Headsets and headset power management
First Claim
1. A headset comprising:
- at least one circuit element;
a capacitive sensor operable to provide a capacitance measurement signal;
a control circuit to enable at least one charge transfer cycle to the capacitive sensor; and
a charge sensing circuit coupled to the control circuit and operable to generate a user presence signal responsive to values of the capacitance measurement signal for the at least one charge transfer cycle, the values indicating whether the headset is being worn by the user, and wherein the charge sensing circuit is operable to control the at least one circuit element dependent on said user presence signal and output an external output signal that is dependent on said user presence signal for receipt by another device to which the headset is connected wherein the charge sensing circuit includes a sample capacitor and is further operable to transfer charge from the capacitive sensor to the sample capacitor to generate an electric potential at the sample capacitor for measuring; and
at least one switch within the control circuit, the at least one switch being operable to transfer a burst of charge packets sequentially from the capacitive sensor to the sample capacitor prior to any measurement of the electric potential being made, wherein the at least one switch includes;
a first switching element to drive electric charge through the capacitive sensor and the sample capacitor when the first switching element is closed;
a second switching element to clear voltage across the capacitive sensor to permit measurement of the sample capacitor when the second switching element is closed; and
a third switching element to reset the charge on the sample capacitor when the third switching element is closed.
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Accused Products
Abstract
The invention relates to an energy saving headset that comprises a power management unit operable to reduce the power consumption of the headset when a user is not present. The power management unit uses capacitive sensing to detect the presence of the user. Capacitive sensing is advantageous since it provides a flexible and reliable sensor that can accurately detect the presence or absence of a user either by detecting user proximity or user contact. Moreover, in various embodiments, the sensitivity of a capacitive sensor may be adjusted to account for user movement or changes in environmental conditions, such as, for example, the presence of water, or sweat, on the headset to further improve sensing reliability. The invention further relates to headsets using user presence signals based on capacitive sensing to control other functions of the headset or to control external devices to which the headset is connected, either wirelessly or by wires.
107 Citations
14 Claims
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1. A headset comprising:
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at least one circuit element; a capacitive sensor operable to provide a capacitance measurement signal; a control circuit to enable at least one charge transfer cycle to the capacitive sensor; and a charge sensing circuit coupled to the control circuit and operable to generate a user presence signal responsive to values of the capacitance measurement signal for the at least one charge transfer cycle, the values indicating whether the headset is being worn by the user, and wherein the charge sensing circuit is operable to control the at least one circuit element dependent on said user presence signal and output an external output signal that is dependent on said user presence signal for receipt by another device to which the headset is connected wherein the charge sensing circuit includes a sample capacitor and is further operable to transfer charge from the capacitive sensor to the sample capacitor to generate an electric potential at the sample capacitor for measuring; and at least one switch within the control circuit, the at least one switch being operable to transfer a burst of charge packets sequentially from the capacitive sensor to the sample capacitor prior to any measurement of the electric potential being made, wherein the at least one switch includes; a first switching element to drive electric charge through the capacitive sensor and the sample capacitor when the first switching element is closed; a second switching element to clear voltage across the capacitive sensor to permit measurement of the sample capacitor when the second switching element is closed; and a third switching element to reset the charge on the sample capacitor when the third switching element is closed. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of operating a headset, the method comprising:
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measuring a capacitance of a capacitive sensor by enabling at least one charge transfer cycle to the capacitive sensor and determining values of the capacitance for the at least one charge transfer cycle, wherein measuring the capacitance of the capacitive sensor further includes; transferring a burst of charge packets from the capacitive sensor to a sample capacitor; measuring an electric potential at the sample capacitor; and determining the values of the capacitance of the capacitive sensor for the at least one transfer charge cycle from the electric potential measured at the sample capacitor; determining from the values of the capacitance whether a user is present or not; and controlling a function of the headset by outputting an external output signal that can be received by another device to which the headset is connected, in response to determining whether the user is present or not; and wherein transferring a burst of charge packets in sequence from the capacitive sensor to the sample capacitor includes; closing a first switching element that drives electric charge through the capacitive sensor and the sample capacitor; closing a second switching element that clears voltage across the capacitive sensor to permit measurement of the sampling capacitor; and closing a third switching element that resets the charge on the sampling capacitor. - View Dependent Claims (8, 9, 10, 11)
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12. An apparatus comprising:
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a sensing element, which is electrically conductive, wherein a first capacitance is formed between the sensing element and a user of the apparatus; a capacitance measurement circuit that includes a sampling capacitor electrically coupled to the sensing element, wherein a voltage applied to the sampling capacitor results in a first electrical potential at the sampling capacitor and a second electrical potential at the sensing element; and a control unit to receive a capacitance measurement signal from the capacitance measurement circuit, the control unit further to output a control signal to control a function of the apparatus in response to the capacitance measurement signal; and wherein the capacitance measurement circuit includes plurality of switches that are operable to transfer a burst of charge packets sequentially from the sensing element to the sampling capacitor prior to any measurement of the electric potential being made, wherein the plurality of switches includes; a first switching element to drive electric charge through the sensing element and the sampling capacitor when the first switching element is closed; a second switching element to clear voltage across the sensing element to permit measurement of the sampling capacitor when the second switching element is closed; and a third switching element to reset the charge on the sampling capacitor when the third switching element is closed. - View Dependent Claims (13, 14)
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Specification