PWM Circuit Using Dual Control Words for Flexible Duty Cycles
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Solution Overview
Problem
Current PWM circuits have limited flexibility and reliability in generating pulse signals due to their counter control units' limited counting range, leading to restricted frequency and duty cycle capabilities, and poor anti-interference capabilities when controlling analog circuits.
Innovation Solution
A PWM circuit comprising a control word providing circuit and a pulse generation circuit that generates target frequency control words based on a desired duty cycle, allowing for flexible and reliable generation of pulse signals with adjustable duty cycles, using a comparison sub-circuit, pulse generation sub-circuit, and output selection sub-circuit to produce target pulse signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a counter control unit is used to generate pulse signals, then the circuit structure is simple, but the counting range is limited which restricts frequency and duty cycle capabilities
Solution Approach 1:
The patent replaces the traditional mechanical counter-based control system with a direct digital frequency control word input mechanism. Instead of using a counter that increments through fixed states, the system accepts frequency control words directly as input parameters, allowing arbitrary frequency and duty cycle values to be set without mechanical counting limitations. This substitution enables continuous adjustment of pulse signal parameters while maintaining circuit simplicity.
2Adaptability or versatility
If the counting range is increased to improve frequency capabilities, then the pulse signal generation flexibility improves, but the device complexity increases
Solution Approach 1:
The patent transitions from a one-dimensional counter approach (single counting sequence) to a multi-dimensional parameter input approach where frequency control words and duty cycle control words are independently adjustable parameters. This dimensional change allows the system to access a much larger parameter space without increasing the fundamental circuit complexity, as the additional degrees of freedom are achieved through parallel parameter inputs rather than sequential counting stages.
3Ease of operation
If traditional PWM circuits are used to control analog circuits, then the control function is achieved, but the anti-interference capability is poor
Solution Approach 1:
The patent replaces the traditional analog PWM control mechanism with a direct digital control approach where frequency control words and duty cycle control words are processed digitally. This substitution enhances anti-interference capability by using digital logic that is inherently more resistant to noise and interference compared to analog circuits, while maintaining full control functionality through the digital-to-analog conversion inherent in the PWM generation process.
Data Source
AI summary
A pulse width modulation (PWM) circuit, a method for PWM, and an electronic device are provided. In the PWM circuit, a control word providing circuit can generate, based on an obtained target duty cycle, two target frequency control words with a ratio of the target duty cycle, and output the two target frequency control words to a pulse generation circuit, wherein a ratio of the first target frequency control word to the second target frequency control word is the target duty cycle; and the pulse generation circuit can output a target pulse signal with the target duty cycle under the control of the two target frequency control words.