US 6,982,559 B2
Accurate and efficient sensing circuit and method for bi-directional signals
John P. Taylor, San Diego, Calif. (US)
Assigned to Kyocera Wireless Corp., San Diego, Calif. (US)
Filed on Jan. 14, 2004, as Appl. No. 10/757,902.
Prior Publication US 2005/0151543 A1, Jul. 14, 2005
Int. Cl. G01R 27/02 (2006.01); H04B 1/04 (2006.01)
U.S. Cl. 324—609 20 Claims
OG exemplary drawing
 
14. A mobile communication device comprising:
a transceiver for transmitting and receiving an RF signal;
a mobile power source coupled to the transceiver for supplying power to the transceiver;
a resistive element coupled in series between the mobile communication device and one of the mobile power source and ground;
a sampling unit switchably coupled to the resistive element, the sampling unit configured to sample a voltage across the resistive element during a sampling mode; and
a charge transfer unit switchably coupling a first input of an amplifier to the sampling unit, the first input switchably coupled to a first terminal of the sampling unit when the current flows through the resistive element in a first direction, the first input switchably coupled to a second terminal of the sampling unit when the current flows through the resistive element in a second direction opposite the first direction, the charge transfer unit and the amplifier operable to convert the voltage to a ground-referenced output voltage during a charge transfer mode.