GB2473524A

GB2473524A - Portable power supply

Info

Publication number: GB2473524A
Application number: GB1011335A
Authority: GB
Inventors: Paul Amsallem
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-07-06
Filing date: 2010-07-06
Publication date: 2011-03-16
Also published as: GB0911659D0; GB201011335D0

Abstract

A portable power supply for charging or operating portable electronic devices comprises an energy converter such as a solar panel 8 to convert energy from a non-electrical energy source into electrical energy; an energy store such as rechargeable batteries 22 to store the electrical energy and a power outlet 12 to provide power to a portable electronic device. The re-chargeable batteries may be a standard size, removable from the charging unit for use in the portable device and in a user-accessible battery compartment. Converted electrical energy can be diverted between the store and the outlet depending on the current drawn and the available current from the power converter. A power inlet 10 can be connected to charge the energy store. The voltage available at the outlet can be selected by a user or the power outlet can be a USB socket providing a fixed voltage.

Description

Power Supplies This invention relates to electrical power supplies, particularly those which are suitable for operating or recharging portable electronic devices.

There is an ever increasing use of portable electronic devices. In the developed world the average number of devices owned by each particular is increasing.

Moreover there is expanding ownership of portable electronic devices by those in the developing world, often in rural or remote locations, which may not have access to reliable mains electricity supplies. The problem of being able to keep such devices charged is tending to grow rather than diminish.

There are available on the market various designs of solar panel chargers which can be used for providing some small top-up charge for mobile devices, but the practical requirement to keep these small and light so as to make them a practical prospect for carrying together with a mobile device places a significant limitation on the usefulness of such chargers and they have remained a niche product used mainly for providing a small amount of emergency charge.

It is an aim of the present invention to take a different approach and to tackle different needs.

When viewed from a first aspect the invention provides a portable power supply for charging or operating portable electronic devices, said power supply comprising conversion means for converting energy from an available non-electrical energy source into electrical energy, storage means for storing said electrical energy and power outlet means for providing electrical power to a portable electronic device.

Thus it will be seen by those skilled in the art that in accordance with the invention there is provided a power supply which can be used to charge or operate portable devices which is itself also portable. This means that such devices can be operated or charged when there is no mains electricity available. Furthermore, by being able to store as electrical energy, energy converted from the non-electrical source, the power supply can be used even when the non-electrical energy source is not available.

The non-electrical energy source could take any of a number of possible forms. For example, it could comprise a generator connected to a handle or the like for manual operation by a user. Another possibility would be a miniature fuel cell. In a set of currently preferred embodiments however the energy source is solar energy and thus the conversion means comprises a solar panel for converting solar energy into electrical energy. As mentioned above, the ability to store electrical energy means that unlike conventional solar chargers, the power supply described herein can be used to charge or operate portable electronic devices even when there is insufficient solar energy to do so directly. Thus, the power supply can be "charged" when it is sunny and this can then be used to charge the portable electronic device whenever necessary.

The means for storing electrical energy could take a number of forms, e.g. capacitors, but preferably it comprises one or more rechargeable batteries. In a convenient set of embodiments, the rechargeable battery or batteries is/are removable from the charging unit and preferably of a standard international size such as AA. This allows the battery(ies) to be removed from the charging unit and used in electronic devices which do not necessarily themselves have the ability for recharging them. It also allows replacement of the rechargeable battery(ies) when it or they reach the end of their design life and so begin to become less efficient. IN a set of preferred embodiments therefore the power supply comprising a user-accessible battery compartment.

The charging unit could be arranged such that the electrical energy converted from the energy source is always stored in the storage means and the portable electronic device is always powered or charged from the storage means. Preferably, however, the electrical energy converted from the energy source is available to charge or operate the portable device directly if required. This could be under user control, but in a set of preferred embodiments the charging unit is arranged to direct the converted electrical energy to the storage means and/or the power outlet automatically depending upon the current drawn from the power outlet and the current available from the energy conversion means. This provides the unit with maximum flexibility so that the electrical energy available from the power source can either all be used to charge or operate the portable device, or some of it can be stored in the storage means to recharge the internal batteries thereof. In a preferred subset of such embodiment, the storage means is arranged so that it can supply power to the power outlet even when the power available from the non-electrical energy source (e.g. the solar panel) is at a maximum. Thus, the internal storage means allows more power than would be available from the energy source (e.g. solar panel) alone which further increases the flexibility of its possible applications.

