The TPS62065-Q1, TPS62067-Q1 step-down converters operates with 3-MHz (typical) fixed-frequency pulse-width modulation (PWM) at moderate to heavy load currents. At light load currents, the converter can automatically enter power save mode and then operate in pulse-frequency mode (PFM). The TPS62067A-Q1 operates with 3-MHz (typical) fixed-frequency pulse-width modulation (PWM) at all loads.

During PWM operation, the converter uses a unique fast-response voltage-mode controller scheme with input-voltage feedforward to achieve good line and load regulation, which allows the use of small ceramic input and output capacitors. At the beginning of each clock cycle initiated by the clock signal, the high-side MOSFET switch is turned on. The current flows from the input capacitor through the high-side MOSFET switch through the inductor to the output capacitor and load. During this phase, the current ramps up until the PWM comparator trips and the control logic turns off the switch. The current-limit comparator also turns off the switch in case the current-limit of the high-side MOSFET switch is exceeded. After a dead time preventing shoot-through current, the low-side MOSFET rectifier is turned on and the inductor current ramps down. The current now flows from the inductor to the output capacitor and to the load. The current returns back to the inductor through the low-side MOSFET rectifier.

The next cycle is initiated by the clock signal again turning off the low-side MOSFET rectifier and turning on the high-side MOSFET switch.