Clockless self tuning rfid tag
AssigneeNXP B.V.
InventorsJorge Vicente De la Cruz Marin, Jacobus de Meulmeester, Rainer Stadlmair
Life of this patent
Estimating the term…
Abstract
A self-tuning device and related method includes a first voltage indicative of a first magnitude of an input signal to an antenna stored in a first capacitor when a variable capacitor bank coupled to the antenna is in a first configuration and a second voltage indicative of a second magnitude of the input signal when the variable capacitor bank is in a second configuration are compared. A first output signal based on the comparison is used to determine, the first configuration of the variable capacitor bank results in an optimized configuration of the variable capacitor bank. The variable capacitor bank is configured in the first configuration.
Claims20
A radio frequency identification (RFID) tag, comprising:
- an antenna configured to receive an input signal;
- a variable capacitor bank electrically coupled to the antenna;
- and
- a self-tuning circuit coupled with the antenna, wherein the self-tuning circuit is configured to modify a capacitance of the variable capacitor bank to optimize a signal strength of the input signal according to a self-tuning algorithm, wherein the self-tuning circuit does not include a clock source and the self-tuning circuit includes:
- a first comparator, including:
- a first capacitor configured to store a first voltage indicative of a first magnitude of the input signal when the variable capacitor bank is in a first configuration, and
- a first comparator device having a first input terminal and a second input terminal, wherein the first input terminal is configured to receive a second voltage indicative of a second magnitude of the input signal when the variable capacitor bank is in a second configuration and the second input terminal is configured to receive the first voltage from the first capacitor, wherein the first comparator device is configured to generate a first output signal based on a difference between the first voltage and the second voltage;
- and
- a controller configured to determine, using the first output signal of the first comparator device, that the first configuration of the variable capacitor bank results in an optimized configuration of the variable capacitor bank compared to the second configuration and to configure the variable capacitor bank in the first configuration.
A device, comprising:
- a first comparator, including:
- a first capacitor configured to store a first voltage indicative of a first magnitude of an input signal when a variable capacitor bank coupled to an antenna is in a first configuration, and
- a first comparator device having a first input terminal and a second input terminal, wherein the first input terminal is configured to receive a second voltage indicative of a second magnitude of the input signal when the variable capacitor bank is in a second configuration and the second input terminal is configured to receive the first voltage from the first capacitor, wherein the first comparator device is configured to generate a first output signal based on a difference between the first voltage and the second voltage;
- and
- a controller configured to determine a configuration of a variable capacitor bank using the first output signal of the first comparator device.
A method of executing a self-tuning algorithm for a radio frequency identification tag, comprising:
- storing a first voltage indicative of a first magnitude of an input signal to an antenna in a first capacitor when a variable capacitor bank coupled to the antenna is in a first configuration;
- providing a second voltage indicative of a second magnitude of the input signal when the variable capacitor bank is in a second configuration to a first input terminal of a first comparator device;
- providing the first voltage from the first capacitor to a second input terminal of the first comparator device, wherein the first comparator device is configured to generate a first output signal based on a difference between the first voltage and the second voltage;
- determining, using the first output signal of the first comparator device, that the first configuration of the variable capacitor bank results in an optimized configuration of the variable capacitor bank compared to the second configuration;
- and
- configuring the variable capacitor bank in the first configuration.
Dependencies are inferred from the claim text.