AN1484 - APPLICATION NOTE

8/11

Figure 9a: Standby Consumption at 100V

Figure 9b: Standby Consumption at 380V

The only change is due to the internal startup

current source of 22uA which consumption goes

from 2mW at 100V up to 8mW at 380V. Another

factor due to the VIPer12A is the current used on

the feedback pin, regulated around 1mA in standby

that leads to a 10mW consumption in the primary

and 6mW in the secondary (with an opto gain of 1).

Note that it is necessary to keep a certain level of

current in the regulating zener to improve the load

regulation. As load increases, the current in the

opto and the zener decreases lowering the output

regulated voltage. Overall, VIPer12A needs 50mW

to operate in standby.

It is possible to spare some mW in the auxiliary

supply, especially the 22

Ω serial resistor which is

necessary to regulate the transformer ringing

voltage peak. In the demoboard the transformer

voltage has a narrow dynamic so R2 becomes

useless. So the standby consumption is decreased

if the resistor is removed and the transformer is

tuned to set 10V or less on VIPer12A Vdd.

The standby consumption is less than 60mW at

100V and 80mW at 380V: fairly good considering

the 50mW required by VIPer12A.

4.0 DESIGN MATERIAL

4.1 PCB Solder Side

Figure 10a: Bottom view of Charger’s Board.

Figure 10b: PCB Art Work

4.2 Silk Screen Solder Side

Figure 11: SMD components

Clamper

0mW

22

Ω

20mW

VIPer12A

37mW

Opto

11mW

Zener

5mW

Opto

1mW

Rectifier

Diode

1mW

Rectifier

Diode

5mW

Switching

Losses

2mW

22uA

2mW

0mW

Transfo.

4mW

Vin

100V

12V

Vout

6V

Primary : 81mW

Secondary : 7m

Clamper

0mW

22

Ω

31mW

VIPer12A

34mW

Opto

10mW

Zener

5mW

Opto

1mW

Rectifier

Diode

1mW

Rectifier

Diode

7mW

Switching

Losses

12mW

22uA

8mW

10mW

Transfo.

4mW

Vin

380V

11V

Vout

6V

Primary : 112mW

Secondary : 7m