Stylus detection system having touch object detecting mode and stylus detecting mode
A stylus detecting system includes a sense array including N number of first lines and M number of second lines crossing the N number of first lines; and a touch controller connected to the sense array and configured to: (i) in a touch object detecting mode, drive the N number of first lines as transmission (TX) lines with a finger sensing TX signal and measure reception (RX) signals on the M number of second lines as RX lines, and (ii) in a stylus detecting mode, measure a stylus TX signal transmitted by a stylus, on both the N number of first lines and the M number of second lines, using #number of multiple RX channels (#RX channels) to sense more than one line of the first and second lines at the same time, such that a complete stylus scan includes (N+M)/(#RX channels) number of scans.
1. A stylus detecting system, comprising:
a sense array including N number of first lines and M number of second lines crossing the N number of first lines; and
a touch controller connected to the sense array and configured to:
(i) in a touch object detecting mode, drive the N number of first lines as transmission (TX) lines with a finger sensing TX signal and measure reception (RX) signals on the M number of second lines as RX lines, and
(ii) in a stylus detecting mode, measure a stylus TX signal transmitted by a stylus, on both the N number of first lines and the M number of second lines, using #number of multiple RX channels (#RX channels) to sense more than one line of the N number of first lines and the M number of second lines at the same time, such that a complete stylus scan includes (N+M)/(#RX channels) number of scans.
2. The stylus detecting system according to claim 1 , wherein the touch controller is configured to:
(i) in the touch object detecting mode, sense the M number of second lines as RX lines using the #RX channels, such that a complete touch scan includes (N*M)/(#RX channels) number of scans.
3. The stylus detecting system according to claim 1 , wherein the touch controller is configured to:
(ii) in the stylus detecting mode, transmit synchronization or timing data to cause the stylus to transmit the stylus TX signal.
4. The stylus detecting system according to claim 3 , wherein the stylus TX signal transmitted by the stylus has a greater amplitude than the finger sensing TX signal.
5. The stylus detecting system according to claim 4 , wherein the stylus TX signal ranges approximately between 20V-50V.
6. The stylus detecting system according to claim 5 , wherein the finger sensing TX signal is less than 10V.
7. The stylus detecting system according to claim 6 , wherein the finger sensing TX signal is more than 5 V.
8. The stylus detecting system according to claim 3 , wherein the stylus TX signal is different in either frequency or phase from a TX signal from a TX drive circuit.
9. The stylus detecting system according to claim 3 , wherein the stylus TX signal has a higher frequency than the finger sensing TX signal.
10. The stylus detecting system according to claim 9 , wherein the stylus TX signal has at least double the upper frequency limit of the finger sensing TX signal.
11. The stylus detecting system according to claim 3 , wherein the stylus TX signal has a different code for code modulation than a code used in a TX signal from a TX drive circuit.