dastali писал(а):
откуда возьмутся vcc15v без генерации
там по другому
Что значит по другому?
Start−up Sequence
When the power supply is first connected to the mains
outlet, the internal current source is biased and charges up
the VCC capacitor. When the voltage on this VCC capacitor
reaches the VCC(on) level (typically 15 V), the current source
turns off, reducing the amount of power being dissipated. At
this time, the VCC capacitor only supplies the controller, and
the auxiliary supply should take over before VCC collapses
below VCC(min)
.......
The first startup period is calculated by the formula C x V
= I x t, which implies a 22 x 1.8 / 200 = 198 ms startup
time for the first sequence. The second sequence is obtained
by changing to 2 mA with a delta V of VCC(on) – VTh = 15
– 1.8 = 13.2 V, which finally leads to a second startup time
of 13.2 x 22 / 2m = 145 ms. The total startup time becomes
198 m + 140 m = 343 ms with a worst case condition on the
startup source only. Please note that this calculation is
approximated by the presence of the knee in the vicinity of
the transition.
As soon as VCC reaches VCC(on), drive pulses are
delivered on pin 9 and the auxiliary winding increases the
voltage on the VCC pin.
Как бы более, чем понятно.
