Power Management Unit (PMU)

The Power Management Unit (PMU) provides four power domains that are internally generated by LDOs and supervised by several voltage monitors:

Core

Core domain is the main power domain for the RF and digital part inside the chip. The subsequent LDO_C converts the V_CORE input to respective voltages, which must be connected with a decoupling capacitor through the LDO_C pin. LDO_C drives the digital logic parts.

IO

IO power domain is powered by VDD_IO, including the chip IO devices, on-chip Flash, etc. The voltage supply of VDD_IO is 2.7 V to 3.6 V. Except IO devices, other PMU devices are powered by a dedicated LDO_EX. LDO_EX must be connected with a decoupling capacitor through LDO_EX pin.

Backup

Backup domain runs the RTC section and Retention RAM. This domain uses VDD_IO and V_BACK as the voltage sources. When the range of VDD_IO is normal, it uses VDD_IO, otherwise uses V_BACK. The allowed range of V_BACK is 1.7 V to 3.6 V. Therefore, an ordinary lithium battery or other battery can be directly connected to this pin. If you do not need the RTC and backup function, you must connect the V_BACK pin to VDD_IO.

TCXO

The clock domain supplies power to TCXO. This domain has a dedicated LDO called LDO_X, which is also powered by VDD_IO. If TCXO is powered by LDO_X, LDO_X should be connected to the power pin of TCXO and be decoupled by a capacitor. You can also choose an external power source other than LDO_X to power TCXO.

Based on the above division of power domains and hardware design, UC6580 has three modes of power consumption:

• Running mode: Every power source of the chip is normal, CPU runs normally, and the power supply of each domain is set by the software. All events, including external interruption, communication request, timing, etc., can be processed normally.

• V_BACK mode: The IO and main power supply of the chip is cut off from the outside, and there is only V_BACK power supply left. At this time, the power consumption of the chip drops to a very low level, and the specific functions and power consumption depend on the mode set by the software. It can wake up as soon as it is powered on.

• Power off mode: All power supplies are cut off from the outside, and the chip does not work at all.