Isolator including bi-directional regulator

Patent metadata

Field	Value
Publication number	US-9537581-B2
Application number	US-201414319601-A
Country	US
Kind code	B2
Filing date	Jun 30, 2014
Priority date	Jun 30, 2014
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

An apparatus includes a first terminal, a second terminal, a bi-directional regulator circuit, and functional circuitry. The bi-directional regulator circuit generates a voltage across a first power supply node and a second power supply node in response to an input current flowing through the first terminal and the second terminal with a first polarity. The bi-directional regulator circuit also generates the voltage across the first power supply node and the second power supply node in response to the input current flowing through the first terminal and the second terminal with a second polarity opposite the first polarity. The functional circuitry is powered by the voltage and is configured to generate a signal using the voltage. The signal is indicative of the input current in response to the input current being supplied to the first terminal and is indicative of the input current in response to presence of the input current.

First claim

What is claimed is:

1. An apparatus comprising:
a first terminal;
a second terminal;
a bi-directional regulator circuit configured to generate a voltage across a first power supply node and a second power supply node in response to an input current flowing through the first terminal into the bi-directional regulator circuit and from the bi-directional regulator circuit through the second terminal with a first polarity and configured to generate the voltage across the first power supply node and the second power supply node in response to the input current flowing through the second terminal into the bi-directional regulator circuit and from the bi-directional regulator circuit through the first terminal with a second polarity opposite the first polarity; and
functional circuitry, powered by the voltage and configured to generate a signal using the voltage, the signal being indicative of presence of the input current.

2. The apparatus, as recited in claim 1 , wherein the bi-directional regulator circuit comprises:
a first circuit coupled between the first terminal and the second terminal, the first circuit comprising the first power supply node;
a second circuit coupled between the first terminal and the second terminal, the second circuit being coupled in parallel to the first circuit, the second circuit comprising the second power supply node; and
a third circuit coupled between the first circuit and the second circuit, the third circuit being configured to generate the voltage across the first power supply node and the second power supply node, the voltage having a first voltage polarity in response to the input current having the first voltage polarity and the voltage having the first polarity in response to the input current having the second polarity.

3. The apparatus, as recited in claim 2 , wherein the first circuit comprises a first device of a first type coupled between the first terminal and the first power supply node and a second device of the first type coupled between the first power supply node and the second terminal.

4. The apparatus, as recited in claim 3 , wherein the second circuit comprises a third device of a second type coupled between the first terminal and the second power supply node and a fourth device of the second type coupled between the second power supply node and the second terminal.

5. The apparatus, as recited in claim 2 , wherein the first circuit is a p-type transistor circuit and the second circuit is an n-type transistor circuit.

6. The apparatus, as recited in claim 2 , wherein the third circuit comprises a regulator circuit.

7. The apparatus, as recited in claim 6 , wherein when no input current is supplied to the apparatus, substantially zero voltage is generated by the regulator circuit and the signal is not supplied by the functional circuitry.

8. The apparatus, as recited in claim 2 , further comprising:
an isolation circuit responsive to the signal to supply a representation of the signal across an isolation barrier to an isolation link.

9. The apparatus, as recited in claim 8 , wherein the input current is indicative of a control signal for a driver circuit electrically isolated from the input current by at least the isolation barrier.

10. The apparatus, as recited in claim 8 , further comprising:
a first unit comprising the first circuit, the second circuit, the third circuit, the functional circuitry, and the isolation circuit; and
a second unit comprising a receiver circuit and a high voltage driver circuit,
wherein the first unit and the second unit are coupled by the isolation link, wherein the representation of the signal is provided to the second unit over the isolation link, the representation of the signal being indicative of a control signal for the high voltage driver circuit.

11. The apparatus, as recited in claim 1 , wherein the functional circuitry is coupled such that the voltage is the only voltage supplied to power the functional circuitry.

12. The apparatus, as recited in claim 1 , wherein a voltage drop across the first terminal and the first power supply node is negligible and a second voltage drop across the second power supply node and the second terminal is negligible.

13. A method comprising:
receiving an input current flowing through a first terminal and a second terminal, the input current being one of a first input current having a first polarity and a second input current having a second polarity opposite the first polarity;
generating a voltage across a first power supply node and a second power supply node in response to the input current, the voltage having a first voltage polarity in response to the first input current being received and the voltage having the first voltage polarity in response to the second input current being received;
generating a signal in functional circuitry indicative of presence of the input current using the voltage; and
supplying a representation of the signal across a voltage isolation barrier to an isolation link.

14. The method, as recited in claim 13 , wherein supplying the representation of the signal across the voltage isolation barrier comprises supplying the signal to a capacitor, the capacitor implementing the voltage isolation barrier.

15. The method, as recited in claim 13 , further comprising:
electrically isolating the functional circuitry from a receiver circuit coupled to a high voltage driver circuit using a capacitor to capacitively couple the functional circuitry to the receiver circuit.

16. The method, as recited in claim 13 , further comprising:
transmitting the representation of the signal over the isolation link to a receiver circuit coupled to a high voltage driver circuit that is electrically isolated from the input current; and
generating a control signal for the high voltage driver circuit using the representation of the signal.

17. The method, as recited in claim 13 , wherein generating the voltage across the first power supply node and the second power supply node comprises:
sinking a current, the sinking being from the first terminal to the first power supply node, from the first power supply node to the second power supply node, and from the second power supply node to the second terminal in response to the input current being the first input current; and
sourcing a current from the second terminal to the first power supply node, from the first power supply node to the second power supply node, and from the second power supply node to the first terminal in response to the input current being the second input current.

18. The method, as recited in claim 13 , wherein the receiving comprises:
sourcing the input current from a terminal, the terminal being the first terminal when the input current is the first input current and the terminal being the second terminal when the input current is the second input current.

19. The method, as recited in claim 13 , wherein a voltage drop across the first terminal and the first power supply node is negligible and a second voltage drop across the second power supply node and the second terminal is negligible.

20. An apparatus comprising:
means for receiving an input current flowing through a first terminal and a second terminal, the input current being one of a first input current having a first polarity and a second input current having a second polarity opposite the first polarity;
means for generating a voltage across a first power supply node and a second power supply node in response to the input current, the voltage b

Assignees

• Silicon Lab Inc

Inventors

• Mills Michael J
• Nemmani Anantha Nag
• Sonntag Jeffrey L

Classifications

• H04B10/802 Primary

  for isolation, e.g. using optocouplers · CPC title