Abstract: A device (100) includes detachable main and auxiliary batteries (101, 102) and a circuit (310) for discharging and charging the batteries (101, 102). Discharging is accomplished by an auxiliary switch (420) that connects the auxiliary battery (102) to power the device (100), a detector (422), and a main switch (424) that connects the main battery (101) to power the device (100), without interruption, when the auxiliary battery (102) drops below a predetermined voltage (508) as determined by a detector (422). Charging is performed by switches (440, 442, 446), an internal charger (444), and a controller (306). When both batteries (101, 102) are attached, the controller (306) uses the switches (440, 442, 446) to select and couple charging current generated by the internal charger (444) to the main battery (101). Once charged, the controller (306) switches to charge the auxiliary battery (102).

Abstract: A bi-directional voltage translator (102) includes a first port (300/302), a second port (302/300), and a switch circuit (310). The first port (300/302) communicates a first signal at a first voltage or a second voltage (V.sub.1 /V.sub.2). The second port (302/300) communicates a second signal at the first voltage or a third voltage (V.sub.2 /V.sub.1). The second and third voltages (V.sub.1 /V.sub.2) are different. The switch circuit (310) is coupled to the first port (300/302) and the second port (302/300). The switch circuit (310), responsive to the first signal at the first voltage and the second signal at the third voltage (V.sub.2/ V.sub.1), communicates to the second port (302/300) the second signal at the first voltage. The switch circuit (310), responsive to the second signal at the first voltage and the first signal at the second voltage (V.sub.1 /V.sub.2), communicates to the first port (300/302) the first signal at the first voltage.

Abstract: A battery charger (100) includes a charging pocket (112) capable of receiving either a first battery (102) in a first orientation or a second battery (104) in a second orientation. The charging pocket (112) includes a first set of contacts (170) and a second set of contacts (152). The contacts (172-175) of the first set of contacts (170) have a first spacing so as to mate with contacts (187) disposed on the first battery (102) when the first battery (102) is inserted into the charging pocket (112). The contacts (154-157) of the second set of contacts (152) have a second spacing so as to mate with contacts (199) disposed on the second battery (104) when the second battery (104) is inserted into the charging pocket (112). By providing two sets of contacts (170, 152) in a single charging pocket (112), the battery charger (100) can charge batteries (102, 104) having dissimilarly positioned contacts.

Abstract: A battery identification system (100) includes a battery (104), a device (102), and an apparatus (106). The battery (104) is of a particular type (e.g., NiCd, NiMH, Lithium Ion) and is detachably coupled to the device (102). The device (102) includes a controller (112) that determines the type of the battery (104) and generates a number of signals according to the type. The apparatus (106) is detachably coupled to the device (102) and includes a current source (164) and a controller (162) that detects the number of signals. The controller (162), responsive to the controller (112), controls the current source (164) to initially provide charging current at a first rate to the battery (104) until reception of a first one of the number of signals. The controller (162) thereafter identifies the type of the battery (104) from the detection of additional ones of the number of signals.