Level shifter, controller, and dc-to-dc converter

A controller comprising:

• a level shifter including:
• a current generator connected between a first high potential terminal and a first low potential terminal and configured to generate a first current at a first output line;
• a current switch connected between a second high potential terminal and a second low potential terminal and configured to receive the first current with a larger current supply capacity than the current generator and pass the first current or cut off the first current in accordance with an input signal;
• and
• a protection circuit connected to the first output line between the current generator and the current switch and configured to limit an electric potential of the first output line to not less than an electric potential of the first low potential terminal and not more than an electric potential of the first high potential terminal;
• a PWM circuit connected between the second high potential terminal and the second low potential terminal and configured to produce a PWM signal as the input signal of the level shifter;
• a first switch element connected to the first output line of the level shifter and configured to be controlled to ON or OFF based on an electric potential of the first output line;
• and
• a second switch element connected in series to the first switch element and configured to be controlled to ON or OFF by the PWM circuit.

A DC-DC converter comprising:

• a controller including:
• a level shifter including:
• a current generator connected between a first high potential terminal and a first low potential terminal and configured to generate a first current at a first output line;
• a current switch connected between a second high potential terminal and a second low potential terminal and configured to receive the first current with a larger current supply capacity than the current generator and pass the first current or cut off the first current in accordance with an input signal;
• and
• a protection circuit connected to the first output line between the current generator and the current switch and configured to limit an electric potential of the first output line to not less than an electric potential of the first low potential terminal and not more than an electric potential of the first high potential terminal;
• a PWM circuit connected between the second high potential terminal and the second low potential terminal and configured to produce a PWM signal as the input signal of the level shifter;
• a first switch element connected to the first output line of the level shifter and configured to be controlled to ON or OFF based on an electric potential of the first output line;
• and
• a second switch element connected in series to the first switch element and configured to be controlled to ON or OFF by the PWM circuit;
• an inductor, one end of the inductor being connected to a connection point between the first switch element and the second switch element;
• a smoothing capacitor connected between another end of the inductor and the first low potential terminal or the second low potential terminal;
• and
• a detector connected in parallel to the smoothing capacitor and configured to detect an electric potential of the other end of the inductor and feed it back to the controller.