4.1.4 Typical Powering Schematics

The device supports single-supply operation. Restrictions on this range may apply depending on enabled features. Refer to the section Electrical Characteristics.

Note that in the typical power supply schemes that follow, with or without a backup battery, the SLCD and the internal LCD voltage regulator can be used in all power modes. The LCD voltage regulator can be disabled to save its operating current. VDDLCD must then be provided externally and thus the contrast level must be managed by adjusting this supply. Internal and external wake-up sources (WKUPx, TMPx, FWUP) can be used in the power schemes illustrated below. Extra tamper or wake-up input pins referenced to VDD3V3 can be used in Backup mode as long as VDD3V3 is supplied in Backup mode.

Important: The figures in the following sections show simplified schematics of the power section. Underwriters Laboratories (UL) standards, and specifically the UL standard 60950-1 battery protection circuit, are not represented.