An improved external charger for an implantable medical device is disclosed in which charging is at least partially controlled based on a sensed pressure impingent on its case, which pressure is indicative of the pressure between the external charger and a patient's tissue. The improved external charger includes pressure detection circuitry coupled to one or more pressure sensors for controlling the external device in accordance with the sensed impingent pressure. The sensed pressure can be used to control charging, for example, by suspending charging, by adjusting a maximum set point temperature for the external charger based on the measured pressure, or by issuing an alert via a suitable user interface. By so controlling the external charger on the basis of the measured pressure, the external charger is less likely to create potentially problematic or uncomfortable conditions for the user.