Canela Giménez, Arturo

The present invention discloses a backward-compatible wireless charger that automatically identifies fast and slow charging receiving load, comprising a wireless charger and a receiving load, the wireless charger comprises two-level variable DC voltage regulator circuit, a main resonance circuit, a resonant current sampling voltage divider and comparison circuit, the receiving load comprises a receiving resonant circuit, and the resonant frequency of the receiving load is compared with the resonant frequency of resonant circuit in the wireless charger to distinguish different receiving loads and to charge correspondingly. Only common circuit components are used and the circuit is simple, of small size, at low cost, with low energy consumption, safe, effective and reliable, to achieve the high cost-performance of the whole circuit, and at the same time it realizes the compatible fast charging and slow charging receiving load.