SMPS Loop Filter Trigger Circuit for Fast Transient Response
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Solution Overview
Problem
Switch-mode power supplies (SMPS) experience delays in supplying full power to connected elements and peripherals due to lag time in responding to sudden load current demands, leading to system performance issues like output voltage sag and overshoot.
Innovation Solution
A circuit with an SMPS loop filter and trigger mechanism that enables or disables the loop filter based on current demand, using an op-amp and feedback network to rapidly adjust current levels without a separate reservoir or boost power supply, allowing for fast transient response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a traditional SMPS loop filter circuit is used to maintain stable output voltage, then voltage stability is improved, but the response time to sudden load current demands worsens (lag time increases)
Solution Approach 1:
The circuit charges a feedback capacitor to an anticipated current level in advance, before the actual load demand occurs. This preliminary charging action allows the capacitor to immediately supply the required current when load changes occur, eliminating the lag time while maintaining voltage stability through the pre-positioned energy reserve.
Solution Approach 2:
The circuit dynamically adjusts the feedback capacitor charge level based on anticipated load conditions. The trigger circuit detects upcoming load changes and modifies the capacitor charging level accordingly, allowing the system to adapt its response characteristics in real-time rather than relying on fixed loop filter parameters.
2Speed
If digital solutions or separate reservoir/boost power supplies are added to improve transient response, then response speed is improved, but device complexity increases
Solution Approach 1:
The circuit merges the transient response improvement function directly into the existing SMPS loop filter by utilizing the feedback capacitor that is already part of the control loop. This integration eliminates the need for separate reservoir capacitors or boost power supply circuits, achieving fast transient response while maintaining simple circuit architecture.
Solution Approach 2:
The feedback capacitor serves dual purposes: it performs its normal function in the loop filter for voltage regulation while simultaneously providing the transient current response capability. This self-service approach allows a single component to fulfill multiple functions, eliminating the need for additional dedicated transient response components.
Data Source
AI summary
A circuit includes a reference voltage, a switched mode power supply (SMPS) loop filter circuit configured to provide an inductor current limit based on the reference voltage, and a trigger circuit configured to enable or disable the SMPS loop filter circuit. When the SMPS loop filter circuit is enabled, an output of the circuit is based on output of the SMPS loop filter circuit and output voltage of the SMPS. When the SMPS loop filter circuit is disabled, the SMPS current control circuit output is based on an estimated current limit that is increased when load current demand will increase and decreased when load current demand will decrease.