|Robust DCDC Converter for Automotive Applications||293|
|IL AV G max =VE RR CL P||(9)|
itation to 2 A, while during the VERR CLP slope (see Fig. 26), the current limitation In our case, Rs = 0.25 � and ACSA = 6. This sets the steady state current lim-
9.1 I-V Characteristics
The DCDC I-V characteristics for each particular mode are displayed in the figures below. In the actual application, a coil with saturation current of 1 A is used. The impact is clearly seen in Figs. 28 and 29. In the moment the coil current exceeds 1 A, VO abruptly declines. From Fig. 29 it is obvious that in the buck mode the coil current is always below 1 A if the load current is below 1 A as well. In this case, VO is flat with respect to the output current while the load current easy reaches 1 A. Using a coil with higher saturation current, the overall DCDC load performance improves accordingly.
The next most important test required for automotive field is a periodical short and release on the DCDC output voltage. Such captured waveforms are displayed in Fig. 31. Reliable start-up, no uncontrolled current spikes nor thermal shut down are a must for automotive application.
9.4 EMC – Susceptibility and Radiation Results