A battery charging circuit comprising: a semiconductor switch having an output connected to a rechargeable battery; a battery charge controller for receiving power from an external source, and supplying output power to a portable device and the input of the semiconductor switch, the current output of the battery charge controller being controllable; and a voltage sensing circuit for: measuring the voltage drop across the battery charge controller; and responding to the voltage drop across the battery charge controller by modulating the semiconductor switch to reduce the quantity of current supplied to the rechargeable battery when the voltage drop is too great; whereby the total power dissipated by the battery charge controller is controlled, the portable device receiving the power it needs to operate and the rechargeable battery receiving any additional available power.

Circuit and method of operation for an electrical power supply

A wake up circuit according to one embodiment includes a comparison circuit and an output decision circuit. The comparison circuit may be adapted to receive a first signal representative of a charging current level provided to a battery via a path and a second signal representative of a predetermined wake up current level and to provide a comparison output signal in response to the first and second signal. The output decision circuit may be adapted to receive at least the comparison output signal and a selector signal from a selector circuit, the output decision circuit providing one of the comparison output signal and the selector signal to a switch to control a state of the switch, the switch coupled to the path.

Power management topologies

A power management topology for portable electronic devices that includes a feed-enabled AC/DC adapter that receives feedback data from a charge controller associated with the portable device. The feedback data can include battery charging current, battery voltage, or power requirements of the portable device. Using the feedback data, the external AC/DC adapter can adjust the DC output to meet the charging requirement of the battery and/or the power requirements of the portable device.

Power management for battery powered appliances

A system, method and apparatus for charging rechargeable battery packs. A battery charger has a means to measure a voltage and a battery temperature and a means to determine a rate of increase in battery temperature of a rechargeable battery pack. The battery charger to fast charge if the voltage and battery temperature indicate its safe and to terminate the fast charge in response to the charge condition. Methods include measuring a battery temperature of the rechargeable battery pack and determining a rate of increase in battery temperature during fast charging to determine a charge condition, One method further includes terminating fast charging if the rate of increase in battery temperature exceeds a maximum rate or if the increase in battery temperature rises non-logarithmically. Another method further includes terminating fast charging in response to the charge condition.

Methods and apparatuses for rechargeable battery pack chargers

A portable electrical device may include a DC to DC converter coupled to a common node, a load coupled to the common node, and a controller configured to control the DC to DC converter. The DC to DC converter may be configured to provide a charging current to a rechargeable battery from an adapter when the controller operates said DC to DC converter in a first adapter supply mode. The DC to DC converter may be configured to provide a battery supply current to the load via the common node when the controller operates the DC to DC converter in a second adapter supply mode. The adapter supply current and the battery supply current may add together at the common node to simultaneously provide a load supply current to the load in the second adapter supply mode.

Parallel powering of portable electrical devices

A circuit and method for charging batteries while a power supply also powers a dynamically varying load. All power in excess of that required by the load is used by a power converter to charge the batteries. The circuit advantageously allows the load to change from external power to battery power without switching delays.

Richard A. Faulk

Papers

Battery charge control architecture for constant voltage maximum power operation