Applying Effective Dynamic Frequency Scaling Method in Contactless Smart Card

A creative dynamic frequency scaling method in contactless smart card is presented for the first time. A low power magnetic field detection circuit, a simple load detection circuit, the quick load comparator and the simple clock switch scheme in the method are also presented. The test result shows that the longest communication distance is improved from 6 to 8 cm compared to the same contactless smart card (CSC) chip using the fixed frequency divided by 4 and the transaction time is saved by 18% in average, compared to the same CSC chip using the fixed frequency divided by 8.