LM1229
I2C Compatible CMOS TV RGB and Deflection Processor
General Description
The LM1229 pre-amp is an integrated CMOS CRT RGB
preamp plus horizontal and vertical deflection processing
with an I2C compatible interface for controlling all the parameters
necessary to directly adjust the gain, contrast and
brightness and geometry of the CRT display.
In the RGB section, the CRT bias is controlled by the three
DAC outputs which are matched to the LM248x integrated
bias clamp ICs. The brightness control operates on the video
channels rather than the bias channels and is designed to
maintain the CRT color temperature through the full range of
adjustment. The On Screen Display inputs accept either
digital or analog input levels. Black level clamping of the
video signal is carried out directly on the AC coupled input
signal into the high impedance preamplifier input, thus eliminating
the need for additional clamp capacitors. Blanking
inputs are provided which can accept both horizontal and
vertical flyback inputs for composite blanking of the video. A
vertical blanking output pulse is provided which can drive a
G1 blanking amplifier such as the one in National’s LM2485
clamp IC. The LM1229 RGB outputs are compatible with
National’s high gain drivers (http://www.national.com).
The Deflection section uses a 12.0 MHz resonator and with
it the horizontal processor is capable of locking to seven
different television signal formats, 15.734, 28.1, 31.468,
33.7, 37.9, 45.0, and 48.08 kHz by configuring two external
tri-state pins. The resonator frequency can be scaled up or
down by as much as 5% to accommodate custom scan
frequencies, however all scan modes will be scaled up or
down by the same percentage. Additional inputs are provided
for H and V synchronization, X-Ray protection, V scan
protection, and H and V EHT compensation. Deflection output
signals are provided for horizontal drive, variable amplitude
vertical ramp, vertical ramp reference voltage, variable
amplitude dynamic focus, and E-W correction with DC level
adjustment for size.
A status register is also provided for the system microcontroller
to read and check for failure conditions.
The IC is packaged in an industry standard 64 lead LQFP
molded plastic package.
Features
n Fully bus controllable via an I2C compatible interface.
n Contrast control for simultaneously adjusting the RGB
output peak to peak levels.
n Gain controls for aligning the CRT color temperature.
n Color tracking brightness control for maintaining color
temperature throughout the full range of adjustment.
n Black level clamping to ensure output level stability. The
polarity of the logic pulse input is register selectable.
n Digital or analog RGB OSD inputs, with adjustable
transparency available in the digital mode and clamping
in the analog mode for black level stability.
n Choice of four levels of OSD amplitude.
n Window highlight using the OSD Transparency feature.
n ABL input for reducing the video contrast when the CRT
beam current exceeds the predetermined threshold set
by an external resistor.
n Horizontal and/or vertical blanking directly from
deflection signals. The blanking can be disabled, if
desired.
n Matched to National’s driver and clamp IC families
(http://www.national.com).
n Black level output adjustable from 0.5V to 1.4V for
compatibility with NSC CRT driver IC’s with or without
PNP transistor buffers.
n Three DAC outputs for setting CRT cathode bias, which
can be set to full or half scale like the LM1267 series of
preamplifiers.
n Spot killer which blanks the video outputs when VCC
falls below the specified threshold.
n RGB Power Saving Mode with 35% power reduction.
n Support for seven different TV signal formats.
n RGB blanking for scan loss protection.
n I2C control over horizontal and vertical position and size,
pincushion, pin balance, trapezoidal, parallelogram, top
and bottom corner corrections, vertical S and C
correction, and dynamic focus amplitude.
n Programmable duration 5V vertical blanking output
pulse.
n Uses a low cost resonator.
n Status register indicating vertical scan loss, X-Ray,
horizontal flyback and horizontal lock status.
n Blanks the RGB outputs whenever the loss of vertical
scan is detected.
n Independent control over horizontal and vertical sync
input polarities.
Applications
n Television deflection and RGB video processing with
National’s CRT drivers.