Datasheet

TEA1832LTS All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 1 — 15 December 2014 5 of 23
NXP Semiconductors
TEA1832LTS
GreenChip SMPS control IC
7. Functional description
7.1 General control
The TEA1832LTS contains a controller for a flyback circuit. A typical configuration is
shown in Figure 3
.
7.2 Start-up and UnderVoltage LockOut (UVLO)
Initially, the capacitor on the VCC pin, C3, is charged from the high-voltage mains via
resistor R1.
As long as the voltage on the VCC pin is below V
startup
, the IC current consumption is low
(11 A typical). When the voltage on the VCC pin reaches V
startup
, the IC first checks the
PROTECT pin. Only when the current exceeds the brownin level (I
mains(bi)
) during mains
detect and the voltage surpasses V
det(PROTECT)
during external OTP measurement the IC
starts switching. An internal soft-start time of 3.5 ms allows the ISENSE peak voltage to
increase gradually to prevent audible noise. In a typical application, the auxiliary winding
of the transformer takes over the supply voltage.
If a protection is triggered, the controller stops switching. Depending on the protection
triggered, it either causes a restart or latches the converter to an off-state.
The brownin/brownout and the maximum duty cycle protections cause a safe restart.
OPP, UVLO, the internal and external OVP, and the internal and external OTP latch the
converter to an off-state.
A restart protection disables the switching of the IC. The supply voltage of the IC drops to
the UVLO level. When the UVLO level is reached, the IC switches to power-down mode,
where it consumes a low supply current (11 A typical). The VCC capacitor is recharged
via R1 until the VCC start-up level is reached. The IC starts switching again.
When a latched protection is triggered, the TEA1832LTS immediately enters power-down
mode. The VCC pin is clamped to a voltage just above the latch protection reset voltage
(V
rst(latch)
+1V).
Fig 3. TEA1832LTS typical configuration
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