On-chip power-down generation for LDO-based mutual capacitance touchscreen controllers
First Claim
1. A mutual capacitance touchscreen controller, comprising:
- an analog core comprising touchscreen sense circuitry configured to be operably connected to capacitive touchscreen sense lines external to the controller;
a first on-chip low drop out regulator (LDO) configured to receive and regulate as a first input thereto an input supply voltage (VSUPPLY), and to provide as an output therefrom a first regulated output voltage (VDDA);
a first comparator configured to receive as first and second inputs thereto VSUPPLY and VDDA and to provide as an output therefrom a signal EN, EN being provided to the first LDO as a second input thereto;
wherein the first LDO is configured to operate in a first off mode and is turned off by signal EN when the difference between VSUPPLY and VDDA is less than a predetermined threshold, and the touchscreen controller is configured to operate in an LDO mode wherein VDDA is provided as an output from the first LDO when the difference between VSUPPLY and VDDA is greater than or equal to the predetermined threshold and the first LDO is turned on and operating in a second on mode.
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Accused Products
Abstract
Various embodiments of methods and devices are provided for a mutual capacitance touchscreen controller comprising a first on-chip low drop out regulator (LDO) configured to receive and regulate as a first input thereto an input supply voltage (VSUPPLY), and to provide as an output therefrom a first regulated output voltage (VDDA). A first comparator in the controller is configured to receive as first and second inputs thereto VSUPPLY and VDDA and to provide as an output therefrom a signal EN, EN being provided to the first LDO as a second input thereto. The first LDO is configured to operate in a first off mode and is turned off by signal EN when the difference between VSUPPLY and VDDA is less than a predetermined threshold.
7 Citations
21 Claims
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1. A mutual capacitance touchscreen controller, comprising:
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an analog core comprising touchscreen sense circuitry configured to be operably connected to capacitive touchscreen sense lines external to the controller; a first on-chip low drop out regulator (LDO) configured to receive and regulate as a first input thereto an input supply voltage (VSUPPLY), and to provide as an output therefrom a first regulated output voltage (VDDA); a first comparator configured to receive as first and second inputs thereto VSUPPLY and VDDA and to provide as an output therefrom a signal EN, EN being provided to the first LDO as a second input thereto; wherein the first LDO is configured to operate in a first off mode and is turned off by signal EN when the difference between VSUPPLY and VDDA is less than a predetermined threshold, and the touchscreen controller is configured to operate in an LDO mode wherein VDDA is provided as an output from the first LDO when the difference between VSUPPLY and VDDA is greater than or equal to the predetermined threshold and the first LDO is turned on and operating in a second on mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of operating a mutual capacitance touchscreen controller, comprising:
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providing an analog core comprising touchscreen sense circuitry configured to be operably connected to capacitive touchscreen sense lines external to the controller; providing an input supply voltage (VSUPPLY) to a first on-chip low drop out regulator (LDO) as a first input thereto and generating a regulated output voltage VDDA therefrom; providing VSUPPLY and VDDA to a comparator and generating as an output therefrom a signal EN, EN being provided to the first LDO as a second input thereto; operating the first LDO in a first off mode where the first LDO is turned off by signal EN when the difference between VSUPPLY and VDDA is less than a predetermined threshold; operating the touchscreen controller in an LDO mode when the difference between VSUPPLY and VDDA is greater than or equal to the predetermined threshold and the first LDO is turned on and operating in a second on mode. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification