High-efficiency bidirectional voltage boosting device

A method for boosting a voltage at an input of a voltage boosting device having a phase generator stage generating phase signals, and a charge pump circuit having an input and an output, and phase inputs receiving said phase signals, said charge-pump circuit comprising a plurality of voltage boosting stages cascade connected between said input and said output, each voltage boosting stage defining a first and a second transfer node connected to a respective adjacent voltage boosting stage, each voltage boosting stage comprising a storage capacitor with a first and a second terminal, said first terminal of said storage capacitor receiving a first one of said phase signals, and said second terminal of said storage capacitor connected to said second transfer node;

• a switch element formed by an NMOS transistor interposed between said first and second charge transfer nodes and having a control terminal;
• a voltage boosting capacitor having a first terminal receiving a second one of said phase signals, and a second terminal connected to said control terminal of said switch element;
• the method comprising:
• selectively enabling a first or a second precharge circuit connected to said control terminal of said switch element, thereby selectively controlling transfer of electric charges from said first to said second transfer node, and transfer of electric charges from said second to said first transfer node.

A voltage boosting circuit, comprising:

• a plurality of voltage boosting stages connected in cascade, each voltage boosting stage connected to adjacent stages by first and second transfer nodes;
• each voltage boosting stage comprising a switch element with a first terminal coupled to the first transfer node, a second terminal coupled to a second transfer node, and a control terminal;
• a first precharge circuit comprising a first terminal coupled to the first transfer node, a second terminal coupled to the control terminal of the switch element, and a control terminal coupled to a first activation signal source, the first precharge circuit configured to control charge transfer from the first transfer node to the second transfer node in response to a first activation signed from the first activation signed source;
• and
• a second precharge circuit comprising a first terminal coupled to the second transfer node, a second terminal coupled to the control terminal of the switch element, and a control terminal coupled to a second activation signal source, the second precharge circuit configured to control charge transfer from the second transfer node to the first transfer node in response to a second activation signed from the second activation signed source.