TEA1833TS

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

© NXP Semiconductors N.V. 2015. All rights reserved.

Product data sheet

Rev. 1 — 31 August 2015

11 of 25

NXP Semiconductors

TEA1833TS

GreenChip SMPS control IC

The output voltage can drop, for instance, because a load is too high or a short circuit

event occurs. If the output voltage drops, the decrease of the transformer current during

peak current.

Also, at the next cycle, the minimum on-time equals the blanking time. During this

blanking time, the peak current can increase to above the targeted regulation level. If the

transformer current does not decrease sufficiently during the secondary stroke, the peak

current can continuously increase to such a level that the transformer saturates

(see Figure 10).

To avoid this continuous peak current increase, also called runaway, the IC features a

special protection (see Figure 11).

If the system detects that the peak current already exceeds the targeted level after 1

s,

the next switching period time is extended from 7.7

s (f

transformer current to below the targeted peak current again.

To avoid activation at low loads, the OSCP is only enabled when the overpower timer is

OVP level.

is measured.

To limit the input power during a short circuit or an overload event, the OPP time is

reduced to 50 % when OSCP is enabled.

Fig 11. OSCP peak current runaway