Operating a bi-directional double-base bipolar junction transistor (B-TRAN). One example is a method comprising: conducting a first load current from an upper terminal of the power module to an upper collector-emitter of the transistor, through the transistor, and from a lower collector-emitter to a lower terminal of the power module; and then responsive assertion of a first interrupt signal, interrupting the first load current from the lower collector-emitter to the lower terminal by opening a lower-main FET and thereby commutating a first shutoff current through a lower base of the transistor to the lower terminal; and blocking current from the upper terminal to the lower terminal by the transistor.