Ink-jet head driving circuit and ink-jet printer with ink-jet head driving circuit

An ink-jet head driving circuit comprising:

• a first PMOS transistor including a first drain terminal, a first source terminal and a first Nwell area, the first drain terminal being connected to a piezoelectric element for jetting ink from a nozzle;
• a second PMOS transistor including a second drain terminal, a second source terminal and a second Nwell area, the second drain terminal being connected to the piezoelectric element;
• and
• an NMOS transistor connected to the first drain terminal of the first PMOS transistor and the second drain terminal of the second PMOS transistor,
• wherein:
• the first source terminal of the first PMOS transistor is connected to a first power source;
• the second source terminal of the second. PMOS transistor is connected to a second power source, voltage of the second power source being higher than voltage of the first power source;
• and
• both the first Nwell area of the first PMOS transistor and the second Nwell area of the second PMOS transistor are connected to the second power source.

An ink-jet head driving circuit comprising:

• a first PMOS transistor including a first drain terminal, a first source terminal and a first Nwell area, the first drain terminal being connected to a piezoelectric element for jetting ink from a nozzle;
• a second PMOS transistor including a second drain terminal, a second source terminal and a second Nwell area, the second drain terminal being connected to the piezoelectric element;
• and
• an NMOS transistor connected to the first drain terminal of the first PMOS transistor and the second drain terminal of the second PMOS transistors,
• wherein:
• the first source terminal of the first PMOS transistor is connected to a first power source;
• the second source terminal of the second PMOS transistor is connected to a second power source;
• both the first Nwell area of the first PMOS transistor and the second Nwell area of the second PMOS transistor are connected to a third power source;
• and
• voltage of the third power source is higher than the first and second power sources.