Patent ID: 9331472
Filing Date: 2016-05-03
CPC Classification: H02H

Claim Text:
1. An electrostatic discharge (ESD) protection circuit, comprising: a first resistor having a first end coupled to a power line, and a second end coupled to a pad; a first clamp unit directly coupled between the second end of the first resistor and a ground line; a second clamp unit coupled between the pad and the first resistor, conducting a first ESD current caused by positive voltage ESD pulses from the pad to the first clamp unit, wherein no ESD current flows to the power line through the first resistor when the first ESD current is conducted from the pad to the first clamp unit; and a third clamp unit coupled between the pad and the ground line, conducting a second ESD current by negative voltage ESD pulses from the ground line to the pad, wherein no ESD current flows to the power line through the first resistor when the second ESD current is conducted from the ground line to the pad.