Design of charge pump with very low conducted emission controlling the majority carrier injection

This work evaluates how reducing the conducted emission of battery line of an alternator regulator by reducing substrate majority carrier injection of a charge pump circuitry. The investigation shows the significant impact of substrate Nwell junction (PN junction) of poly poly capacitors on conducted emission on battery input /output during charge pumping. When Nwell layer of poly-poly capacitors is left open, parasitic Nwell to substrate capacitor will be added to the poly -poly capacitor and increase efficiency of charge pump in term of current delivered at a given voltage. In the other hand this parasitic capacitor will couple the generated noise during switching ON/OFF to charge/discharge the poly-poly capacitor to the substrate. This noise will be conducted to global pins through ESD parasitic capacitor and any other parasitic capacitor between substrate and a global pin. This study will give a solution to improve charge pump capability and at the same time reducing drastically it´s conducted emission.