Siemens Aktiengesellschaft

Andreas Rampold

Jörg Weiss

A power supply includes a storage capacitor which can be charged with a rectified input current by means of a current-limiting element which is controlled by a drive circuit. The direct-axis component of current and the direct-axis component of voltage on the current limiting element are supplied to the control circuit as input values and the current limiting element is controlled in such a way that it is not subjected to more than a predetermined maximum power loss.

Power supply with low loss making current limitation

The apparatus is used for detecting an output direct current (Ia) produced by a pulse controller (PS). This pulse controller (PS) has at least one chopper device (Z) for forming a pulsed intermediate voltage (Up) and a pulsed intermediate current (Ip), which are converted by a smoothing device (GA) into an output DC voltage (Ua) and an output direct current (Ia). The apparatus includes a circuit (Ms) for electrically floating detection of the pulsed intermediate current (Ip) and for converting it into a pulsed measurement voltage (Us), and a switching device (Se) which is clocked by the pulsed intermediate voltage. This switching device (Se) supplies the pulsed measurement voltage (Us) in synchronism with the pulsed intermediate voltage to a low-pass filter (Tp), which produces a measurement DC voltage (Um,) that is proportional to the output direct current (Ia).

Circuit arrangement for accurately detecting a direct current derived from clocked electric input values

An electrical power supply (EPS) including a voltage regulator (SR1) and an inrush current limiter (ICL1) having a current limiting circuit (CL1) and a support capacitor (C1). Charging current spikes produced in particular when the electrical power supply (EPS) is switched on are limited by the current limiting circuit (CL1). The current limiting circuit (CL1) is connected in series with the support capacitor (C1), thus preventing load current from flowing through the current limiting circuit. A step-up converter circuit (SUC) is connected upstream of the current limiting circuit (CL1) with the particular purpose of increasing the voltage (V). An advantage of the arrangement is that, due to the step-up converter circuit (SUC), the support capacitor (C1) has considerably improved support characteristics with regard to the switching regulator (SR1). Furthermore, the boosted voltage (V) at the terminals (T1 and T3) of the inrush current limiter (ICL1) considerably reduces the disruptive effects of interference voltages caused by the switching regulator (SR1). Additional interference suppression, e.g., by means of a costly radiointerference suppression network, is thereby advantageously rendered unnecessary.

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Mittweida, Germany

Andreas Rampold