Linear Frequency-Modulated Oscillator for DC-DC Startup Stability
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Solution Overview
Problem
Existing oscillators fail to effectively control inductor current slope during the startup phase of DC-to-DC converters, leading to potential damage due to large voltage differences and current fluctuations.
Innovation Solution
An oscillator with a reference current generating circuit, voltage modulator circuit, and oscillating circuit performs linear frequency modulation on the oscillation signal to stabilize the inductor current and output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If frequency hopping modulation operation is performed, then frequency modulation is achieved, but drastic changes in output voltage and inductor current occur
Solution Approach 1:
The patent implements dynamic frequency modulation by continuously adjusting the oscillation frequency based on real-time feedback voltage from the output terminal. The oscillator circuit modifies its operating frequency dynamically rather than hopping between discrete frequencies, creating a smooth frequency transition that stabilizes output voltage and inductor current during startup and short-circuit conditions
2Adaptability or versatility
If frequency hopping modulation operation is performed, then frequency modulation is achieved, but drastic changes in inductor current occur
Solution Approach 1:
The oscillator continuously adjusts frequency based on feedback voltage, creating a dynamic response that prevents large inductor current fluctuations. This gradual frequency adaptation allows the inductor current to change smoothly rather than experiencing drastic variations associated with frequency hopping
Solution Approach 2:
The patent employs feedback control where the oscillation frequency is continuously adjusted based on the feedback voltage from the output terminal. This closed-loop control mechanism ensures that frequency changes are proportional to actual output conditions, preventing excessive inductor current fluctuations during startup and fault conditions
3Ease of operation
If conventional oscillator is used during startup phase, then oscillation signal is generated, but inductor current slope becomes too large to control
Solution Approach 1:
The oscillator dynamically adjusts its frequency based on the feedback voltage level during startup. When output voltage is low during startup, the feedback voltage causes the oscillator to operate at a lower frequency, which reduces the inductor current slope and makes current control feasible during the critical startup phase
Data Source
AI summary
The oscillator includes a reference current generating circuit, a voltage modulator circuit, and an oscillating circuit. The reference current generating circuit is arranged to generate a reference current. The voltage modulator circuit is arranged to receive a feedback voltage, and perform a voltage modulation operation according to a first reference voltage and the feedback voltage, to generate a modulated voltage. The oscillating circuit is coupled to the reference current generating circuit and the voltage modulator circuit, and arranged to generate an oscillation signal with an oscillation frequency according to the reference current and the modulated voltage.