Switched-mode power converter with a current limit circuit

A switched-mode power converter comprising

• a feedback loop for controlling the output voltage of the switched-mode power converter;
• a first voltage comparison unit within the feedback loop configured to compare a voltage indicative of the output voltage with a reference voltage and to output an error voltage based on the comparison;
• a current control unit for limiting an output current at the output of the switched-mode power converter, the current control unit comprising
• a current comparison unit configured to compare the output current with a current threshold and to output an intermediate voltage based on the comparison, and
• a connection unit connected to the output of the current comparison unit and configured to connect, in case the output current exceeds the current threshold, the output of the current comparison unit to the output of the first voltage comparison unit;
• wherein the current comparison unit comprises a voltage clamp whose output is connected to the output of the current comparison unit and the current comparison unit is configured to adjust the intermediate voltage based on a clamp reference voltage at an input of the voltage clamp, and wherein the current control unit is configured to adjust, by adjusting the clamp reference voltage, the intermediate voltage such that an over-shoot of the output current is minimized.

A method for limiting an input current into a switched-mode power converter, the method comprising:

• comparing a voltage indicative of the output voltage of the switched-mode power converter with a reference voltage in a feedback loop for controlling the output voltage of the switched-mode power converter;
• determining, at an output of a first voltage comparison unit, an error voltage based on said comparing;
• comparing an input current into the switched-mode power converter with a current threshold;
• determining, at an output of a current comparison unit, an intermediate voltage based on said comparing the input current;
• connecting, in case the input current exceeds the current threshold, the output of the current comparison unit to the output of the first voltage comparison unit to apply the intermediate voltage to the error voltage;
• and
• wherein the current comparison unit comprises a voltage clamp whose output is connected to the output of the current comparison unit and the current comparison unit adjusts the intermediate voltage based on a clamp reference voltage at an input of the voltage clamp;
• and wherein the intermediate voltage is adjusted, by adjusting the clamp reference voltage, such that an over-shoot of the input current is minimized.

A method for limiting an output current at the output of a switched-mode power converter, the method comprising:

• comparing a voltage indicative of the output voltage of the switched-mode power converter with a reference voltage in a feedback loop for controlling the output voltage of the switched-mode power converter;
• determining, at an output of a first voltage comparison unit, an error voltage based on said comparing;
• comparing an output current at the output of the switched-mode power converter with a current threshold;
• determining, at an output of a current comparison unit, an intermediate voltage based on said comparing the output current;
• and
• connecting, in case the output current exceeds the current threshold, the output of the current comparison unit to the output of the first voltage comparison unit for applying the intermediate voltage to the error voltage;
• wherein the current comparison unit comprises a voltage clamp whose output is connected to the output of the current comparison unit and the current comparison unit adjusts the intermediate voltage based on a clamp reference voltage at an input of the voltage clamp;
• and wherein the intermediate voltage is adjusted, by adjusting the clamp reference voltage, such that an over-shoot of the input current is minimized.