AN10907
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2010. All rights reserved.
Application note
Rev. 1 — 28 December 2010
17 of 82
NXP Semiconductors
AN10907
TEA1613T resonant power supply control IC
6.3.4 Difference between UVP on SNSOUT/PFCON and SNSCURHBC OCP/OCR
In a system that uses output voltage sensing by means of the SNSOUT/PFCON function,
there can be an overlap in functionality in an over-power or short circuit situation. In such
a situation, often both the SNSOUT/PFCON UnderVoltage Protection (UVP) and the
OverCurrent Protection/Regulation on SNSCURHBC, activates the protection timer.
There are basic differences between both functions:
•
OCP/OCR monitors the power in the system by sensing the primary current in detail
•
SNSOUT/PFCON monitors (indirectly) the HBC output voltage or another external
protection circuit (e.g. NTC temperature measurement)
SNSOUT/PFCON is a more general protection input while SNSCURHBC is specifically
designed for HBC operation.
In addition, SNSOUT/PFCON also offers two other functions: OVP (latched) and an
output signal for PFC bursting.
6.4 SUPIC supply by external voltage
6.4.1 Start-up
When the TEA1613T is supplied by an external DC supply, the SUPHV pin can be left
unconnected. The SUPIC start level is now 17 V.
When the SUPIC exceeds 17 V, the internal regulator is activated and charges SUPREG.
At SUPREG ³ 10.7 V, GATELS is switched on for the bootstrap function to charge SUPHS.
The TEA1613T starts the converter as soon as V
BOOST
reaches a preset level
(SNSBOOST ³ 1.6 V).
6.4.2 Stop
Operation of the TEA1613T can be stopped by switching off the external source for
SUPIC. As soon as the voltage level on SUPIC drops below 15 V, operation is stopped.
In case of shutdown (because of protection), this state is reset by internal logic as soon as
the SUPIC voltage drops below 7 V.
6.5 SUPREG
SUPIC has a large voltage range for easy application. But because of this, SUPIC can not
directly be used to supply the internal MOSFET drivers as they would exceed the allowed
gate voltage of many external MOSFETs.
To avoid this issue (and create a few other benefits), the TEA1613T contains an
integrated series stabilizer. The series stabilizer generates an accurate regulated voltage
on SUPREG on the external buffer capacitor.
This stabilized SUPREG voltage is used for:
•
Supply of internal low-side HBC driver
•
Supply of internal high-side driver via external components
•
Reference voltage or supply of external circuits
