Voltage regulator

A voltage regulator for converting an input voltage fed to a power-supply input terminal into a regulated voltage equal to a command level, and outputting the regulated voltage via a power-supply output terminal, the voltage regulator comprising:

• a voltage detection circuit for detecting a regulator output voltage;
• a current detection circuit for detecting a regulator output current;
• a first amplifier circuit for generating a voltage error signal in response to a command output voltage level indicative of a target value of the regulator output voltage, and in response to the regulator output voltage detected by the voltage detection circuit;
• a second amplifier circuit for generating a current limiting signal in response to a command limit current level indicative of a limit value of the regulator output current, and in response to the regulator output current detected by the current detection circuit;
• a current feed path connected between the power-supply input terminal and the power-supply output terminal;
• a first transistor provided in the current feed path, and being driven in response to the voltage error signal generated by the first amplifier circuit;
• and
• a second transistor provided in the current feed path and being connected in series with the first transistor, the second transistor being driven in response to the current limiting signal generated by the second amplifier circuit.

A voltage regulator comprising:

• a power feed line for transmitting electric power toward a load;
• an output transistor provided in the power feed line and having a base;
• a control line extending from the base of the transistor for transmitting a base current from the output transistor;
• first and second control transistors connected in series and provided in the control line;
• first means for detecting a voltage of the electric power transmitted toward the load;
• second means for controlling the first control transistor to control the output-transistor base current in response to the voltage detected by the first means;
• third means for detecting a current of the electric power transmitted toward the load;
• and
• fourth means for controlling the second control transistor to control the output-transistor base current in response to the current detected by the third means.

A voltage regulator comprising:

• a power feed line for transmitting electric power toward a load;
• first and second control transistors connected in series and provided in the power feed line;
• first means for detecting a voltage of the electric power transmitted toward the load;
• second means for controlling the first control transistor to control the electric power transmitted toward the load in response to the voltage detected by the first means;
• third means for detecting a current of the electric power transmitted toward the load;
• and
• fourth means for controlling the second control transistor to control the electric power transmitted toward the load in response to the current detected by the third means.