Method and apparatus for improved input sensing using a display processor reference signal
View Patent ↗Embodiments of the invention generally provide a method and apparatus that is configured to reduce the effects of interference that is undesirably provided to a transmitter signal that is delivered from a transmitter signal generating device to a sensor processor to determine if an input object is disposed within a touch sensing region of a touch sensing device. In one embodiment, the sensor processor includes a receiver channel that has circuitry that is configured to separately receive a transmitter signal delivered from a display processor and a sensor processor reference signal that is based on a display processor reference signal to reliably sense the presence of an object. Embodiments of the invention described herein thus provide an improved apparatus and method for reliably sensing the presence of an object by a touch sensing device.
1. An integrated circuit for a capacitive sensing device, the integrated circuit configured to:
acquire a first resulting signal by modulating a first sensor electrode of a plurality of sensor electrodes with a sensor processor reference signal, the plurality of sensor electrodes comprising common electrodes configured to be driven for display updating and capacitive sensing, wherein the integrated circuit comprises:
a first receiver channel configured to:
receive the first resulting signal with the first sensor electrode; and
provide an output signal based on a comparison of at least a portion of the first resulting signal and the sensor processor reference signal that is based on a display processor reference signal.
2. The integrated circuit of claim 1 , wherein the sensor processor reference signal is modulated relative to the display processor reference signal.
3. The integrated circuit of claim 2 , wherein modulating the sensor processor reference signal relative to the display processor reference signal comprises:
adjusting a voltage difference between the sensor processor reference signal and the display processor reference signal.
4. The integrated circuit of claim 1 , wherein the integrated circuit is further configured to:
acquire a second resulting signal by modulating a second sensor electrode of the plurality of sensor electrodes with the sensor processor reference signal, and
wherein the first receiver channel is further configured to:
receive the second resulting signal with the second sensor electrode.
5. The integrated circuit of claim 4 , wherein the first receiver channel comprises a multiplexer.
6. The integrated circuit of claim 4 further configured to:
acquire a third resulting signal by modulating a third sensor electrode of the plurality of sensor electrodes with the sensor processor reference signal, and a fourth resulting signal by modulating a fourth sensor electrode of the plurality of sensor electrodes with the sensor processor reference signal, and wherein the integrated circuit further comprises:
a second receiver channel configured to:
receive the third resulting signal with the third sensor electrode; and
receive the fourth resulting signal with the fourth sensor electrode.
7. The integrated circuit of claim 6 , receiving the first resulting signal at least partially overlaps with receiving the third resulting signal.
8. The integrated circuit of claim 1 , wherein the display processor reference signal comprises a display processor ground.
9. An input device, comprising:
a plurality of sensor electrodes comprising common electrodes configured to be driven for display updating and capacitive sensing; and
a processing system configured to acquire a first resulting signal by modulating a first sensor electrode of the plurality of sensor electrodes with a sensor processor reference signal, and wherein the processing system comprises:
a first receiver channel configured to:
receive the first resulting signal with the first sensor electrode; and
provide an output signal based on a comparison of at least a portion of the first resulting signal and the sensor processor reference signal that is based on a display processor reference signal.
10. The input device of claim 9 , wherein the sensor processor reference signal is modulated relative to the display processor reference signal.
11. The input device of claim 10 , wherein modulating the sensor processor reference signal relative to the display processor reference signal comprises:
adjusting a voltage difference between the sensor processor reference signal and the display processor reference signal.
12. The input device of claim 9 , wherein the processing system is further configured to: acquire a second resulting signal by modulating a second sensor electrode of the plurality of sensor electrodes, and
wherein the first receiver channel is further configured to:
receive the second resulting signal with the second sensor electrode.
13. The input device of claim 12 , wherein the first receiver channel comprises a multiplexer.
14. The input device of claim 12 , wherein the processing system is further configured to:
acquire a third resulting signal by modulating a third sensor electrode of the plurality of sensor electrodes with the sensor processor reference signal; and
acquire a fourth resulting signal by modulating a fourth sensor electrode of the plurality of sensor electrodes with the sensor processor reference signal, and wherein the processing system further comprises:
a second receiver channel configured to:
receive the third resulting signal with the third sensor electrode; and
receive the fourth resulting signal with the fourth sensor electrode.
15. The input device of claim 9 , wherein the display processor reference signal comprises a display processor ground.
16. A method for capacitive sensing, the method comprising:
modulating a first sensor electrode of a plurality of sensor electrodes with a sensor processor reference signal, wherein each of the plurality of sensor electrodes comprises at least one common electrode of a plurality of common electrodes, wherein the plurality of common electrodes is configured to be driven for display updating and capacitive sensing;
receiving, with a first receiver channel, a first resulting signal with the first sensor electrode; and
providing an output signal based on a comparison of at least a portion of the first resulting signal and the sensor processor reference signal that is based on a display processor reference signal.
17. The method of claim 16 , wherein the sensor processor reference signal is modulated relative to the display processor reference signal.
18. The method of claim 17 , wherein modulating the sensor processor reference signal relative to the display processor reference signal comprises:
adjusting a voltage difference between the sensor processor reference signal and the display processor reference signal.
19. The method of claim 16 further comprising:
modulating a second sensor electrode of the plurality of sensor electrodes with the sensor processor reference signal; and
receiving, with the first receiver channel, a second resulting signal with the second sensor electrode.
20. The method of claim 19 further comprising:
modulating a third sensor electrode of the plurality of sensor electrodes with the sensor processor reference signal;
modulating a fourth sensor electrode of the plurality of sensor electrodes with the sensor processor reference signal; and
receiving, with a second receiver channel, a third resulting signal with the third sensor electrode and a fourth resulting signal with the fourth sensor electrode.
21. An integrated circuit for a capacitive sensing device, the integrated circuit configured to:
acquire a first resulting signal by modulating a first sensor electrode of a plurality of sensor electrodes with a sensor processor reference signal, the plurality of sensor electrodes comprising common electrodes configured to be driven for display updating and capacitive sensing;
acquire a second resulting signal by modulating a second sensor electrode of the plurality of sensor electrodes with the sensor processor reference signal;
acquire a third resulting signal by modulating a third sensor electrode of the plurality of sensor electrodes with the sensor processor reference signal; and
acquire a fourth resulting signal by modulating a fourth sensor electrode of the plurality of sensor electrodes with the sensor processor reference signal, wherein the integrated circuit comprises:
a first receiver channel configured to:
receive the first resulting signal with the first sensor electrode;
receive the second resulting signal with the second sensor electrode;
provide a first output signal based on a comparison of at least a portion of the first resulting signal and the sensor processor reference signal that is based on a display processor reference signal; and
provide a second output signal based on a comparison of at least a portion of the second resulting signal and the sensor processor reference signal; and
a second receiver channel configured to:
receive the third resulting signal with the third sensor electrode;
receive the fourth resulting signal with the fourth sensor electrode;
provide a third output signal based on a comparison of at least a portion of the first resulting signal and the sensor processor reference signal; and
provide a fourth output signal based on a comparison of at least a portion of the second resulting signal and the sensor processor reference signal.