Radio frequency data communications device

A method for conserving power in a radio frequency identification device of a type including a single integrated circuit having a microprocessor, a transmitter, a receiver, and circuitry for performing the following:

• periodically switching from a sleep mode to a receiver-on mode and performing tests to determine whether to further switch to a microprocessor-on mode, in which more power is consumed than in the receiver-on mode, because a valid radio frequency signal is present, the tests including counting transitions in spread spectrum data to determine if the number of transitions within a predetermined time period fall within a predetermined range and, if so, determining if chip lock has occurred and, if not, returning to the sleep mode;
• if chip lock has occurred, determining if frequency lock has occurred and, if so, switching to a microprocessor-on mode and, if not, returning to the sleep mode;
• and
• selectively disabling the periodic switching from the sleep mode for a predetermined amount of time, the selective disabling being performed in response to a radio frequency command, wherein the selective disabling cannot be cancelled by a subsequent radio frequency command, the selective disabling comprising setting a countdown timer, the length of the predetermined amount of time being a variable amount and being selectable from a number of predetermined selectable amounts of time via a radio frequency command.

A method of operating a radio frequency identification device comprising:

• determining when a predetermined timer interval has elapsed;
• providing, after determining that the predetermined timer interval has elapsed, a receiver wake-up signal;
• asserting a bias control signal in response to the receiver wake-up signal to turn on a master receiver bias to provide electrical power to a radio receiver;
• testing to verify presence of the master receiver bias;
• repeating asserting the bias control signal when the testing determines that the master receiver bias is not present;
• determining, when the testing determines that the master receiver bias is present, when a radio frequency signal is being received by the radio receiver and returning the radio receiver to the sleep mode when the radio frequency signal is not present;
• determining when a first number of spread spectrum transitions of the radio frequency signal falls within in a predetermined first range of numbers and occurs during a first predetermined interval, and, when the first number of transitions within the predetermined first range of numbers does not occur during the first predetermined interval, returning the radio receiver circuit to the sleep mode;
• determining when a second number of spread spectrum transitions of the radio frequency signal falls within a predetermined second range of numbers and occurs during a second predetermined interval, and, when the second number of transitions does not occur during the second predetermined interval, returning the radio receiver circuit to the sleep mode;
• and
• providing a microprocessor wake-up signal to a microprocessor that is co-integrated in a single integrated circuit with the radio receiver circuit when the first number of transitions occurs during the first predetermined interval and the second number of transitions occurs during the second predetermined interval.

A method of operating a radio frequency identification device comprising:

• determining, in a wake-up controller circuit, that a predetermined timer interval has elapsed, while the radio frequency identification devices is in a sleep mode requiring a first power level;
• providing, when the predetermined interval has elapsed, a receiver wake-up signal to set the radio frequency identification device to a receiver on mode requiring a second power level greater than the first power level;
• determining, when testing determines that the master receiver bias is present, when a radio frequency signal is being received by the radio receiver;
• returning the radio receiver to the sleep mode when the radio frequency signal is not present;
• enabling a master receiver bias when the radio frequency signal is present to set the radio frequency identification device to a test mode requiring a third power level greater than the second power level, the master receiver bias providing electrical power to a radio receiver, a clock and data recovery circuit and a voltage controlled oscillator;
• initiating the voltage controlled oscillator to oscillate at a first frequency;
• determining, by the wake-up controller, when a first number of spread spectrum transitions of the radio frequency signal occurs during a first predetermined interval, and, when the first number of transitions does not occur during the first predetermined interval, returning the radio receiver circuit to the sleep mode;
• determining, by the wake-up controller, when a second number of spread spectrum transitions of the radio frequency signal occurs during a second predetermined interval, and, when the second number of transitions does not occur during the second predetermined interval, returning the radio receiver circuit to the sleep mode;
• determining, during an interval of predetermined length, presence or absence of voltage controlled oscillator signal acquisition from the radio frequency signal by the clock and data recovery circuit, and, when absence of clock signal acquisition is determined, returning the radio receiver to the sleep mode;
• and
• providing a microprocessor wake-up signal from the wake-up controller to a microprocessor that is co-integrated in a single integrated circuit with the radio receiver circuit and the wake-up controller when the first number of transitions occurs during the first predetermined interval and the second number of transitions occurs during the second predetermined interval, the microprocessor wake-up signal setting the radio frequency identification device to a processor-on mode requiring a fourth power level that is greater than the third power level.

