tea1733t NXP Semiconductors, tea1733t Datasheet - Page 4

• Manufacturer Part Number: tea1733t
• Description: Greenchip Smps Control Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
7. Functional description
TEA1733T_TEA1733LT_1
Objective data sheet
Fig 3.
Typical configuration
7.1 General control
7.2 Start-up and UnderVoltage LockOut (UVLO)
The TEA1733(L) contains a controller for a flyback circuit. A typical configuration is shown
in
Initially the capacitor on the VCC pin is charged from the high voltage mains via a resistor.
As long as V
V
voltage and for the PROTECT pin to reach the V
are reached, the IC charges the ISENSE pin to the V
switching. In a typical application the supply voltage is taken over by the auxiliary winding
of the transformer.
If a protection is triggered the controller will stop switching. Depending on which protection
is triggered and on the version of the IC (TEA1733T or TEA1733LT) the protection will
cause a restart or will latch the converter to an off-state.
A restart caused by a protection will charge the OPTIMER pin to 4.5 V (typ.) rapidly. The
TEA1733(L) will then enter the Power-down mode until the OPTIMER pin is discharged to
1.2 V (typ.). In Power-down mode, the IC consumes a very low supply current (10 A typ.)
and the VCC pin will be clamped to 22 V (typ.) by an internal clamp circuit. A restart will be
made when the voltage on pin OPTIMER drops below 1.2 V (typ.) and the VCC pin
voltage is above the VCC start-up voltage (See
When a latched protection is triggered, the TEA1733(L) will enter Power-down mode
immediately. The VCC pin will be clamped to a voltage just above the latch protection
reset voltage (V
CC
Figure
reaches V
3.
CC
startup
is below V
rst(latch)
VINSENSE
PROTECT
OPTIMER
CTRL
the IC first waits for the VINSENSE pin to reach the V
Rev. 01 — 26 October 2009
+ 1 V).
5
6
7
8
startup
TEA1733T
, the IC current consumption is low (typically 10 A). When
4
3
2
1
ISENSE
DRIVER
GND
VCC
TEA1733T; TEA1733LT
Figure
det(PROTECT)(L)
start(soft)
4).
GreenChip SMPS control IC
level and then starts
voltage. When both levels
© NXP B.V. 2009. All rights reserved.
start(VINSENSE)
014aaa928
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