The power supply was plugged in for the waveforms taken in the following images.

6-V Input Voltage

C2 ⇒ input voltage; 2 V / div

C1 ⇒ output voltage; 1 V / div

(All) 2 ms / div; 20-MHz bandwidth

Figure 3-21 Start-up With 6-V Input Voltage

12-V Input Voltage

C2 ⇒ input voltage; 5 V / div

C1 ⇒ output voltage; 1 V / div

(All) 2 ms / div; 20-MHz bandwidth

Figure 3-22 Start-up With 12-V Input Voltage

18-V Input Voltage

C2 ⇒ input voltage; 5 V / div

C1 ⇒ output voltage; 1 V / div

(All) 2 ms / div; 20-MHz bandwidth

Figure 3-23 Start-up With 18-V Input Voltage