Datasheet

TLE 6389

Datasheet Rev. 2.1 29 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 R

SI2

, the

desired threshold of the input voltage V

IN, UV

and the lower sense threshold V

SI, low

the

resistor R

SI1

is given to:

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

SI_GND NMOS (typ. 100Ω) has to be added to R

SI2

7.6 Undervoltage reset - delay time

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

input voltage V

, the output voltage V

VOUT

or V

SI1

SI2

IN UV,

SI low,

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