Device for protecting a vertical deflection integrated circuit for a monitor

摘要

A vertical deflection IC protection device for a monitor employing a dedicated display data channel (DDC) chip which can prevent the vertical deflection IC from being damaged by intercepting an input of a high frequency of about 25 KHz to the vertical deflection IC when monitor information data stored in the DDC chip is read out by a computer. The protection device includes a DDC section receiving a vertical sync signal from a computer I/O section and outputting DDC data to the computer I/O section when a predetermined time elapses thereafter, and a vertical frequency selection control section which intercepts the input of an abnormal vertical sync signal, which has a frequency higher than the normal vertical sync signal, to the vertical deflection IC when the abnormal vertical sync signal is inputted from the computer I/O section for the DDC data transmission.