A method of operating a radio frequency identification device comprising:

• changing a state of the identification device from a sleep mode requiring a first power level to a second mode by turning a radio receiver in the identification device on in response to a first criterion, the radio receiver requiring a second power level greater than the first power level;
• changing the state of the identification device from the second mode to a third mode when a second criterion is met, the third mode requiring a third power level greater than the second power level, and, when the second criterion is not met, changing the state from the second mode to the sleep mode;
• and
• changing the state of the identification device from the third mode to a fourth mode when a third criterion is met, the fourth mode requiring a fourth power level greater than the third mode, and, when the third criterion is not met, changing the state from the third mode to the sleep mode.

A radio frequency identification device comprising:

• a radio receiver having an output;
• a wake-up timer circuit providing a receiver wake-up signal to the radio receiver at predetermined intervals to change a state of the radio frequency identification device from a sleep mode requiring a first power level to a second mode requiring a second power level greater than the first power level;
• a radio frequency signal detection circuit having an input coupled to the radio receiver output, the radio frequency detection circuit providing an output signal returning the radio frequency identification device to the sleep mode when no radio frequency signal is detected, the radio frequency signal detection circuit setting the radio frequency detection device to a third mode requiring more power than the second mode when a radio frequency circuit is detected;
• a wake-up controller circuit having an input coupled to the radio receiver output, the wake-up controller circuit first testing the radio frequency signal to determine when a first number of spread spectrum transitions of the radio frequency signal occurs during a first predetermined interval, the wake-up controller circuit providing an output signal returning the radio frequency identification device to the sleep mode when the wake-up controller circuit determines that the first number of transitions does not occur during the first predetermined interval, the wake-up controller circuit then testing the radio frequency signal to determine when a second number of spread spectrum transitions of the radio frequency signal occurs during a second predetermined interval and providing an output signal returning the radio frequency identification device to the sleep mode when the wake-up controller circuit determines that the second number of transitions does not occur during the second predetermined interval;
• a clock and data recovery circuit including a phase-locked loop, the clock and data recovery circuit having an input coupled to the radio receiver output, the clock and data recovery circuit determining, during an interval of predetermined length, presence or absence of voltage controlled oscillator signal acquisition from the radio frequency signal and returning the radio receiver to the sleep mode when absence of clock signal acquisition is determined;
• and
• a microprocessor having a data input coupled to the radio receiver output and a control input coupled to the wake-up controller circuit, the wake-up controller circuit providing a microprocessor wake-up signal to the microprocessor when the first number of transitions occurs during the first predetermined interval, the second number of transitions occurs during the second predetermined interval and the wake-up controller determines presence of voltage controlled oscillator signal acquisition from the radio frequency signal, the microprocessor wake-up signal setting the radio frequency identification device to a processor-on mode requiring a fourth power level that is greater than the third power level.

A radio frequency identification device comprising:

• a radio receiver having an output and a control input;
• a microprocessor having a data input coupled to the radio receiver output and having a control input;
• a timer having an output coupled to the control input of the radio receiver, the timer providing an output signal to the radio receiver control input changing a state of the identification device from a sleep mode requiring a first power level to a second mode by turning the radio receiver in the identification device on in response to a first criterion, the radio receiver requiring a second power level greater than the first power level;
• and
• a wake-up controller circuit including an output coupled to the microprocessor control input, the wake-up controller circuit changing the state of the identification device from the second mode to a third mode when a second criterion is met, the third mode requiring a third power level greater than the second power level, and, when the second criterion is not met, changing the state from the second mode to the sleep mode, the wake up controller circuit providing an output signal to the microprocessor control input changing the state of the identification device from the third mode to a fourth mode when a third criterion is met, the fourth mode requiring a fourth power level greater than the third mode, and, when the third criterion is not met, changing the state from the third mode to the sleep mode.