TA1204AF Datasheet, PDF (17/25 Pages) Toshiba Semiconductor – γ CORRECTION IC FOR LCD TV

TA1204AF
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Typical γ characteristics, inter-axis deviation, polarity difference
• Test condition 4 (CP mode)
• Input : X In1
Test signal 3
Input test signal 3 including black, white, and 60% levels to input A (X In1). Measure the voltage
difference (set at 1) between the white and black levels and the voltage difference (set at 2) between
the 60% input and black levels in the waveform of an output pin (pin 21 when X = B, pin 19 when X
= G, and pin 14 when X = R). Obtain a voltage difference ratio of 2:1. Repeat for the positive and
negative polarity outputs.
Repeat this measurement replacing B, G, and R as the X-axis.
γ characteristic variable range, maximum and minimum-characteristic variable range, inter-axis deviation
• Test condition 4 (CP mode)
• Input : X In1
Test signal 3
• VR44 : Max / Min (pin 44←0V / 5V)
Input test signal 3 including black, white, and 60% levels to input A (X In1). Change SW44 from a to
b, adjust VR44 and set the voltage applied to pin 44 at 0V, thereby maximizing the γ control.
Measure the voltage difference (set to 1) between the white and black waveform levels for an output
pin (pin 21 when X = B, pin 19 when X = G, and pin 14 when X = R) and the voltage difference (set
at 2) between the 60% input and black levels. Obtain a voltage difference ratio of 2:1 and set this as
the maximum value for the γ characteristics. Next, adjust VR44 in the opposite direction, set the
voltage applied to pin 44 to 5V, and thus minimize the γ control. Obtain a voltage difference ratio of
2:1 as for the measurement of the maximum value, and set this as the minimum value of the γ
characteristics.
Repeat this measurement replacing B, G, and R as the X-axis.
γ fine adjustment characteristic variable range, maximum and minimum γ fine adjustment characteristic
variable ranges, inter-axis deviation
• Test condition 4 (CP mode)
• Input : X In1 (X = B or R)
Test signal 3
X = B : VR43 : Max / Min (pin 43←5V / 2.5V)
X = R : VR1 : Max / Min (pin 1←5V / 2.5V)
When measuring channel B, change SW43 from OFF to ON, and input test signal 3 including black,
white, and 60% levels to input A (B In1). Turn VR43 fully, set the voltage applied to pin 43 at 5V, and
thus maximize the γ control.
Measure the voltage difference (fixed at 1) between white and black waveform levels for output pin
21 and the voltage difference (fixed at 2) of 60% input and black levels. Obtain a voltage difference
ratio of 2:1 and set this as the maximum value of the γ characteristics. Next, set the voltage applied
to pin 43 to 2.5V by turning VR43 fully in the opposite direction, thereby minimizing the γ
characteristics. Obtain a voltage difference ratio of 2:1 and thereby minimize the value of the γ
characteristics in the same way the maximum value was measured. When measuring channel R (X =
R) change SW1 from OFF to ON, turn VR1 clockwise and anticlockwise with R In1 as the input pin,
and thus measure output pin 14 in the same way as channel B.
Typical amplitude of common electrode signals
• Test condition 4
• Input : no signal
Measure the voltage difference between H and L levels in the output waveform of pin 10.
Amplitude of common electrode signals, maximum variable range, amplitude of common electrode
signals, minimum variable range
• Test condition 4
• Input : no signal
Measure the voltage difference between H and L waveform levels for pin 10 output when terminal 11
is shorted to GND, and thus set this as the maximum amplitude.
Measure the voltage difference between the H and L levels for the output waveform of pin 10 when
pin 11 is shorted with VCC (%V), and set this as the minimum amplitude.
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