Apparatus and Method For High Voltage I/O Electro-Static Discharge Protection

• US 20140177113A1
• Filed: 12/18/2013
• Published: 06/26/2014
• Est. Priority Date: 12/19/2012
• Status: Active Grant

• Current Assignee: Knowles Electronics Llc (Knowles Corporation)
• Original Assignee: Knowles Electronics Llc (Knowles Corporation)
• Inventors: Gueorguiev, Svetoslav Radoslavov, Furst, Claus Erdmann, Joergensen, Tore Sejr
• Granted Patent: US 9,343,455 B2
• Time in Patent Office: Days
• US Class Current: 361/56
• CPC Class Codes: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81B 3/0027 Structures for transforming mechanical energy, e.g. potential energy of a spring into translation, sound into translation
• CPC Class Codes: H01L 27/0248 for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection
• CPC Class Codes: H01L 27/0266 using field effect transistors as protective elements
• CPC Class Codes: H01L 29/7816 Lateral DMOS transistors, i.e. LDMOS transistors
• CPC Class Codes: H02H 9/04 responsive to excess voltage lightning arrestors H01C7/12, H01C8/04, H01G9/18, H01T
• CPC Class Codes: H02H 9/046 responsive to excess voltage appearing at terminals of integrated circuits protection by specific structural integration design H01L27/0248
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps
• CPC Class Codes: H04R 1/04 Structural association of microphone with electric circuitry therefor in deaf-aid sets H04R25/00
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 2201/003 Mems transducers or their use of the electrostatic type H04R19/005

Abstract

An electronics chip includes a charge pump and at least one high voltage (HV) electro-static discharge (ESD) module. The charge pump is configured to provide a predetermined voltage across a microphone. The devices described herein are implemented in a standard low voltage CMOS process and has a circuit topology that provides an inherent ESD protection level (when it is powered down), which is higher than the operational (predetermined) DC level. At least one high voltage (HV) electro-static discharge (ESD) module is coupled to the output of the charge pump. The HV ESD module is configured to provide ESD protection for the charge pump and a microelectromechanical system (MEMS) microphone that is coupled to the chip. The at least one HV ESD module includes a plurality of PMOS or NMOS transistors having at least one high voltage NWELL/DNWELL region formed within selected ones of the PMOS or NMOS transistors. The at least one high voltage NWELL/DNWELL region has a breakdown voltage sufficient to allow a low voltage process to be used to construct the chip and still allow the HV ESD module to provide ESD protection for the chip.

Claims

1. An electronics chip, the chip comprising:

a charge pump, the charge pump configured to provide a predetermined voltage across a microphone, the charge pump being implemented in a low voltage CMOS process;

at least one high voltage (HV) electro-static discharge (ESD) module coupled to the output of the charge pump, the HV ESD module configured to provide ESD protection for the charge pump and a microelectromechanical system (MEMS) microphone that is coupled to the chip;

wherein the at least one HV ESD module includes a plurality of PMOS or NMOS transistors having at least one high voltage NWELL/DNWELL region formed within selected ones of the PMOS or NMOS transistors, the at least one high voltage NWELL/DNWELL region having a breakdown voltage sufficient to allow a low voltage process to be used to construct the chip and still allow the HV ESD module to provide ESD protection for the chip.

2. The chip of claim 1 wherein a high voltage terminal is formed at a drain terminal of a selected one of the plurality of NMOS transistors to form an LDMOS transistor, the high voltage terminal is effective to increase a drain to source breakdown voltage of the selected transistor.

3. The chip of claim 1 wherein the microphone comprises a diaphragm and a back plate.

4. The chip of claim 1 further comprising a charge pump filter.