Signal converter, RFID tag having signal converter, and method of driving RFID tag

• US 20070176809A1
• Filed: 10/30/2006
• Published: 08/02/2007
• Est. Priority Date: 01/13/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Song, Il-jong, Kim, Cheong-worl, Min, Young-hun
• Granted Patent: US 7,593,690 B2
• Time in Patent Office: Days
• US Class Current: 341/143
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs

Abstract

A signal converter capable of stabling converting input signals in an extended operation margin, a radio frequency identification (RFID) tag having the signal converter and a method of driving a RFID tag. The signal converter includes a first signal converter which converts an incoming analog signal into a power signal, a second signal converter which converts the analog signal into a first demodulation signal, a signal amplifier which amplifies the first demodulation signal to output a second demodulation signal such that a value of an externally-supplied reference signal is included in a peak-to-peak range of the second demodulation signal, and a logic signal generator which converts the second demodulation signal into a digital signal in response to the power signal. Because the second demodulation signal has an extended operation margin in converting analog signal into digital signal, stable conversion of the input signals is possible, and rate of recognizing RFID tag is improved.

Claims

1. A signal converter, comprising:

a first signal converter which converts an incoming analog signal into a power signal;

a second signal converter which converts the analog signal into a first demodulation signal;

a signal amplifier which amplifies the first demodulation signal to output a second demodulation signal such that a value of an externally-supplied reference signal is included in a peak-to-peak range of the second demodulation signal; and

a logic signal generator which converts the second demodulation signal into a digital signal in response to the power signal.

2. The signal converter of claim 1, wherein the signal amplifier comprises a differential amplifier.

3. The signal converter of claim 2, wherein the signal amplifier further comprises a second amplifier which increases an output gain of the differential amplifier.

4. The signal converter of claim 1, further comprising a signal detector which detects and amplifies the first demodulation signal when the peak-to-peak range of the first demodulation signal is narrow.

5. The signal converter of claim 4, wherein the signal amplifier outputs the first demodulation signal, which is amplified at the signal detector, as a second demodulation signal.

6. The signal converter of claim 1, further comprising an over-voltage preventive part which discharges the first demodulation signal to a ground terminal when the first demodulation signal outputted from the second signal converter is in an over-voltage exceeding a predetermined level.

7. The signal converter of claim 1, further comprising an impedance matching part which matches impedance with an output source of the analog signal.

8. The signal converter of claim 1, wherein the first signal converter comprises:

a first rectifier which rectifies the analog signal; and

a first smoothing circuit which converts by smoothing the rectified analog signal into the power signal.

9. The signal converter of claim 8, wherein the second signal converter comprises:

a second rectifier which rectifies the analog signal; and

a second smoothing circuit which converts by smoothing the rectified analog signal into the first demodulation signal.

10. The signal converter of claim 9, wherein the first smoothing circuit comprises a capacitor which has a capacitance relatively larger than that of the second smoothing circuit.

11. The signal converter of claim 1, wherein the logic signal generator comprises buffers in series connection with a plurality of inverters.

12. A radio frequency identification (RFID) tag, comprising:

a first conversion circuit which converts a first incoming analog signal into a power signal and a demodulation signal, amplifies the demodulation signal such that a value of a predetermined reference signal is included in a peak-to-peak range of the demodulation signal, and outputs a digital signal using the amplified demodulation signal;

a memory which stores tag data;

a second conversion circuit which converts the tag data into a second analog signal and outputs the converted signal; and

a controller which reads out tag data from the memory in response to the digital signal and controls the operation of the second conversion circuit in response to the read tag data.

13. The RFID tag of claim 12, wherein the first conversion circuit comprises:

a first signal converter which converts the first analog signal into a power signal;

a second signal converter which converts the first analog signal into a first demodulation signal;

a signal amplifier which amplifies the first demodulation signal to output a second demodulation signal such that a value of an externally-supplied reference signal is included in a peak-to-peak range of the second demodulation signal; and

a logic signal generator which converts the second demodulation signal into a digital signal in response to the power signal.

14. The RFID tag of claim 12, wherein the second signal converter comprises a modulation circuit which modulates the data signal into a second analog signal.

15. A method of driving a radio frequency identification (RFID) tag, comprising:

rectifying and smoothing a first incoming analog signal to generate a power signal and a first demodulation signal;

amplifying the first demodulation signal to output a second demodulation signal such that a value of an externally-supplied reference signal is included in a peak-to-peak range of the second demodulation signal; and

converting the second demodulation signal into a digital signal in response to the power signal.

16. The method of claim 15, further comprising:

decoding and reading out pre-stored tag data in response to the digital signal;

encoding the read tag data; and

modulating the encoded tag data to output a second analog signal.