A kind of ask amplitude modulation signal demodulation circuit and demodulation method

Abstract

The invention relates to the technical field of electronics, in particular to a wireless charging amplitude modulation signal demodulation circuit and method. An ASK amplitude modulation signal demodulation circuit comprises a first filter, a first differentiator, a second differentiator and a first hysteresis comparator. The first differentiator is used for carrying out differential or differential simultaneous amplification on the second envelope signal and outputting a first differential signal (Vo _ 1d _ diff); The second differentiator is used for carrying out differential or differentialsimultaneous amplification on the first differential signal and outputting a second differential signal (Vo _ 2n _ diff); And the first hysteresis comparator is used for detecting the inflection point of the second envelope signal according to the positive value and the negative value of the second differential signal and outputting a data signal (Dout) which can be decoded to output original data information. The modulation signal is detected in the mode that the inflection point is judged through twice differentiation, and compared with traditional envelope demodulation mentioned in the background technology, the mcircuit has the advantages of being high in response speed, resistant to intermediate frequency disturbance and high in detection precision.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to a wireless charging amplitude modulation signal demodulation circuit and method. Background technique [0002] The market demand for wireless charging technology is increasing, among which the Wireless Power Consortium (WPC) QI standard is the most widely used. The market has launched various corresponding signal demodulation schemes according to the QI standard. Since the frequency of the ASK AM signal under the QI standard is as low as about 2kHz, most of the solutions still require multiple peripheral amplifiers, resistors, and capacitors to realize functions such as low-pass filtering and DC blocking. However, these solutions have been unable to meet the growing demand for low cost, are not conducive to reducing the size of the application circuit, and are not conducive to reducing the complexity of debugging. [0003] Envelope demodulation is a commonly used ASK demodu...

AI Technical Summary

Problems solved by technology

[0004] The disadvantage of the commonly used envelope demodulation circuit is that when the input signal envelope is disturbed by the intermediate frequency, since the reference voltage of the comparator is generated by a low-pass filter with a lower cut-off frequency, the reference voltage cannot quickly respond to the intermediate frequency disturbance, resulting in output The duty cycle of the demodulated signal changes greatly, even deviates from the recognizable area

This shortcoming is especially obvious in the wireless charging system: the change of the position of the receiving end will lead to the change of the coupling coefficient, thus the envelope will be disturbed; the change of the duty cycle will also cause the change of the envelope signal, resulting in a disturbance similar to the The phenomenon; the output duty cycle error caused by the disturbance will cause an error in the subsequent decoding circuit

Images