US 12,451,686 B2
Electrostatic discharge robustness for a single rail transmitting driver
Jaseem Ahammed, San Diego, CA (US); Ashwin Sethuram, San Clemente, CA (US); and Gurmukh Singh, San Marcos, CA (US)
Assigned to QUALCOMM INCORPORATED, San Diego, CA (US)
Filed by QUALCOMM Incorporated, San Diego, CA (US)
Filed on Jan. 20, 2023, as Appl. No. 18/157,211.
Prior Publication US 2024/0250526 A1, Jul. 25, 2024
Int. Cl. H02H 9/04 (2006.01)
CPC H02H 9/046 (2013.01) 25 Claims
OG exemplary drawing
 
1. An electrostatic discharge protection circuit in an interface circuit, comprising:
a first diode coupled between a power source of an integrated circuit device and an input/output pad of the integrated circuit device, wherein the power source supplies a driver circuit coupled to the input/output pad;
a second diode coupled between a first terminal of a first resistive element and the input/output pad, wherein a second terminal of the first resistive element is coupled to the power source;
a second resistive element that couples the second diode to the first diode and to the input/output pad;
a first clamping circuit coupled between the power source and a ground reference of the integrated circuit device; and
a second clamping circuit coupled between the first terminal of the first resistive element and the ground reference, wherein the second clamping circuit is activated during an electrostatic discharge event by a trigger signal provided by the first clamping circuit.
 
10. An apparatus, comprising:
means for driving an input/output pad of an integrated circuit device;
means for diverting a first portion of an electrostatic discharge current that is conducted through the input/output pad, including a first diode that is coupled between a power source of the integrated circuit device and the input/output pad, wherein the power source supplies the means for driving the input/output pad;
means for diverting a second portion of the electrostatic discharge current, including a second diode that is coupled between a first terminal of a first resistive element and the input/output pad, wherein a second terminal of the first resistive element is coupled to the power source, and wherein a terminal of the second diode is coupled to the input/output pad and to a corresponding terminal of the first diode through a second resistive element; and
means for clamping voltages, including a first clamping circuit coupled between the power source and a ground reference of the integrated circuit device and a second clamping circuit coupled between the first terminal of the first resistive element and the ground reference, wherein the second clamping circuit is activated during an electrostatic discharge event by a trigger signal provided by the first clamping circuit.
 
18. A method for protecting an interface circuit from electrostatic discharge, comprising:
coupling a first diode between a power source of an integrated circuit device and an input/output pad of the integrated circuit device, wherein the power source supplies a driver circuit coupled to the input/output pad;
coupling a second diode between a first terminal of a first resistive element and the input/output pad, wherein a second terminal of the first resistive element is coupled to the power source;
coupling the second diode to the first diode and to the input/output pad through a second resistive element;
coupling a first clamping circuit between the power source and a ground reference of the integrated circuit device; and
coupling a second clamping circuit between the first terminal of the first resistive element and the ground reference, wherein the second clamping circuit is activated during an electrostatic discharge event by a trigger signal provided by the first clamping circuit.