Flyback pulse wideth adjustment circuit in one-chip video signal processing unit and method

Abstract

A fly-back pulse width adjustment circuit and a method for adjusting the width of a fly-back pulse which are applied to a video signal processing unit realized as one chip are provided. The fly-back pulse width adjustment circuit is built into a video signal processing unit including a video amplifier, an on screen display unit, and a horizontal / vertical synchronous signal processing unit. Moreover the fly-back pulse width adjustment circuit includes a pulse shaping unit which shapes the fly-back pulse received from the outside via an input terminal and then applies the shaped fly-back pulse to the horizontal / vertical synchronous signal processing unit, and a pulse-width adjustment unit which adjusts the width of the shaped fly-back pulse in response to a predetermined control signal, generates the horizontal blank signal having a different occurrence time from the result of the adjustment in response to a selection signal, and applies the horizontal blank signal to the video amplifier and the on screen display unit. The circuit structure is simple and can be mounted into a video signal processing unit.

Description

technical field [0001] The present invention relates to a video signal processing unit for a monitor, and more particularly, to a circuit and method for adjusting fly-back pulse width, applied to video signal processing implemented in a single chip Unit Apparatus and Methods. Background technique [0002] Typically, the horizontal blanking signal used for blocking the electron beam during the horizontal retrace period of the monitor system is generated by receiving retrace pulses from an external horizontal deflection transformer. Conventionally, a video amplifier, an on-screen display (OSD) using a horizontal blanking signal, and a horizontal / vertical synchronizing signal processing unit using a retrace pulse are fabricated in separate chips. [0003] figure 1 is a schematic block diagram showing a video signal processing unit in which a conventional circuit for adjusting the retrace pulse width is applied. The video signal processing unit inc...

AI Technical Summary

Problems solved by technology

Therefore, capacitors C21, C22, and C23 cannot be fabricated as a single chip, but must be provided as external components

In addition, in figure 2 In the case of the flyback pulse width adjustment circuit 12 shown, the capacitors C21, C22, C23 and the resistors R21, R22, R23 are set to fixed values, therefore, there is a disadvantage that the pulse width is fixed

Therefore, it is difficult to manufacture a printed circuit board (PCB) using the flyback pulse width adjustment circuit 12 provided as an external component, thus causing an additional increase in manufacturing cost

In addition, there is another disadvantage that the width of the retrace pulse must be adjusted to suit the characteristics of newly introduced monitors

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