Voltage Regulator Startup Overshooting Control
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Solution Overview
Problem
Voltage regulators in existing technologies experience significant overshooting in output voltage when the source voltage rapidly increases, such as during the startup of a power source, due to inadequate timing in supplying current to the gate of the output transistor.
Innovation Solution
Incorporation of an ON/OFF circuit that controls the overshooting control circuit to turn on the output transistor only after a predetermined time has passed since the error amplifier circuit is activated, along with a source voltage fluctuation detector circuit to manage the gate voltage of the PMOS transistor, preventing overshooting by delaying the output voltage stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the error amplifier circuit is turned on immediately at startup, then the output voltage can be regulated quickly, but significant overshooting occurs in the output voltage
Solution Approach 1:
The ON/OFF control circuit activates the error amplifier circuit in advance before the main power switch is turned on. This preliminary activation allows the error amplifier to be ready and prevents output voltage overshooting when the power switch is subsequently activated, as the error amplifier can immediately respond to regulate the output voltage.
2Productivity
If the output transistor is turned on immediately when source voltage increases, then power delivery is fast, but the current timing is inadequate causing great overshooting
Solution Approach 1:
The error amplifier circuit is activated in advance to prepare the control system before the power switch is turned on. This ensures that when the power switch activates and power delivery begins, the error amplifier is already ready to precisely control the output transistor, preventing voltage overshooting while maintaining fast power delivery.
Solution Approach 2:
The error amplifier circuit continuously monitors the output voltage and provides feedback control to the output transistor. This feedback mechanism ensures that the output voltage remains stable and precise during power delivery, preventing overshooting while maintaining fast response.
3Ease of operation
If the circuit is activated without delay control, then the startup process is simple and fast, but erroneous operations or malfunctions occur due to overshooting
Solution Approach 1:
The ON/OFF control circuit automatically manages the sequencing of circuit activation, turning on the error amplifier circuit before the main power switch. This automated preliminary action maintains startup simplicity while preventing erroneous operations or malfunctions that would otherwise occur due to voltage overshooting.
Data Source
AI summary
A voltage regulator is provided which can suppress an occurrence of overshooting in an output voltage at the time of starting a power source with a source voltage or the like. The voltage regulator includes an error amplifier circuit, an overshooting control circuit that is connected to the gate of an output transistor, and an ON/OFF circuit that controls ON and OFF states of at least the error amplifier circuit. Here, the ON/OFF circuit controls the overshooting control circuit so as to turn on the output transistor when a predetermined time passes after at least the error amplifier circuit is turned on at the time of starting the voltage regulator.