Method and apparatus for a buck converter with pulse width modulation and pulse frequency modulation mode

A buck converter device with minimum off-time operation, the device comprising a comparator providing an output signal of a minimum off time, a first amplifier, a p-channel MOSFET whose gate is connected to the output of a first amplifier providing a signal threshold voltage to a positive terminal of a comparator, a second amplifier; and, a second p-channel MOSFET whose gate is connected to the output of a second amplifier providing a signal to a negative terminal of a comparator, and a capacitor element.. A capacitor establishes a voltage whose rate of change is proportional to power supply Vdd, establishing a time to charge the capacitor to a threshold voltage proportional to (Vdd-Vref)/Vdd, and establishing a minimum off time on the output of a comparator. The buck converter minimum off time is adaptive at high loads, and is proportional to (1-D), where D is the duty cycle. The frequency is thereby stable and the interferences are controlled.