Bypass Voltage Regulator Soft-Start for Current Surge Control
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Solution Overview
Problem
Voltage regulators in bypass mode experience rapid output voltage rise, leading to potential circuit damage due to high current generation, necessitating a soft-start mechanism to manage this transition safely.
Innovation Solution
A voltage regulator design incorporating an amplifier, start signal generator, and power transistor, where the start signal is incremental during startup in bypass mode, allowing the output voltage to rise gradually by setting the reference voltage equal to the operating power and controlling the driving voltage through a feedback loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the voltage regulator operates in bypass mode with direct output voltage generation, then the response speed is improved, but the output stage generates very large current that may damage the circuit
Solution Approach 1:
The patent applies preliminary action by implementing a soft-start mechanism that pre-controls the output voltage transition before full bypass mode operation. A startup time interval is established during which the output voltage is gradually increased from 0V to the operating power level, preventing sudden current surges that would occur with direct voltage generation. This preliminary controlled transition resolves the contradiction by maintaining fast response after startup while eliminating the harmful current spike during initialization.
Solution Approach 2:
The patent applies dynamics by making the voltage regulation mode adjustable and time-dependent. During the startup time interval, the regulator operates in a controlled mode with gradual voltage increase. After startup completion, it dynamically switches to bypass mode for fast response. This dynamic mode switching resolves the contradiction by allowing the system to exhibit different behavioral characteristics at different times - slow and safe during startup, fast and efficient during normal operation.
2Reliability
If a soft-start mechanism is implemented in bypass mode, then the circuit safety is improved, but the startup time interval extends the response time
Solution Approach 1:
The patent applies partial action by implementing soft-start only during the necessary startup time interval and then transitioning to full bypass mode. The soft-start mechanism is not continuously applied but only during the initial phase when voltage transition is needed. This resolves the contradiction by providing safety measures (soft-start) only when necessary during startup, while allowing full performance (bypass mode) to be utilized during normal operation, thus minimizing the time penalty.
3Productivity
If the output voltage rapidly rises from 0V to operating power, then the productivity is improved, but the output stage generates excessive current
Solution Approach 1:
The patent applies beforehand cushioning by introducing a controlled resistance or current limiting mechanism during the startup time interval that cushions the voltage transition. This cushioning effect gradually allows current flow as voltage increases, preventing the sudden current surge that would occur with direct voltage application. After startup, the cushioning is removed and full power delivery is enabled. This resolves the contradiction by providing protective cushioning only when needed during voltage establishment, while maintaining full productivity during normal operation.
Data Source
AI summary
A voltage regulator including an amplifier, a start signal generator and a power transistor is provided. The amplifier has a first positive input terminal, a second positive input terminal, and a negative input terminal to receive a start signal, a reference voltage and a feedback voltage respectively. An output terminal of the amplifier generates a driving voltage. The start signal generator is coupled to the first positive input terminal of the amplifier and generates the start signal, which is incremental, during a startup time interval in a voltage bypass mode. The power transistor generates an output voltage according to the driving voltage based on an operating power. In the voltage bypass mode, the reference voltage is equal to the operating power. A soft-start effect can be effectively achieved by the voltage regulator in the voltage bypass mode.