyback. Thus, the flyback
voltage is twice the supply voltage.
Vertical output
The vertical output stage is a quasi-complementary
class-B amplifier with a high linearity. The output contains
SOAR (short-circuit protection) and thermal protection.
The output current on pin 5 is reduced for a short time
(to let the temperature decrease to T
< 150 °C), when the
j
junction temperature (Tj) exceeds 160 °C.
Deflection GUARD
Pin 9 will go HIGH if the junction temperature goes too
high (see Fig.3). A pulse signal with 50% duty cycle is
output on pin 9, if the deflection coil is open-circuit.
A flyback pulse signal is output at normal conditions.
Further watching can be achieved by means of an external
GUARD circuit as shown in Fig.4. The 22 µF capacitor is
charged during flyback time (V
) at normal conditions.
5>V8
In the event of failures, the capacitor is discharged and the
GUARD output goes HIGH.
GUARD output level (see Fig.4):
• LOW for normal conditions
• HIGH for deflection coil short-circuit respectively
open-circuit
• HIGH when there are neither input or output signals.
1997 Jan 20 4
Loading...