Overview

The LA7851 is a sync deflection circuit IC dedicated to CRT display use. It can be connected to the LA7832, 7833 (for vertical output use) to form a sync deflection circuit that meets every requirement for CRT display use.

So far, ICs for color TV use have been applied to the sync deflection circuit for CRT display use and general-purpose ICs such as one-shot multivibrator, inverter and a lot of transistors have been used to form the peripherals such as sync input interface, horizontal phase shifter. The LA7851 contains these peripherals on chip, has a wide vertical pullin range of 20Hz, and adopts a stable circuit for horizontal oscillation from 15kHz to 100kHz aiming at improving the characteristics requierd for CRT display use.

Features

• The vertical pull-in range 20Hz permits non-adjusting at vertical sync 50Hz/60Hz.

• The horizontal oscillation frequency can be adjusted stably from 15kHz to 100kHz.

• The horizontal display can be shifted right/left.

• The horizontal/vertical sync input can be used intact regardless of the difference in pulse polarity and pulse width.

• The AFC feedback sawtooth wave can be obtained by simply applying a flyback pulse to the IC as a trigger pulse.

• Any duty of the horizontal pulse can be set.

• Good linearity because DC bias at vertical output stage is subject to sampling control within retrace time.

On-Chip Functions

[Horizontal Block]

• AFC

• Horizontal OSC

• X-ray protector

• Horizontal phase shift

• AFC sawtooth wave generator

• Horizontal pulse duty setting

[Vertical Block]

• Vertical OSC

• Vertical sawtooth wave generator

• Sampling type DC voltage control