Multipoint Touch Surface Controller

• US 20090315850A1
• Filed: 08/27/2009
• Published: 12/24/2009
• Est. Priority Date: 05/02/2006
• Status: Active Grant

• Current Assignee: Brian Quentin Huppi, Christoph Horst Krah, Steven Porter Hotelling
• Original Assignee: Brian Quentin Huppi, Christoph Horst Krah, Steven Porter Hotelling
• Inventors: HOTELLING, Steven Porter, Krah, Christoph Horst, Huppi, Brian Quentin
• Granted Patent: US 9,547,394 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A multipoint touch surface controller is disclosed herein. The controller includes an integrated circuit including output circuitry for driving a capacitive multi-touch sensor and input circuitry for reading the sensor. Also disclosed herein are various noise rejection and dynamic range enhancement techniques that permit the controller to be used with various sensors in various conditions without reconfiguring hardware.

Claims

1. A charge amplifier comprising:

an operational amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal;

a feedback capacitor connected between the output terminal and the inverting input terminal, wherein the feedback capacitor is programmable to take on a range of values; and

a feedback resistor connected between the output terminal and the inverting input terminal, wherein the feedback resistor is programmable to take on a range of values.

2. The charge amplifier of claim 1 wherein the charge amplifier further comprises a resistor coupled between the non-inverting input terminal and an input to form an anti-aliasing filter in combination with the feedback resistor and capacitor.

3. The charge amplifier of claim 1 wherein the non-inverting input of the amplifier is coupled to ground.