Electrostatic discharge protection device and operation method thereof

Patent metadata

Field	Value
Publication number	US-2017194786-A1
Application number	US-201514985462-A
Country	US
Kind code	A1
Filing date	Dec 31, 2015
Priority date	Dec 31, 2015
Publication date	Jul 6, 2017
Grant date	—

Abstract

An electrostatic discharge (ESD) protection device and an operation method of the ESD protection device are provided. The ESD protection device includes an ESD current rail, an ESD protection element string, and a bias circuit. A first end and a second end of the ESD protection element string are electrically connected to the ESD current rail and a signal pad, respectively. The ESD protection element string includes a first ESD protection element and a second ESD protection element that are serially connected. The bias circuit is electrically connected to the ESD protection element string to provide a bias voltage to a common connection node between the first ESD protection element and the second ESD protection element.

First claim

What is claimed is:

1 . An electrostatic discharge (ESD) protection device comprising:
a first ESD current rail; a first ESD protection element string, a first end and a second end of the first ESD protection element string being electrically connected to the first ESD current rail and a signal pad, respectively, wherein the first ESD protection element string comprises a first ESD protection element and a second ESD protection element serially connected to each other; and a first bias circuit electrically connected to the first ESD protection element string to provide a first bias voltage to a first common connection node between the first ESD protection element and the second ESD protection element.

2 . The ESD protection device of claim 1 , wherein the first ESD current rail is a supply voltage rail or a ground voltage rail.

3 . The ESD protection device of claim 1 , wherein an anode of the first ESD protection element is electrically connected to the signal pad, a cathode of the first ESD protection element and an anode of the second ESD protection element are electrically connected to the first common connection node, and a cathode of the second ESD protection element is electrically connected to the first ESD current rail.

4 . The ESD protection device of claim 3 , wherein the first bias voltage is greater than an original division voltage, and the original division voltage is a voltage of the first common connection node when the first bias circuit is not electrically connected to the first ESD protection element string.

5 . The ESD protection device of claim 1 , wherein a cathode of the first ESD protection element is electrically connected to the signal pad, an anode of the first ESD protection element and a cathode of the second ESD protection element are electrically connected to the first common connection node, and an anode of the second ESD protection element is electrically connected to the first ESD current rail.

6 . The ESD protection device of claim 5 , wherein the first bias voltage is less than an original division voltage, and the original division voltage is a voltage of the first common connection node when the first bias circuit is not electrically connected to the first ESD protection element string.

7 . The ESD protection device of claim 1 , wherein the first ESD protection element string further comprises a third ESD protection element serially connected to the first ESD protection element and the second ESD protection element, an anode of the first ESD protection element is electrically connected to the signal pad, a cathode of the first ESD protection element and an anode of the second ESD protection element are electrically connected to the first common connection node, a cathode of the second ESD protection element and an anode of the third ESD protection element are electrically connected to a second common connection node, and a cathode of the third ESD protection element is electrically connected to the first ESD current rail.

8 . The ESD protection device of claim 7 , wherein the first bias circuit further provides a second bias voltage to the second common connection node, the first bias voltage is greater than a first original division voltage, the second bias voltage is less than a second original division voltage, the first original division voltage is a voltage of the first common connection node when the first bias circuit is not electrically connected to the first ESD protection element string, and the second original division voltage is a voltage of the second common connection node when the first bias circuit is not electrically connected to the first ESD protection element string.

9 . The ESD protection device of claim 1 , wherein the first ESD protection element string further comprises a third ESD protection element serially connected to the first ESD protection element and the second ESD protection element, a cathode of the first ESD protection element is electrically connected to the signal pad, an anode of the first ESD protection element and a cathode of the second ESD protection element are electrically connected to the first common connection node, an anode of the second ESD protection element and a cathode of the third ESD protection element are electrically connected to a second common connection node, and an anode of the third ESD protection element is electrically connected to the first ESD current rail.

10 . The ESD protection device of claim 9 , wherein the first bias circuit further provides a second bias voltage to the second common connection node, the first bias voltage is less than a first original division voltage, and the second bias voltage is greater than a second original division voltage, the first original division voltage is a voltage of the first common connection node when the first bias circuit is not electrically connected to the first ESD protection element string, and the second original division voltage is a voltage of the second common connection node when the first bias circuit is not electrically connected to the first ESD protection element string.

11 . The ESD protection device of claim 1 , wherein the first bias circuit comprises:
a diode, an anode of the diode being electrically connected to the first ESD current rail, a cathode of the diode being electrically connected to the first common connection node.

12 . The ESD protection device of claim 1 , wherein the first bias circuit comprises:
a p-type transistor, a source of the p-type transistor being electrically connected to the first ESD current rail, a gate and a drain of the p-type transistor being electrically connected to the first common connection node.

13 . The ESD protection device of claim 1 , wherein the first bias circuit comprises:
a diode, an anode of the diode being electrically connected to the first ESD current rail; and a resistor, a first end and a second end of the resistor being electrically connected to a cathode of the diode and the first common connection node, respectively.

14 . The ESD protection device of claim 1 , wherein the first bias circuit comprises:
a p-type transistor, a source of the p-type transistor being electrically connected to the first ESD current rail; and a resistor, a first end of the resistor being electrically connected to a gate and a drain of the p-type transistor, a second end of the resistor being electrically connected to the first common connection node.

15 . The ESD protection device of claim 1 , wherein the first bias circuit comprises:
a p-type transistor, a source of the p-type transistor being electrically connected to the first ESD current rail; and a resistor, a first end of the resistor being electrically connected to a drain of the p-type transistor, a second end of the resistor being electrically connected to the first common connection node and a gate of the p-type transistor.

16 . The ESD protection device of claim 1 , wherein the first bias circuit comprises:
a resistor string, a first end and a second end of the resistor string being electrically connected to the first ESD current rail and a reference voltage, respectively, a voltage-dividing node of the resistor string being electrically connected to the first common connection node.

17 . The ESD protection device of claim 1 , wherein the first bias circuit comprises:
a diode, a cathode of the diode being electrically connected to the first ESD current rail, an anode of the diode being electrically connected to the first common connection node.

18 . The ESD protec

Assignees

• Novatek Microelectronics Corp

Inventors

• Tzeng Tzu-Chien
• Chen Jie-Ting
• Lin Chun-Yu
• Ker Ming-Dou

Classifications

• H10W42/60 Primary

  protecting against electrostatic charges or discharges, e.g. Faraday shields (integrated devices comprising arrangements for electrical protection H10D89/60) · CPC title

• H02H9/041 Primary

  using a short-circuiting device · CPC title

• H02H9/00

  Emergency protective circuit arrangements for limiting excess current or voltage without disconnection · CPC title

• H02H9/046

  responsive to excess voltage appearing at terminals of integrated circuits · CPC title

• H02H9/04 Primary

  responsive to excess voltage (lightning arrestors H01C7/12, H01C8/04, H01G9/18, H01T) · CPC title