Operation description

STNS01

20/29

DocID024654 Rev 2

If the temperature goes back into the normal operating range before the maximum charging

time has elapsed, the charging process is resumed from where it left off and the alarm signal

is cleared. If the charging timeout expires while the temperature is still outside the normal

operationg range, the charging process is stopped but can be restarted using the CEN pin.

Both temperature thresholds feature a 3 °C hysteresis.

The battery temperature monitoring block is designed to work with an NTC thermistor

having R

25

= 10 k

Ω and ß = 3370 (e.g. Mitsubishi TH05-3H103F).

8.4

Battery overcharge protection

The battery overcharge protection is a safety feature which is active when a valid input

voltage is connected and prevents the battery voltage from increasing over V

OCHG

. When an

overcharge condition is detected, the current path from the input to the battery is blocked

and the fault signal is activated (the CHG pin toggles). When the battery voltage falls again

under V

OCHG

the input voltage (V

IN

) must be disconnected and re-connected to restore

normal operating conditions.

8.5

Battery overdischarge protection

When there is no valid input voltage and the device is running on battery power, the battery

voltage is monitored to avoid overdischarge. If the battery voltage falls below V

ODC

for more

than t

ODD

, the device is turned off and battery drain is reduced to less than 500 nA. This

condition is called the overdischarge state.

When a valid input voltage is connected while in the overdischarge state, the charger and

the LDO are activated. If the input voltage is then disconnected, normal operation is

restored only if the battery voltage has increased above the overdischarge release threshold

(V

ODCR

), otherwise the STNS01 remains in the battery overdischarge state.

Figure 21. Discharging cycle profile

AM17199v1

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

0.22

0.24

2

2.2

2.4

2.6

2.8

3

3.2

3.4

3.6

3.8

4

4.2

4.4

5:52

6:01

6:10

6:18

6:27

6:36

Time [ h:m ]