Contents

AN4324

2/31

DocID024963 Rev 2.0

Contents

1

Architectural overview .................................................................... 4

2

STC3115 selection guide ................................................................ 5

2.1

STC3115 version selection ............................................................... 5

2.2

STC3115 version detection ............................................................... 6

3

Battery parameters.......................................................................... 7

3.1

Battery internal impedance identification........................................... 8

3.2

Battery open circuit voltage (OCV) curve measurement and

calculation ...................................................................................................... 9

4

Schematic guidelines.................................................................... 10

4.1

Sense resistor selection .................................................................. 10

4.1.1

Sense resistor impedance value ...................................................... 10

4.1.2

Sense resistance impedance accuracy............................................ 10

4.1.3

Sense resistance power dissipation capability ................................. 10

4.1.4

Sense resistor deviation over temperature range (TCR) ................. 11

4.1.5

Sense resistor selection proposal .................................................... 11

4.2

BatD pin system integration ............................................................ 11

4.3

RSTIO pin system integration ......................................................... 14

5

Place and route guidelines ........................................................... 16

5.1

Vin pin connection........................................................................... 16

5.2

External sense resistor.................................................................... 17

5.3

Temperature considerations............................................................ 18

5.4

STMicroelectronics PCB design recommendations ........................ 19

6

Software ......................................................................................... 20

6.1

STC3115 RAM memory organization proposal ............................... 21

6.2

Chip initialization ............................................................................. 22

6.3

STC3115 running configuration....................................................... 27

6.4

Periodic device access.................................................................... 27

6.4.1

First STC3115 access after initialization .......................................... 27

6.5

STC3115 task procedure ................................................................ 28

6.5.1

How often the STC3115 has to be called in run mode..................... 28

6.6

STOP procedure ............................................................................. 28

6.7

Power saving mode software management .................................... 29