Multi-Phase DC/DC Converter PWM Control for Current Balancing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multi-phase DC/DC converters, current imbalance occurs due to deviations in coil inductance values, leading to current concentration in specific channels.
Innovation Solution
A control device with an error signal generation circuit, current detection circuit, PWM modulation circuit, and drive circuits that adjust pulse-width modulation signals to equalize current flow across channels by identifying and correcting the channel with the greatest deviation from the average current value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple coils are used in parallel channels to increase power output, then the power handling capability is improved, but current imbalance occurs due to inductance deviation among coils
Solution Approach 1:
The patent implements a feedback mechanism where the control device continuously monitors the current in each channel and adjusts the PWM duty cycle accordingly. The control device calculates the difference between each channel's current and the average current, then modifies the PWM signal to equalize currents across all channels, ensuring reliable operation while maintaining high power output capability
Solution Approach 2:
The patent dynamically adjusts the PWM duty cycle for each channel based on real-time current measurements. By making the duty cycle variable rather than fixed, the system can adapt to inductance deviations and maintain current balance across channels, allowing the multi-phase converter to operate reliably at high power levels
2Stability of the object's composition
If phase difference is configured at the switch of multiple output-stage circuits to obtain stable output voltage, then the output voltage stability is improved, but current concentration occurs in specific channels due to inductance deviation
Solution Approach 1:
The patent changes the PWM duty cycle parameter for each channel based on detected current levels. By adjusting this key parameter dynamically, the system maintains both output voltage stability (through phase difference control) and current distribution balance (through duty cycle adjustment), preventing current concentration in specific channels
Solution Approach 2:
The patent applies different PWM duty cycles to different channels based on their individual current characteristics. Instead of using a uniform control approach, the system tailors the control parameters locally for each channel, compensating for inductance variations and ensuring balanced current distribution while maintaining overall voltage stability
3Reliability
If current detection and adjustment control is implemented for each channel to equalize currents, then the current balance is improved, but the device complexity increases
Solution Approach 1:
The patent implements a universal control architecture where a single control device performs multiple functions: it detects current in all channels, calculates average current, determines current differences, and generates adjusted PWM signals for all channels. This multi-functional approach achieves current balance without requiring separate complex control circuits for each channel, minimizing overall device complexity
Data Source
AI summary
The present disclosure provides a control device of a multi-phase DC/DC converter. The control device generates an error signal between a feedback voltage and a reference voltage according to an output voltage. For each channel, a detected current value of a target current is derived by A/D converting the target current flowing through a switching transistor during an ON period of the switching transistor. A PWM signal is generated based on the error signal and a current corresponding signal corresponding to the target current to drive the switching transistor. An average value of multiple detected current values corresponding to multiple channels is derived. The channel corresponding to the detected current value with largest difference from the average value is specified as a target channel. The value of the target current in the target channel approaches the average value. The PWM signal corresponding to the target channel can be generated.