Stepping inductor for fast transient response of switching converter

A power converter comprising:

• an input for receiving input power;
• an output for providing regulated output power;
• a variable inductance device coupled between the input and the output, said variable inductance device having a higher inductance state and a lower inductance state, said variable inductance device being controllable to switch between said higher inductance state and said lower inductance state;
• said variable inductance device further comprising:
• a lower inductance element;
• a switch coupled in series with said lower inductance element thereby forming a switch and lower inductance element series combination;
• and
• a higher inductance element coupled in parallel with said switch and lower inductance element series combination;
• and
• wherein said switch is operable to switch said variable inductance device between said lower inductance state and said higher inductance state and
• a control circuit that is operable to sense voltage at the output and is operable to signal said variable inductance device to switch from one of said inductance states to said other inductance state in response to the sensed output voltage.

A device comprising:

• an input for receiving input power;
• an output for providing regulated output power;
• an electrical load coupled to said output to receive regulated output power;
• a variable inductance device coupled between the input and the output, said variable inductance device having a higher inductance state and a lower inductance state, said variable inductance device being controllable to switch between said higher inductance state and said lower inductance state;
• and
• a control circuit that is operable to sense voltage at the output and is operable to signal said variable inductance device to switch from one of said inductance states to said other inductance state in response to a deviation in the output voltage.

A switching power converter apparatus comprising:

• a first node of the apparatus that provides switching voltage pulses;
• a first inductor;
• a first transformer having a plurality of windings magnetically coupled with one another, said transformer including a first winding coupled to said first inductor, a second winding, and a third winding;
• a voltage source;
• a first switch coupled to said second winding and operable to couple voltage from said voltage source to said second winding;
• a second switch coupled to said third winding and operable to couple voltage from said voltage source to said third winding;
• a first control circuit that is operable to cause said first switch to couple said voltage from said voltage source to said second winding;
• a second control circuit that is operable to cause said second switch to couple said voltage from said voltage source to said third winding;
• a unit, comprising said first inductor and first transformer, coupled to said first node that provides switching voltage pulses;
• an output capacitor coupled to said unit and to a return node of said converter;
• output terminals coupled to said output capacitor for connection to a load;
• and
• an overvoltage protection circuit that is operable to guard said first and said second switches against exposure to overvoltages.

A switching power converter apparatus comprising:

• a pair of input terminals for connection to a DC voltage source, the first of said terminals being a positive terminal and the second of said terminals being a negative terminal;
• a first node of the apparatus that provides switching voltage pulses;
• a first inductor;
• a first transformer having a plurality of windings magnetically coupled with one another, said windings including a first winding coupled to said first inductor, a second winding, and a third winding;
• a first switch coupled to said second winding;
• a second switch coupled to said third winding;
• a unit, comprising the said first inductor and first transistor, coupled to said first node that provides switching voltage pulses;
• an output capacitor coupled to said unit and to a return node of said converter;
• a pair of output terminals, the first of said output terminals being a positive terminal and the second of said output terminals being a negative terminal, coupled to said output capacitor for providing a connection point for a load;
• a first control circuit that is operable to cause said first switch to couple said second winding to said output capacitor;
• a second control circuit that is operable to cause said second switch to couple said third winding to said output capacitor;
• and
• an overvoltage protection circuit that is operable to guard said first and said second switches against exposure to overvoltages.

A switching power converter apparatus comprising:

• a pair of input terminals for connection to a DC voltage source, the first of said terminals being a positive terminal and the second of said terminals being a negative terminal;
• a first node of the apparatus that provides switching voltage pulses having a high voltage level and a low voltage level;
• a first inductor coupled to said first node;
• a second inductor coupled to a first series switch thereby forming an inductor series-switch combination, said combination being coupled in parallel with said first inductor;
• a first diode with its cathode coupled to said positive input terminal and its anode coupled to a node joining said second inductor and said first series switch;
• a second diode with its anode coupled to said negative input terminal and its cathode coupled to a node joining said second inductor and said first series switch;
• a control circuit that is operable to cause said first series switch to couple said second inductor in parallel with said first inductor;
• an output capacitor coupled to said first inductor and a return node of the converter;
• a pair of output terminals coupled to said output capacitor for providing a connection point for a load;
• and
• an overvoltage protection circuit that is operable to guard said first switch against exposure to an overvoltage.