US-12625578-B2 - Dynamic configuration of driven shield BGA balls of a capacitive sensor array

Abstract

An apparatus may include a capacitive touch controller, a ball grid array package, firmware, and a driven shield driver circuitry. The ball grid array package may comprise a plurality of balls arranged in multiple concentric rings. The firmware may dynamically select a driven shield pattern based on a received aspect ratio input corresponding to a capacitive sensor array. The driven shield driver circuitry may activate the driven shield balls according to the dynamically selected driven shield pattern to electrically isolate drive balls from sense balls.

Inventors

• Richard P. Collins
• Tor Erik Leistad

Assignees

• MICROCHIP TOUCH SOLUTIONS LIMITED

Dates

Publication Date

20260512

Application Date

20250312

Claims (20)

1. 1 . An apparatus comprising: a capacitive touch controller; a ball grid array package comprising a plurality of balls arranged in multiple concentric rings; firmware to dynamically select a driven shield pattern based on a received aspect ratio input corresponding to a capacitive sensor array; and driven shield driver circuitry to activate the driven shield balls according to the dynamically selected driven shield pattern to electrically isolate drive balls from sense balls.
2. 2 . The apparatus of claim 1 , wherein the balls comprise drive balls, sense balls, and driven shield balls.
3. 3 . The apparatus of claim 2 , wherein the driven shield pattern is configured to prevent direct vertical, horizontal, and diagonal capacitive coupling paths between adjacent drive and sense balls.
4. 4 . The apparatus of claim 1 , wherein the firmware stores multiple predefined driven shield patterns, each pattern corresponding to a different aspect ratio configuration.
5. 5 . The apparatus of claim 1 , wherein the driven shield balls are positioned along a crossover boundary defined between the drive balls and the sense balls.
6. 6 . The apparatus of claim 4 , wherein the firmware selects a driven shield pattern from the stored predefined driven shield patterns upon receiving the aspect ratio input.
7. 7 . The apparatus of claim 1 , wherein individual balls within the ball grid array package are configurable by the capacitive touch controller as driven shield balls or functional balls including drive balls, sense balls, power balls, ground balls, or general-purpose input/output (GPIO) balls.
8. 8 . The apparatus of claim 1 , comprising power and ground balls positioned at corners of the ball grid array package to provide supplemental shielding.
9. 9 . The apparatus of claim 1 , wherein the driven shield driver circuitry applies static shield signals to the driven shield balls.
10. 10 . The apparatus of claim 1 , wherein the capacitive touch controller continuously monitors for changes in aspect ratio input to dynamically update the driven shield pattern.
11. 11 . The apparatus of claim 1 , wherein the driven shield pattern includes at least three driven shield balls arranged in an L-shaped configuration.
12. 12 . The apparatus of claim 1 , wherein the driven shield pattern includes four driven shield balls arranged to surround at least one side of adjacent sense balls.
13. 13 . The apparatus of claim 1 , wherein the dynamically selected driven shield pattern reduces ball-to-ball capacitive coupling.
14. 14 . A method for dynamically configuring driven shield balls in a capacitive touch sensing system comprising: receiving, at a capacitive touch controller, an aspect ratio input corresponding to a capacitive sensor array coupled to the system; retrieving, from firmware, a driven shield pattern corresponding to the received aspect ratio input; configuring ball functions of a ball grid array package according to the retrieved driven shield pattern; and activating configured driven shield balls to electrically isolate drive balls from sense balls within the ball grid array.
15. 15 . The method of claim 14 , further comprising: receiving a further aspect ratio input corresponding to a different capacitive sensor array aspect ratio; retrieving a further driven shield pattern corresponding to the further aspect ratio input; reconfiguring the ball functions of the ball grid array according to the retrieved further driven shield pattern; and activating the reconfigured driven shield balls.
16. 16 . The method of claim 14 , wherein retrieving the driven shield pattern comprises accessing a stored configuration file maintained by the firmware that contains multiple predefined driven shield patterns.
17. 17 . The method of claim 16 , wherein each of the predefined driven shield patterns corresponds uniquely to a supported sensor aspect ratio.
18. 18 . The method of claim 14 , wherein configuring ball functions comprises individually setting each ball in the ball grid array as a driven shield ball or as a functional ball selected from a group consisting of drive balls, sense balls, power balls, ground balls, and general-purpose input/output (GPIO) balls.
