PWM Signal Generation Circuit Soft-Start Control
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Solution Overview
Problem
Existing PWM signal generation circuits require significant computational resources and cannot output a PWM signal immediately after starting, limiting their ability to optimally control the timing of the destination circuit's transition from a stop state to an operational state.
Innovation Solution
A PWM signal generation circuit and processor system that utilize a duty setting unit, period setting unit, and output control unit to generate a PWM signal based on initial and target duty ratios, slope settings, and a clock signal, allowing immediate generation and soft-start control of the PWM signal without relying on output voltage monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the processor calculates the difference between reference voltage and output voltage through computing process, then soft-start control can be achieved, but the processor requires high computing capacity
Solution Approach 1:
The patent replaces the computational approach (processor calculating voltage differences) with a direct electrical comparison approach. The PWM comparator circuit directly compares the triangular wave voltage with the error amplifier output voltage, eliminating the need for computational processing and reducing processor burden while maintaining soft-start control functionality.
Solution Approach 2:
The patent introduces an error amplifier as an intermediary component that converts voltage differences into a comparable signal form. The error amplifier processes the voltage comparison function, allowing the PWM comparator to operate with voltage signals rather than requiring digital computation, thus simplifying the overall system complexity.
2Reliability
If predetermined time is taken from start of PWM signal generation process until actual output, then circuit stability can be ensured, but the circuit cannot output PWM signal immediately and optimal timing control is restricted
Solution Approach 1:
The patent performs preliminary setup of all control parameters (initial duty ratio, target duty ratio, slope setting value, period setting value) in registers before PWM signal generation begins. The triangular wave generation and comparison circuits are pre-configured, allowing the PWM signal to be output immediately without waiting for computational processing or sequential initialization, thus eliminating delay time while maintaining stability.
Solution Approach 2:
The patent implements dynamic duty ratio adjustment during PWM signal generation. The duty ratio changes from initial to target value according to the slope setting, allowing the circuit to adapt its output characteristics in real-time. This dynamic control enables immediate PWM output with optimized timing, as the system can adjust parameters on-the-fly rather than requiring predetermined stable states.
Data Source
AI summary
A PWM signal generation circuit according to the present invention includes a duty setting unit (10) configured to generate a duty control signal designating a duty ratio corresponding to each period of a PWM signal on the basis of an initial duty setting signal, a target duty setting signal, a slope setting signal, and a clock signal, a period setting unit (20) configured to output a period setting value, and an output control unit (30) configured to generate the PWM signal having a period corresponding to the period setting value and having a duty ratio corresponding to a value of the duty control signal. The duty setting unit (10) increases the value of the initial duty ratio to the value of the target duty ratio each time the number of a clock pulse of the clock signal reaches the period setting value reaches the slope setting value.