US 11,705,725 B2
Integrated circuit with electrostatic discharge protection
Chuan-Chen Chao, Taipei (TW); and Ching-Yao Pai, Taipei (TW)
Assigned to RichWave Technology Corp., Taipei (TW)
Filed by RichWave Technology Corp., Taipei (TW)
Filed on Oct. 29, 2020, as Appl. No. 17/83,323.
Claims priority of provisional application 62/929,112, filed on Nov. 1, 2019.
Claims priority of application No. 109135417 (TW), filed on Oct. 14, 2020.
Prior Publication US 2021/0135451 A1, May 6, 2021
Int. Cl. H02H 9/04 (2006.01); H01L 27/02 (2006.01)
CPC H02H 9/046 (2013.01) [H01L 27/0255 (2013.01); H01L 27/0266 (2013.01); H01L 27/0288 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An integrated circuit (IC) with electrostatic discharge (ESD) protection, comprising:
a signal pad, configured to receive an input signal during a normal mode, and receive an ESD signal during an ESD mode;
an internal circuit, configured to process the input signal during the normal mode;
a variable impedance circuit, comprising a first end coupled to the signal pad, a second end coupled to the internal circuit, and a control end, wherein the variable impedance circuit provides a low impedance path between the signal pad and the internal circuit during the normal mode, and provides a high impedance path between the signal pad and the internal circuit during the ESD mode; and
a switch circuit, comprising a first end coupled to the control end of the variable impedance circuit, a second end coupled to a reference voltage terminal, and a control end configured to receive a node voltage, wherein the switch circuit is configured to switch the control end of the variable impedance circuit to have a first specific voltage during the normal mode, and to switch the control end of the variable impedance circuit to be electrically floating during the ESD mode.