Voltage converter

Patent metadata

Field	Value
Publication number	US-9716443-B2
Application number	US-201514791230-A
Country	US
Kind code	B2
Filing date	Jul 2, 2015
Priority date	Jul 4, 2014
Publication date	Jul 25, 2017
Grant date	Jul 25, 2017

Abstract

A radio frequency transponder circuit, comprising: an AC-DC converter ( 70 ) connected to an RF input terminal ( 21 a ) and a DC output terminal ( 81 ) and operable to convert an RF signal (RF A ) at the RF input terminal ( 21 a ) to a DC output signal (V DD ) at the DC output terminal ( 81 ); and a voltage limiting circuit ( 50 ) connected to the RF input terminal ( 21 a ) and operable to limit the amplitude of the RF signal (RF A ); wherein the voltage limiting circuit ( 50 ) comprises a NMOS limiting transistor ( 51 ) in parallel with a complimentary PMOS limiting transistor ( 52 ).

First claim

The invention claimed is:

1. A voltage converter, comprising:
an AC-DC converter connected to an RF input terminal and a DC output terminal and operable to convert an RF signal at the RF input terminal to a DC output signal at the DC output terminal; and
a voltage limiting circuit connected to the RF input terminal and operable to limit the amplitude of the RF signal;
wherein the voltage limiting circuit comprises a NMOS limiting transistor in parallel with a complimentary PMOS limiting transistor.

2. The voltage converter of claim 1 , wherein the voltage limiting circuit further comprises a biasing means operable to generate a positive and negative bias voltage for controlling the operation of the NMOS and PMOS limiting transistors respectively.

3. The voltage converter of claim 2 , wherein the biasing means is configured to provide symmetric bias potentials to the NMOS and PMOS limiting transistors.

4. The voltage converter of claim 3 , wherein the biasing means comprises a charge pump.

5. The voltage converter of claim 4 , wherein the biasing means comprises a charge pump arranged to generate a negative bias potential from the RF signal.

6. The voltage converter of claim 5 , wherein the biasing means comprises a first charge pump and a second charge pump, wherein the first charge pump is arranged to generate a negative bias signal from the RF signal, and the second charge pump is arranged to generate a positive bias signal from the RF signal.

7. The voltage converter of claim 4 , wherein at least one charge pump of the biasing means is configured with a minimum input voltage amplitude below which the charge pump is inoperable.

8. The voltage converter of claim 7 , wherein the minimum input voltage amplitude is greater than 0.3 V.

9. The voltage converter of claim 2 , wherein the biasing means comprises a resistive load connected to a gate of each limiting transistor.

10. The voltage converter of claim 2 , wherein the biasing means comprises a transistor connected to the gate of each limiting transistor.

11. The voltage converter of claim 1 , wherein the voltage limiting circuit is connected between the RF input terminal and ground.

12. The voltage converter of claim 1 , wherein the AC-DC converter is configured for connection to a differential RF input comprising a first and second RF input terminal, such that the voltage limiting circuit is arranged between the first and second RF terminals.

13. The voltage converter of claim 1 , wherein the voltage limiting circuit has a substantially symmetric response to positive and negative over voltage of the RF signal.

14. The voltage converter of claim 1 , wherein the voltage converter is for providing a DC voltage to a UHF transponder.

15. A radio frequency transponder comprising: an antenna, the voltage converter of claim 1 , a demodulator for receiving data from the antenna and a modulator for transmitting data via the antenna, wherein the voltage limiting circuit is arranged to regulate the amplitude of an RF signal from the antenna.

Assignees

• Nxp Bv

Inventors

• Zoescher Lukas

Classifications

• H04B1/40

  Circuits · CPC title

• G06K19/0701 Primary

  at least one of the integrated circuit chips comprising an arrangement for power management · CPC title

• H02M7/217

  using semiconductor devices only · CPC title

• H02M7/537 Primary

  using semiconductor devices only, e.g. single switched pulse inverters · CPC title