A method for operating a dc / dc - transducer with a fixed pwm - frequency and with a spreading - code - a process for the spectrum of modification

摘要

The present invention relates to a process for the dc / dc conversion by means of a modulated signal pwm -. A first periodic signal (i_sum) with a period (t is₁) generates. To the first periodic signal (i_sum) , a periodic spreading - - code signal (i_sig) with a spreading code - - signal period (t_sp) to be added to the. In this way, a modulated periodic signal (i_sum + I_sig) generates. An integration capacitor (c₁) the modulated integrated of the periodic signal (i_sum + I_sig) as the integration means and is produced as a capacitor voltage (v_c.) on the integration capacitor (c₁) a modulated ramp signal (v_mrp). In this case, the autocorrelation function of the spreading - code - signal (i_sig) with a spreading code - - period (t_sp) periodically. In addition, the autocorrelation function of the spreading - code - signal (i_sig) between t = 0 s and t = t_sp to at least to a point in time is different from zero. In particular, lifts it extends over the system noise, which means that, in magnitude is greater than a threshold value, which itself lies above the noise. A comparison device, in particular a comparator, compares the modulated ramp signal (v_mrp) with a first threshold value. A switching device in dependence upon the comparison result of the comparison device their switching state. In this case depend on various points in time of the change, which characterize the pwm - signal, a result of this comparison, without, in that the pwm - frequency or the pwm - period depends on.