High-Voltage Regulator Disable Circuit for Asynchronous Supply Rails
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Solution Overview
Problem
Existing voltage regulators face challenges in being disabled independently of supply voltage synchronization, particularly when dealing with asynchronous external power sources, leading to undesirable electrical flow conditions and potential component damage due to high voltages.
Innovation Solution
A circuit is developed that includes a voltage selection circuit and a power-down generator circuit to generate a selected voltage based on the higher of two supply voltages, ensuring the regulator gate voltage is appropriately controlled to prevent excessive voltage drops across components, using transistors and voltage dividers to manage power-down signals and protect electrical components from high voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voltage regulator is disabled independently of supply voltage synchronization, then the regulator can be controlled to prevent excessive voltage drops, but asynchronous external power sources may cause undesirable electrical flow conditions
Solution Approach 1:
The patent introduces an intermediary voltage selection circuit between the external power source and the voltage regulator. This circuit monitors both the external low voltage supply and the internal high voltage supply, and selectively connects them to the regulator based on which supply is active. This intermediary mechanism prevents direct connection of asynchronous power sources, thereby avoiding harmful electrical flow while maintaining reliable regulator control.
2Reliability
If high voltage supplies are used to ensure proper regulator operation, then the regulator can function correctly, but components may be damaged due to excessive voltage drops
Solution Approach 1:
The patent implements a dynamic voltage selection mechanism that continuously monitors the states of both external low voltage supply and internal high voltage supply. The voltage selection circuit dynamically switches between these supplies based on real-time conditions, ensuring the regulator receives appropriate voltage without exposing components to excessive voltage drops. This dynamic adaptation allows correct regulator operation while preventing component damage.
3Reliability
If voltage selection circuitry is added to manage power supplies, then voltage drops can be controlled within safe limits, but the device complexity increases
Solution Approach 1:
The voltage selection circuit is designed to perform multiple functions: it monitors both power supply sources, determines which supply is active, selectively connects the appropriate supply to the regulator, and prevents harmful electrical flow. By consolidating these multiple functions into a single integrated circuit, the patent achieves effective voltage drop control without proportionally increasing overall device complexity.
Data Source
AI summary
An example power management unit utilizing an example circuit to disable a voltage regulator is provided. The example circuit includes a voltage selection circuit and a power-down switching device. The voltage selection circuit configured to receive a first voltage source and a second voltage source to output a selected voltage based on the higher of the two input voltages. The voltage selection circuit utilizes a first transistor electrically connected in parallel with a second transistor between the first voltage source and the second voltage source to generate the selected voltage. The second transistor gate voltage at the second transistor gate is generated based at least in part on a voltage at the first transistor drain. The selected voltage is generated based on a voltage at the second transistor drain. The power-down switching device is configured to generate a voltage for a voltage regulator based on the selected voltage.