Electronic pen generation of tilt orientation data based on capacitance difference detection
A method includes generating, by a first drive-sense circuit of circuitry of an electronic pen, a first error signal corresponding to an electrical characteristic of a first orientation capacitor of the electronic pen; and generating, by a second drive-sense circuit of the circuitry, a second error signal corresponding to an electrical characteristic of a second orientation capacitor. The method further includes subtracting, by a first subtraction module, the first and second error signals to produce a first difference error signal; receiving, by the circuitry, a self-signal transmitted by one or more electrodes of a touch screen via a primary conductor of the electronic pen; transmitting, by the circuitry, a ring back signal to the touch screen via the primary conductor in response to the self-signal; and transmitting, by the circuitry, the first difference error signal to the touch screen via a secondary conductor of the electronic pen.
1. A method comprises:
generating, by a first drive-sense circuit of circuitry of an electronic pen, a first error signal corresponding to an electrical characteristic of a first orientation capacitor of two or more orientation capacitors of the electronic pen, wherein the first drive-sense circuit is coupled to the first orientation capacitor;
generating, by a second drive-sense circuit of the circuitry, a second error signal corresponding to an electrical characteristic of a second orientation capacitor of the two or more orientation capacitors of the electronic pen, wherein the second drive-sense circuit is coupled to the second orientation capacitor, and wherein the first orientation capacitor is substantially parallel to the second orientation capacitor;
subtracting, by a first subtraction module of one or more subtraction modules of the circuitry, the first and second error signals to produce a first difference error signal, wherein the first difference error signal is representative of tilt orientation data of the electronic pen with respect to a touch screen;
receiving, by the circuitry, a self-signal transmitted by one or more electrodes of the touch screen via a primary conductor of the electronic pen;
transmitting, by the circuitry, a ring-back signal to the touch screen via the primary conductor in response to the self-signal; and
transmitting, by the circuitry, the first difference error signal to the touch screen via a secondary conductor of the electronic pen, wherein the primary conductor is shielded from the secondary conductor.
2. The method of claim 1 further comprises:
generating, by a third drive-sense circuit of the circuitry of the electronic pen, a third error signal corresponding to an electrical characteristic of a third orientation capacitor of the two or more orientation capacitors, wherein the third drive-sense circuit is coupled to the third orientation capacitor;
generating, by a fourth drive-sense circuit of the circuitry, a fourth error signal corresponding to an electrical characteristic of a fourth orientation capacitor of the two or more orientation capacitors, wherein the fourth drive-sense circuit is coupled to the fourth orientation capacitor, wherein the third orientation capacitor is substantially parallel to the fourth orientation capacitor, and wherein the third and fourth orientation capacitors are substantially perpendicular to the first and second orientation capacitors; and
subtracting, by a second subtraction module of the one or more subtraction modules of the circuitry, the third and fourth error signals to produce a second difference error signal, wherein the second difference error signal is representative of second tilt orientation data of the electronic pen with respect to the touch screen.
3. The method of claim 2 further comprises:
wherein the tilt orientation data obtained from the first and second orientation capacitors is with respect to an x-plane direction; and
wherein second tilt orientation data obtained from the third and fourth orientation capacitors is with respect to a y-plane direction.
4. The method of claim 1 , wherein the generating the first error signal further comprises:
generating, by the first drive-sense circuit, a drive signal in accordance with a regulation signal;
supplying, by the first drive-sense circuit, the drive signal to the first orientation capacitor;
detecting, by the first drive-sense circuit, an effect on the drive signal based on the electrical characteristic of the first orientation capacitor;
generating, by the first drive-sense circuit, the first error signal based on the effect on the drive signal and a reference signal;
generating, by the first drive-sense circuit, the regulation signal based on the first error signal; and
outputting, by the first drive-sense circuit, the first error signal to the first subtraction module.
5. The method of claim 1 further comprises:
receiving, by a first secondary circuit of one or more secondary circuits of the circuitry, from the first drive-sense circuit;
up-converting, by the first secondary circuit, the first difference error signal into a data transmit signal; and
transmitting, by the first secondary circuit, the data transmit signal via the secondary conductor to the touch screen.
6. The method of claim 5 further comprises:
receiving, by an input of an operational amplifier circuit of the first secondary circuit, the first difference error signal;
providing, by a feedback circuit of the first secondary circuit, a gain for the operational amplifier circuit, wherein the feedback circuit is coupled to a second input and an output of the operational amplifier; and
up-converting, by a power output circuit of the first secondary circuit, the first difference error signal outputted by the operational amplifier to produce the data transmit signal.
7. The method of claim 1 further comprises:
generating, by a transmit/receive circuit of the circuitry, the ring-back signal based on the self-signal, wherein the transmit/receive circuit is operably coupled to the primary conductor.
8. The method of claim 7 , wherein the generating the ring-back signal further comprises:
generating, by an amplifier circuit of the transmit/receive circuit, a comparison signal based on the self-signal from the touch screen and a reference signal;
generating, by a feedback circuit of the transmit/receive circuit, a regulation signal based on the comparison signal; and
generating, by a dependent supply circuit of the of the transmit/receive circuit, an adjustment signal based on the regulation signal, wherein the adjustment signal adjusts the self-signal to produce the ring-back signal.
9. The method of claim 1 further comprises:
generating, by a z-direction pressure sensor of the electronic pen, a change in capacitance signal representative of z-direction pressure;
providing, by the z-direction pressure sensor, the change in capacitance signal to the circuitry; and
transmitting, by the circuitry, the change in capacitance signal to the touch screen via the secondary conductor.