Optically isolated micromachined (MEMS) switches and related methods comprising a light transmitting adhesive layer between an optical receiver and a light source

Patent metadata

Field	Value
Publication number	US-10848152-B2
Application number	US-201816137640-A
Country	US
Kind code	B2
Filing date	Sep 21, 2018
Priority date	Mar 15, 2018
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

Optically isolated micromachined (MEMS) switches and related methods are described. The optically isolated MEMS switches described herein may be used to provide isolation between electronic devices. For example, the optically isolated MEMS switches of the types described herein can enable the use of separate grounds between the receiving electronic device and the control circuitry. Isolation of high-voltage signals and high-voltage power supplies can be achieved by using an optical isolator and a MEMS switch, where the optical isolator controls the state of the MEMS switch. In some embodiments, utilizing optical isolators to provide high voltages, the need for electric high-voltage sources such as high-voltage power supplies and charge pumps may be removed, thus removing the cause of potential damage to the receiving electronic device. In one example, the optical isolator and the MEMS switch may be co-packaged on the same substrate.

First claim

What is claimed is:

1. A high-voltage optical isolation system comprising:
a switch having a control terminal;
an optical receiver coupled to the control terminal of the switch, the optical receiver being configured to output, in response to receiving an optical signal, a voltage that is between 20V and 10000V; and
a light transmitting adhesive layer positioned between the optical receiver and a light source.

2. The high-voltage optical isolation system of claim 1 , wherein the switch and the optical receiver are disposed in a same package.

3. The high-voltage optical isolation system of claim 1 , wherein the optical receiver is configured to output, in response to receiving an optical signal, a voltage that is between 60V and 10000V.

4. The high-voltage optical isolation system of claim 1 , wherein the light source comprises a light emitting diode.

5. The high-voltage optical isolation system of claim 1 , wherein the high-voltage optical isolation system lacks charge pumps and high-voltage supplies.

6. The high-voltage optical isolation system of claim 2 , wherein the light source is disposed in the package.

7. The high-voltage optical isolation system of claim 6 , wherein the light source is stacked on top of the optical receiver.

8. The high-voltage optical isolation system of claim 1 , wherein the light transmitting adhesive layer is configured to focus the optical signal on the optical receiver.

9. The high-voltage optical isolation system of claim 1 , further comprising a non-planar optical separator disposed adjacent to the optical receiver.

10. The high-voltage optical isolation system of claim 1 , wherein the switch comprises a MEMS switch having a movable beam.

11. The high-voltage optical isolation system of claim 1 , further comprising a slew rate limiting circuit coupled to the optical receiver and to the control terminal of the switch, the slew rate limiting circuit being configured to limit a slew rate of a voltage applied to the control terminal of the switch.

12. The high-voltage optical isolation system of claim 1 , further comprising a release circuit coupled to the optical receiver and to the control terminal of the switch, the release circuit being configured to provide a discharge path for the control terminal of the switch.

13. A method for providing electric isolation between electronic devices, the method comprising:
driving a light source with an input signal to cause the light source to emit an optical signal and to cause the optical signal to pass through a light transmitting adhesive layer;
with an optical receiver, generating a voltage greater than 20V in response to receiving the optical signal, wherein the light transmitting adhesive layer is disposed between the light source and the optical receiver; and
controlling a state of a switch with the voltage.

14. The method of claim 13 , further comprising causing an electric signal to pass through the MEMS switch.

15. The method of claim 13 , wherein the optical receiver comprises a plurality of photodetectors and wherein controlling the state of the switch comprises timing activation of the plurality of photodetectors to obtain a desired slope in a control signal.

16. A high-voltage optical isolation system, comprising:
a switch having a control terminal;
an optical receiver coupled to the control terminal of the switch, the optical receiver being configured to output, in response to receiving an optical signal, a voltage that is between 20V and 10000V;
a light transmitting adhesive layer positioned between the optical receiver and a light source; and
a release circuit coupled to the optical receiver and to the control terminal of the switch, the release circuit being configured to provide a discharge path for the control terminal of the switch.

17. The high-voltage optical isolation system of claim 16 , wherein the optical receiver comprises a plurality of photodetectors.

18. The high-voltage optical isolation system of claim 16 , wherein the release circuit comprises a plurality of transistors arranged in a cascode configuration.

19. The high-voltage optical isolation system of claim 16 , wherein the switch and the optical receiver are disposed in a same package.

20. The high-voltage optical isolation system of claim 16 , further comprising a slew rate limiting circuit coupled to the optical receiver and to the control terminal of the switch, the slew rate limiting circuit being configured to limit a slew rate of a voltage applied to the control terminal of the switch.

Assignees

• Analog Devices Global Unlimited Co

Inventors

• Zhao Ying
• O'Donnell Alan
• Twohig Michael James
• Kierse Olly J
• Sheeran James Thomas
• Coln Michael C W
• Stevens Paul W
• Hecht Bruce A
• Fitzgerald Padraig
• Schirmer Mark

Classifications

• H10W90/00 Primary

  Package configurations · CPC title

• H10H20/857

  Interconnections, e.g. lead-frames, bond wires or solder balls · CPC title

• G02B26/0833 Primary

  the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B) · CPC title

• H01H59/0009

  making use of micromechanics · CPC title

• H03K17/943 Primary

  using a plurality of optical emitters or detectors, e.g. keyboard · CPC title