* Question

Which power-manager parameters are statically configurable?

* Answer

In a power-management system—whether inside an MCU, SoC, or dedicated PMIC—statically configurable parameters refer to settings that are defined once at design time or boot time and do not change during runtime. These values are typically stored in hardware straps, eFuses, OTP memory, or the device tree, and they determine the foundational behavior of the power architecture.

Below are the core parameters that are normally considered statically configurable.

1. Power-domain definitions

These describe how the chip’s logic is divided into independent regions.

• Domain boundaries
• Default ON/OFF state at reset
• Parent–child dependencies
• Which blocks belong to each domain

Because power domains are tied to the hardware topology, they are not dynamically modified.

2. Voltage-rail and regulator defaults

These values establish safe startup conditions and remain fixed during system operation.

• Default output voltages
• Power-up and power-down sequencing order
• Current-limit thresholds
• Brown-out reset levels

These parameters protect the device from incorrect sequencing or over-current conditions.

3. Clock and reset topology

The base configuration of the clock tree is usually static.

• Default clock sources for each domain
• Reset ordering and dependency rules
• Minimum safe boot frequencies

These ensure that the system reaches a known good state after power-on.

4. Low-power mode retention rules

Certain retention decisions are defined ahead of time.

• Which memories retain content in deep sleep
• Which regulators remain active
• Clock-gating rules during sleep entry

These behaviors are typically encoded in firmware or OTP.

5. Wake-up source configuration (if stored in nonvolatile memory)

In some devices, wake-up capabilities are fixed at manufacturing.

• Allowed wake-up pins or events
• Edge or level sensitivity
• Deep-sleep exit rules

If stored in eFuses or OTP, these are treated as static parameters.

6. Thermal and safety thresholds

To protect the silicon, safety limits are rarely changed at runtime.

• Thermal shutdown trigger points
• Over-voltage or under-voltage protection limits
• Over-current detection thresholds

These ensure consistent device safety across all operating conditions.

Summary

Statically configurable power-manager parameters typically include:

• Power-domain boundaries and dependencies
• Regulator default voltages and sequencing
• Brown-out, OVP/OCP thresholds
• Clock and reset initialization behavior
• Deep-sleep retention policies
• Wake-up source definitions (when fuse-based)
• Thermal and safety limits

These parameters collectively establish the non-modifiable foundation of a system’s power architecture, ensuring predictable startup behavior, reliable low-power operation, and safe system performance.