A demodulation circuit for wireless charging

Abstract

A demodulation circuit for wireless charging. The sampling module is used to sample the inductance current of the charging base in the wireless charging system and convert it into a corresponding voltage signal. The amplification module receives the voltage signal output by the sampling module and uses a band-pass structure to amplify the output current to obtain the output current. The processing module processes the current signal output by the amplification module to obtain one or more of its average current, peak current, and valley current, and the demodulation module demodulates the current signal output by the processing module. The invention adds peak current demodulation and valley current demodulation to ensure normal demodulation under light load conditions; the amplifying module adopts a band-pass structure to solve the swing problem during current amplification, ensuring peak current demodulation and Valley current demodulation can also be demodulated normally when the current changes greatly before and after demodulation; in addition, when multiple demodulation schemes are used together, time-division multiplexing is used for processing, which reduces the chip area and power consumption.

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 as figure 1 Shown is a realization circuit diagram of the wireless charging system. The charging base (Transimitter) and the mobile phone terminal (Receiver) have built-in coils respectively. The transmitting coil of the charging base generates a certain current in the receiving coil of the mobile phone through electromagnetic induction based on a certain frequency alternating current. The power is transferred from the transmitter of the base to the receiver 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 as figure 1 As...

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

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