Switched-mode regulator with inductor current simulation circuit

Claim 1

Circuit arrangement for the conversion of an unregulated DC input voltage (UE) into a constant DC output voltage (UA), which has a common reference point (OV) with respect to its polarity, and with which the DC input voltage (UE) can assume both a higher and a lower value than the desired output voltage (UA), with an inductance (L2), serving as energy store for the conversion of the DC input voltage (UE) by alternating charging and discharging, and two switches (V1, V2), effecting the charging operation, a regulating circuit (RS), controlling the charging and discharging operation by periodic sensing, with a set/actual value comparator (SIV) for the setting of a pulse duty factor yielding the output voltage (UA), characterized in that a simulation circuit (SNB) is provided, which simulates a current (IL) through the inductance (L2) during the charging of the inductance (L2) as capacitor voltage (UC5) of a capacitor (C5), the capacitor (C5) being connected via a resistor (R13) to the input voltage (UE) and, as a result, the charging of the capacitor (C5) increasing proportionally to the level of the input voltage (UE), and synchronism between the capacitor voltage (UC5) and the current (IL) through the inductance (L2) being achievable when there are variations in the input voltage (UE), and in that the two switches (V1, V2) are switched off on reaching a certain value of the capacitor voltage (UC5).