High voltage drive circuit employing capacitive signal coupling and associated devices and methods

• US 7,741,896 B2
• Filed: 06/27/2008
• Issued: 06/22/2010
• Est. Priority Date: 02/15/2008
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Lum, Richard Kok Keong, Chow, Fun Kok, Ng, Gek Yong
• Primary Examiner(s): Berhane; Adolf
• Assistant Examiner(s): Mehari; Yemane
• Application Number:
  US12/163,275
• Publication Number:
  US 20090206817A1
• Time in Patent Office: 725 Days
• Field of Search: 327/108, 327/427, 327/434, 327/435, 257/500, 323/303
• US Class Current: 327/427
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 23/48 Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
• CPC Class Codes: H01L 23/5223 Capacitor integral with wiring layers
• CPC Class Codes: H01L 23/642 Capacitive arrangements H01L23/49589, H01L23/645, H01L23/647, H01L23/66 take precedence; capacitive effects between wiring layers on the semiconductor body H01L23/5222
• CPC Class Codes: H01L 27/0248 for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection
• CPC Class Codes: H01L 28/40 Capacitors
• CPC Class Codes: H01L 28/60 Electrodes
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/1305 Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/13055 Insulated gate bipolar transistor [IGBT]
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H04L 25/0266 Arrangements for providing Galvanic isolation, e.g. by means of magnetic or capacitive coupling

Abstract

According to one embodiment, there is provided a high voltage drive circuit comprising drive and sense electrodes formed substantially in a single plane. The device effects signal transfer between drive and receive circuits through the drive and sense electrodes by capacitive means, and permits high voltage devices, such as IGBTs, to be driven thereby without the use of high voltage transistors, thereby eliminating the need to use expensive fabrication processes such as SOI when manufacturing high voltage gate drive circuits and ICs. The device may be formed in a small package using, by way of example, using CMOS or other conventional low-cost semiconductor fabrication and packaging processes.

Claims

1. A high voltage drive circuit, comprising:

at least one drive electrode comprising a drive input connected to a low voltage portion of the circuit, the drive electrode being formed of a first electrically conductive metal, metal alloy or metal mixture;

at least one sense electrode comprising a sense output connected to a high voltage portion of the circuit, the sense electrode being formed of a second electrically conductive metal, metal alloy or metal mixture;

an electrically conductive ground plane substrate spaced apart from the drive and sense electrodes by an electrically insulative layer;

a drive circuit forming a portion of the low voltage portion and configured to receive an input signal provided to the high voltage drive circuit, the drive circuit being operably coupled to the drive input and configured to transmit a drive signal based on the input signal therethrough, and

a receive circuit forming a portion of the high voltage portion and operably coupled to the sense output, the receiver circuit being configured to receive the drive signal transmitted between the sense and drive electrodes and to provide at least one gate drive output signal having power and amplitude sufficient to drive an insulated-gate bipolar transistor (IGBT);

wherein the drive and sense electrodes are substantially disposed in a single plane and are operably configured and associated in respect of one another to effect the transfer of drive signals therebetween by capacitive means, the gate drive circuit is a non-silicon-on-insulator CMOS integrated circuit, and high voltage isolation between the low and high voltage portions of the circuit is provided by the drive and sense electrodes.

2. The high voltage drive circuit of claim 1, wherein the low voltage portion further comprises a glitch filter configured to filter the input signal.

3. The high voltage drive circuit of claim 1, wherein the low voltage portion further comprises an oscillator circuit configured to provide an output oscillator signal.

4. The high voltage drive circuit of claim 1, wherein the at least one drive electrode and the at least one sense electrode comprise a plurality of pairs of drive and sense electrodes forming a plurality of driver channels.

5. The high voltage drive circuit of claim 1, wherein the at least one drive electrode and the at least one sense electrode comprise first and second pairs of drive and sense electrodes forming first and second driver channels.

6. The high voltage drive circuit of claim 1, wherein the receive circuit further comprises an output gate driver stage.

7. The high voltage drive circuit of claim 1, further comprising a bootstrap supply circuit.

8. The high voltage drive circuit of claim 1, wherein a first breakdown voltage between the at least one drive electrode and the at least one sense electrode exceeds about 2,000 volts RMS when applied over a time period of about one minute.

9. The high voltage drive circuit of claim 1, wherein an inter-electrode spacing T_d between the drive electrode and the sense electrode is at least about 1.5 times greater than a thickness d of the electrically insulative layer.

10. The high voltage drive circuit of claim 1, wherein the first and second metals, metal alloys or metal combinations comprise one or more of gold, silver, copper, tungsten, tin, aluminium, and aluminium-copper.

11. The high voltage drive circuit of claim 1, wherein the electrically insulative layer comprises one or more of a semiconductor dielectric material, silicon oxide, silicon nitride and thick oxide.

