A circuit for preventing inductor saturation during a step-up load
transient in a multi-phase converter circuit where phases are turned ON
sequentially by a shared clock signal with a fixed phase shift, each
phase having high- and low-side switches series connected at a switching
node, the circuit including at least one closed loop connected to at
least one phase for providing ripple current cancellation in input and
output sides of the multi-phase converter circuit; an oscillator circuit
for providing a signal to turn ON and OFF the high- and low-side switches
of each of the phases of the multi-phase converter circuit; and a
detection circuit to detect the transient. The detect circuit includes an
error amplifier circuit to receive input signals from an output of the
multi-phase converter and to provide an error signal; and a clock
oscillator frequency changing circuit receiving the error signal for
increasing the clock oscillation frequency when said detection circuit
detects a step-up load transient.