A charge/discharge switch control circuit 202 for a battery pack 200 includes a set of driving terminals 212, 216 and detection circuitry coupled to the driving terminals 212, 216. The driving terminals 212, 216 provide driving signals to control a status of a switch circuit QCHG, QDSG to enable charging or discharging of the battery pack 200. The detection circuitry receives voltages at multiple terminals 210, 214, 218 of the switch circuit QCHG, QDSG, and detects a status of an interface PACK+, PACK-of the battery pack 200 according to the status of the switch circuit QCHG, QDSG and a difference between the voltages by comparing the difference to a reference 224 using a comparator 226. In this way the presence of a charger at the pack interface PACK+, PACK- can be detected. By using a capacitor (336, figure 3) the presence of a load at the pack interface PACK+, PACK- can also be detected. The interface PACK+, PACK- can receive power to charge the battery pack 200 and provide power from the battery pack 200
