Kyocera Wireless Corporation

Qualcomm Incorporated

National Semiconductor Corporation

Larry Bradley

Jonathan Robert Knight

Richard J Kerr

Luan Minh Vu

Bruno Kranzen

Mahmoud Azartash

David E Wang

Jim Pieronek

Frank Newman

A voltage regulation and battery charging system is provided. The system may include a switching regulator selection control circuit, two switching regulator controller circuits, two power transistors, a common synchronous transistor, and a common LC circuit. The two switching regulator controller circuits may synchronously switch the two power transistors and the one common synchronous transistor. One of the switching regulator controller circuits may receive a voltage from an AC adapter and the other may receive a voltage from a USB port. Further, the switching regulation selection control circuit selects which of the two switching regulator controller circuits controls the regulation of the system output voltage employing the common LC filter.

Apparatus and method for dual source, single inductor magnetic battery charger

A system for providing a first signal to a flip circuit and receiving a second signal from the flip circuit over an electrical path adapted for use with a keypad having a keypad lighting circuit. The system includes a first circuit for providing the first signal to the flip circuit via a first electrical path, the first signal having alternating first and second states. A second circuit generates a second signal. A third circuit receives the second signal via the first electrical path. The second signal is received during the second state of the first signal. In a more specific embodiment, the first and second states are continuously alternating states. The first signal provides power to the flip circuit when the first signal is in the first state. The first circuit further includes a signal generator for adjusting a duty cycle of the first signal. The signal generator includes a voltage source, a switching circuit connected to the voltage source, and a control circuit connected to the switching circuit. The control circuit causes the switching circuit to output the first signal having first and second states at the duty cycle. The switching circuit includes a transistor having a control terminal connected to the control circuit. One terminal is connected to the voltage source and another terminal is connected to the electrical path. The second circuit includes a keypad. The flip circuit includes at least one light source to illuminate the keypad. The light source is powered by the first signal during the first state thereof. The second signal is generated by the keypad during the second state of the first signal. The keypad includes a plurality of resistive elements connected in a resistive ladder network. Each resistive element corresponds to a respective key of the keypad. A computer processes the second signal to ascertain which key is depressed.

System and method for providing back-lighting to a keypad

In an embodiment of the present invention, a charge voltage is coupled between the positive and negative terminals of a rechargeable battery, to charge the battery. The charge voltage is disconnected for a predetermined relax time period. A rechargeable battery voltage is present between the positive and negative terminals of the battery during the relax time. The battery voltage is measured and compared to a predetermined target voltage that is associated with a sample time. The comparison is then used to determine if the battery is charged.

Battery charger

A system and a method are provided for bi-directional power conversion in a portable device. The system uses a single inductor to perform both buck and boost power conversion operations and a controller to supply signals to two switches, enabling electric current paths. The system includes a battery connected to ground and to an inductor terminal. The first switch has a terminal connected to a portable device power bus, a second terminal connected to a second inductor terminal, and an input to accept a control signal. The second switch has a terminal connected to the second inductor terminal, a second terminal connected to a portable device ground, and an input to accept a control signal. Controller inputs accept the bus voltage and the battery voltage and outputs supply power conversion control signals to the switches in response to evaluating the bus and battery voltages. The controller supplies buck power conversion control signals to: close the first switch and open the second switch to build up voltage across the inductor to reduce the voltage supplied to the battery by an external power supply connected to the bus; and to open the first switch and close the second switch to discharge the inductor built-up voltage to the battery. The controller supplies boost power conversion control signals to open the first switch and close the second switch to build up voltage across the inductor and to close the first switch and open the second switch to add the inductor built-up voltage to the voltage supplied by the battery to the bus.

System and method for bi-directional power conversion in a portable device

Growing community of inventors

San Diego, CA, United States of America

Larry Bradley