| 摘要 |
A battery power supply for a portable radio telephone 1, or a portable data communication device (21, Fig.5), has two (or more) battery cells 2a, 2b and switches 14a, 14b, 14c for selectively connecting the cells 2a, 2b in series or parallel. The switches 14a-c may be MOSFETs and may be provided in a battery pack 2 or in the portable device. The cells 2a, 2b are connected in series when the device is in a communication mode and in parallel for standby mode, thus saving battery power. In a TDMA system, the switching of the connection status of the cells 2a, 2b is executed during time slots which are not sent to the portable device. The battery pack 2 may have two positive output terminals 3a, 3b so that when the cells are in series, a transmitter 5a is fed with the voltage of the series connected cells via a further switch 14f and terminal 3a, and a receiver 5b and other circuits are supplied from cell 2b only. The cells may be non-rechargeable or rechargeable, a battery pack for rechargeable cells having charging terminals 15, 16 and the cells 2a, 2b being connected in series in response to the presence of a charging voltage at the terminals 15, 16. Additional switches (14d, 14e, Fig.5) may be provided between the cells and a grounded supply terminal 4 and the negative charging terminal 16 for overcharge and overdischarge protection of the cells. During switching between the series and parallel states, all three switches 14a-c are temporarily simultaneously open to avoid short circuiting of the cells, and a large capacitor 11 supplies the device during such periods. |
