User Manual

Apollo3 Blue Datasheet

DS-A3-0p9p1 Page 771 of 909 2019 Ambiq Micro, Inc.

20. Voltage Regulator Module

Figure 93. Block Diagram for the Voltage Regulator Module

20.1 Functional Overview

The Voltage Regulator Module down-converts and regulates the supply voltage, VDD, with extremely high

efficiency. A pair of Buck Converters enables down-conversion from the power supply input (e.g., a

battery) at efficiency of >80%. With ultra-low quiescent current, the Buck Converters are optimized for low

power environments. There are also integrated low dropout linear regulators which are used in very low

power modes and can also be utilized to provide a lower cost system solution by eliminating the need for

the external capacitors/inductors required in buck mode.

The Buck Converters and LDOs of the Voltage Regulator Module are tightly coupled to the various low

power modes in the Apollo3 Blue MCU. When the Apollo3 Blue MCU enters deep sleep mode, the Buck

Converters will switch into a low power mode to provide very high efficiency at low quiescent current

20.2 SIMO Buck

The SIMO buck sources the primary supplies for the core and memory domains. This buck is a very high

efficiency, single-inductor/multiple-output design. The SIMO buck is enabled via an OTP

CUSTOMER_TRIM setting. Upon initial reset, if enabled, the SIMO buck will be power up and stabilized

through hardware control. The status of the SIMO buck can be queried via the

PWRCTRL_SUPPLYSTATUS register (See Section Section 3.5.3.1.2.2 on page 79). The SIMO buck has

an efficiency ultra low power mode that is entered automatically via hardware control based on active load

current of the system.

LDO

SIMO Buck

LDO

VDD

To Core

To Logic

To Analog

Blocks

To Memory

Buck

LDO

To Comms