Low power wake on radio
AssigneeSilicon Laboratories Inc.
InventorsPio Balmelli, Praveen Vangala, John M. Khoury
Life of this patent
Estimating the term…
Abstract
A low power wake on radio circuit detects if an RF signal is present on an input to the wake on radio circuit. An RF sense circuit supplies an RF sense signal indicating whether the RF signal is present on the input. The RF sense signal is used to incrementally turn on digital decode logic to determine if a radio transmission that is unique to the wake on radio circuit has been received. If the unique radio transmission have been received, the wake on radio circuit supplies a wakeup signal to the rest of the system.
Claims25
A method comprising:
- receiving a radio frequency (RF) signal at an input to a wake on radio circuit at a gate of a first transistor operating in an open-drain configuration having the gate biased so that a drain of the first transistor toggles from high to low responsive to an amplitude of the RF signal reaching a threshold level;
- supplying a bias current to first and second programmable resistors coupled in series;
- supplying a voltage from a middle node between the first and second programmable resistors as a reference voltage to a comparator;
- biasing the gate of the first transistor based, at least in part, on the voltage from the middle node;
- comparing the voltage from the middle node to a drain voltage on the drain of the first transistor using the comparator to determine if the RF signal is present on the input to the wake on radio circuit;
- and
- supplying a detection indication based on the comparing having a first value indicating that the RF signal was detected on the input and having a second value indicating that the RF signal was not detected on the input.
An apparatus comprising:
- an analog portion of a wake on radio circuit including,
- an input transistor having a gate coupled to an input to the wake on radio circuit to detect presence of a radio frequency (RF) signal on the input;
- a comparator having a first comparator input coupled to a drain of the input transistor in an operational mode and having a second comparator input coupled to a reference voltage in the operational mode, the comparator to supply a comparison indication indicating whether the RF signal was detected on the input;
- a digital control portion of the wake on radio circuit coupled to receive the comparison indication;
- and
- wherein the digital control portion of the wake on radio circuit is configured to periodically cause the analog portion to enter a calibration mode that uses the comparator for calibration.
A wake on radio circuit comprising:
- an input transistor having a gate coupled to an input to the wake on radio circuit to detect a radio frequency (RF) signal on the input, the input transistor having the gate biased so that a drain of the input transistor toggles from high to low responsive to an amplitude of the RF signal reaching a threshold level;
- a comparator having a first comparator input coupled to a drain of the input transistor in an operational mode and having a second comparator input coupled to a reference voltage in the operational mode, the comparator to supply an RF sense indication indicating whether the RF signal was detected on the input;
- and
- wherein the gate of the input transistor is coupled to the reference voltage to bias the gate.
Dependencies are inferred from the claim text.