Wireless charging demodulation circuit

Abstract

A wireless charging demodulation circuit is characterized in that a sampling module is used for sampling inductive current of a charging base in a wireless charging system and converting the inductivecurrent into a corresponding voltage signal, an amplification module receives the voltage signal output by the sampling module and carries out amplification processing through a band-pass structure to obtain output current, a processing module processes a current signal output by the amplification module to obtain one or more of average current, peak current and valley current of the current signals, and a demodulation module demodulates the current signal output by the processing module. According to the invention, peak current demodulation and valley current demodulation are added, so thatnormal demodulation can be realized under the condition of light load; the amplification module adopts the band-pass structure, so that the problem of swing amplitude during current amplification canbe solved, and peak current demodulation and valley current demodulation can be normally demodulated when the current is greatly changed before and after demodulation; and in addition, when multiple demodulation schemes are used together, a time division multiplexing mode is adopted for processing, so that the chip area and the power consumption are reduced.

Description

Technical field[0001]The invention belongs to the technical field of wireless charging, and relates to a novel wireless charging demodulation circuit.Background technique[0002]At present, most wireless charging uses the principle of electromagnetic induction for charging, such asfigure 1 Shown is an implementation circuit diagram of a wireless charging system. The charging base (Transimitter) and the mobile terminal (Receiver) have built-in coils respectively. The transmitter coil of the charging base generates a certain current in the mobile phone receiving coil through electromagnetic induction based on a certain frequency of alternating current, thereby The energy is transferred from the transmitting end of the base to the receiving end of the mobile phone, so that the charging base starts to supply power to the mobile phone.[0003]The amount of energy that the base needs to transmit is controlled by the relevant commands issued by the mobile phone, such asfigure 1 As shown, the m...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the problem of demodulation failure in the above-mentioned traditional current demodulation scheme, the present invention proposes a wireless charging demodulation circuit, which introduces peak current demodulation and valley current demodulation, and solves the problem that the average current demodulation is prone to failure under no-load conditions. In addition, the amplifying module uses a band-pass voltage amplifier to process the voltage signal converted by the inductor current, which solves the problem of the swing when the current is amplified, so that when the load current is large, the center point of the output current ILsns_out of the amplifying module is still at 1 / 2VDD Nearby, the upper and lower swings are guaranteed to be as equal as possible, so that even if the current changes greatly before and after demodulation, the normal demodulation of peak current and valley current can be guaranteed

Images