Highly configurable analog preamp with analog to digital converter
View Patent ↗A mode-configurable amplifier comprises a single-ended input for receiving a received signal from a capacitive touch panel, a differential output operable to carry a differential processed signal to a subsequent processing stage, and processing circuitry in communication with the single ended input and the differential output. The processing circuitry comprises mode selection inputs and mode selection circuitry in communication with the mode selection inputs. The mode selection circuitry is operable to configure the processing circuitry into a current operating mode selected from a high-pass filter mode, bandpass filter mode, and a trans-capacitive gain mode. The high-pass filter mode is operable to high-pass filter the received signal to obtain the differential processed signal. The bandpass filter mode is operable to bandpass filter the received signal to obtain the differential processed signal. The wideband gain mode is operable to amplify the received signal to obtain the differential processed signal.
1. A mode-configurable amplifier comprising:
a single-ended input for receiving a received signal from a capacitive touch panel;
a differential output operable to carry a differential processed signal to a subsequent processing stage; and
processing circuitry in communication with the single ended input and the differential output, the processing circuitry comprising:
mode selection inputs; and
mode selection circuitry in communication with the mode selection inputs, the mode selection circuitry operable to configure the processing circuitry into a current operating mode selected from:
a high-pass filter mode operable to high-pass filter the received signal to obtain the differential processed signal;
a bandpass filter mode operable to bandpass filter the received signal to obtain the differential processed signal; and
a wideband gain mode operable to amplify the received signal to obtain the differential processed signal.
2. The amplifier of claim 1 , where the processing circuitry is configurable, when in high-pass filter mode, to provide:
programmable gain;
programmable corner frequency;
programmable quality factor; or any combination thereof.
3. The amplifier of claim 1 , where the processing circuitry is configurable, when in bandpass filter mode, to provide:
programmable gain;
programmable corner frequency;
programmable quality factor; or any combination thereof.
4. The amplifier of claim 1 , where the processing circuitry is configurable, when in wideband gain mode, to provide
programmable gain.
5. The amplifier of claim 1 , further comprising an analog-to-digital converter circuit in communication with the differential output, wherein the analog-to-digital converter is operable to provide a selectable noise transfer function for reducing quantization noise of the processed signal.
6. The amplifier of claim 1 , where the differential output comprises:
a first high-pass output; and
a second high-pass output; and
where the high-pass filter mode comprises, in the processing circuitry:
a first amplifier that drives the first high-pass output;
a second amplifier that feeds back into the first amplifier; and
a third amplifier that drives the second high-pass output and that feeds back into the second amplifier, and where the first amplifier also drives the third amplifier.
7. The amplifier of claim 1 , where the mode selection circuitry comprises:
multiplexers selectively interconnecting multiple amplifiers.
8. A method for mode-configurable amplification comprising:
receiving an input signal on a single-ended input;
generating a differential output signal from the input signal using processing circuitry in communication with the single-ended input;
receiving a mode selection on a mode selection input; and
configuring the processing circuitry, according to the mode selection, into an operating mode selected from:
a high-pass filter mode operable to high-pass filter the input signal to obtain the differential output signal;
a bandpass filter mode operable to bandpass filter the input signal to obtain the differential output signal; and
a wideband gain mode operable to amplify the input signal to obtain the differential output signal.
9. The method of claim 8 , further comprising:
selecting among different available gains of the high-pass filter mode;
selecting among different available corner frequencies of the high-pass filter mode;
selecting among different available quality factors of the high-pass filter mode; or any combination thereof.
10. The method of claim 8 , further comprising:
selecting among different available gains of the bandpass filter mode;
selecting among different available corner frequencies of the bandpass filter mode;
selecting among different available quality factors of the bandpass filter mode; or any combination thereof.
11. The method of claim 8 , further comprising:
selecting among different available gains of the wideband gain mode.
12. The method of claim 8 , further comprising:
selecting a noise transfer function in an analog to digital converter; and
converting the differential output signal to digital form using the analog to digital converter.
13. The method of claim 8 , where generating a differential output signal comprises generating a first high-pass output and a second high-pass output; and
where configuring the processing circuitry into high-pass filter mode establishes:
a first amplifier that drives the first high-pass output;
a second amplifier that feeds back into the first amplifier; and
a third amplifier that drives the second high-pass output and that feeds back into the second amplifier, and where the first amplifier also drives the third amplifier.
14. The method of claim 8 , where configuring the processing circuitry comprises:
selectively interconnecting multiple amplifiers with multiplexers.
15. A mobile data processing device:
a display;
a capacitive touch panel arranged over the display; and
a touch-panel controller operative to detect touch interactions with the capacitive touch panel, the touch-panel controller comprising:
a single-ended input that accepts a received signal from the capacitive touch panel;
a differential output that carries a differential processed signal to a subsequent processing stage; and
processing circuitry between the single ended input and the differential output, the processing circuitry comprising:
mode selection inputs; and
mode selection circuitry in communication with the mode selection inputs, the mode selection circuitry operable to configure the processing circuitry into a current operating mode selected from:
a high-pass filter mode operable to high-pass filter the received signal to obtain the differential processed signal;
a bandpass filter mode operable to bandpass filter the received signal to obtain the differential processed signal; and
a wideband gain mode operable to amplify the received signal to obtain the differential processed signal.
16. The device of claim 15 , where the processing circuitry is configurable, when in high-pass filter mode, to provide:
programmable gain;
programmable corner frequency;
programmable quality factor; or any combination thereof.
17. The device of claim 15 , where the processing circuitry is configurable, when in bandpass filter mode, to provide:
programmable gain;
programmable corner frequency; and
programmable quality factor; or any combination thereof.
18. The device of claim 15 , where the processing circuitry is configurable, when in wideband gain mode, to provide:
programmable gain.
19. The device of claim 15 , where the subsequent processing stage comprises:
an analog-to-digital converter that implements a selectable noise transfer function.
20. The device of claim 15 , where the mode selection circuitry comprises:
multiplexers selectively interconnecting multiple amplifiers.