Integrated Switch Conduction Time Adjustment for Power Supply Transients
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In switching power supplies, transient disturbances during start-up cause undesirable deviations in voltage and current due to the slow response of feedback circuits, which do not account for switch conduction time adjustments based on current conditions.
Innovation Solution
An integrated circuit with a control circuit that reduces the switch's conduction time in response to the current during each switching period, independent of the control signal, using a pulse width modulator and current sensing mechanism to adjust the duty ratio and stabilize the power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the feedback circuit regulates the average value of output over many switching periods, then the output regulation is accurate, but the response to transient disturbances is slow
Solution Approach 1:
The patent applies preliminary action by adjusting the switch conduction time based on predicted current conditions before disturbances fully manifest. The control circuit proactively modifies conduction time in response to current during each switching period, preventing transient disturbances from causing large deviations rather than merely correcting them after detection by the feedback circuit.
2Device complexity
If the conduction time is determined solely by the feedback signal, then the control is simple, but the response to transient disturbances is delayed
Solution Approach 1:
The patent merges two control approaches: the feedback signal determination and the current-based conduction time adjustment. The total conduction time is formed by combining the feedback signal component with an additional adjustment component that responds to current conditions during each switching period. This integration provides both simplicity and improved transient response.
Solution Approach 2:
The patent implements feedback by continuously monitoring the current during each switching period and using this information to adjust the conduction time. The control circuit receives feedback about current conditions and modifies the switch operation in real-time, creating a rapid response mechanism that complements the slower average-value feedback regulation.
3Stability of the object's composition
If the feedback circuit is designed to regulate average output values, then the steady-state regulation is stable, but transient events cause undesirable voltage and current deviations
Solution Approach 1:
The patent applies preliminary anti-action by implementing a control mechanism that counteracts transient disturbances before they cause significant deviations. The current-based conduction time adjustment acts in opposition to emerging transient effects, reducing the magnitude of voltage and current deviations during start-up and other transient events while preserving steady-state stability.
Data Source
AI summary
An apparatus and method of providing a pulse width modulated signal that is responsive to a current are disclosed. An integrated circuit according to aspects of the present invention regulates an output of a power supply and includes a switch coupled to receive an external current. The integrated circuit also includes a controller coupled to the switch to control a switching of the external current by the switch in response to an external control signal and an internal current sense signal. The internal current sense signal is proportional to a current in the switch. The output of the power supply is also regulated in the absence of the internal current sense signal.