User's Manual Part 1

MC75 Hardware Interface Description

Strictly confidential / Draft

MC75_V00.190a Page 32 of 91 15.02.2005

3.2.3.4 Undervoltage Shutdown if no Battery NTC is Present

The undervoltage protection is also effective in applications, where no NTC connects to the

BATT_TEMP terminal. Thus, you can take advantage of this feature even though the

application handles the charging process or MC75 is fed by a fixed supply voltage. All you

need to do is executing the write command AT^SBC=<current> which automatically enables

the presentation of URCs. You do not need to specify <current>.

Whenever the supply voltage falls below the specified value (see table TBD.) the URC

^SBC: Undervoltage

appears several times before the module switches off.

3.2.3.5 Overvoltage Shutdown

In the event of the voltage rising above the maximum voltage (see Table TBD) the module

sends a URC and then performs an orderly shutdown. Further details: TBD

Keep in mind that several MC75 components are directly linked to BATT+ and, therefore, the

supply voltage remains applied at major parts of MC75, even if the module is switched off.

Especially the power amplifier is very sensitive to high voltage and might even be destroyed.