1.  Field of the Invention
The present invention relates to ESD protection circuitry with multi-finger SCRs, especially to ESD protection circuitry which can turn on all of its multi-finger SCRs. 
2.  Description of the Prior Art
The electrostatic discharge (ESD) is a sudden and momentary electric current generated by friction or induction and then flows through circuitry.  It may cause damage to electronic equipment.  Some circuitry and devices are vulnerable to ESD, for example MOSFETs (Metal Oxide Semiconductor Field Effect Transistor).  Therefore, ESD protection circuitry is often applied in IC designs.