SENSOR TAG, SENSOR TAG DEVICE, POWER RECEIVING CIRCUIT, AND SENSOR TAG DEVICE POWER SUPPLY METHOD

• US 20090121837A1
• Filed: 07/14/2006
• Published: 05/14/2009
• Est. Priority Date: 07/15/2005
• Status: Active Grant

• Current Assignee: Hitoshi Kitayoshi, Kunio Sawaya
• Original Assignee: Hitoshi Kitayoshi, Kunio Sawaya
• Inventors: Kitayoshi, Hitoshi, Sawaya, Kunio
• Granted Patent: US 8,493,181 B2
• Time in Patent Office: Days
• US Class Current: 340/10.100
• CPC Class Codes: G06K 19/0713 the arrangement including a power charge pump
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 13/08 Radiating ends of two-conductor microwave transmission lines, e.g. of coaxial lines, of microstrip lines
• CPC Class Codes: H04B 5/48 Transceivers
• CPC Class Codes: H04B 5/73 for taking measurements, e.g. using sensing coils
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

There is provided a sensor tag device capable of detecting event data by a sensor tag all the time even when no radio wave is received, saving power supply for a microprocessor, and enlarging the radio communication distance. The sensor tag device includes generation means 6 and 7 using one or more environmental changes, power supply voltage rise control means 8, and power supply synthesis means 9, and power is supplied to a microprocessor 12 and event data is stored in the microprocessor 12 when an event, i.e., an environmental change has occurred. A power receiving circuit having a transmission/reception antenna, a built-in power receiving circuit, and the microprocessor and capable of bi-directional communication by radio waves is combined with a stab resonance RF boost circuit and a ladder boost rectification circuit.

Claims

1. A sensor tag including a transmission/reception antenna, a power receiving circuit, and a microprocessor, wherein the power receiving circuit enabling bi-directional communication is combined with a stab resonance boost circuit and a ladder boost rectification circuit.

4. The sensor tag according to any claim 1, wherein a signal is taken out from a middle stage of the ladder boost rectification circuit, and a part of the power receiving circuit is utilized as an ASK demodulation circuit.

5. The sensor tag according to claim 4, wherein an output signal from the ASK demodulation circuit is utilized and an output voltage from a last stage of the ladder boost rectification circuit is charge-pumped to serve as a power supply voltage of the microprocessor.

6. The sensor tag according to claim 5, wherein a power sufficient for initialization and a reception sequence operation is supplied to the microprocessor by inputting a reset signal to the microprocessor in synchronization with the charge pump operation.

7. The sensor tag according to claim 6, wherein the reset signal is transmitted from an inquirer in a cycle T, and the microprocessor enables an output required to continuously supply a power after end of a power supply ON sequence and then resets an internal power flag, sets a timer waiting period slightly shorter than the reset cycle T, and thereafter sets the internal power flag at the end of the timer waiting period to detect that a power supply voltage is equal to or above a stable operation threshold value of the microprocessor.

8. The sensor tag according to claim 7, wherein a primary delay circuit having a long time constant and a primary delay circuit having a short time constant are used with respect to the ASK demodulation signal to take out and utilize a reset signal and a serial data signal.

11. A sensor tag device comprising the sensor tag according to claim 1 and having:

generation means for utilizing one or more changes in an environment;

power supply voltage rise control means; and

power supply synthesis means, wherein a change in the environment is determined as an event, a power is supplied to a microprocessor and event data is transmitted at the same time to be stored in the microprocessor when this event occurs.

12. The sensor tag device according to claim 11, having a time constant circuit that can be charged with electric charges under control of the microprocessor, wherein the microprocessor reads information of a time elapsed from charging.

13. The sensor tag device according to claim 11, wherein an event factor and a sensor data are wirelessly sent back with respect to an inquirer carrier signal when an event occurs.

14. The sensor tag device according to claim 11, wherein an event factor, sensor data, and information of an occurrence time are stored in a non-volatile memory in the microprocessor when an event occurs, and such information is wirelessly sent back when the inquirer inquires.

15. The sensor tag device according to claim 11, wherein time information and sensor information in the tag are stored in the non-volatile memory in the microprocessor when the inquirer issues a writing request, and such information is wirelessly sent back when the inquirer inquires.

19. The sensor tag device according to claim 12, wherein an event factor and a sensor data are wirelessly sent back with respect to an inquirer carrier signal when an event occurs.

20. The sensor tag device according to claim 12, wherein an event factor, sensor data, and information of an occurrence time are stored in a non-volatile memory in the microprocessor when an event occurs, and such information is wirelessly sent back when the inquirer inquires.

2. A sensor tag, wherein a divided microstrip antenna is used as the transmission/reception antenna.

3. The sensor tag according to claim 2, wherein a divided position of a strip conductor of the divided microstrip antenna deviates from the center of a length of the strip conductor.

9. A sensor tag device having:

generation means for utilizing one or more changes in an environment;

power supply voltage rise control means; and

power supply synthesis means, wherein a change in the environment is determined as an event, a power is supplied to a microprocessor and event data is stored in the microprocessor at the same time when this event occurs.

10. The sensor tag device according to claim 9, having a time constant circuit that can be charged with electric charges under control of the microprocessor, wherein the microprocessor reads information of a time elapsed from charging.

16. A power receiving circuit as a circuit which includes a stab resonator and a ladder boost rectification circuit, is connected with an antenna power feed point through a capacitive power feed impedance, and boosts and rectifies an input signal supplied from the antenna power feed point to feed a power to an external load, wherein the power receiving circuit resonates the stab resonator and the capacitive power feed impedance in series and resonates the stab resonator and a capacitive load impedance formed of the ladder boost rectification circuit in parallel.

17. The power receiving circuit according to claim 16, wherein, in a Cockcroft-Walton circuit formed of a plurality of diodes, a plurality of ground-side capacitors, and a plurality of power-receiving-side capacitors, the ladder boost rectification circuit is a circuit in which a first diode on an input side is removed and a capacitance value of each power-receiving-side capacitor is smaller than a capacitance value of each ground-side capacitor.

18. A sensor tag device power supply method, the sensor tag device comprising a stab resonator and a ladder boost rectification circuit, the method comprising:

achieving connection through an antenna power feed point and a capacitive power feed impedance;

resonating the stab resonator and the capacitive power feed impedance in series and resonating the stab resonator and a capacitive load impedance formed of the ladder boost rectification circuit in parallel; and

boosting and rectifying an input signal supplied from the antenna power feed point to feed a power to an external load.