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TDA4950
TV EAST/WEST CORRECTION CIRCUIT
. . . . . . . .
LOW DISSIPATION SQUARE GENERATOR FOR PARABOLIC CURRENT EXTERNAL KEYSTONE ADJUSTMENT (symmetry of the parabola) INPUT FOR DYNAMIC FIELD CORRECTION (beam current change) STATIC PICTURE WIDTH ADJUSTMENT PULSE-WIDTH MODULATOR FINAL STAGE D-CLASS WITH ENERGY REDELIVERY PARASITIC PARABOLA SUPPRESSION, DURING FLYBACK TIME OF THE VERTICAL SAWTOOTH
POWERDIP8 (Th = 0.4mm) (Plastic Package) ORDER CODE : TDA4950
DESCRIPTION The TDA4950 is a monolithic integrated circuit in a 8 pin minidip plastic package designed for use in the east-west pin-cushion correction by driving a diode modulator in TV and monitor applications. PIN CONNECTIONS
KEYSTONE CORRECTION INPUT FRAME SAWTOOTH CURRENT INPUT CURRENT REFERENCE GND
1 2 3 4
8 7 6 5
NON-INVERTING INPUT 100A CURRENT SINK PARABOLA OUTPUT INVERTING INPUT +VS OUTPUT
October 1998
1/5
4950-01.EPS
TDA4950
BLOCK DIAGRAM
7 8 COMPARATOR AND OUTPUT STAGE 6 Q14 Q15 Q16 Q1 VS - 3 VBE Q2 Q13 Q4 VREF Q13 R2 Q17 Q18 D1 +VS
TDA4950
CURRENT LIMITER
R5 R3 OP2 R6 Q12
R4 5 Q19 OUTPUT
R5 R7 1 OP1 Q5 Q21 R8
Q20
2 IIN Q7 VS - 6 VBE Q6 Q10 Q11 D2 D3 Q8 Q9 Z1 R9 R10 R11 R12 R13 OP3 Q22 4 GND IREF
FULL-WAVE RECTIFIER
PARABOLA NETWORK
CURRENT REFERENCE 3
ABSOLUTE MAXIMUM RATINGS
Symbol VS IS Ptot Tstg, Tj Parameter Supply Voltage Supply Current Power Dissipation at Tamb = 70 C Storage and Junction Temperature Value 35 500 800 - 25, +150 Unit V mA mW C
THERMAL DATA
Max. Max.
4950-02.TBL 4950-03.TBL
Symbol Rth (j-a) Rth (j-c)
Parameter Thermal Resistance Junction-ambient Thermal Resistance Junction-pin (4)
Value 100 70
Unit C/W C/W
ELECTRICAL CHARACTERISTICS (Tamb = 25oC, VS = 26 V, Vfr = 0, S1 and S2 in "a" position, refer to test circuit unless otherwise specified)
Symbol VS IS Vref - Iref V7(A) V7(B) 2/5 Parameter Supply Voltage Supply Current Internal Reference Voltage Internal Reference Current Pin 7 Output Voltage Pin 7 Output Voltage Test Conditions Min. 17 7.6 Vref/R3 Ifr = 0 A, see Figure 2 Ifr = 30 A, see Figure 2 15.3 Typ. 24 4.5 8.0 0.73 16.0 15 Max. 30 7 8.8 16.7 Unit V mA V mA V V
4950-01.TBL
4950-02.EPS
TDA4950
ELECTRICAL CHARACTERISTICS (Tamb = 25oC, VS = 26 V, Vfr = 0, S1 and S2 in "a" position, refer to test circuit unless otherwise specified) (continued)
Symbol K1 K2 V7 (*) I8 VSATL VSATH VF Ifr Parameter Parabola Coefficient Parabola Coefficient Test Conditions V7A - V7B , see Figure 2 K1 = V7A - V7C V7A - V7C , see Figure 2 K2 = V7A - V7D V7 = V7E - V7F, see Figure 2 S1 b Io = 400 mA Sink S2 b Io = 100 mA Source S2 c S1 b Io = 400 mA S2 d S1 b Vfr = 6.6 VPP Min. Typ. 0.28 0.71 - 40 100 1 0.8 1.2 66 40 2 1.5 1.7 mV A V V V A Max. Unit
Figure 1 : Test CIrcuit
VS R7 10k IFR 2 VFR R1 3 10k R3 11k VREF 4 8 IF R8 20k
4950-03.EPS
R6 10k 7 6 VF a S2 b c d VSATH IO
R2 1
TDA4950
5
-IO
VSATL
b a S1
Figure 2 : Parabola Characteristics
V7 (V) V7A V7B V7C V7D
-60
0
15
36 30
60
IFR (A)
