Negative Voltage Detector for High-Voltage Ramp-Down Control
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Solution Overview
Problem
The ramping down of high voltage supplies in storage devices like 3D crosspoint memory arrays can lead to uncontrolled high current, posing a danger to circuitry and causing system power delivery issues, and existing methods to mitigate this by cutting off low voltage supplies before high voltage may be impractical or infeasible.
Innovation Solution
A voltage detector is used to sense a negative high voltage level and trigger a lower power state when it crosses a threshold, allowing controlled ramp-down of high voltage rails, thereby simplifying the supply ramp down sequence and reducing excessive current and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high voltage supplies are ramped down in storage devices, then power consumption is reduced, but uncontrolled high current occurs posing danger to circuitry
Solution Approach 1:
The patent implements a feedback mechanism by monitoring the voltage level on the high voltage rail (VNN) and using this information to control the timing of low voltage supply cutoff. The system continuously detects the voltage state and adjusts the power supply sequence accordingly, ensuring that low voltage is cut off only when the high voltage has reached a safe level, thus preventing uncontrolled current while enabling energy reduction.
Solution Approach 2:
The patent applies preliminary action by first ramping down the high voltage supply (VNN) before cutting off the low voltage supply. This sequencing ensures that the potentially harmful high current condition is eliminated in advance before the low voltage cutoff occurs, preventing circuitry damage while still achieving the goal of reducing power consumption through controlled shutdown.
2Reliability
If low voltage supplies are cut off before high voltage to prevent uncontrolled current, then circuitry safety is improved, but the supply ramp down sequence becomes complex and impractical
Solution Approach 1:
The patent inverts the conventional approach by ramping down the high voltage supply first and then cutting off the low voltage supply, rather than cutting off low voltage first as traditionally done. This reversal simplifies the control logic while maintaining circuitry safety, as the high voltage monitoring automatically determines the appropriate timing for low voltage cutoff without requiring complex coordinated control.
Solution Approach 2:
The system uses the high voltage rail itself to provide the control signal for shutdown sequencing. The VNN voltage level directly controls the gating of the low voltage supply through voltage-dependent switches, eliminating the need for external control circuits or complex sequencing logic. The high voltage supply essentially services its own shutdown timing requirement.
3Object-affected harmful factors
If voltage detection and control circuitry is added to enable controlled ramp-down, then current control is improved, but device complexity increases
Solution Approach 1:
The patent introduces voltage detection circuitry and control switches as intermediary elements between the power supplies and the load. These intermediaries monitor the high voltage level and automatically control the low voltage supply timing, providing precise current control without requiring complex external control systems. The intermediaries translate voltage level information into appropriate control actions.
Solution Approach 2:
The patent combines the voltage detection function and the supply control function into a unified control mechanism. The same circuit elements that detect the high voltage level also directly control the low voltage supply gating, merging sensing and actuation functions. This integration reduces the number of separate components and simplifies the overall control architecture.
Data Source
AI summary
An apparatus comprising an input to couple to a negative voltage source; and circuitry to detect whether the input has crossed a negative voltage threshold, wherein the circuitry comprises a first capacitor that is selectively coupled to the first input and a second capacitor that is selectively coupled to a second input coupled to a positive voltage source.