Circuit for improving contactless card strong field modulation waveform and modulation length

A modulation waveform and non-contact card technology, which is applied to record carriers used in machines, instruments, computer components, etc., can solve the problems of unsatisfactory modulation waveform, shallow modulation depth of strong field, and large area of ​​modulation discharge devices, etc.

Active Publication Date: 2015-03-25
BEIJING CEC HUADA ELECTRONIC DESIGN CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to solve the problems that the modulation depth of the strong field is too shallow, the modulation waveform is not ideal and the area of ​​the modulation discharge device is too large, and provide a method that does not increase the area of ​​the modulation discharge device additionally, but also increases the depth of the strong field modulation, improving Modulation Waveform Scheme

Method used

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  • Circuit for improving contactless card strong field modulation waveform and modulation length
  • Circuit for improving contactless card strong field modulation waveform and modulation length

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Embodiment Construction

[0015] The invention proposes a circuit for improving the modulation waveform and modulation depth of the non-contact card strong field. The circuit comprises: a voltage stabilizing circuit (1), a modulating circuit (2) and an inverter (4).

[0016] In the voltage stabilizing circuit, there is a switch K3 between the output VO of the detection circuit and the control terminal VC1 of the discharge switch K1, and the on and off of K3 are controlled by the modulation data. The modulation stage K3 is turned off, and the non-modulation stage K3 is turned on. The switch K3 can be implemented with NMOS or PMOS, and can also be implemented with a transmission gate. The switch K1 can be implemented in the form of a MOS transistor, or replaced by two switches connected between LA, ground and LB, ground, or replaced by a switch connected between the radio frequency power supply and ground.

[0017] The modulation circuit includes a switch K2 connected between the two ends of the antenna...

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Abstract

The invention provides a circuit for improving contactless card strong field modulation waveform and modulation length. Under the situation that other circuits are not changed, better modulation waveform and better modulation length can be obtained in a strong field.

Description

technical field [0001] The present invention relates to a voltage stabilizing circuit and a modulating circuit of a non-contact card chip, and more specifically, the present invention relates to a circuit for improving the modulation waveform and modulation depth of a non-contact card strong field. Background technique [0002] There are two parts of the discharge circuit inside the contactless card chip: the discharge circuit of the voltage stabilizing circuit and the discharge circuit of the modulation circuit. The discharge current of the voltage stabilizing circuit is related to the antenna voltage and the RF power supply voltage. When it is detected that the antenna and RF power supply are lowered, the discharging current of the voltage stabilizing circuit decreases. When the card sends data to the card reader, the modulation circuit starts to discharge current, causing the amplitude of the card antenna to drop. When the voltage regulator circuit detects this drop, it ...

Claims

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Application Information

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IPC IPC(8): G06K19/077
Inventor 李罗生马哲陈永强陈波涛刘华茂周建锁
Owner BEIJING CEC HUADA ELECTRONIC DESIGN CO LTD
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