TEA1738FT Ver la hoja de datos (PDF) - NXP Semiconductors.

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TEA1738FT

GreenChip SMPS control IC

NXP Semiconductors. 

NXP Semiconductors

TEA1738FT

GreenChip SMPS control IC

7.6 Protection input (PROTECT PIN)

Pin PROTECT is a general purpose input pin, which can be used to switch off the

converter (latched protection). The converter is stopped when the voltage on this pin is

pulled above Vdet(H)(PROTECT) (0.8 V typical) or below Vdet(L)(PROTECT) (0.5 V typical). A

current of 32 A (typical) flows out of the chip when the pin voltage is at the

Vdet(L)(PROTECT) level. A current of 107 A (typical) flows into the chip when the pin voltage

is at the Vdet(H)(PROTECT) level.

The PROTECT input can be used to create an overvoltage detection and OTP functions.

A small capacitor can be connected to the pin if the protections on this pin are not used.

An internal clamp of 4.1 V (typical) protects this pin from excessive voltages.

7.7 Duty cycle control (CTRL pin)

The output power of the converter is regulated by the CTRL pin. This pin is connected to

an internal 5.4 V supply using an internal 7 k resistor.

The CTRL pin voltage sets the peak current which is measured via pin ISENSE.

(see Section 7.11) At low and medium output power the switching frequency is reduced

(see Section 7.13). The maximum duty cycle is limited to 80 % (typical).

7.8 Slope compensation (CTRL pin)

A slope compensation circuit is integrated in the IC for CCM. Slope compensation

guarantees stable operation for duty cycles greater than 50 %.

7.9 Overpower timer (OPTIMER pin)

If the OPTIMER pin is connected to capacitor C4 (see Figure 3), a temporary overload

situation is allowed. Vctrl(Ipeak) (see Figure 1) is set by pin CTRL. When Vctrl(Ipeak) is above

400 mV, the IIO(OPTIMER) current (11 A typical) is sourced from the OPTIMER pin. If the

voltage on the OPTIMER pin reaches the Vprot(OPTIMER) voltage (2.5 V typical) the

OverPower Protection (OPP) is triggered (see Figure 5).

When the Vprot(OPTIMER) voltage is reached, the TEA1738FT restarts.

TEA1738FT

Preliminary data sheet

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

Rev. 1 — 30 December 2010

© NXP B.V. 2010. All rights reserved.

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