System and Method for Receiving Data Across an Isolation Barrier

• US 20110189952A1
• Filed: 01/29/2010
• Published: 08/04/2011
• Est. Priority Date: 01/29/2010
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Barrenscheen, Jens, Hammerschmidt, Dirk
• Granted Patent: US 8,660,489 B2
• Time in Patent Office: Days
• US Class Current: 455/41.1
• CPC Class Codes: G08C 17/06 using capacity coupling
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H04B 5/0031 for data transfer
• CPC Class Codes: H04B 5/72 for local intradevice communication

Abstract

In one embodiment, A system for communication has a receiver for receiving data from a passive transmitter capacitively coupled to the receiver. The receiver has a sensing element having a plurality of terminals configured to be capacitively coupled to the passive transmitter and DC isolated from the passive transmitter.

Claims

1. A system for communication comprising:

a receiver for receiving data from a passive transmitter capacitively coupled to the receiver, the receiver comprising a sensing element having a first plurality of terminals configured to be capacitively coupled to the passive transmitter and DC isolated from the passive transmitter.

2. The system of claim 1, further comprising the passive transmitter comprising a passive transmitting element comprising a second plurality of terminals capacitively coupled to the receiver, the passive transmitter modulating an impedance between the second plurality of terminals according to a transmitted data value.

3. The system of claim 2, wherein the passive transmitting element comprises a switch coupled between the second plurality of terminals.

4. The system of claim 2, wherein the receiver comprises a first coreless transformer (CT) coupled to an isolation barrier, and the passive transmitter comprises a second CT coupled to the isolation barrier.

5. The system of claim 2, further comprising at least one additional impedance coupled to at least one of the second plurality of terminals.

6. The system of claim 5, wherein the at least one additional impedance comprises a capacitor.

7. The system of claim 2, wherein at least one of the first plurality of terminals is coupled to the passive transmitter via a printed circuit board (PCB).

8. The system of claim 7, wherein the sensing element is disposed on a first device coupled to the PCB, and the passive transmitter is disposed on a second device coupled to the PCB.

9. The system of claim 2, wherein the passive transmitter and the sensing element are isolated from each other within a package.

10. The system of claim 2, wherein:

the passive transmitter is disposed on a first portion of an integrated circuit; and

the sensing element is disposed on a second portion of the integrated circuit.

11. The system of claim 1, wherein the sensing element further comprises:

a first terminal for sending a reference signal; and

a second terminal for receiving an input signal, wherein a state of the passive transmitter is determined by determining a transmission factor between the reference signal and the received input signal and comparing the transmission factor or portions of the transmission factor to a threshold.

12. The system of claim 1, wherein the sensing element is configured to receive a differential signal from the passive transmitter.

13. The system of claim 12, further comprising the passive transmitter having a first switch and a second switch, wherein:

the first switch is ON and the second switch is OFF if a first data state is transmitted; and

the first switch is OFF and the second switch is ON if a second data state is transmitted.

14. The system of claim 1, wherein the sensing element measures an impedance between the first plurality of terminals to determine a transferred data value.

15. A semiconductor circuit for receiving data from a capacitively coupled passive transmitter, the circuit comprising:

a sensing element having a plurality of terminals configured to be coupled to the passive transmitter;

a data receiver coupled to an output of the sensing element, the data receiver receiving a stream of data from the sensing element.

16. The semiconductor circuit of claim 15, wherein:

the plurality of terminals of the sensing element comprise a first terminal and a second terminal;

the sensing element measures an impedance between the first terminal and the second terminal;

if the measured impedance exceeds a first threshold, a first data state is sent to the data receiver; and

if the measured impedance does not exceed the first threshold, a second data state is sent to the data receiver.

17. The semiconductor circuit of claim 15, wherein:

the sensing element comprises a first terminal, a second terminal, and a third terminal;

the sensing element measures a first impedance between the first terminal and the second terminal;

the sensing element measures a second impedance between the third terminal and the second terminal;

if the first measured impedance is greater than the second measured impedance, a first data state is sent to the data receiver; and

if the first measured impedance is not greater than the second measured impedance, a second data state is sent to the data receiver.

18. The semiconductor circuit of claim 17, wherein

the sensing element comprises a first terminal, a second terminal, and a third terminal;

the first terminal and the second terminal are configured to be coupled to a first side of the passive transmitter;

the third terminal is configured to be coupled to a second side of the passive transmitter;

the sensing element measures an impedance between the first terminal and the second terminal;

the sensing element measures a second impedance between the first terminal and the third terminal;

if a ratio of the first impedance to the second impedance is greater than a threshold, a first data state is sent to the data receiver; and

if the ratio of the first impedance to the second impedance is not greater than the threshold, a second data state is sent to the data receiver.

19. A method for receiving data from a passive transmitter through an isolation barrier, the method comprising:

measuring impedance between a plurality of terminals coupled to the isolation barrier; and

determining a state of the passive transmitter based on the measured impedance.

20. The method of claim 19, wherein measuring the impedance comprises:

measuring a first impedance between a first terminal and a second terminal;

measuring a second impedance between the second terminal and a third terminal;

determining that the passive transmitter is in a first transmission state if the first measured impedance is greater than the second measured impedance; and

determining that the passive transmitter is in a second transmission state if the first measured impedance is not greater than the second measured impedance.

21. The method of claim 19, wherein measuring the impedance comprises:

determining a first transmission factor between a first terminal and a second terminal;

determining a second transmission factor between the first terminal and a third terminal;

determining that the passive transmitter is in a first state if a ratio of the first transmission factor to the second transmission factor is greater than a threshold; and

determining that the passive transmitter is in a second state if the ratio of the first transmission factor to the second transmission factor is not greater than the threshold.

22. A method of communicating across an isolation barrier, the method comprising:

transmitting data, transmitting comprising modulating an impedance coupled to a first portion of the isolation barrier, wherein the impedance is modulated according to the data;

receiving the data, receiving comprising measuring an impedance of a second portion of the isolation barrier, the second portion opposite the first portion.

23. The method of claim 22, wherein modulating the impedance comprises opening and closing a first switch coupled to the first portion of the isolation barrier.

24. The method of claim 22, further comprising:

transmitting a clock, transmitting the clock comprising modulating a second impedance coupled to a third portion of the isolation barrier, wherein the data transitions according to the clock;

receiving the clock, receiving the clock comprising measuring an impedance of a fourth portion of the isolation barrier, the fourth portion opposite the third portion.

25. A method for synchronously transferring data from one side of an isolation barrier to another other side of the isolation barrier, the method comprising:

transmitting a shift clock signal via a first signal path;

changing an impedance between at least two terminals of a second data path according to data to be transmitted at one edge of the shift clock signal; and

triggering a sensing element to evaluate the impedance at a second edge of the shift clock signal.