Switching power converter with controlled startup mechanism

A switching power converter with controlled startup mechanism, comprising:

• a switching stage comprising a switching element arranged to control the current through an inductor in response to a switching control signal, said switching stage producing an output voltage Vout at said output node;
• a second node, said output node and second node adapted for connection across a non-linear load;
• a current regulating element connected to conduct a current from said second node to a common potential;
• an error amplifier which receives a voltage Vfb at a first input which varies with the current conducted by said load (Iload) and a reference voltage Vref at a second input and which produces an output which varies with the difference between the voltages at its inputs;
• a pulse-width modulated (PWM) controller which receives the output of said error amplifier and provides said switching control signal to said switching stage so as to maintain Iload at a desired value;
• and
• a capacitor having a capacitance Cfb connected between said output node and said first input such that said capacitor conducts a pullup current proportional to the derivative of Vout at said first input such that dVout/dt is controlled when Iload is substantially zero;
• wherein said converter is arranged to adjust Vout as needed to make the voltage at said second node equal to Vref, said voltage at said second node and said current regulating element thereby establishing Iload.

A switching power converter with controlled startup mechanism, comprising:

• a switching stage comprising a switching element arranged to control the current through an inductor in response to a switching control signal, said switching stage producing an output voltage Vout at said output node;
• a second node, said output node and second node adapted for connection across a non-linear load;
• a first current regulating element connected to conduct a current from said second node to a common potential;
• an error amplifier having a first input connected to a first node, a second input which receives a voltage Vfb that varies with the current conducted by said load (Iload) and a third input connected to a reference voltage, said error amplifier arranged such that its output varies with the difference between the voltages at its first and third inputs when Iload is substantially zero, and varies with the difference between the voltages at its second and third inputs when Vfb is approximately equal to said reference voltage;
• a second current regulating element connected to conduct a current Iss from said first node to a common potential;
• a pulse-width modulated (PWM) controller which receives the output of said error amplifier and provides said switching control signal to said switching stage so as to maintain Iload at a desired value;
• and
• a capacitor having a capacitance Cfb connected between said output node and said first node such that said capacitor conducts a pullup current Icfb which is proportional to the derivative of Vout at said first node;
• wherein said converter is arranged to adjust Vout as needed to make the voltage at said second node equal to Vref, said voltage at said second node and said current regulating element thereby establishing Iload.