| 摘要 |
PURPOSE: A step-up/step-down dc-dc converter and a vehicle lamp are provided to suppress discontinuous control points when switching between a voltage dropping mode and a voltage boosting mode is generated, thereby preventing influences of feature changes of a circuit part. CONSTITUTION: A voltage dropping unit(2) outputs an output voltage lower than an input voltage. The voltage dropping unit includes a voltage dropping switch(SW1), a condenser(C1), a diode(D1), and a choke coil. A voltage boosting unit(3) outputs an output voltage which is higher than an input voltage. The voltage boosting unit includes a voltage boosting switch(SW2), a condenser(C2), and a diode(D2), a controller(4) includes an error unit(5), a saw tooth wave generating unit(6), and a driving pulse generating unit(7).
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