PWM Controller Architecture Eliminates ADCs via Inductor Current Inference
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Solution Overview
Problem
Existing electronic power systems that use pulse width modulation (PWM) controllers require analog-to-digital converters (ADCs) to sample output voltages, which increases complexity and costs, and may not efficiently regulate power due to measurement inaccuracies.
Innovation Solution
A PWM controller architecture that infers output voltage based on demagnetization time and current flow through an inductor, eliminating the need for ADCs and allowing for adaptive pulse width modulation without direct voltage measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ADC is used to sample output voltage for PWM control, then voltage measurement capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the ADC component from the PWM controller architecture. Instead of using an ADC to measure output voltage, the system uses the existing current sensing circuitry and timer resources to infer voltage information through alternative measurement methods, thereby removing the complex and costly ADC while maintaining control functionality
Solution Approach 2:
The patent replaces the electronic ADC-based voltage measurement system with a timer-based indirect measurement approach. By substituting the direct voltage sampling mechanism with a time-measurement mechanism that infers voltage from current flow characteristics, the system achieves voltage regulation without requiring an ADC
2Reliability
If ADC is used to sample output voltage, then voltage regulation capability is improved, but power consumption increases
Solution Approach 1:
The patent removes the ADC component from the power consumption budget of the PWM controller. By eliminating this high-power component and replacing it with timer and current-sensing circuitry that consume minimal power, the system maintains reliable voltage regulation while significantly reducing overall controller power consumption
3Measurement precision
If ADC sampling is used for voltage measurement, then measurement capability is improved, but bill of materials cost increases
Solution Approach 1:
The patent extracts and removes the ADC component from the bill of materials. By utilizing existing timer and current-sensing resources already present in the PWM controller, the system eliminates the need to purchase and integrate an additional ADC component, thereby reducing the overall bill of materials cost while maintaining the ability to measure and regulate output voltage
Data Source
AI summary
Systems, apparatuses, and techniques for pulse width modulation (PWM) are described. A described system includes a circuit that contains an inductor and a transistor that controls current through the inductor based on a PWM signal to produce an output; and a controller to provide the PWM signal, which includes PWM cycles that include on-durations and off-durations. The controller can receive a first signal indicating an input voltage that is applied to the inductor, receive a second signal indicating a current through the inductor, use an on-duration parameter value to control the on-duration, determine a maximum off-duration of the off-durations corresponding to the PWM cycles occurring within a first voltage cycle, the first voltage cycle being defined between two consecutive zero-crossing events as indicated by the first signal, and adjust the on-duration parameter value for a second, subsequent voltage cycle based on the maximum off-duration to regulate the output voltage.