could the ADP1047 be used for DC/DC design? I want to design a SEPIC controller like this one:
The requirements are as follows:
It wold be nice to use this controller becouse of abbility for adjusting the Vout. If it is possibel, what settings should I make and should I make changes to the hardware?
Thanks a lot!
Hi NC, Eugen,
To calculate the line voltage, the ADP1047 will try to sense the zero crossing and then calculate the AC line period. If the input voltage is dc, there is no zero crossing. Therefore ADP1047 cannot detect the zero crossing and then calculate the line period. However, the VAC settings allow the user to program the min and max line period. If the sense line period is smaller than the min period, the ADP1047 will use the min period value for line voltage calculation. If the sense line period is larger than the max period, the ADP1047 will use the max period value for line voltage calculation. In this case, the max period will be sed as line period for calculation.
However, since the ADP1047 is designed for PFC. The control loop won't be fast. There might be some issue if you use it to control a dc-dc converter with fast transient. A good choice would be ADP1055. The ADP1055 is a voltage mode controller with outstanding control loop. Its additional zero/pole function is help for boost type converter which has a right half plain zero. If the input voltage is low and the output voltage is very high (like PV, fuel cell inverter etc), the current fed boost type converter using ADP1055 is a very good choice.