Datasheet XDPS21071 (Infineon) - 8

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Forced Frequency Resonant Flyback controller Functional Description
VVCC(t)
Initial startup and normal operation
VVCCon = 20.5 V VCC brown-in window VVCCSS VVCCBI = 9.1 V VCC self supply takes over VVCCoffOP = 7.2 V t VHV(t) ca. 1.2ms internal boot sequence VVACpeak VAC brown-in condition fulfil ed t I VCC(t) Start of GD0 switching IVCCop IVCCop1 = 7.5 mA IVCCUVOFF = 30 µA t TYPICAL STARTUP SEQUENCE
Figure 4 Typical startup sequence 4.1.2 Brown-in monitoring
Once the IC is activated, brown-in monitoring is enabled for input brown-in protection (see Chapter 4.3.4) by measuring the current at HV pin through the internal shunt resistor RM (see Chapter 4.2.2). If the input brown-in is not detected before VCC falls below VVCCBI, the startup cell measurement unit remains enabled until VCC falls down to VVCCoff. Data Sheet 8 Revision 2.0 2019-10-30