12. The high voltage drive circuit of claim 1, wherein the electrically conductive ground plane substrate is formed of a semiconductor dielectric material or silicon.

13. The high voltage drive circuit of claim 1, wherein the drive and sense electrodes, the electrically insulative layer, and the ground plane substrate are fabricated using one or more of a CMOS process, a Bipolar-CMOS process, and a combined Bipolar-CMOS-DMOS (BCD) process.

14. The high voltage drive circuit of claim 1, wherein the circuit is encapsulated at least partially in polyimide or plastic.

15. The high voltage drive circuit of claim 1, wherein the drive and receive circuits are incorporated into an integrated circuit.

16. The high voltage drive circuit of claim 1, wherein the receive circuit further comprises a common mode rejection (CMR) circuit.

17. The high voltage drive circuit of claim 1, wherein the device is configured to transfer data between the drive and receive circuits at a rate of up to about 300 Megabits per second.

18. The high voltage drive circuit of claim 3, further comprising a charge pump circuit configured to voltage multiply the output oscillator signal thereby to amplify the drive signal.

19. The high voltage drive circuit of claim 5, wherein the low voltage portion further comprises a pair of logic driver circuits configured to drive the first and second pairs of sense and drive electrodes.

20. The high voltage drive circuit of claim 5, wherein the high voltage portion further comprises first and second rectifiers configured to receive, respectively, first and second sense electrode outputs provided by the first and second pairs of electrodes.

21. The high voltage drive circuit of claim 8, wherein the first breakdown voltage exceeds about 2,500 volts RMS when applied over a time period of about one minute.

22. The high voltage drive circuit of claim 8, wherein the first breakdown voltage exceeds about 3,000 volts RMS when applied over a time period of about one minute.

23. The high voltage drive circuit of claim 8, wherein the first breakdown voltage is greater than or equal to a second breakdown voltage between the drive electrode and the ground plane substrate.

24. The high voltage drive circuit of claim 19, wherein the logic driver circuits are complementary and are further configured to drive the first and second pairs of electrodes alternately.

25. The high voltage drive circuit of claim 20, wherein at least one of the first and second rectifiers comprises at least one MOSFET source follower.

26. The high voltage drive circuit of claim 20, further comprising first and second comparators operably connected to the first and second rectifiers and to receive first and second rectifier outputs therefrom, respectively.

27. The high voltage drive circuit of claim 24, wherein the alternately driven and complementary logic driver circuits are configured to increase common mode rejection between the first and second driver channels.

28. The high voltage drive circuit of claim 25, further comprising a low pass filter configured to filter an output signal provided by the at least one MOSFET source follower and remove or reduce ripple present therein.

29. The high voltage drive circuit of claim 26, wherein the first and second comparators each comprise means for comparing the oscillator output signal to a reference voltage.

30. The high voltage drive circuit of claim 26, further comprising an RS latch configured to receive first and second comparator outputs from the first and second comparators, respectively.

31. The high voltage drive circuit of claim 29, wherein output states provided by the first and second comparators are configured to toggle or not to toggle on the basis of the comparison between the oscillator output signal and the reference voltage.

32. The high voltage drive circuit of claim 29, wherein the electrically insulative material comprises one or more of a semiconductor dielectric material, silicon oxide, silicon nitride and thick oxide.

33. The high voltage drive circuit of claim 30, wherein outputs of the first and second comparators drive set and reset inputs of the RS latch.

34. A method of making a high voltage drive circuit, comprising:

providing at least one drive electrode comprising a drive input connected to a low voltage portion of the circuit, the drive electrode being formed of a first electrically conductive metal, metal alloy or metal mixture;

providing at least one sense electrode comprising a sense output connected to a high voltage portion of the circuit, the sense electrode being formed of a second electrically conductive metal, metal alloy or metal mixture;

providing an electrically conductive ground plane substrate spaced apart from the drive and sense electrodes by an electrically insulative layer;

providing a drive circuit forming a portion of the low voltage portion and configured to receive an input signal provided to the high voltage drive circuit, the drive circuit being operably coupled to the drive input and configured to transmit a drive signal based on the input signal therethrough, and

providing a receive circuit forming a portion of the high voltage portion and operably coupled to the sense output, the receiver circuit being configured to receive the drive signal transmitted between the sense and drive electrodes and to provide at least one gate drive output signal having power and amplitude sufficient to drive an insulated-gate bipolar transistor (IGBT);

wherein the drive and sense electrodes are substantially disposed in a single plane and are operably configured and associated in respect of one another to effect the transfer of drive signals therebetween by capacitive means, the gate drive circuit is a non-silicon-on-insulator CMOS integrated circuit, and high voltage isolation between the low and high voltage portions of the circuit is provided by the drive and sense electrodes.