Voltage tracking reference for a power regulator

A power regulator, comprising:

• a switching converter which converts an input voltage to an output voltage based on at least one drive signal;
• a feedback circuit having an input sensing said output voltage and an output providing a feedback voltage;
• an error amplifier having a first input receiving said feedback voltage, a second input receiving a first reference voltage signal, and an output providing a compensation signal;
• pulse width modulation (PWM) logic having an input receiving said compensation signal and an output providing a PWM signal indicative of said compensation signal compared with a periodic waveform;
• a switching circuit having an input receiving said PWM signal and an output providing said at least one drive signal;
• a transconductance amplifier having an inverting input, a first non-inverting input receiving a tracking voltage indicative of said input voltage, a second non-inverting input receiving a second reference voltage, and an output coupled to said inverting input and providing said first reference voltage signal to said second input of said error amplifier;
• and
• wherein said transconductance amplifier drives said first reference voltage signal based on whichever of said second reference voltage and said tracking voltage has a lower voltage level.

A method of providing ratio-metric tracking for a power regulator which converts an input voltage to an output voltage, said method comprising:

• providing an error amplifier in a compensation loop of the regulator which compares an output sense voltage with a first reference voltage for generating an error signal;
• receiving a tracking voltage indicative of the input voltage;
• providing the tracking voltage to a first non-inverting input of a transconductance amplifier which has an output with limited output drive capacity providing the first reference voltage;
• providing a second reference voltage to a second non-inverting input of the transconductance amplifier;
• coupling an inverting input to the output of the transconductance amplifier;
• capacitively coupling the output of the transconductance amplifier;
• and
• configuring the transconductance amplifier to select the lesser of the second reference voltage and the tracking voltage for controlling the output of the transconductance amplifier.