TDA16846(2000) 查看數據表（PDF） - Infineon Technologies

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TDA16846
(Rev.:2000)

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

Infineon Technologies 

TDA 16846

TDA 16847

Second 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 dimensioned lower (by R9, C8) than

the current limit level (see “current limiting”). So 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 unlimited time. This has the advantage that the thermal dimensioning of the

power devices is only needed for the lower power level. Once the voltage V6 exceeds

1.2 V there are no more charge or discharge actions at Pin 8. The voltage V6 remains

high due to the bias current out of HPC and the converter remains switched-off. Reset

can be done by either plug-off the supply from the mains or with a high value resistor R6

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

too less current the temporary high power circuit is disabled.

Data Sheet

18

2000-01-14

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