Granted Patent B2

US 9,438,031 · App. 14/379,908 · Granted Sep 6, 2016

Abstract

Claims (29)

1. An electrostatic discharge, ESD, protection circuit arrangement, said protection circuit arrangement being connectable to a first pin and a second pin of an electronic circuit and arranged to at least partly absorb an ESD current entering said electronic circuit through at least one of the first pin or the second pin during an ESD stress event, said protection circuit arrangement comprising:

a first ESD protection circuit arranged to absorb a first portion of said ESD current during a first part of said ESD stress event during which first part a level of said ESD current exceeds a predetermined current threshold; and

a second ESD protection circuit arranged to absorb a second portion of said ESD current, said second portion having a current level below said current threshold, at least during a second part of said ESD stress event, said second ESD protection circuit comprising a current limiting circuit arranged to limit a current through at least a portion of said second ESD protection circuit to said current threshold, wherein said second ESD protection circuit comprises a bridge circuit, said bridge circuit comprising one or more switching elements, each of the one or more switching elements comprising a switching terminal and two channel terminals.

2. The electrostatic discharge protection circuit arrangement as claimed in claim 1 , wherein said bridge circuit is arranged to distribute said second portion of said ESD current between a first branch and a second branch of said bridge circuit.

3. The electrostatic discharge protection circuit arrangement as claimed in claim 1 , wherein said second ESD protection circuit is arranged to provide the same current sustainability characteristics independently from whether said ESD current is received through said first pin or said second pin.

4. The electrostatic discharge protection circuit arrangement as claimed in claim 1 , wherein said current limiting circuit is arranged to control a conductivity between said two channel terminals of at least one of said switching elements in response to said ESD current.

5. The electrostatic discharge protection circuit arrangement as claimed in claim 4 , wherein for said at least one of said switching elements said current limiting circuit comprises a clamping structure and a resistive element, arranged to cause a decrease of said conductivity between said two channel terminals of said at least one of said switching elements when a voltage drop across said resistive element exceeds a difference between a clamping voltage of said clamping structure and a switching voltage threshold of said at least one of said switching elements.

6. The electrostatic discharge protection circuit arrangement as claimed in claim 1 , wherein said first ESD protection circuit comprises a plurality of ESD protection structures connected to at least partly divert said first portion of said ESD current between said ESD protection structures.

7. The electrostatic discharge protection circuit arrangement as claimed in claim 6 , wherein said plurality of ESD protection structures comprises one or more pairs of first directional ESD protection structures and second directional ESD protection structures, wherein for each of said pairs said first directional ESD protection structure and said second directional ESD protection structure are connected with each other in opposite direction.

8. The electrostatic discharge protection circuit arrangement as claimed in claim 6 , wherein at least some of said plurality of ESD protection structures are arranged as a bidirectional circuitry connectable to said first and second pin.

9. The electrostatic discharge protection circuit arrangement as claimed in claim 7 , wherein said first directional ESD protection structures are responsive to first triggering voltages and said second directional ESD protection structures are responsive to second triggering voltages having the same absolute values and opposite signs as compared to said first triggering voltages.

10. The electrostatic discharge protection circuit arrangement as claimed in claim 1 , wherein said first ESD protection circuit is arranged to absorb, during said first part of the ESD event of said ESD stress event, a current comprising a maximum level at least twice as high as said current threshold.

11. The electrostatic discharge protection circuit arrangement as claimed in claim 1 , wherein the second ESD protection circuit is arranged to absorb, in addition to during the second part of the ESD event, a portion of the ESD current during an ESD stress event at least during a part of the first part of the ESD event.

12. The electrostatic discharge protection circuit arrangement as claimed in claim 11 , wherein the first and second ESD protection circuits are arranged such that during the first part, the second protection circuit absorbs a part of the ESD current up to the current threshold and said first protection circuit absorbs a remaining part of the ESD current.

13. The electrostatic discharge protection circuit arrangement as claimed in claim 1 , wherein during said first part said first and second ESD protection circuits provide a plurality of current paths for absorbing said ESD current.

14. The electrostatic discharge protection circuit arrangement as claimed in claim 1 , wherein said first part is shorter than said second part, for example 10 times shorter.

15. The electrostatic discharge protection circuit arrangement as claimed in claim 1 , wherein said first ESD protection circuit is arranged to absorb a current of at least 40 A, and said current threshold is 10 A or less.

16. An electronic circuit, comprising

at least a first and a second pin;

an ESD sensitive device; and

at least one electrostatic discharge protection circuit arrangement as claimed in claim 1 , connected to said first and second pin.

17. The electronic circuit as claimed in claim 11 , wherein said electronic circuit is located in a single integrated circuit package.

18. An electrostatic discharge, ESD, protection method, comprising:

receiving at a first pin or a second pin of an electronic circuit an ESD current during an ESD stress event;

at least partly absorbing the ESD current by an electrostatic protection circuit arrangement connected to the first pin and the second pin; said at least partly absorbing comprising:

absorbing a first portion of said ESD current by a first ESD protection circuit of the electrostatic protection circuit arrangement during a first part of the ESD event, during which first part a level of said ESD current is higher than a predetermined current threshold; and

absorbing by a second ESD protection circuit of the electrostatic protection circuit arrangement a second portion of said ESD current, said second portion having a current level below said current threshold, at least during a second part of said ESD stress event; and

limiting, by a current limiting circuit, a current through at least a portion of said second ESD protection circuit to said current threshold, wherein said second ESD protection circuit comprises a bridge circuit, said bridge circuit comprising one or more switching elements.

19. The method as claimed in claim 1 , wherein said receiving comprises receiving said ESD current during an ESD stress event according to ISO 10605 test procedure.

Assignments (24)