Charge Pump Switch Power Down Protection Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor switches face issues with leakage currents when powered down, leading to power drain and signal distortion, and require sequenced power up to maintain stable logic signals, which existing protection circuits fail to address effectively.
Innovation Solution
A high-speed, low-power switch circuit with a level shifting circuit and power down protection circuit using a voltage-controlled switch and rectifier to isolate nodes and provide stable voltage, reducing leakage and eliminating the need for power up sequencing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If semiconductor switches are used to replace mechanical relays, then switching speed and current transfer capability are improved, but leakage currents occur when powered down causing power drain and signal distortion
Solution Approach 1:
The patent introduces a protection circuit as an intermediary between the semiconductor switch and the powered-down state. This circuit includes isolation transistors and pull-up/pull-down networks that actively manage the switch state during power-down, preventing direct leakage paths while maintaining the high-speed switching capability when powered.
Solution Approach 2:
The protection circuit applies preliminary anti-action by preemptively isolating the switch terminals and establishing defined voltage states before leakage can occur. The pull-up and pull-down networks are configured to counteract potential leakage currents, maintaining signal integrity even when the main power supply is off.
2Loss of energy
If protection circuits are added to prevent leakage currents, then power drain is reduced, but device complexity increases
Solution Approach 1:
The protection circuit functions are merged with the existing semiconductor switch structure. The isolation transistors are integrated alongside the main switch terminals, and the pull-up/pull-down networks share the same power supply nodes, reducing the need for separate discrete protection components.
Solution Approach 2:
The protection circuit is designed to serve multiple functions: preventing leakage currents, maintaining signal integrity, providing defined logic states during power-down, and protecting against signal distortion. This multi-functionality reduces the need for additional dedicated circuits for each protection function.
3Stability of the object's composition
If sequenced power up is implemented to maintain stable logic signals, then signal stability is improved, but power up time and control complexity increase
Solution Approach 1:
The protection circuit with pull-up and pull-down networks provides self-service during power-up by automatically establishing defined logic states at the switch terminals. As power becomes available, the networks self-regulate to prevent undefined states and signal distortion, eliminating the need for external sequencing control.
Solution Approach 2:
The protection circuit performs preliminary action by pre-establishing safe default states at the switch terminals before the main switching operation begins. The pull-up and pull-down networks are ready to immediately define logic levels, preventing signal distortion during the power-up transition without requiring coordinated sequencing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents leakage currents and ensures stable logic signal transfer without distortion, conserving energy and reducing the need for complex power sequencing.
Implementation Method 1
The first power supply can be isolated from the second power supply using a rectifier
Data Source
AI summary
This application discusses, among other things, switch circuit apparatus having power down protection and not requiring power up sequencing. An apparatus embodiment can include a first supply node coupled to a first input of a level shifting circuit via a protection circuit, a second supply node coupled to a second input of the level shifting circuit via a single pull-up transistor, and a switch including a control input, a first node, and a second node controllably isolated from the first node, wherein the control input is coupled to the level shifting circuit. The first and second inputs of the level shifting circuit can be coupled via a rectifier, and the protection circuit can be configured to power the first and second supply nodes to controllably isolate the first and second nodes from each other when a voltage of one of the first or second nodes exceeds a threshold.