TEA18361LT All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 2 — 12 December 2013 9 of 29
NXP Semiconductors
TEA18361LT
GreenChip SMPS control IC
If the system does not detect a positive dV/dt for 28 ms, it assumes that the mains is
disconnected. In that case the HV pin is continuously pulled to ground, discharging the
external X-capacitor.
7.5 Auxiliary winding
The VCC pin is connected via a diode and a capacitor to the auxiliary winding to efficiently
supply the control IC.
To detect demagnetization, valley, and input and output voltage, the auxiliary winding is
connected to the AUX pin via a resistive divider (see Figure 3
). Each switching cycle is
divided in sections. During each section the system knows if the voltage or current out of
the AUX pin reflects the demagnetization, valley, input or output voltage (see Figure 8
).
When the external MOSFET is switched on, the voltage at the auxiliary winding reflects
the input voltage. The AUX pin is clamped to 0.7 V. The output current is a measure of
the input voltage. This current value is internally used for an accurate OPP.
The demagnetization, valley and output voltages are measured as a voltage on the AUX
pin. In this way, the input voltage measurement and OVP can be adjusted independently.
7.6 Protection
If a protection is triggered, the controller stops switching. Depending on the protection
triggered and the IC version, the protection causes a restart or latches the converter to an
off state (See Table 3
).
To avoid false triggering, some protections have a built-in delay.
Fig 8. AUX pin used for demagnetization, valley, and input and output voltage
measurement
9
L
PHDVXUHPHQW GHPDJQHWL]DWLRQ YDOOH\
9
R
PHDVXUHPHQW
GUDLQ
$8;
