Semtech Corporation

Joseph Michael Andruzzi

Brian Ashley Carpenter

John Kenneth Fogg

William E Rader, Iii

Daragh Padraic MacGabhann

In one or more embodiments, a switched mode power supply circuit is configured to monitor and control its output voltage during discontinuous conduction mode (DCM) operation, to prevent output over-voltage conditions. For example, in one embodiment, a switched mode power supply circuit is configured to operate selectively in continuous conduction mode (CCM) and discontinuous conduction mode (DCM), and it includes a control circuit that is configured to detect an output over-voltage condition during DCM operation. The control circuit reduces the output voltage of the switched mode power supply circuit responsive to detecting the output over-voltage condition, such as by activating a pull-down device and/or temporarily reverting the switched mode power supply circuit to continuous conduction mode (CCM) operation.

Switched mode power supply method and apparatus

An apparatus and method for virtual current sensing in a DC-DC switched mode power supply. In a fixed frequency implementation, when a switching phase begins, the phase node goes high when the high-side switching transistor is turned on. At this point, a first programmable current source begins charging a current sensing capacitor and the voltage across the capacitor simulates the rising slope of the voltage across a conventional current sensing resistor. Simultaneously, a ramp capacitor beginning at a reference voltage is charged by a second programmable current source. When the sum of the voltages across the two capacitors exceeds an error voltage, the phase node goes low when the drive signal to the transistor is turned off. At this point, a third programmable current source begins discharging the current sensing capacitor and the voltage across the capacitor simulates the falling slope of the current across the conventional resistor.

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Raleigh, NC, United States of America

Joseph Michael Andruzzi