Switching voltage regulator input voltage and current sensing

Patent metadata

Field	Value
Publication number	US-10069414-B2
Application number	US-201514676384-A
Country	US
Kind code	B2
Filing date	Apr 1, 2015
Priority date	Apr 1, 2015
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

A voltage regulator includes a power stage configured to produce an output voltage from an input voltage at an input voltage terminal, a shunt resistor connected in series between the input voltage terminal and the power stage, a first level shifting resistor connected in series between a first terminal of the shunt resistor and a first sense pin of the controller, and a second level shifting resistor connected in series between a second terminal of the shunt resistor and a second sense pin of the controller. The input current of the regulator is sensed as a function of the voltage across the shunt resistor, as shifted down by the level shifting resistors and measured across the sense pins. The input voltage of the regulator is sensed as a function of the current flowing through either one of the level shifting resistors, as measured at one of the sense pins.

First claim

What is claimed is:

1. A voltage regulator, comprising:
an input voltage terminal;
a power stage configured to produce an output voltage from an input voltage at the input voltage terminal;
a controller configured to control switching of the power stage;
a shunt resistor connected in series between the input voltage terminal and the power stage;
a first level shifting resistor connected in series between a first terminal of the shunt resistor and a first sense pin of the controller; and
a second level shifting resistor connected in series between a second terminal of the shunt resistor and a second sense pin of the controller;
wherein the controller is configured to sense the input current of the regulator as a function of the voltage across the shunt resistor, as shifted down by the level shifting resistors and measured across the sense pins,
wherein the controller is configured to sense the input voltage of the regulator as a function of the current flowing through either one of the level shifting resistors, as measured at one of the sense pins,
wherein the controller comprises a circuit configured to regulate the voltage at one of the sense pins such that the voltage at this sense pin remains constant over a range of voltage levels at the input voltage terminal and the current through this sense pin is a function of the input voltage.

2. The voltage regulator of claim 1 , wherein the level shifting resistors are configured to shift the input voltage to a level equal or lower than a maximum voltage permitted at the sense pins.

3. The voltage regulator of claim 1 , wherein the shunt resistor comprises a plurality of discrete resistors connected in parallel.

4. The voltage regulator of claim 1 , wherein the first level shifting resistor comprises a first plurality of discrete resistors connected in series and the second level shifting resistor comprises a second plurality of discrete resistors connected in series.

5. The voltage regulator of claim 1 , wherein the controller comprises matched current mirrors configured to sink current through the level shifting resistors such that the voltage drop across the level shifting resistors is substantially the same and the voltage across the sense pins substantially matches the voltage across the shunt resistor.

6. The voltage regulator of claim 5 , wherein the controller is configured to average out offset between the current sunk by the matched current mirrors.

7. The voltage regulator of claim 6 , wherein the controller comprises a chopping circuit configured to alternatingly couple the matched current mirrors to each of the level shifting resistors such that effective current measurements for the level shifting resistors average out offset between the current sunk by the matched current mirrors.

8. The voltage regulator of claim 5 , wherein the matched current mirrors have active cascoding.

9. The voltage regulator of claim 1 , wherein the first terminal of the shunt resistor is connected to the input voltage terminal, the second terminal of the shunt resistor is connected to the power stage, and the circuit is configured to regulate the voltage at the second sense pin such that the voltage at the second sense pin remains constant over a range of voltage levels at the input voltage terminal and the current through the second sense pin is a function of the input voltage.

10. The voltage regulator of claim 1 , wherein the controller comprises an analog-to-digital converter configured to digitize a representation of the current through the sense pin whose voltage is regulated at a constant level by the circuit.

11. The voltage regulator of claim 1 , wherein the controller comprises an analog-to-digital converter configured to digitize a representation of a function of the currents through the sense pins, the function being an average, sum or weighted sum.

12. The voltage regulator of claim 1 , wherein the controller comprises an analog-to-digital converter configured to digitize a representation of the current difference between the sense pins.

13. The voltage regulator of claim 1 , wherein the controller comprises a current mirror configured to provide the sensed input voltage through a current to voltage conversion at one of the sense pins.

14. The voltage regulator of claim 1 , wherein the controller comprises an amplifier configured to amplify the difference between the currents through the sense pins and an analog-to-digital converter configured to digitize the output of the amplifier.

15. The voltage regulator of claim 14 , wherein the controller comprises a chopping circuit configured to alternatingly couple the sense pins to each input of the amplifier.

16. The voltage regulator of claim 15 , wherein the controller comprises an additional chopping circuit configured to alternatingly couple the differential outputs of the amplifier to the analog-to-digital converter.

17. The voltage regulator of claim 14 , wherein the controller comprises a chopping circuit configured to alternatingly couple the differential outputs of the amplifier to the analog-to-digital converter.

18. The voltage regulator of claim 1 , wherein the controller comprises a calibration circuit configured to measure the voltage across the sense pins when the input current is expected to be near zero and produce a calibrated value which indicates mismatch between the level shifting resistors, and to use the calibrated value in adjusting the input voltage and current sensing during operation.

19. A method of sensing input current and voltage of a voltage regulator that includes an input voltage terminal, a power stage for producing an output voltage from an input voltage at the input voltage terminal, a shunt resistor connected in series between the input voltage terminal and the power stage, a first level shifting resistor connected in series between a first terminal of the shunt resistor and a first sense pin of a controller, and a second level shifting resistor connected in series between a second terminal of the shunt resistor and a second sense pin of the controller, the method comprising:
regulating the voltage at one of the sense pins such that the voltage at this sense pin remains constant over a range of voltage levels at the input voltage terminal and the current through this sense pin is a function of the input voltage;
sensing the input current of the regulator as a function of the voltage across the shunt resistor, as shifted down by the level shifting resistors and measured across the sense pins; and
sensing the input voltage of the regulator as a function of the current flowing through either one of the level shifting resistors, as measured at one of the sense pins.

20. A voltage regulator, comprising:
an input voltage terminal;
a power stage configured to produce an output voltage from an input voltage at the input voltage terminal;
a controller configured to control switching of the power stage;
a shunt resistor connected in series between the input voltage terminal and the power stage;
a first level shifting resistor connected in series between a first terminal of the shunt resistor and a first sense pin of the controller; and
a second level shifting resistor connected in series between a second terminal of the shunt resistor and a second sense pin of the controller;
wherein the controller is configured to sense the input current of the regulator as a function of the voltage across the shunt resistor, as shifted down by the level shifting resistors and measured across the sen

Assignees

• Infineon Technologies Austria Ag

Inventors

• Sen Sujata
• Tang Benjamim
• Tschirhart Darryl

Classifications

• H02M3/156 Primary

  with automatic control of output voltage or current, e.g. switching regulators · CPC title

• H02M1/00

  Details of apparatus for conversion · CPC title

• H02M3/158 Primary

  including plural semiconductor devices as final control devices for a single load · CPC title

• G05F3/262 Primary

  using field-effect transistors only · CPC title

• H02M1/0009

  Devices or circuits for detecting current in a converter · CPC title