Efficient Start-Up Circuit Design with Charge Pump Control
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Summary
Problems
Existing start up circuits for integrated circuits face issues with high power consumption and heat generation due to large resistors, and complexity in prior art solutions that utilize parasitic transistors and depletion mode FETs, which also suffer from body effects and unnecessary power consumption paths.
Innovation solutions
A start up circuit utilizing a depletion mode transistor controlled by a charge pump, where the charge pump increases the gate voltage of the transistor to counteract body effects and turn it off once the startup voltage is reached, eliminating the need for resistors and complex control circuits.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If a high resistance resistor is used to limit current in the start up circuit, then power consumption is reduced, but the area of the resistor becomes very large and heat generation increases
Why choose this principle:
The invention changes the operating parameters of the depletion mode FET by dynamically adjusting its gate voltage. During start-up, the gate voltage is low allowing high current to quickly charge the capacitor. After start-up, the gate voltage is raised to counteract the body effect and reduce current flow, eliminating the need for large high-value resistors while maintaining low power consumption.
Principle concept:
If a high resistance resistor is used to limit current in the start up circuit, then power consumption is reduced, but the area of the resistor becomes very large and heat generation increases
Why choose this principle:
The invention replaces the passive resistor-based current limiting mechanism with an active FET-based electronic control system. This substitution allows for dynamic current control through voltage regulation, achieving both compact area and low power consumption that cannot be achieved with resistors alone.
Application Domain
Data Source
AI summary:
A start up circuit utilizing a depletion mode transistor controlled by a charge pump, where the charge pump increases the gate voltage of the transistor to counteract body effects and turn it off once the startup voltage is reached, eliminating the need for resistors and complex control circuits.
Abstract
The present invention discloses a charge pump start up circuit comprising: a start up transistor having one end which is electrically connected with a voltage supply source, and another end which is electrically connected to a voltage node; and a charge pump circuit having an input which is electrically connected with the voltage node, and an output which is electrically with the gate of the start up transistor.