Slope compensation for current mode control modulator

A ramp signal generator generating a slope compensated ramp signal for a current mode control modulator, the current mode control modulator generating a pulse-width modulation signal in response to a feedback voltage signal indicative of a regulated output voltage generated from an input voltage, the ramp signal generator comprising:

• a first capacitor coupled between a first node and a second node, the second node being biased to a reference voltage and the first node providing the slope compensated ramp signal;
• a second capacitor coupled between a third node and the second node;
• and
• a first switch coupled between the first node and the third node, the first switch being controlled by a first signal indicative of the pulse-width modulation signal, the first switch being open during a first duration of the pulse-width modulation signal and the first switch being closed during a second duration of the pulse-width modulation signal,
• a current circuit coupled to the first node and the third node and controlled by a second signal indicative of the pulse-width modulation signal to charge or discharge the first and third nodes,
• wherein the first capacitor, the second capacitor and the first switch form a switched capacitor circuit to generate the slope compensated ramp signal;
• wherein in response to the first switch being open during the first duration of the pulse-width modulation signal, the ramp signal generator generates the slope compensated ramp signal having a first ramp portion by using the switched capacitor circuit to divide a charge associated with an expected current level of a current control loop of the current mode control modulator among the first capacitor and the second capacitor during the first duration of the pulse-width modulation signal, the first capacitor being disconnected from the second capacitor and providing the first ramp portion of the slope compensated ramp signal, and
• wherein in response to the first switch being closed during the second duration of the pulse-width modulation signal, the ramp signal generator generates the slope compensated ramp signal having a second ramp portion by using the switched capacitor circuit to share the charge associated with the expected current level of the current control loop of the current mode control modulator between the first capacitor and the second capacitor during the second duration of the pulse-width modulation signal, the first capacitor being connected to the second capacitor and the first and second capacitors providing the second ramp portion of the slope compensated ramp signal.