Patent ID: 9647542
Date: 2017-05-09
CPC Classifications: H02M

Claim:
1. A switched mode power supply, SMPS, comprising: a switch; one or more inductors; an output smoothing capacitor; and a controller comprising: a first current measuring unit configured to measure a current through the or each inductor; a second current measuring unit configured to measure a load current; a voltage measuring unit configured to measure a voltage across the output smoothing capacitor; first energy calculation circuitry configured to determine a first energy difference (EL) that is an instantaneous energy in the inductor(s) minus an energy in the inductor(s) at a load current, wherein the first energy difference is determined by summing, over each of the one or more inductors, an inductance (L) of the inductor multiplied by an instantaneous current (IL) through the inductor multiplied by a difference between the instantaneous current through the inductor and the load current (Iload) (EL∝Σ[LIL (IL+Iload)]), second energy calculation circuitry configured to determine a second energy difference (Ec) that is an energy in the output smoothing capacitor at a reference voltage minus an instantaneous energy in the output smoothing capacitor, wherein the second energy difference is determined by multiplying the reference voltage (Vtarget) by a difference between the reference voltage and the instantaneous voltage (Vc) across the output smoothing capacitor (Ec∝Vtarget (Vtarget-Vc)), and a comparator configured to turn the switch on and off with a clock rate and a variable duty cycle such that the switch is on from the start of each period of the clock until the first energy difference is equal to the second energy difference (EL=Ec), and such that the switch is otherwise off.