BCR401UW6

Document number: DS38542 Rev. 3 - 2

9 of 13

www.diodes.com

May 2017

© Diodes Incorporated

BCR401UW6

The error between the calculated theoretical value and the measured value is due to the turn on and turn off times of the BCR401/2/5. There will

be a small contribution from the switches (a pre-biased transistor or a MOSFET) shown in Figure 3a and 3b towards the total turn on and turn off

times of the BCR401/2/5. It is recommended to keep the external switching delays to the lowest possible value to improve PWM accuracy. The

typical switching times of the BCR401/2/5 for the configuration shown in Figure 3b are:

Turn-On Time = 200ns

Turn-Off Time = 10µs

Please refer to the Figure 5 and 6 for the switching time performance. The percentage contribution of these switching delays increases with

increasing frequency and decreasing duty ratio as can be seen in Figure 4.

Figure 5 Turn-On Time of BCR401/2/5 (PWM method shown in Figure 3b)

Figure 6 Turn-On Time of BCR401/2/5 (PWM method shown in Figure 3c)

However, where possible, the switching performance of the BCR401/2/5 can be significantly improved by switching the power path as shown in

Figure 3c. The resulting turn-off time is shown in Figure 7. This resulted in an improved PWM resolution at 25kHz as shown in Figure 8.

Turn-Off Time = ~200ns