AN2359

Conclusions

17/18

6

Conclusions

Two low cost double outputs Buck-Boost converters have been proposed based on

STMicroelectronics VIPer22A.

Thanks to the regulation feedback connected to –5V output, the converters can be suitably

used to supply a microcontroller or applications where a high output voltage tolerance is

required.

Instead, the -12V or-24V output voltage, achieved by the output inductor turns ratio, can be

used for the auxiliary circuits where a lower tolerance can be accepted.

In particular, the –24V option can be preferred because it guarantees a higher efficiency

(due to lower turn- on losses) and allows to save the cost of a high voltage diode compared

to the –12V solution.

On the other side, the –12V solution has to be used in many applications when it is not

possible to change the auxiliary supply voltage from –12V to –24V.

The same topology can be used for lower power range, replacing the VIPer22 with the

VIPer12.

In this case the device can deliver up to about 2.2W.

7

Revision history

Table 12.

Revision history

Date

Revision

Changes

04-Dec-2006

1

Initial release