Power Supply Detection Circuit for Low-VDDC Output Driver Protection
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Solution Overview
Problem
Integrated circuits face challenges in detecting core and input/output power supply voltages effectively, leading to short circuit power dissipation at output drivers, especially during sleep modes and power up scenarios, and require efficient power management across different voltage levels.
Innovation Solution
A power supply detection circuit comprising an input circuit, sense logic circuit, current mirror circuit, and output circuit that generates and inverts output voltages to detect core power supply voltage activation and inactivation, minimizing power dissipation by regulating voltage levels and preventing static current dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the integrated circuit is operated at a low VDDC to save power, then power consumption is reduced, but short circuit power dissipation occurs at output drivers when VDDC is inactivated
Solution Approach 1:
The power supply detection circuit performs preliminary detection of VDDC presence before enabling IO circuits. The input circuit responds to VDDC to generate a first output voltage, and the sense logic circuit detects voltage drops before the IO circuits are fully activated, preventing short circuit conditions by preparing the system in advance
Solution Approach 2:
The power supply detection circuit acts as an intermediary between the core logic circuit and IO circuits. It uses the current mirror circuit to sense voltage drops and control the timing of IO circuit activation, mediating the power supply sequence to prevent direct short circuit conditions while maintaining low power operation
2Productivity
If VDDIO is provided before VDDC during power up, then IO circuits can be initialized early, but short circuit power dissipation occurs at output drivers
Solution Approach 1:
The sense logic circuit continuously monitors the first output voltage generated by the input circuit for voltage drops that would indicate unsafe conditions. This feedback mechanism prevents VDDIO from being applied to IO circuits until VDDC is confirmed present, eliminating short circuit risk while allowing early initialization when safe
Solution Approach 2:
The detection circuit performs preliminary verification of VDDC presence through the input and sense logic circuits before allowing VDDIO to be provided to IO circuits. This preliminary action ensures the safe sequence is maintained while enabling early IO initialization when conditions permit
3Adaptability or versatility
If the IO circuit is operated at different VDDIOs to optimize power and performance, then operational flexibility is improved, but complex power supply detection and control is required
Solution Approach 1:
The power supply detection circuit serves multiple functions: it detects VDDC presence, monitors for voltage drops, controls VDDIO timing, and enables different VDDIO operating modes. This universal circuit handles all power supply detection and control needs without requiring separate dedicated circuits for each function
Data Source
AI summary
Power supply detection circuit. The power supply detection circuit includes an input circuit responsive to a core power supply voltage to generate a first output voltage at a first node. The power supply detection circuit also includes a sense logic circuit to sense a voltage drop associated with the first output voltage, when the first output voltage is at a logic level HIGH. Further, the power supply detection circuit includes a current mirror circuit responsive to the voltage drop to increase voltage of the first output voltage to an input and output power supply voltage. Moreover, the power supply detection circuit also includes an output circuit that inverts the first output voltage to generate a second output voltage at a second node.