Patent ID: 8716901

Claim:
A circuit for generating a direct current voltage, the circuit comprising: a three-axis antenna set having a first coupling terminal for receiving an X-axis component of a signal transmitted by a reader, a second coupling terminal for receiving a Y-axis component of the signal, a third coupling terminal for receiving a Z-axis component of the signal, and an output terminal; a first capacitor coupled to the output terminal of the three-axis antenna set for generating a first direct current voltage according to the X-axis component, the Y-axis component, and the Z-axis component; a limiting direct current voltage generator having a first input terminal coupled to the first coupling terminal of the three-axis antenna set for receiving the X-axis component, a second input terminal coupled to the second coupling terminal of the three-axis antenna set for receiving the Y-axis component, a third input terminal coupled to the third coupling terminal of the three-axis antenna set for receiving the Z-axis component, a fourth terminal coupled to ground, and an output terminal for outputting an X-axis direct current voltage, a Y-axis direct current voltage, and a Z-axis direct current voltage, wherein the limiting direct current voltage generator is used for converting the X-axis component, the Y-axis component, and the Z-axis component to generate the X-axis direct current voltage, the Y-axis direct current voltage, and the Z-axis direct current voltage; a second capacitor coupled to the output terminal of the limiting direct current voltage generator for generating a second direct current voltage according to the X-axis direct current voltage, the Y-axis direct current voltage, and the Z-axis direct current voltage; and a low dropout regulator coupled to the second capacitor for generating a direct current output voltage according to the second direct current voltage.