November 2007

Rev 4

1/17

AN2544

Application note

Designing a low cost power supply using a

VIPer12/22A-E in a buck configuration

Introduction

Many appliances today use nonisolated power supply to furnish low output power required

to run a micro, LED display, and a few relays or AC switches. This type of power supply has

a single rectifier so as to reference the neutral to output ground in order to fire TRIACs or AC

switches. This article describes the use of the VIPer12A-E and the VIPer22A-E which are

pin-for-pin compatible and can supply power for many applications. This paper provides an

off-line, nonisolated power supply evaluation board based on the VIPer12/22A-E. Four

different examples are covered. The VIPer12A-E is used for 12 V at 200 mA and 16 V at 200

mA. The VIPer22A-E is used for 12 V at 350 mA and 16 V at 350 mA. The same board can

be used for any output voltage from 10 V to 35 V. For outputs less than 16 V, D6 and C4 are

populated and W1 is omitted. For outputs greater than 16 V, D6 and C4 are omitted and W1

is populated. For more design detail, see AN1357 "VIPower: low cost power sullies using

the VIPer12A-E in nonisolated application." The objective of this application note is to

familiarize the end user with this reference design and to quickly modify it for different

voltage output. This design gives:

Figure 1.

Evaluation board (STEVAL-ISA035V1)

Table 1.

Operating conditions for the four samples

Board version (with changes)

Output voltage and current

Input voltage range

Input voltage frequency range

50/60 Hz

Output version 1

VIPer22ADIP-E

12 V at 350 mA

4.2 W

Output version 2

VIPer12ADIP-E

12 V at 200 mA

2.4 W

Output version 3

VIPer22ADIP-E

16 V at 350 mA

5.6 W

Output version 4

VIPer12ADIP-E

16 V at 200 mA

3.2 W

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