DC-DC Converter Pulse-Pairing Circuitry for Load Current Support
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Solution Overview
Problem
DC-DC converters operating in pulse-pairing mode face challenges with lower load current support and higher voltage ripples, especially at light load currents, due to limitations in pulse separation interval selection and symmetry of pulses, leading to potential stall or failure when input and output voltages are near each other.
Innovation Solution
A DC-DC converter system with pulse-pairing circuitry that includes a paired pulse generator, load detector, and maximum on timing controller, which adjusts the pulse duration based on load conditions to ensure symmetric pulses and optimal pulse separation, using a clock signal to maintain a target notch frequency and prevent pulse merging, thereby maximizing load current support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pulse separation interval is limited to a certain range to support DC-DC converter functionality, then the converter operates reliably, but the flexibility of choosing the pulse separation interval is reduced and load current support is limited
Solution Approach 1:
The patent implements dynamic adjustment of the pulse separation interval through a calibration routine that automatically determines the maximum pulse separation interval based on actual converter performance. The system transitions from static, pre-defined interval limits to dynamic, adaptive interval selection that responds to real-time operating conditions, thereby simultaneously maintaining reliability and enhancing flexibility.
Solution Approach 2:
The patent changes the parameter of pulse separation interval from a fixed, limited range to a dynamically determined maximum value through calibration. By measuring actual converter response and adjusting the interval parameter accordingly, the system expands the usable range while maintaining operational reliability, directly resolving the contradiction between reliability and adaptability.
2Stability of the object's composition
If conditions are applied to avoid merging paired pulses, then pulse symmetry is maintained, but load current support is reduced
Solution Approach 1:
The patent performs a preliminary calibration routine before normal operation to determine the maximum pulse separation interval that maintains pulse symmetry. By pre-characterizing the converter's response and storing this information for use during operation, the system can maintain symmetry without the conservative limitations that would otherwise reduce load current support.
Solution Approach 2:
The system uses its own operational characteristics during calibration to automatically determine the optimal pulse separation interval. Through self-testing and self-characterization, the converter identifies the maximum interval that maintains symmetry, eliminating the need for external tuning or conservative design margins that would limit load current support.
3Ease of operation
If the on pulse time is limited to a maximum level for buck converters, then converter operation is controlled, but load current support is insufficient at low input voltage
Solution Approach 1:
The patent replaces static maximum on-time limits with dynamic, calibrated timing parameters that adapt to input voltage conditions. The calibration routine determines optimal timing values for different operating ranges, allowing the converter to maintain control while supporting higher load currents at low input voltages where fixed limits would be insufficient.
Solution Approach 2:
The system uses feedback from calibration measurements to automatically adjust pulse timing parameters. By monitoring the converter's actual response during calibration and using this information to set operating parameters, the system achieves both ease of operation through automatic control and sufficient load current support across all input voltage conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively maximizes load current support and reduces voltage ripples by ensuring symmetric pulses and optimal pulse duration, even at light load currents, and prevents converter stall or failure by automatically calibrating pulse timing to maintain efficient operation.
Implementation Method 1
The DC-DC converter circuitry switches current through an inductive element based on an on time signal between a zero current level and a peak current level to convert a source voltage to an output voltage
Implementation Method 2
The pairing of pulses in the pulse train of a DC-DC converter is referred to herein as pulse-pairing mode. The notch frequency of a DC-DC converter operating in pulse-pairing mode may be adjusted at the radio frequency (RF) frequency band of the receiver to minimize the effect of EMI on the sensitivity of the receiver
Data Source
AI summary
A DC-DC converter including converter circuitry, a voltage detector providing a low voltage signal, and pulse-pairing circuitry. The converter circuitry may be configured according to a buck or a boost configuration switching between a zero and peak current levels. The pulse-pairing circuitry includes a paired pulse generator, a load detector, and a maximum on timing controller. In response to the low voltage signal, the paired pulse generator activates an on signal for a pair of equal duration on pulses separated by a predetermined pulse separation interval. The on time periods are based on an adjustable time value and a peak current indication. The load detector provides a load adjust signal for adjusting the time value based on sampling the low voltage signal and an off time signal at the start of the second pulse. The maximum on timing controller adjusts the adjustable time value based on the load adjust signal.