TLE6389_07 datasheet(29/38 Pages) INFINEON

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TLE 6389

Datasheet Rev. 2.1

2007-08-13

7.4

SI_Enable

Connecting SI_ENABLE to 5V causes SI_GND to have low impedance. Thus the SI

comparator is in operation and can be used to monitor the battery voltage. SO output

signal is valid. Connecting SI_ENABLE to GND causes SI_GND to have high

impedance. Thus the SI comparator is not able to monitor the battery voltage. SO output

signal is invalid.

7.5

Battery sense comparator - voltage divider

The formula to calculate the resistor divider for the sense comparator is basically the

same as for the feedback divider in section before. With the selected resistor RSI2, the

desired threshold of the input voltage VIN, UV and the lower sense threshold VSI, low the

resistor RSI1 is given to:

For high accuracy and low ohmic resistor divider values the On-resistance of the

SI_GND NMOS (typ. 100

Ω) has to be added to RSI2.

7.6

Undervoltage reset - delay time

The diagram below shows the typical behavior of the reset output in dependency on the

input voltage VIN, the output voltage VVOUT or VFB.

RSI1

RSI2

VIN UV

VSI low

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TLE6389 Datasheet(PDF) 29 Page - Infineon Technologies AG