A method for generating from a single supply voltage Vdd output voltages in three modes by a charge pump, comprising the following steps: providing an input voltage Vdd and a charge pump circuit, having a positive and a negative output port, comprising a digital controller, a set of eight switches (S1-S8), only one flying capacitor, and two reservoir capacitors (3, 4); setting output voltage modes desired on the digital controller, wherein the possible output modes comprise doubler, inverter, or half the input supply voltage; setting switches (S1-S8) in order to put voltages on the flying capacitor and on the output ports (CSP, CSN) according to a switching sequence and phases required for the output mode selected wherein the switching sequences comprise two phases, wherein - In doubler mode in phase 1 the flying capacitor Is charged to Vdd voltage level and the negative output port Is set to ground; and in phase 2 the flying capacitor Is coupled in series between the positive output port and Vdd voltage level, thus achieving a double Vdd voltage level at the positive output port (CS P), - in inversion mode in phase 1 the flying capacitor is charged to Vdd voltage level and the positive output port is set to ground; and In phase 2 the flying capacitor is coupled between ground voltage level and the negative output port, thus achieving an inverted Vdd voltage level at the negative output port, and In half mode in phase 1 a top plate of the flying capacitor is connected to VDD and a bottom plate is connected to the positive output port; and phase 2 said top plate Is connected to ground, and said bottom plate is connected to the negative output port check If the charge pump is still on, if it so, the process flow goes to step, else the process flow goes to step 7; check if the process will be continued with the actual output voltage mode, if it so, the process flow will go back to step, else the process flow goes to step; setting output voltage mode as required and go to step; and end of operation. providing an input voltage Vdd and a charge pump circuit, having a positive and a negative output port, comprising a digital controller, a set of eight switches (S1-S8), only one flying capacitor, and two reservoir capacitors (3, 4); setting output voltage modes desired on the digital controller, wherein the possible output modes comprise doubler, inverter, or half the input supply voltage; setting switches (S1-S8) in order to put voltages on the flying capacitor and on the output ports (CSP, CSN) according to a switching sequence and phases required for the output mode selected wherein the switching sequences comprise two phases, wherein - In doubler mode in phase 1 the flying capacitor Is charged to Vdd voltage level and the negative output port Is set to ground; and in phase 2 the flying capacitor Is coupled in series between the positive output port and Vdd voltage level, thus achieving a double Vdd voltage level at the positive output port (CS P), - in inversion mode in phase 1 the flying capacitor is charged to Vdd voltage level and the positive output port is set to ground; and In phase 2 the flying capacitor is coupled between ground voltage level and the negative output port, thus achieving an inverted Vdd voltage level at the negative output port, and In half mode in phase 1 a top plate of the flying capacitor is connected to VDD and a bottom plate is connected to the positive output port; and phase 2 said top plate Is connected to ground, and said bottom plate is connected to the negative output port - In doubler mode in phase 1 the flying capacitor Is charged to Vdd voltage level and the negative output port Is set to ground; and in phase 2 the flying capacitor Is coupled in series between the positive output port and Vdd voltage level, thus achieving a double Vdd voltage level at the positive output port (CS P), - in inversion mode in phase 1 the flying capacitor is charged to Vdd voltage level and the positive output port is set to ground; and In phase 2 the flying capacitor is coupled between ground voltage level and the negative output port, thus achieving an inverted Vdd voltage level at the negative output port, and check If the charge pump is still on, if it so, the process flow goes to step, else the process flow goes to step 7; check if the process will be continued with the actual output voltage mode, if it so, the process flow will go back to step, else the process flow goes to step; setting output voltage mode as required and go to step; and end of operation.