TDA3681A Ver la hoja de datos (PDF) - Philips Electronics

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TDA3681A

Multiple voltage regulator with switch and ignition buffer

Philips Electronics 

Philips Semiconductors

Multiple voltage regulator with

switch and ignition buffer

Product specification

TDA3681A

During an overload condition or a short circuit

(VSW < VP − 3.7 V), the voltage on the reset delay

capacitor rises 0.6 V above the voltage of regulator 2. This

rise time depends on the capacitor connected to

pin CCRES. During this time, the power switch can deliver

more than 3 A. When regulator 2 is out of regulation and

generates a reset, the power switch can only deliver 2 A

and will immediately go into foldback protection.

At supply voltages > 17 V, the power switch is clamped at

16 V maximum (to avoid externally connected circuits

being damaged by an overvoltage) and the power switch

will switch off at load dump.

Interfacing with the microcontroller (simple full or semi

on/off logic applications) can be realized with an

independent ignition Schmitt trigger and ignition output

buffer (push-pull output).

The timing diagrams are illustrated in Figs 4 and 5.

The second supply voltage VP2 is used for the switchable

regulators 3 and 4. This input can be connected to a lower

supply voltage of ≥ 6 V to reduce the power dissipation of

the TDA3681A. A DC-to-DC converter could be used for

this purpose.

handbook, full pagewidth

VP1 = VP2

18 V

8.9 V

7.0 V

4.0 V

enable ≥1.8 V

regulator 1/3 1.3 V

8.5 V

regulator 1

0V

5.0 V

regulator 3

0V

enable >1.8 V

regulator 4

<1.3 V

3.3 V

regulator 4

0V

16.9 V

VP

7.0 V

4.0 V

enable

power

switch

power

switch

output

>1.8 V

<1.3 V

16 V

0V

2003 Aug 29

load dump

VP and enable Schmitt trigger

load dump

Power switch behaviour

Fig.4 Timing diagram of regulators and power switch.

7

MGL906

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