TDA16846G View Datasheet(PDF) - Infineon Technologies

Part Name

Description

Manufacturer

TDA16846G

Controller for Switch Mode Power Supplies Supporting Low Power Standby and Power Factor Correction

Infineon Technologies 

TDA 16846

TDA 16846-2

Secondly, a High Power Shutdown Comparator (FC2) is implemented: When the voltage

V6 at Pin 6 exceeds 1.2 V the Error Flip Flop (ERR) is set. The output voltage of the

power measurement circuit (Pin 8) is smoothed by R8/C6 and applied to the “high power

shutdown” input at Pin 6. The relation between this voltage V6 and the output power of

the converter P is approximately:

V6 ≈ (P × LSecondary × 5 V)/(VOUT2 × C8 × R9)

LSecondary: The transformers secondary inductance

VOUT: The converters output voltage

So the time constant of R9/C8 for a certain high power shutdown level PSD is:

R9 × C8 ≈ (PSD × LSecondary × 4.2)/VOUT2

The converters high power shutdown level can be adjusted lower (by R9, C8) than the

current limit level (see “current limiting”). Thus because of the delay R8/C6, the converter

can deliver maximum output power (current limit level) for a certain time (e. g. for power

pulses like motor start current) and a power below the high power shutdown level for an

unlimited time. This is of advantage because the thermal dimensioning of the power

devices needs to be done for the lower power level only. Once the voltage V6 exceeds

1.2 V no more charging or discharging happens at Pin 8. The voltage V6 remains high

due to the bias current out of FC2 and the converter remains switched-off. Reset can be

done either by plugging-off the supply from the mains or by a high value resistor R6

(Figure 14). R6 causes a reset every few seconds. When Pin 9 is not connected or gets

too little current (I9 < I9FC2), the temporary high power circuit is disabled.

Data Sheet

18

2003-07-31

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