TEA1733T

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

© NXP B.V. 2013. All rights reserved.

Product data sheet

Rev. 7 — 11 July 2013

5 of 21

NXP Semiconductors

TEA1733T

GreenChip SMPS control IC

7.

Functional description

7.1 General control

The TEA1733T contains a flyback circuit controller, a typical configuration of which is

shown in Figure 3.

7.2 Start-up and UnderVoltage LockOut (UVLO)

Initially, the capacitor on the VCC pin is charged from the high voltage mains via resistor

R3.

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

TEA1733T enters 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

Atypical)

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 Figure 4), the IC restarts.

When a latched protection is triggered, the TEA1733T immediately enters Power-down

mode. The VCC pin is clamped to a voltage just above the latch protection reset voltage

Fig 3.

Typical configuration

001aan639

TEA1733T

5

6

7

8

4

3

2

1

R1

R2

R3

R4

Z1

C4

R8

C5

R9

C3

C1

C2

R7

C6

R6

R10

S1

R5

Θ

DRIVER

GND

VCC

ISENSE

VINSENSE

PROTECT

CTRL

OPTIMER