tea1733mt NXP Semiconductors, tea1733mt Datasheet - Page 5

• Manufacturer Part Number: tea1733mt
• Description: Tea1733mt Greenchip Smps Control Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
7. Functional description
TEA1733MT
Preliminary data sheet
Fig 3.
Typical configuration
R3
7.1 General control
7.2 Start-up and UnderVoltage LockOut (UVLO)
The TEA1733MT contains a flyback circuit controller, a typical configuration of which is
shown in
Initially, the capacitor on the VCC pin is charged from the high voltage mains via resistor
R3.
If V
reaches V
and for pin PROTECT to reach the V
reached, the IC charges the ISENSE pin to the V
typical application the supply voltage is taken over by the auxiliary winding of the
transformer.
If a protection is triggered the controller stops switching. Depending on the protection
triggered, the protection causes a restart or latches the converter to an off-state.
A restart caused by a protection rapidly charges the OPTIMER pin to 4.5 V (typical). The
TEA1733MT enters the Power-down mode until the OPTIMER pin discharges down to
1.2 V (typical). In Power-down mode, the IC consumes a very low supply current
(10 μA typical) and the VCC pin is clamped at 22 V (typical) by an internal clamp circuit.
When the voltage on pin OPTIMER drops below 1.2 V (typical) and the VCC pin voltage is
above the VCC start-up voltage (See
When a latched protection is triggered, the TEA1733MT immediately enters Power-down
mode. The VCC pin is clamped to a voltage just above the latch protection reset voltage
(V
Θ
Z1
C1
C2
R2
rst(latch)
R4
CC
is lower than V
+ 1 V).
Figure
R1
startup
All information provided in this document is subject to legal disclaimers.
the IC first waits for pin VINSENSE to reach the V
C3
3.
VINSENSE
PROTECT
OPTIMER
C4
startup
CTRL
Rev. 1 — 4 February 2011
, the IC current consumption is low (typically 10 μA). When V
TEA1733MT
R8
5
6
7
8
4
3
2
1
det(L)(PROTECT)
ISENSE
DRIVER
GND
VCC
Figure
C5
R5
4), the IC restarts.
start(soft)
R10
voltage. When both levels are
R6
C6
R7
S1
level and starts switching. In a
R9
GreenChip SMPS control IC
TEA1733MT
start(VINSENSE)
© NXP B.V. 2011. All rights reserved.
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voltage
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