US 12,405,696 B2
No-ground plane differential touch screen display
Daniel Keith Van Ostrand, Leander, TX (US)
Assigned to SigmaSense, LLC., Austin, TX (US)
Filed by SigmaSense, LLC., Austin, TX (US)
Filed on Sep. 5, 2024, as Appl. No. 18/825,403.
Application 18/825,403 is a continuation of application No. 18/214,722, filed on Jun. 27, 2023, granted, now 12,093,495.
Application 18/214,722 is a continuation of application No. 17/820,499, filed on Aug. 17, 2022, granted, now 11,733,820, issued on Aug. 22, 2023.
Application 17/820,499 is a continuation of application No. 17/449,228, filed on Sep. 28, 2021, granted, now 11,435,864, issued on Sep. 6, 2022.
Prior Publication US 2024/0427464 A1, Dec. 26, 2024
Int. Cl. G06F 3/044 (2006.01); G06F 3/041 (2006.01)
CPC G06F 3/0446 (2019.05) [G06F 3/0412 (2013.01)] 1 Claim
OG exemplary drawing
 
1. A differential drive sense circuit comprises:
a non-inverting section operable for coupling to a non-inverting electrode of a differential electrode, wherein the non-inverting section includes:
a first operational amplifier;
a first dependent current source; and
a first feedback circuit, wherein the first feedback circuit provides a first feedback signal to an input of the first dependent current source, wherein:
the first feedback signal is based on a first output voltage of the first operational amplifier,
the first dependent current source generates a first dependent current based on the first feedback signal,
a first input of the first operational amplifier is coupled to an output of the first dependent current source and to the non-inverting electrode,
the first dependent current is sourced to the non-inverting electrode,
a second input of the first operational amplifier is coupled to receive a non-inverting reference signal that includes an AC component, and
the first operational amplifier adjusts the first output to regulate a voltage on the first input of the first operational amplifier to substantially matches a voltage of the non-inverting reference signal;
an inverting section operable for coupling to a non-inverting electrode of a differential electrode, wherein the non-inverting section includes:
a second operational amplifier;
a second dependent current source; and
a second feedback circuit, wherein the second feedback circuit provides a second feedback signal to an input of the second dependent current source, wherein:
the second feedback signal is based on a second output voltage of the second operational amplifier,
the second dependent current source generates a second dependent current based on the second feedback signal,
a first input of the second operational amplifier is coupled to an output of the second dependent current source and to the non-inverting electrode,
the second dependent current is sourced to the non-inverting electrode,
a second input of the second operational amplifier is coupled to receive an inverting reference signal that includes an AC component, and
the second operational amplifier adjusts the second output to regulate a voltage on the second input of the second operational amplifier to substantially match a voltage of the non-inverting reference signal.