TEA2017ABTSLASH2 datasheet(26/67 Pages) NXP

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NXP Semiconductors

TEA2017ABT/2

Digital configurable LLC and DCM/QR PFC controller

aaa-038661

LLC converter

PFC converter

PFC output voltage

PFC burst mode ripple = 0

LLC converter

PFC converter

PFC output voltage

PFC burst mode ripple ≥ 0

PFC burst mode ripple

Vreg = 2.5 V

Figure 24. PFC burst mode

When the PFC is in burst mode and its output voltage drops to below the regulation

level minus an adjustable ripple voltage, the PFC starts switching. When it reaches the

regulation level again, the PFC stops switching.

When the ripple voltage is set to zero, the PFC always starts switching as soon as the

LLC starts switching. When the output voltage reaches the regulation level and the LLC

stops switching, the PFC stops switching as well.

When the PFC is activated in burst mode, it continues switching until it reaches the

regulation level. As, during this time, the LLC may already have stopped switching, the

system is not supplied via the auxiliary winding and the SUPIC capacitor is discharged.

To avoid that the SUPIC voltage reaches the Vuvp(SUPIC) level, which causes the system

to restart, the PFC stops switching when the SUPIC reaches Vlow(SUPIC) level. The

system then enters the non-operating state and the internal current source is activated to

supply the IC.

8.5.7 PFC burst mode soft start/soft stop

To reduce the audible noise, a soft start and a soft stop can be added to the PFC burst

mode. During a soft start, the average PFC current starts at zero and increases to the

required level. A soft stop implies that the average PFC current decreases from the

regulation level down to zero. The rates of increase and decrease are independently

adjustable.

8.5.8 Valley switching and demagnetization

The PFC MOSFET of the TEA2017ABT is switched on after the transformer is

demagnetized.

To reduce switching losses and electromagnetic interference (EMI), the next stroke is

started when the PFC MOSFET drain-source voltage is at its minimum (valley switching).

The demagnetization and valley detection are measured via the SNSCURPFC and the

DRAINPFC pin.

If no valley signal is detected on the DRAINPFC pin, the controller generates a valley

signal (tto(vrec); 7 μs typical) after demagnetization is detected.

TEA2017ABT_2

All information provided in this document is subject to legal disclaimers.

Product data sheet

Rev. 1.1 — 17 May 2023

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