Ball grid array current meter with a current sense loop

Patent metadata

Field	Value
Publication number	US-11226369-B2
Application number	US-201916583521-A
Country	US
Kind code	B2
Filing date	Sep 26, 2019
Priority date	Sep 26, 2019
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

Electrical current flow in a ball grid array (BGA) package can be measured by an apparatus including an integrated circuit (IC) electrically connected to the BGA package. Solder balls connect the BGA package to a printed circuit board (PCB). A current sense loop can be fabricated on a wiring plane of the PCB to encircle a current supply via that supplies current to an IC mounted on the BGA package. A MUX/Sequencer can sequentially connect wires of the current sense loop to an amplifier. The amplifier can amplify a voltage induced on the current sense mesh by current flow into the BGA package. A sensing analog-to-digital converter (ADC) is electrically connected to convert a voltage at the output of the amplifier into digital output signals.

First claim

What is claimed is:

1. A ball grid array (BGA) current meter apparatus for measuring electrical current flow in a BGA package, the BGA current meter apparatus comprising:
an integrated circuit (IC), electrically connected to the BGA package;
a set of solder balls electrically connected to a corresponding first set of attachment pads located on a lower surface of the BGA package;
a printed circuit board (PCB) including:
a second set of attachment pads positionally corresponding to the first set of attachment pads;

a plurality of current sense loops each at least partially located on a wiring plane of the PCB, each current sense loop each encircling, within the PCB, a via configured to supply current to an IC package, each current sense loop electrically connected, sequentially, to an amplifier;
the amplifier configured to amplify a voltage induced, by current flow into the BGA package, on each current sense loop sequentially connected to the amplifier input; and
a sensing analog-to-digital converter (ADC) electrically connected to and configured to convert, into digital output signals, a voltage at an output of the amplifier.

2. The BGA current meter apparatus of claim 1 , further comprising a second IC electrically connected to the BGA package, wherein the set of solder balls is further electrically connected to supply, from the PCB, current to the second IC.

3. The BGA current meter apparatus of claim 1 , wherein each current sense loop of the plurality of current sense loops is fabricated from a metal selected from the group consisting of: copper, copper alloys and aluminum.

4. The BGA current meter apparatus of claim 1 , wherein a portion of the plurality of current sense loops encircle, within the PCB, a plurality of vias configured to supply current to an IC package.

5. The BGA current meter apparatus of claim 1 , further comprising an external logic device electrically connected to receive the digital output signals from the ADC.

6. The BGA current meter apparatus of claim 5 , wherein the external logic device is selected from the group consisting of: a computer system, a processor, a service processor, a test instrument and an external logic IC.

7. The BGA current meter apparatus of claim 5 , wherein the external logic device is configured to initiate a corrective action in response to receiving digital output signals representing a current that is above a threshold.

8. The BGA current meter apparatus of claim 5 , wherein the external logic device is located on the PCB.

9. The BGA current meter apparatus of claim 5 , wherein the external logic device is located in a location remote to the PCB.

10. The BGA current meter apparatus of claim 1 , wherein a portion of the plurality of current sense loops are each at least partially located on two wiring planes of the PCB.

11. The BGA current meter apparatus of claim 1 , wherein the plurality of current sense loops are electrically connected to the MUX/sequencer circuit by interconnect selected from the group consisting of: wires, flex cable(s) and conductive traces on the PCB.

12. The BGA current meter apparatus of claim 11 , further comprising a blind via configured to electrically connect a first portion of a current sense loop located on a first wiring plane to a second portion of the current sense loop located on a second wiring plane.

13. A method of assembling a ball grid array (BGA) current meter apparatus to measure electrical current flow in a BGA package, the method comprising:
fabricating current sense loops on a wiring layer of a PCB;
applying a conductive attachment material to a first set of attachment pads located on an upper surface of a printed circuit board (PCB);
placing solder balls onto attachment pads of the first set of attachment pads;
reflowing the solder balls to bond them to the attachment pads of the first set of attachment pads;
attaching a BGA package to the PCB, the BGA package including an electrically connected integrated circuit (IC), by:
aligning the BGA package with the PCB, the BGA package having a second set of attachment pads, located on a lower surface of the BGA package, positionally corresponding to the first set of attachment pads, the second set of attachment pads including an applied conductive attachment material;
positioning the BGA package so that the second set of attachment pads is adjacent to corresponding solder balls; and
connecting the conductive attachment material to the second set of attachment pads and to the solder balls to create the BGA current meter apparatus.

14. The method of claim 13 , wherein each current sense loop is fabricated from a metal selected from the group consisting of: copper, copper alloys and aluminum.

15. The method of claim 13 , wherein the BGA package further comprises an additional electrically connected IC.

16. A method of operating a ball grid array (BGA) current meter apparatus to measure electrical current flow in a BGA package, the method comprising:
monitoring, with a current sense loop, a voltage induced by supply current flowing into a BGA package, the BGA package including at least one integrated circuit (IC);
amplifying, with an amplifier circuit, the voltage to produce an amplified voltage;
converting, with an analog-to-digital converter (ADC), the amplified voltage into a digital value representing the supply current;
transmitting, with the ADC, the digital value to external logic device;
logging, with the external logic device, the digital value and a corresponding time value; and
initiating, with the external logic device, in response to the digital value exceeding a threshold, a corrective action.

17. The method of claim 16 , wherein the amplifier circuit is an operational amplifier.

18. The method of claim 16 , wherein the external logic device is selected from the group consisting of: a computer system, a processor, a service processor, a test instrument and an external logic IC.

19. The method of claim 16 , further comprising performing analysis on logged digital values and corresponding time values.

20. The method of claim 16 , wherein the corrective action includes reducing power supplied to at least one IC.

Assignees

• IBM

Inventors

• Berge Layne A
• Doyle Matthew
• Schoneck Kyle
• Liang Thomas W
• Walther Matthew A
• Bjorgaard Jason J
• Dangler John R

Classifications

• G01R31/2853

  Electrical testing of internal connections or -isolation, e.g. latch-up or chip-to-lead connections (G01R31/31717 takes precedence; test of chip-to-PCB or lead-to-PCB connections G01R31/66) · CPC title

• G01R31/287

  Procedures; Software aspects · CPC title

• G01R31/2886

  Features relating to contacting the IC under test, e.g. probe heads; chucks (G01R31/2865 takes precedence, test connections, e.g. test sockets, or probes per se, G01R1/04 or G01R1/06) · CPC title

• G01R31/2879 Primary

  related to electrical aspects, e.g. to voltage or current supply or stimuli or to electrical loads · CPC title

• G01R31/2896 Primary

  Testing of IC packages; Test features related to IC packages (containers per se H10W76/10, encapsulations per se H10W74/00) · CPC title