19. 19 . The method of claim 14 , wherein the driven shield pattern is selected to eliminate direct vertical, horizontal, and diagonal capacitive coupling paths between adjacent drive balls and sense balls.
20. 20 . The method of claim 14 , wherein activating the configured driven shield balls comprises applying static shield signals to the driven shield balls using driven shield driver circuitry.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 U.S.C. § 119(e) of the priority date of U.S. Provisional Patent Application Ser. No. 63/565,434, filed Mar. 14, 2024, for “TOUCH SENSOR X TO Y BGA PACKAGE CROSSTALK REDUCTION WITH A MOVING DRIVEN SHIELD,” the contents and disclosure of which is incorporated herein in its entirety by this reference. FIELD Capacitive touch sensing systems are widely utilized in electronic devices to provide intuitive user interfaces. These systems typically employ sensor arrays comprising intersecting drive and sense lines, detecting user inputs through capacitive coupling changes at intersections. BACKGROUND Capacitive touch sensing systems are widely utilized in electronic devices to provide intuitive user interfaces. These systems typically employ sensor arrays comprising intersecting drive and sense lines, detecting user inputs through capacitive coupling changes at intersections. In the implementation of capacitive touch controllers, integrated circuits (ICs) are commonly packaged using ball grid array (BGA) packaging, which offers high pin-density and compact form factors advantageous for space-constrained applications. However, the dense configuration of balls within BGA packages can lead to capacitive coupling issues, commonly known as crosstalk, adversely affecting system performance. BRIEF DESCRIPTION OF THE DRAWINGS To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced. FIG. 1 is a schematic diagram illustrating pin-to-pin capacitive coupling within a BGA package for a capacitive touch sensor controller, in accordance with one or more examples. FIG. 2 illustrates a detailed, schematic layout representation of a portion of the BGA package 200 for a capacitive touch sensor controller, in accordance with one or more examples. FIG. 3 is a block diagram illustrating a capacitive touch sensor system 300 incorporating dynamically configurable shielding, in accordance with one or more examples. FIG. 4 illustrates an example process 400 to dynamically configure a driven shield ball(s) for a BGA operable to be coupled to a capacitive sensor array, in accordance with one or more examples. FIG. 5 is a detailed, schematic layout of a BGA package 500 for a capacitive touch sensor controller, in accordance with one or more examples. FIG. 6 depicts a detailed schematic of BGA package 600 for a capacitive touch sensor controller, specifically showing an alternative arrangement of balls optimized for different sensor aspect ratio configurations compared to that shown in FIG. 5. FIG. 7 depicts a detailed schematic of BGA package 700 for a capacitive touch sensor controller, specifically showing an alternative arrangement of balls optimized for different sensor aspect ratio configurations compared to that shown in FIG. 5. FIG. 8 is a block diagram of circuitry that, in some examples, may be used to implement various functions, operations, acts, processes, or methods disclosed herein. DETAILED DESCRIPTION In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which are shown, by way of illustration, specific examples of embodiments in which the present disclosure may be practiced. These embodiments are described in sufficient detail to enable a person of ordinary skill in the art to practice the present disclosure. However, other embodiments may be utilized, and structural, material, and process changes may be made without departing from the scope of the disclosure. The illustrations presented herein are not meant to be actual views of any particular method, system, device, or structure, but are merely idealized representations that are employed to describe the embodiments of the present disclosure. The drawings presented herein are not necessarily drawn to scale. Similar structures or components in the various drawings may retain the same or similar numbering for the convenience of the reader; however, the similarity in numbering does not mean that the structures or components are necessarily identical in size, composition, configuration, or any other property. The following description may include examples to help enable one of ordinary skill in the art to practice the disclosed embodiments. The use of the terms “exemplary,” “by example,” and “for example,” means that the related description is explanatory, and though the scope of the disclosure is intended to encompass the examples and legal equivalents, the use of such terms is not intended to limit the scope of an embodiment or this disclosure to the specified components, steps, features, functions, or the like. It will be readily understood that the components of the embodiments as generally described herein and illustrated in the drawing could be arranged and designed in a wide variety of dif