Multiphase Power Regulator Blanking Control for Load Transients
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Solution Overview
Problem
Multiphase power regulators face challenges in reducing transients such as voltage undershoot and overshoot due to rapid changes in load current, which can lead to insufficient output voltage margins and require larger output capacitors, increasing costs.
Innovation Solution
A control circuit with a phase management circuit and PWM circuit that dynamically adjusts the blanking time and phase interleave to reduce transients by adding or shedding phases and modifying the blanking control signal in response to transient events, thereby minimizing undershoot and overshoot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiphase power regulators are used to reduce ripple and improve response times, then power conversion performance is improved, but transient events such as voltage undershoot and overshoot occur due to rapid load current changes
Solution Approach 1:
The transient detector proactively monitors output voltage and current to detect transient events before they cause significant voltage deviations. By triggering the phase management circuit in advance, the system can rapidly reconfigure phases to counteract the transient, preventing severe undershoot or overshoot conditions
2Reliability
If the number of phases is increased to reduce transients, then transient reduction is improved, but device complexity and cost increase
Solution Approach 1:
The phase management circuit dynamically adjusts the number of active phases based on real-time transient conditions. During normal operation, fewer phases are active, reducing complexity. When transients are detected, the circuit rapidly activates additional phases to suppress the transient, providing adaptive transient reduction without permanently increasing system complexity
Solution Approach 2:
The system changes the operational parameters of existing phases dynamically. The phase management circuit modifies PWM duty cycles, phase shifting angles, and activation sequences based on transient severity, allowing the same physical phases to adapt their behavior to different transient conditions without adding hardware
3Reliability
If output capacitor size is increased to maintain voltage margins during transients, then output voltage stability is improved, but cost and device size increase
Solution Approach 1:
The transient detector continuously monitors output voltage and current, providing real-time feedback to the phase management circuit. This feedback loop enables the system to detect transient events and adjust phase configuration dynamically, maintaining voltage margins without requiring oversized capacitors to provide passive voltage support during transients
Data Source
AI summary
An example circuit includes a loop controller having current phase inputs, a feedback input, a control loop output and a transient event output. The feedback input is adapted to be coupled to an output terminal of a multi-phase power stage. A PWM circuit has a blanking input, a control input and a PWM output, the control input coupled to the control loop output. A phase management circuit has a transient detect input, a PWM input, a blanking output and phase outputs. The transient detect input is coupled to the transient event output. The PWM input is coupled to the PWM output and the blanking output is coupled to the blanking input. Each of the phase outputs is adapted to be coupled to a respective phase of the multi-phase power stage. The phase management circuit is configured to provide a blanking control signal representative of a variable blanking time.