It will be seen that particularly in the preferred embodiment, the power supply described herein provides a highly useful and flexible power supply which makes it a viable alternative to a reliable mains electricity supply since it is not restricted by the times of availability or amounts of power available from an energy source such as the sun. For example, in one embodiment the solar panel can be used to charge the internal batteries and then the internal batteries and the solar panel can be used simultaneously to provide enough power to operate or recharge a laptop computer.

This would simply not be possible with current designs of portable solar panel rechargers.

In a set of preferred embodiments, the charging unit further comprises an electrical power inlet which can be or is connected to the storage means, thereby allowing power from the inlet to be stored in the storage means. It will be appreciated that the provision of a power inlet further enhances the flexibility of the unit since it allows for example additional solar panels to be added to provide more power or it allows the internal batteries to be recharged when an electrical power source such as a mains outlet or a car battery is available.

In accordance with a preferred set of embodiments, the voltage available at the power outlet means is selectable by a user. This could be by means of a switch, by means of a plurality of discrete leads or sockets or a combination of these. In a preferred set of embodiments, the power outlet means comprises a USB socket.

This is particularly convenient for connection to a portable computer and to operate any of a large number of devices which are now available which draw electrical power from a USB socket.

When viewed from a further aspect, the invention provides a portable power supply for charging or operating portable electronic devices, said power supply comprising energy conversion means for converting an available non-electrical energy source into electrical energy, power outlet means for providing electrical power to a portable electronic device and means for varying the voltage at which said power outlet means provides power.

Although not essential, in preferred embodiments of this aspect of the invention the charging unit comprises storage means for storing said electrical energy, e.g. one or more rechargeable batteries.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a power supply in accordance with the invention; and Fig. 2 is a circuit diagram of the power supply.

Fig. 1 shows a perspective view of a portable power supply unit 2 in accordance with an embodiment of the invention. The unit comprises a base portion 4 and a hinged lid part 6. Each of these comprises a solar panel 8 occupying most of the respective surface area. However, at the front of the base portion 4 is a user interface panel comprising two jack sockets 10,12; two LED indicators 14,16; and two switches 18,20.

The leftmost jack socket 10 is a power inlet for connection to an auxiliary power source as will be described in greater detail later. The jack socket 12 on the right hand side is a power outlet for connection to a portable electronic device in order to recharge the battery in such a device. The two LED indicators 14 and 16 are each variable colour (red/green) LED indicators used to indicate various operational states of the unit as will be described later. Each comprises independently operable red and green LEDs in a common package. The switch 18 is a simple on/off switch and the other switch 20 is a voltage selector switch for selecting the voltage output at the power outlet 12.

Fig. 2 shows a schematic diagram of the power supply. At the top left corner of the diagram is represented the power inlet jack socket 10. Connected in parallel with this are the two solar panels 8, although these connections are not shown on the schematic diagram..

Also visible near the top of the diagram is the on/off switch 18 which can be used to turn the power supply on or off. Also in parallel with the power input jack 10 except for the provision of a protective diode Di, is a set of rechargeable batteries 22.

Although not shown, in the preferred embodiment these are standard size, e.g. AA nickel cadmium or other rechargeable batteries and housed in a user-accessible compartment on the underside if the unit to facilitate removal and replacement by a user. A double voltage comparator arrangement comprising comparators U3A and U3B is shown for giving an indication of the charging voltage across the batteries 22. The outputs of the comparators U3A, U3B are connected respectively to the red and green LEDs 1 4a, 1 4b of one of the front panel indicators 14. The comparators U3A, U3B are configured identically, except in reverse to one another, so that if the charging voltage across the battery is below a threshold (indicating that charging is not taking place, the red LED 14a will be lit, whereas if the voltage is above the threshold, the green led 1 4b will be lit.

A voltage regulator comprising two integrated circuits U5, U2 and associated discrete components Ci, C2, C3, C5, R9, Ri 2 and Ri 3 is provided and is controlled by the multi-position switch 20 in conjunction with a series of resistors of different values Ri to R8 to provide a variable output voltage regulated power supply to the output jack 12. The integrated circuit U5 and U2 is an LTC1 871 from Linear Technology.

A further pair of comparators U4A, U4B are used to indicate whether the level of battery charge is sufficient to give the voltage selected from the selector switch 20.

A Zener diode D5 is used to provide a reference voltage for the comparison. The comparators U4A, U4B are connected to the red and green LEDs i6a, i6b of the other dual colour indicator 16 on the front panel. Thus, the red LED 1 6a is lit if there is insufficient power in the batteries 22 to operate the power supply and the green LED 1 6b is lit if there is sufficient power.

