Voltage Regulator Rapid Stabilization via Pre-Charged Capacitor
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Solution Overview
Problem
Conventional voltage regulators take a long time to activate the output voltage to a stable level due to large load capacitance and low output current, which can cause damage to internal circuits with low breakdown voltage.
Innovation Solution
A voltage regulator design incorporating an amplifier, an output MOS transistor, and capacitive elements with a control circuit that adjusts the gate voltage of the output transistor, allowing for rapid stabilization of the output voltage by controlling the capacitance ratio between the capacitive elements, thereby preventing direct application of the input power supply voltage to internal circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a pre-charge circuit is used to speed up activation, then the output voltage stabilizes faster, but the device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-charging the compensation capacitor through a dedicated pre-charge circuit before the main output transistor is activated. This ensures that when the voltage regulator starts operating, the compensation capacitor is already charged to the appropriate voltage level, enabling immediate stable output voltage without requiring additional stabilization time. The pre-charge circuit is controlled to activate before the main output transistor, preparing the compensation network in advance.
2Speed
If the output transistor gate voltage is immediately set to Vin level, then the output voltage rises quickly, but internal circuits with low breakdown voltage may be damaged
Solution Approach 1:
The patent uses preliminary action by first charging the compensation capacitor to an appropriate voltage level before activating the output transistor. This ensures that when the output transistor gate voltage rises, the compensation capacitor is already prepared to provide the necessary voltage division, preventing excessive voltage spikes that could damage internal circuits. The control circuit is designed to activate the pre-charge circuit before the main output transistor, preparing the compensation network in advance.
Solution Approach 2:
The compensation capacitor serves as an intermediary element between the output transistor gate and the feedback network. By controlling the voltage on this capacitor through the pre-charge circuit, the patent mediates the voltage transition, ensuring that the gate voltage rises in a controlled manner that prevents damage to internal circuits while still achieving quick stabilization. The capacitor acts as a buffer that smooths out abrupt voltage changes.
3Stability of the object's composition
If the load capacitance is large and output current is small, then the voltage regulator provides stable output, but the activation time becomes excessively long
Solution Approach 1:
The patent applies preliminary action by pre-charging the compensation capacitor before the main output transistor is activated. This preliminary charging of the compensation network compensates for the effect of large load capacitance, allowing the output voltage to stabilize quickly even when the load capacitance is large and the output current is small. The pre-charged compensation capacitor provides the necessary voltage reference immediately, preventing the long activation time that would otherwise occur.
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
This design significantly shortens the activation time of the output voltage to a prescribed range, preventing damage to internal circuits and allowing for a smaller voltage regulator size without the need for a pre-charge circuit.
Implementation Method 1
A first capacitive element has a first terminal connected to the output terminal of the amplifier and a second terminal connected to ground or an output terminal of the output MOS transistor. A second capacitive element has a first terminal connected to the output terminal of the amplifier.
Data Source
AI summary
An output voltage of a voltage regulator is set to within a prescribed voltage range in a short time. The voltage regulator comprises: an amplifier (AMP) that amplifies a difference between a reference voltage and a voltage proportional to an output voltage; an NMOS transistor (MN1) that has a control terminal connected to an output terminal of the amplifier (AMP) and that drops a power supply voltage to output an output voltage; a first capacitive element (C1) that has a first terminal connected to the output terminal of the amplifier (AMP) and a second terminal connected to ground; a second capacitive element (C2) that has a first terminal connected to the output terminal of the amplifier (AMP); and a control circuit (11) that, subsequent to supply of the power supply voltage, controls operation activation of the amplifier (AMP) and also supplies a drive signal to a second terminal of the second capacitive element (C2).