Patent ID: 7692416

Claim:
A voltage up and down synchronization and rectification type DC-DC converter for going up and down an input voltage using an inductor, said voltage up and down synchronization and rectification type DC-DC converter comprising: a control circuit configured to output a control signal; a voltage up and down use rectification circuit configured to operate in accordance with the control signal, said voltage up and down use rectification circuit including a pair of PMOS and NMOS transistors connected in parallel to each other; and a driving device configured to turn on the NMOS transistor and turn on and off the PMOS transistor when an input voltage goes up, said driving device turning on at least the NMOS transistor when an input voltage goes down, wherein said driving device includes: a first driving member configured to cause a gate voltage of the NMOS transistor to be a high level lower than the input voltage both of when an input voltage goes up and the NMOS transistor is turned on, and when an input voltage goes down, said first driving member causing the gate voltage of the NMOS transistor to be a low level when an input voltage goes up and the NMOS transistor is turned off; and a second driving member configured to cause a gate voltage of the PMOS transistor to be a low level both of when an input voltage goes up and the PMOS transistor is turned on and when an input voltage goes down, said second driving member causing the gate voltage of the PMOS transistor to be a high level lower than the output voltage when an input voltage goes down and the PMOS transistor is turned off.