Broad-range current measurement using duty cycling

Patent metadata

Field	Value
Publication number	US-9891249-B2
Application number	US-201414289397-A
Country	US
Kind code	B2
Filing date	May 28, 2014
Priority date	May 28, 2014
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

An apparatus, method and integrated circuit for broad-range current measurement using duty cycling are disclosed. Embodiments of an apparatus for sensing current through a transistor device may include an interface configured to receive a current from the transistor device for sensing. Additionally, embodiments may include a sensor component coupled to the interface and configured to receive the current from the transistor device and to generate a responsive sensor voltage. Embodiments may also include a sense control circuit configured to control a duty cycle of the sensor component.

First claim

What is claimed is:

1. An apparatus for sensing current through a transistor device, comprising:
an interface configured to receive a current from the transistor device for sensing;
a sensor component coupled to the interface and configured to receive the current from the transistor device and to generate a responsive sensor voltage; and
a sense control circuit configured to control a duty cycle of the sensor component according to a duty cycle ratio which is a portion of a total measurement period for which the sensor component is activated.

2. The apparatus of claim 1 , wherein the sensor component comprises an adjustable resistance component, a resistance value of the adjustable resistance component being selectable in response to a level of the current received at the interface.

3. The apparatus of claim 2 , wherein the sense control circuit further comprises an automatic ranging device configured to automatically scale the resistance in response to a magnitude value of the current.

4. The apparatus of claim 3 , wherein the automatic ranging device is configured to switch the current to a resistor in the sense component on and off according to the duty cycle of the sensor component.

5. The apparatus of claim 2 , wherein the sense control circuit further comprises a comparator configured to trigger adjustment of the adjustable resistance component in response to an output voltage of the sensor component crossing a threshold set by a reference voltage.

6. An integrated circuit for sensing current through a transistor device, the integrated circuit comprising:
an interface configured to receive a current from the transistor device for sensing;
a sensor component coupled to the interface and configured to receive the current from the transistor device and to generate a responsive sensor voltage; and
a sense control circuit configured to control a duty cycle of the sensor component according to a duty cycle ratio which is a portion of a total measurement period for which the sensor component is activated.

7. The integrated circuit of claim 6 , wherein the sense control circuit further comprises an automatic ranging device configured to automatically scale the resistance in response to a magnitude value of the current.

8. The integrated circuit of claim 7 , wherein the automatic ranging device is configured to switch the current to a resistor in the sense component on and off according to the duty cycle of the sensor component.

9. The integrated circuit of claim 7 , wherein the sense control circuit further comprises a comparator configured to trigger adjustment of the adjustable resistance component in response to an output voltage of the sensor component crossing a threshold set by a reference voltage.

10. The integrated circuit of claim 6 , wherein the interface comprises:
a gate node interface configured interface with a gate node of the transistor device;
a drain node interface configured to interface with a drain node of the transistor device;
a source node interface configured to interface with a source node;
a Kelvin node interface configured to interface with a Kelvin node of the transistor device; and
a sense current node interface configured to receive the current from a sense current node of the transistor device, the current being a sense current that is smaller than a main current that flows through the transistor device by a predetermined ratio.

11. The integrated circuit of claim 10 , further comprising an Operational Amplifier (OPAMP) coupled to the sense node interface and the Kelvin node interface and configured to force a voltage value at the sense node interface and at the Kelvin node interface to equal levels.

12. The integrated circuit of claim 11 , further comprising a current sense transistor coupled to the OPAMP, the current sense transistor configured to drive a current to the sensor component for generating a sensor voltage across the current sense component.

13. The integrated circuit of claim 6 , wherein the integrated circuit further comprises:
a plurality of interfaces, each interface configured to receive a current from one of a plurality of transistor devices for sensing;
a plurality of sensor components, each coupled to one of the plurality of interfaces; and
a shared Analog to Digital (ADC) converter coupled to each of the plurality of sensor components, the ADC converter configured to convert analog sensor data into digital sensor data.

14. The integrated circuit of claim 13 , further comprising a digital format converter configured to reformat the digital sensor data into a digital data format that is readable by an external data processing device.

15. A method for sensing current through a transistor device, the method comprising:
receiving a current from the transistor device for sensing at an interface configured to receive the current from the transistor device;
generating a sensor voltage with a sensor component, the sensor voltage being responsive to the current from the transistor device; and
controlling a duty cycle of the sensor component with a sense control circuit according to a duty cycle ratio which is a portion of a total measurement period for which the sensor component is activated.

16. The method of claim 15 , further comprising selecting a resistance value of an adjustable resistance component in response to a level of the current received at the interface, the sensor component comprising the adjustable resistance component.

17. The method of claim 16 , further comprising automatically scaling the resistance in response to a magnitude value of the current, wherein the sense control circuit further comprises an automatic ranging device configured to control the automatic scaling.

18. The method of claim 17 , further comprising switching the current to a resistor in the sense component on and off according to the duty cycle of the sensor component using the automatic ranging device.

19. The method of claim 17 , further comprising triggering adjustment of the adjustable resistance component in response to an output voltage of the sensor component crossing a threshold set by a reference voltage.

Assignees

• Nxp Bv

Inventors

• Van Dijk Luc
• Waardenburg Cornelis Klaas

Classifications

• G01R19/16519

  using FET's · CPC title

• G01R19/0092

  Measuring current only · CPC title

• H03K17/0822

  in field-effect transistor switches · CPC title

• H03K2217/0027

  Measuring means of, e.g. currents through or voltages across the switch · CPC title

• G01R15/09 Primary

  Autoranging circuits · CPC title