RFWireless Charging Technologies: Qi, PMA, and A4WP Comparison
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With the proliferation of wireless electronic devices, the demand for wireless charging has spurred the development of various standards and technologies. Some of the most prominent include Qi (from the EPC), PMA, and A4WP.
The following table highlights the key differences between these wireless charging technologies. It compares factors like operating frequency, coupling factor, cost, metal usage, form factor, and efficiency.
Comparison of Wireless Charging Standards
| Specifications | EPC (Qi) | PMA | A4WP |
|---|---|---|---|
| Frequency of operation | 100 to 205 KHz | 250 to 400 KHz | 6.78MHz |
| Coupling range | 0.4 to 0.7 | 0.6 to 0.8 | 0.1 to 0.5 |
| Quality factor | 6 to 10 | 6 to 10 | 40 to 100 |
| Cost | Medium | High | Small |
| Thickness | 0.3 to 1.0 mm | 0.8 to 1.3 mm | 0.2 to 0.5 mm |
| Heating of metal | Medium | Medium | Low |
| Form factor flexibility | Medium | Low | Medium to High |
| Efficiency | Higher than 70% | Higher than 70% | Approx. 50% |
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