TEA1532BT 데이터 시트보기 (PDF) - NXP Semiconductors.

부품명

상세내역

제조사

TEA1532BT

GreenChip II SMPS control IC

NXP Semiconductors. 

NXP Semiconductors

TEA1532BT; TEA1532CT

GreenChip II SMPS control IC

protection is reset. The latch is reset as soon as VCC drops below 4.5 V (typical value)

(this only occurs when the mains has been disconnected). The internal

overtemperature protection will also trigger this latch; see also Figure 1.

For the TEA1532BT the IC always enters the latched mode protection independent of the

voltage on pin CTRL.

A voltage higher than 3 V on pin PROTECT will always latch the IC. This is independent of

the state or the version of the IC.

7.15 OverTemperature Protection (OTP)

The IC provides accurate OTP. The IC will stop switching when the junction temperature

exceeds the thermal shutdown temperature. When VCC drops to Vth(UVLO), capacitor CVCC

will be recharged to the Vstartup level, however switching will not restart. Subsequently, VCC

will drop again to Vth(UVLO), etc.

Operation only recommences when VCC drops below a level of about 4.5 V (typically,

when Vmains is disconnected for a short period).

7.16 Brown-out protection

During the so called brown-out test, the input voltage is slowly decreased. Since the

on-time depends on Vi, long on-times at low Vi can damage the (external) power device.

This is prevented by stopping the converter when the input voltage drops too low.

When the voltage on pin DEM drops below −50 mV during the on-time (QR mode), the

maximum on-time is set to 25 µs. The maximum on-time will be reached while Vi is low.

Subsequently, the IC stops switching and VCC drops below Vth(UVLO). Capacitor CVCC will

only be recharged and the supply will restart only when voltage VI is high enough

(Vmains(oper)(en), also see Section 7.1). In addition to this, a VI level at which the converter

has to enter a safe restart can be set with a demagnetization resistor. During the primary

stroke, the rectified mains input voltage is measured by sensing the current drawn from

pin DEM. This current depends on the mains voltage, according to the following equation:

I DEM ≈ -R-V---D-a--E-u---Mx-- ≈ -N------×R----DV----E-m--M--a--i--n---s

Where: N = -N--N--a---up---x (ratio of the number of auxiliary to the number of primary windings)

The latter function requires an on-time of at least 2 µs. This on-time ensures that a reliable

demagnetization current can be measured.

When pin DEM is grounded (CCM), the brown-out protection is disabled. In this case the

duty cycle is limited to 0.7, so at low mains voltage the on-time is limited and therefore the

dissipation in the FET is limited.

7.17 Driver

The driver circuit to the gate of the power MOSFET has a current sourcing capability of

typically 170 mA and a current sink capability of typically 700 mA. This permits fast

turn-on and turn-off of the power MOSFET for efficient operation.

TEA1532BT_TEA1532CT_1

Product data sheet

Rev. 01 — 18 January 2007

© NXP B.V. 2007. All rights reserved.

11 of 23

Share Link: