A high efficiency power supply for producing two regulated output voltages (i.e. 3.3 and 5 volts) from an unregulated input voltage. The supply includes a 4-15 volt battery pack, a first (5.0 volt) output, a second (3.3 volt) output, and a ground. The positive terminal of the battery is connected directly to the second output. The 3.3 volt differential with ground is maintained by a voltage regulator that couples the negative terminal of the battery pack to ground (i.e. ground floats relative to the battery). A second voltage regulator couples the positive terminal of the battery pack to the first output, and maintains this first output at 5.0 volts relative to ground. This latter regulator is capable of boost operation, permitting a 5.0 volt output to be maintained even if the battery pack voltage is less than this value. Neither regulator includes a transformer, making the supply particularly well suited for use in miniaturized equipment, such as palmtop computers.

Dual voltage power supply

A controller executes local generation and local consumption pathways of: supplying power from a solar cell to an appliance, and charging a storage cell with power that remains after subtracting power consumed by the appliance from the solar cell power. In the absence of excess power, the storage cell and solar cell supply power. Power supply from a commercial electrical grid covers a power shortage that remains after subtracting solar cell power and storage cell power from the power consumed by the appliance. The controller also executes a second excess power selling mode pathway wherein excess power flows into the commercial electrical grid, and an assist mode wherein all solar cell power flows into the commercial electrical grid, and storage cell power flows to the appliance.

Power supply system.

A computer monitor for allowing the easy connection of computer peripherals thereto, and supplying a power supply voltage from an internal power supply therein to the computer peripherals via universal serial bus hubs. The monitor has a power supply for converting externally applied AC power into DC power; and a universal serial bus hub having at least one upstream port and at least two downstream ports; wherein the upstream port is electrically connected in communication with the computer system, and the downstream ports receive DC power in response for a power switching signal in accordance with power supply control information from the computer system through the upstream port to selectively provide the DC power to external devices connected therewith in response to the power switching signal.

Monitor for use with computer system and method of controlling supply of power to computer peripherals connected with the monitor

When the contacts are electrically disconnected under a condition where a handset is set in a concave of a charging stand, the output of a connection condition detecting circuit is of low level Then, an inverted output thereof, that is, a high-level output is provided through an inverter to one input terminal of an AND circuit, and a switch is closed by the weight of the handset, so that a high-level output is provided also to the other input terminal of the AND circuit Then, a logical product output of the AND circuit is of high level As a result, a warning buzzer generates a warning sound to attract the user's attention

Cordless telephone set having a warning signal representing that a storage battery is not being charged

An electrical power management system for supplying power to a computer peripheral having a relatively high intermittent power demand, such as a packet-switched data radio. A first self-contained rechargeable power supply, outputting power appropriate for the electrical appliance, stores electrical energy and supplies power to the appliance. A second self-contained rechargeable power supply stores electrical energy and supplies electrical power to intermittently recharge the first power supply. The first and the second power supplies can be such self-contained units as single or multicell batteries or capacitors. Preferably, the first power supply is a battery or a capacitor and the second power source is an internal power supply of a portable personal computer.

Portable computer/radio power management system

A plurality of voltage regulator circuits are connected to a battery for producing regulated positive and negative output voltages of different values. A warning circuit is provided for causing a light emitting diode to blink when the battery voltage falls below a first value. An automatic shutdown circuit is provided for disabling the regulator circuits when the battery voltage falls below a second and lower value. An overload circuit is provided for rapidly blowing a protective fuse when the output voltage of one of the regulator circuits exceeds a desired value.

H Carcia

Papers

Direct-current power supply system