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1. A circuit comprising:
a control circuit having an input configured to receive a first current measurement signal from a current source comprising a first inductive storage element coupled between an input terminal and a first node, a capacitive storage element coupled between the first node and a second node, a second inductive storage element coupled between the second node and an output terminal, a switching element coupled between the first node and a reference node, a free-wheeling element coupled between the second node and the reference node, and a first current measurement circuit configured to generate the first current measurement signal based on at least one of a current through the switching element and a current through the free-wheeling element, the control circuit configured to control a current at the output terminal by:
generating a periodic drive signal at a drive signal output configured to be coupled to a control node of the switching element, the periodic drive signal configured to switch on the switching element for an on-time and to switch off the switching element for an off-time in each switching cycle, andsampling the first current measurement signal at a sample time to obtain a discrete-time sample value in a first switching cycle, wherein the periodic drive signal for the switching element is generated in a subsequent switching cycle dependent on the discrete-time sample value sampled during the first switching cycle, wherein the periodic drive signal comprises a pulse width modulated drive signal having a duty cycle, the control circuit is configured to adjust the duty cycle dependent on the discrete-time sample value, and the control circuit is further configured to:
calculate a mean value of a current through the second inductive storage element from at least two discrete-time sample values,compare the calculated mean value with a reference current value to produce a comparison result, andadjust the duty cycle based on the comparison result. |
