PI3V724 Datasheet, PDF (5/14 Pages) Pericom Semiconductor Corporation – 1 to 2 VGA Demux

PI3V724
1 to 2 VGA Demux
Application Note
Introduction
PI3V724 is a full VGA de-mux switch with integrated monitor detection circuit. Port switching can be selected manually or auto-
matically to offer more flexibility to users.
Automatic Monitor Detection
If MS pin (pin 8) is set to low or float, PI3V724 enters auto switch mode. When external monitor(s) is/are properly detected,
PI3V724 can support automatic switching.
Detection Pulse
When auto switch mode is selected via MS pin, PI3V724 sends a detection pulse through BLUE signal to check if any termination is
present. Once a monitor is attached, its termination is determined. PI3V724 will switch to the port with such termination accord-
ingly.
Result
detect
EN
B1
Result
B
V
V
detect
EN
B2
MS
Priority/SEL
CE
Rref
VV
Logic
Control
Detection Start Logic
Timer
pulse
PI3V724 Detection Block Diagram
A detection pulse is sent by PI3V724 every 1.6 seconds when source or sink is not attached. Furthermore, the detection pulse is sent
immediately after sensing Vsync pulse. The detection pulse is of the width within 30us and the voltage level around 0.7V.
14-0168
PI3V724 Detection Pulse on Blue B2 without Source or Sink Device
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www.pericom.com 10/22/14