CIRCUIT OPERATION (see the shematic diagram) A differential amplifier OP1 is driven by a vertical frequency sawtooth current of 33A which is produced via an external resistor from the sawtooth voltage. The non-inverting input of this amplifier is connected with a reference voltage corresponding
4950-04.EPS
V7E
V7F
to the DC level of the sawtooth voltage. This DC voltage should be adjustable for the keystone correction. The rectified output current of this amplifier drives the parabola network which provides a parabolic output current. This output current produces the corresponding voltage due to the voltage drop across the external resistor at pin 7. If the input is overmodulated (> 40A) the internal current is limited to 40A. This limitation can be used for suppressing the parasitic parabolic current generated during the flyback time of the frame sawtooth. A comparator OP2 is driven by the parabolic current. The second input of the comparator is connected with a horizontal frequency sawtooth voltage the DC level of which can be changed by the external circuitry for the adjustment of the picture width. The horizontal frequency pulse-width modulated output signal drives the final stage. It consists of a class D push-pull output amplifier that drives, via an external inductor, the diode modulator.
3/5
4950-04.TBL
Current Source Saturation Voltage Saturation Voltage Forward Voltage Frame Sawtooth Current
TDA4950
Figure 3 : Application Circuit with Keystone Correction
Line Transformer (L.T.)
LM
L1 10mH
Pin-cushion adjustment RT2 47k 7 R4 18k C1 47nF
R3 4.7k VFRAME R1 = 66APP Pin 1 Voltage VFRAME 2 5
TDA4950
1
6 C2 100nF
VS
3
4
8 C3 4.7nF D1 1N4148
RT1 Keystone 100k Adj.
R2 12k
Hfly from L.T.
H. Width R5 RT3
Figure 4 : P.C. Board and Component Layout of the Circuit of Figure 3 (1:1 scale)
RT3 R5 HFLY
TDA4950
D1
C3 R1
VFRAME RT1 VS GND TO LM R2
C1 R4
C2 RT2 L1 R3
4950-06.EPS
4/5
4950-05.EPS
1k
TDA4950
PACKAGE MECHANICAL DATA 8 PINS - PLASTIC POWERDIP
Dimensions A a1 B B1 b b1 D E e e3 e4 F I L Z
Min. 0.7 1.39 0.91
Millimeters Typ. 3.3
Max.
Min. 0.020 0.055 0.036
Inches Typ. 0.130
Max.
1.65 1.04 0.5 0.5 9.8 8.8 2.54 7.62 7.62 7.1 4.8 3.3
0.065 0.041 0.020 0.020 0.386 0.346 0.100 0.300 0.300
DIP8PW.TBL
0.38
0.015
0.280 0.189 0.130 0.017 0.063
0.44
1.6
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No licence is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics (c) 1998 STMicroelectronics - All Rights Reserved Purchase of I2C Components of STMicroelectronics, conveys a license under the Philips I2C Patent. Rights to use these components in a I2C system, is granted provided that the system conforms to the I2C Standard Specifications as defined by Philips. STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Italy - Japan - Korea - Malaysia - Malta - Mexico - Morocco - The Netherlands Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. http://www.st.com
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PM-DIP8.EPS

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