ACCUMULATOR DEVICE FOR AN ELECTRICAL AND/OR ELECTRONIC APPARATUS AND TELECOMMUNICATION TERMINAL COMPRISING SUCH A DEVICE

Abstract: This accumulator device for an apparatus intermittently operating between a standby state and an active state, comprises: a first accumulator (10) of the lithium type and a second accumulator (11) of the lead-acid type capable of rapidly supplying energy; a connection circuit (20, 21, 25, 26, 28) for connecting the accumulators to said apparatus, comprising switch elements (20, 25); a control circuit (40) of said switch elements for connecting the second accumulator to the apparatus during the active state.

Description: Accumulator device for an electrical and/or electronic apparatus and telecommunication terminal comprising such a device FIELD OF THE INVENTION The invention relates to an accumulator device for an apparatus intermittently operating between a standby state and an active state, comprising: at least a first accumulator assembly formed by at least one accumulator element, at least a second accumulator assembly formed by at least one accumulator element. The invention also relates to a telecommunication terminal comprising such a device. Such a device finds highly significant applications, notably for telecommunication apparatus such as terminals for cordless telephone, GSM, ... , and so on. BACKGROUND OF THE INVENTION A device of this type is described in European Patent No. 0 688 082. This document proposes to extend a main accumulator by a back-up accumulator so that, when the main accumulator is discharged, it can be exchanged without data being lost, because the energy of the back-up accumulator is sufficient for maintaining them. The invention proposes a device of this type which may provide the back¬ up function, but which is rather adapted to the apparatus operating intermittently. This is notably the case with terminals of the GSM network which, when they are communicating, work only one eighth of the time. SUMMARY OF THE INVENTION Therefore, such a device is characterized in that it furthermore comprises: a connection circuit for connecting said assemblies to said apparatus which comprises at least one switch element, a control circuit of said switch elements for connecting said second assembly to said apparatus during the active state. BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. In the drawings: Fig. 1 shows a terminal according to the invention, Fig. 2 shows a GSM frame, and Fig. 3 shows a device according to the invention. DESCRIPTION OF PREFERRED EMBODIMENTS The terminal shown in Fig. 1 is a GSM terminal, for example. It comprises a casing 1 on which are provided a microphone 2, a screen 3, a keypad 4, an earpiece 5 and an antenna 6. For supplying power to this device, it includes two accumulator assemblies 10 and 11. The accumulator 10 is the main accumulator which forms what may be called the pack battery and the accumulator 11 is placed inside the casing 1 and forms an auxiliary accumulator represented in a dashed line in the Figure. The terminal concerned can only transmit in time slots ... TI , T2, T3, ... provided in a time frame generated by the GSM transmission system. This time frame is represented in a diagrammatic form in Fig. 2. These time slots ... TI, T2, T3, ... are separated by seven time slots during which the terminal is in the state of rest. According to the invention, the power to the terminal is supplied by the auxiliary accumulator during the time slots ... TI, T2, T3, .... The device that provides this power supply is shown in Fig. 3. The accumulator 10 may be formed by an assembly of accumulator elements of the lithium type which may contain much energy but which cannot rapidly restore the energy in their charging circuit. The accumulator 11 may be formed by an assembly of accumulator elements of the lead-acid type as described in United States Patent No. 5,047,300. This type of accumulator is well adapted to rapid discharges in their charging circuit. These two accumulators 10 and 11 are connected by a connection circuit formed by: a first series combination of a switch circuit 20 and a charging circuit 21 which interconnects the accumulators 10 and 11, - a first series combination of a switch circuit 20 and a charging circuit 21 which interconnects the accumulators 10 and 11, a second series combination of a second switch circuit 25 and a converter 26 for adapting the voltage produced by the accumulator 11 with the voltage required by the terminal across its power supply terminal 27, and a connection 28 which directly connects the accumulator to the load. The circuit 21 may be formed by a simple wire, or also a circuit which regulates the load of the assembly 11. Reference 30 indicates in this figure the electronic circuit of this terminal. In this circuit 30, a signal is derived which is active during said time slots ... TI, T2, T3, ... , notably coming from a microprocessor 35 which manages the transmission time. Based on this signal, a control circuit 40 supplies control signals to the switch elements 20 and 25 in the following manner. When the terminal is in the state of rest, it is directly fed by the accumulator 10 and the switch element 20 is closed, so that the charging of the accumulator 11 is ensured. The switch element 25 is open. When the terminal is in the active state, it is fed by the converter 26 which supplies the required voltage by obtaining the energy in the accumulator 11. The switch element 20 is open so that the accumulator 11 is separated from the accumulator 10. The switch element 25 is then closed. The voltage supplied by the converter 26 starts to assist accumulator 10. As a variant, it is also possible to replace a connection 28 by a connection 28' shown in a dashed line. This connection comprises a switch element 42 which disconnects this link under the control of the circuit 40 during the active states. Therefore, the switch element 42 is put in the open position. The switch elements may be formed by a series and/or parallel assembly of accumulator elements, whereas the switch elements 20, 25, 42 may be MOS-type solid- state switches. The accumulator may be constituted by (a) high-capacity condenser(s).

Claims: CLAIMS: 1. An accumulator device for an apparatus intermittently operating between a back-up state and an active state, comprising: at least a first accumulator assembly formed by at least one accumulator element, - at least a second accumulator assembly formed by at least one accumulator element, characterized in that it further comprises: a connection circuit for connecting said assemblies to said apparatus which comprises at least one switch element, a control circuit of said switch elements for connecting said second assembly to said apparatus during the active state. 2. An accumulator device as claimed in claim 1, characterized in that said control circuit connects to said second assembly during the state of rest. 3. An accumulator device as claimed in claim 1 , characterized in that said control circuit isolates the first accumulator assembly of the device during the active state. 4. An accumulator device as claimed in one of the claims 1 to 3, characterized in that the first accumulator assembly is of the lithium type. 5. An accumulator device as claimed in one of the claims 1 to 3, characterized in that the second accumulator assembly is of the lead-acid type. 6. An accumulator device as claimed in one of the claims 1 to 5, characterized in that at least one of the accumulators is constituted by a condenser. 7. A terminal comprising an accumulator device as claimed in one of the claims 1 to 5.

Inventors: VAN LERBERGHE STEVEN, VAN LERBERGHE, STEVEN
Applicants: LERBERGHE STEVEN VAN, PHILIPS ELECTRONICS NV, PHILIPS ELECTRONICS N.V., VAN LERBERGHE, STEVEN
Application year: 1997
Main classification: H02J9
IPC codes: H02J7, H02J9, H04B1