Circuit arrangement for producing a control voltage for controlling the charging of storage heaters

摘要

In the case of the arrangement according to the invention, a first variable (Ua) which is dependent on the external temperature is applied to a first input of a first comparator (3b), a second variable (Ub) which is dependent on setting values is supplied to the input of a first triangular-waveform generator (1a), and a third variable (Uc), which is proportional to the square of the operating voltage, is supplied to the input of a second triangular-waveform generator (3a). Each triangular-waveform generator (1a, 3a) supplies on the output side a triangular-waveform voltage at a fixed frequency, whose amplitude is proportional to its input variable (Ub, Uc). The output of the second triangular-waveform generator (3a) is connected to a second input of the first comparator (3b), the output of the first comparator (3b) is connected via a smoothing element (2) to a first input of a second comparator (1b), and the output of the first triangular-waveform generator (1a) is connected to a second input of the second comparator (1b). The control voltage (Us) is present at the output of the second comparator (1b). In this way, the desired control voltage (Us) is produced in a simple manner, compensating for influences of the operating voltage on the charging.