Power-On Control Circuit for Multi-Domain Write Protection
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Solution Overview
Problem
In multiple power domain circuits, especially non-volatile memory circuits, there is a challenge in preventing unintentional writing due to improper voltage application, leading to standby power consumption and area penalties from large power switch designs.
Innovation Solution
A novel power on control (POC) circuit that detects voltage levels and enables or disables sensitive circuits only when both voltage supplies are ready, ensuring zero standby current when not asserted, thereby preventing unintentional enabling of biasing-sensitive circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large power switch designs are used to control multiple power domains, then reliability is improved by preventing unintentional writing, but standby power consumption increases and area is penalized
Solution Approach 1:
The power control function is segmented into multiple independent power domains (first power domain with first voltage supply, second power domain with second voltage supply). Each domain can be independently controlled and powered on/off, allowing the system to prevent unintentional writing by controlling power to specific domains rather than using large power switches that consume standby power.
Solution Approach 2:
The power on control circuit is configured to be automatically enabled when the first voltage supply is active, and it autonomously detects when the second voltage supply is ready. This self-service mechanism eliminates the need for external control signals and large standby power switches, as the circuit automatically manages its own power domain transitions.
2Reliability
If large power switch designs are used to control multiple power domains, then reliability is improved by preventing unintentional writing, but device area is penalized
Solution Approach 1:
The power control function is segmented into multiple independent power domains (first power domain with first voltage supply, second power domain with second voltage supply). Each domain can be independently controlled and powered on/off, allowing the system to prevent unintentional writing by controlling power to specific domains rather than using large power switches that consume standby power.
3Ease of operation
If voltage levels are not properly monitored before enabling circuits, then circuit operation simplicity is improved, but manufacturing precision deteriorates due to unintentional writing
Solution Approach 1:
The power on control circuit includes a feedback mechanism that continuously monitors the voltage level of the second voltage supply through a second input terminal. When the second voltage supply reaches a sufficient level, the circuit automatically enables the second power domain. This feedback-based voltage monitoring ensures precise control without complicating the overall operation, as the monitoring is integrated into the power on control circuit itself.
Data Source
AI summary
An electronic device includes a first circuit, a second circuit, and a power on control (POC) circuit. The POC circuit includes an enable terminal electrically connected to a first output of the first circuit, a first input terminal electrically connected to a first voltage supply, a second input terminal electrically connected to a second voltage supply, and an output terminal. The second circuit includes a biasing-sensitive circuit, and a logic circuit including a first input terminal electrically connected to a second output of the first circuit, a second input terminal electrically connected to the output of the POC circuit, and an output terminal electrically connected to an enable terminal of the biasing-sensitive circuit.