Touch sensor panel with multi-power domain chip configuration

An electronic device comprising:

• a touch sensor panel including one or more touch electrodes;
• a guard signal generation chip operating in a first power domain referenced to a first voltage, the guard signal generation chip configured to generate a guard signal;
• a touch sensing chip operating in a second power domain, different from the first power domain, referenced to the guard signal, the touch sensing chip configured to sense touch at the one or more touch electrodes included in the touch sensor panel operating in the second power domain referenced to the guard signal, and the touch sensing chip a different chip than the guard signal generation chip;
• and
• a voltage regulator configured to selectively regulate a voltage of the guard signal at the touch sensing chip.

A method for operating a touch sensing system, the method comprising:

• operating a guard signal generation chip in a first power domain referenced to a first voltage, the guard signal generation chip configured to generate a guard signal;
• operating a touch sensing chip in a second power domain, different from the first power domain, referenced to the guard signal, the touch sensing chip configured to sense touch at one or more touch electrodes included in a touch sensor panel operating in the second power domain referenced to the guard signal, and the touch sensing chip a different chip than the guard signal generation chip;
• and
• selectively regulating a voltage of the guard signal at the touch sensing chip.

A touch sensing system comprising:

• a guard signal generation chip operating in a first power domain referenced to a first voltage, the guard signal generation chip configured to generate a guard signal;
• a touch sensing chip operating in a second power domain, different from the first power domain, referenced to the guard signal, the touch sensing chip configured to sense touch at one or more touch electrodes included in a touch sensor panel operating in the second power domain referenced to the guard signal, and the touch sensing chip a different chip than the guard signal generation chip;
• and
• switching circuitry configured to selectively couple a voltage input of the touch sensing chip to the guard signal generation chip based on a state of the guard signal.