Abstract: A battery charging method (300) determines a current at which to start charging the battery which provides the capability for faster higher current sourcing capability. A start current(Istart)is determined based on the battery's cut off voltage, steady state voltage, and characteristic impedance (314). This start current is then compared and adjusted based on the rated power supply current for the power supply (316, 318) and rated charge current for the battery (320, 322). The adjusted current is then applied to the battery (324) at the beginning of the charge sequence to provide faster higher current sourcing capability.
Abstract: A tuning circuit (202) uses a precision current reference (Iref) along with an analog-to-digital converter (218) to produce a digital output (228) to represent variations of internal resistance values. The precision current reference (Iref) is fed to an internal tuning resistor (R210) in order to provide an analog voltage signal to the analog-to-digital converter (218). The analog voltage signal changes in accordance with the variations in the tuning resistor value over process and temperature. The digital output (228) controls programmable capacitor arrays (C220, C222) which are included in the tuning circuit (202) as well as in an active RC filter (208) whose bandwidth is controlled by the programmable capacitor arrays (C220, C222) and internal resistors (R212, R214, R216).
Type:
Grant
Filed:
July 1, 1994
Date of Patent:
April 29, 1997
Assignee:
Motorola, Inc.
Inventors:
Mark J. Chambers, Jesus P. Finol, James B. Phillips
Abstract: A base station (102) automatically remotes to a speakerphone mode of operation and connects an incoming call while an external electronic device (104) is simultaneously controlled.
Type:
Grant
Filed:
August 1, 1994
Date of Patent:
July 30, 1996
Assignee:
Motorola, Inc.
Inventors:
Sybren D. Smith, Argyrios Chatzipetros, Rudy Yorio
Abstract: The present invention comprises a method and apparatus for selecting one of at least two antennas (202, 204) in a communication unit (200) for use in a wireless communication system (100). A signal is received by a radio frequency receiver during a receiving period from one of the at least two antennas (202, 204) currently selected by an antenna switch (206), the signal transmitted in a digital communications format comprising a plurality of bits. The quality of the receive signal is determined by a switch diversity algorithm programmed into a microcomputer (212) that bases the decision to switch antennas on predetermined thresholds established for each of: a received signal strength indicator, a phase error signal, and a recovered clock signal.