TEA1732CTS

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© NXP Semiconductors N.V. 2014. All rights reserved.

Product data sheet

Rev. 1 — 18 March 2014

5 of 20

NXP Semiconductors

TEA1732CTS

GreenChip SMPS control IC

controller stops switching. The TEA1732CTS waits for the rectified mains to charge the

VCC pin using resistor R1.

7.3 Supply management

All internal reference voltages are derived from a temperature compensated on-chip band

gap circuit. Internal reference currents are derived from a trimmed and temperature

compensated current reference circuit.

7.4 External overtemperature protection and mains detect input

(pin PROTECT)

The PROTECT input combines the functions of the external OverTemperature Protection

(OTP) and the mains voltage detection. An internal clock separates the period of

measuring the mains voltage and the period of detecting external OverTemperature

Protection (OTP). In a typical application, the PROTECT pin is connected to the mains via

a resistor. It is connected to ground via a negative temperature coefficient (NTC)

thermistor and a diode.

When measuring the mains voltage, the PROTECT pin is regulated to 0.25 V so that the

external diode does not conduct any current. The current into the PROTECT pin is

measured and stored. Once the measured current is above the brownin level, the system

is allowed to start switching. If the mains voltage is continuously below the brownout level

for at least 32 ms, a brownout is detected. The system immediately stops switching and

performs a restart. The VCC capacitor is discharged to the UVLO level and then charged

Fig 4.

Start-up sequence, normal operation and restart sequence