The present invention is a multi-phase method, circuit and system for programming non-volatile memory cells in an NVM array. In one embodiment, a railway car includes an underframe and at least one hopper for transporting lading. The feedback circuit includes a first input coupled to the output of the charge pump, a second input configured to be coupled to a reference signal, an enable input configured to enable and disable the feedback circuit, and a feedback output coupled to the first input of the charge pump. Each adder circuit is coupled to a corresponding bandpass filter circuit which is in turn coupled to a corresponding phase-locked loop circuit. Within the stocker apparatus and the method, the minimum of six inputoutput ports provides for more efficient operation of the stocker apparatus.