This test is designed to demonstrate the adapter-to-battery switchover capabilities of the design. The test is run with 19 V on the input supply. The E-Load is then connected to the system rail and draws a constant current of 8 A. The input supply is then removed and the VIN, VSYS, and VBAT rails are monitored for the switchover timings. The test is then repeated while replacing the 19-V input supply with a 13-V supply to mimic a car charging adapter.

In Figure 3-1 through Figure 3-4, VIN is measured by CH1 (Blue), VBAT is measured by CH2 (Red) and, VSYS is measured by CH3 (Green). For these captures all channels are based at 0 V with no offset to better illustrate the switchover mechanism.

Figure 3-1 shows the 19 V to battery switchover with a time division of 200 μs. The minimum voltage at VSYS is 9.21 V. The approximate switchover timing is 10 μs and the VSYS rail has increased to 12.87 V by 20 μs after the switchover event.

Figure 3-1 19 V to Battery Switchover 200-μs Time Division

Figure 3-2 shows the 19 V to battery switchover with a time division of 20 μs. The minimum voltage at VSYS is 9.28 V. The approximate switchover timing is 10 μs and the VSYS rail has increased to 11.82 V by 10 μs after the switchover event.

Figure 3-2 19 V to Battery Switchover 20-μs Time Division

Figure 3-3 shows the 12 V to battery switchover with a time division of 100 μs. The minimum voltage at VSYS is 9.12 V. The approximate switchover timing is 10 μs and the VSYS rail has increased to 12.73 V by 20 μs after the switchover event.

Figure 3-3 12 V to Battery Switchover 10-μs Time Division

Figure 3-4 shows the 12 V to battery switchover with a time division of 20 μs. The minimum voltage at VSYS is 9.31 V. The approximate switchover timing is 10 μs and the VSYS rail has increased to 10.63 V by 10 μs after the switchover event.

Figure 3-4 12 V to Battery Switchover 20-μs Time Division