In operation of the unit 2, the lid 6 can be opened to expose the two solar panels 8 whenever sunlight is available. Even if power is not required at that particular time, this will recharge the internal batteries 22 so that the unit is ready for use when sunlight is no longer available. While the batteries 22 are being charged, the charge indicator 14 is illuminated green since the green LED element 14b is powered. Either in addition to charging by means of the solar panels 8, or instead, power may be supplied through the jack socket 10 to charge the batteries 22. For example even when sunlight is available, an external supply allows the batteries to be charged more quickly. Any DC power source of suitable voltage can be connected to the power input 10 such as an additional solar panel, a mains power adaptor or a car power outlet connector. The battery 22 can be charged regardless of whether or not the unit is switched on by means of the on/off switch 18.

When it is desired to operate or recharge a portable electronic device, the device may be connected to the unit 2 by means of the power outlet socket 12. A number of different leads could be provided for connection to the outlet socket 12 for connection to a wide variety of electronic devices. One particularly useful example is a lead having at the other end an in-line USB socket to allow power to be supplied to any device which is designed to derive power from a USB connection.

In another embodiment, not shown, a plurality of different sockets could be provided for connection to different devices and these could either be supplied at a fixed or variable voltage. For example, a USB socket might be provided with a fixed 5 volt power supply with standard coaxial power connector might be able to supply a variety of different voltages. The switch 20 is used to select the voltage at which the power is supplied. This could provide any convenient series of voltages e.g. 4� volts, 5 volts, 5� volts, 6 volts, 7 volts, 9 volts, 10 volts and 12 volts. Power can be supplied by means of the power outlet 12 regardless of whether sunlight is available or whether an external power source is available so long as the internal batteries 22 have been charged. However, if a higher current supply is required, then an external power source may be connected to the input 10 and/or the solar panels 8 placed in sunlight so that the instantaneous power available either from the external power source and/or the solar panels 8 can be supplemented by the power supplied by the batteries 22.

In this embodiment, as in other preferred embodiments, the rechargeable batteries are of standard size and accessible through a user accessible compartment. Thus, another way of using the device would be to remove the rechargeable batteries once they have been charged and install them directly in an electronic device. It is even envisaged that the portable power supply unit 2 could be used simply for its voltage regulator by installing standard, non-rechargeable batteries into the battery compartment and using these, for example as an emergency measure, to recharge a portable electronic device, although steps would need to be taken within the circuitry to prevent the standard batteries from receiving current from the solar panels and/or the external power source in order to prevent inadvertent attempts to recharge them.

Thus it will be seen that in at least the preferred embodiments described above, a highly versatile and useful portable power supply unit has been described.

Claims

Claims: 1. A portable power supply for charging or operating portable electronic devices, said power supply comprising conversion means for converting energy from an available non-electrical energy source into electrical energy, storage means for storing said electrical energy and power outlet means for providing electrical power to a portable electronic device.
2. A portable power supply as claimed in claim 1 wherein the conversion means comprises a solar panel for converting solar energy into electrical energy.
3. A portable power supply as claimed in claim 1 or 2 wherein the means for storing electrical energy comprises one or more rechargeable batteries.
4. A portable power supply as claimed in claim 3 wherein the rechargeable battery or batteries is/are removable from the charging unit.
5. A portable power supply as claimed in claim 3 or 4 wherein the battery or batteries is/are of a standard international size.
6. A portable power supply as claimed in any preceding claim comprising a user-accessible battery compartment.
7. A portable power supply as claimed in any preceding claim which is arranged such that the electrical energy converted from the energy source is available to charge or operate the portable device directly if required.
8. A portable power supply as claimed in claim 7 which is arranged to direct the converted electrical energy to the storage means and/or the power outlet automatically depending upon the current drawn from the power outlet and the current available from the energy conversion means.
9. A portable power supply as claimed in claim 8 wherein the storage means is arranged so that it can supply power to the power outlet even when the power available from the non-electrical energy source is at a maximum.
10. A portable power supply as claimed in any preceding claim further comprising an electrical power inlet which can be or is connected to the storage means.
11. A portable power supply as claimed in any preceding claim wherein the voltage available at the power outlet means is selectable by a user.
12. A portable power supply as claimed in any preceding claim wherein the power outlet means comprises a USB socket.
13. A portable power supply for charging or operating portable electronic devices, said power supply comprising energy conversion means for converting an available non-electrical energy source into electrical energy, power outlet means for providing electrical power to a portable electronic device and means for varying the voltage at which said power outlet means provides power.
14. A portable power supply as claimed in claim 14 comprising storage means for storing said electrical energy.