TEA1733LT 데이터 시트보기 (PDF) - NXP Semiconductors.

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TEA1733LT

GreenChip III SMPS control IC

NXP Semiconductors. 

NXP Semiconductors

TEA1733T; TEA1733LT

GreenChip III SMPS control IC

7. Functional description

7.1 General control

The TEA1733(L) contains a flyback circuit controller, a typical configuration of which is

shown in Figure 3.

C1

R1

C2

R2

R3

R4

Θ

Z1

TEA1733T

VINSENSE 5

PROTECT 6

4 ISENSE

R5

3 DRIVER

CTRL 7

OPTIMER

8

C3

2 GND

1 VCC

C4

R8

C5

S1

R10

R6

C6

R9

Fig 3. Typical configuration

R7

014aaa928

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.

If VCC is lower than Vstartup, the IC current consumption is low (typically 10 μA). When VCC

reaches Vstartup, the IC first waits for the VINSENSE pin to reach the Vstart(VINSENSE)

voltage and PROTECT pin to reach the Vdet(PROTECT)(L) voltage. When both levels are

reached, the IC charges the ISENSE pin to the Vstart(soft) level and starts 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 stops switching. Depending on the protection

triggered and IC version (TEA1733T or TEA1733LT), 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

TEA1733(L) 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 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 Figure 4), the IC restarts.

When a latched protection is triggered, the TEA1733(L) immediately enters Power-down

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

(Vrst(latch) + 1 V).

TEA1733T_TEA1733LT_2

Product data sheet

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

Rev. 02 — 26 March 2010

© NXP B.V. 2010. All rights reserved.

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