System and method for extending the maximum duty cycle of a step-down switching converter without maximum duty control

A step-down switching converter system comprising:

• a leading edge blanking (“LEB”) network configured to generate an a reset bar signal (RSTB signal) for reinitiating a slope signal based on a first clock signal operating at a desired switching frequency;
• a switch network configured to connect an input node having an input voltage to an inductor, which is further connected to an output node having an output voltage, the switch network comprising
• a high-side switch connected between the input node and a phase node having a phase node voltage;
• and
• a low-side switch connected between the phase node and ground;
• a current sensing network configured to generate a current sensing signal indicative of a current through the inductor when the high-side switch is turned on and reinitiates periodically at the desired switching frequency based the RSTB signal, the current sensing network being connected to the LEB network, the input node, and the phase node;
• a feedback network, connected to the output node, configured to generate a feedback voltage signal indicative of the output voltage;
• an error amplifier, receiving the feedback voltage signal, configured to generate an error signal based on comparison of the feedback signal to a reference voltage;
• a pulse width modulation (“PWM”) network, connected to the error amplifier, configured to generate a duty signal based on the error signal, a second clock signal, and a sum signal indicative of the slope signal;
• and
• a gate driver, connected to the PWM network, configured to generate one or more control signals for controlling the switch network based on the duty signal;
• wherein the sum signal resets to a base voltage for a predetermined period of time during a blanking duration of the RSTB signal.