Switching Converter Stability with Current Limiting Oscillator
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Summary
Problems
Switching converters experience instability and potential damage due to drastic changes in switching frequency when an external adjustment resistor is short-circuited or open-circuited, leading to electromagnetic interference and stability issues.
Innovation solutions
The oscillator incorporates a charging current generating circuit with a variable resistor and a current limiting module, which limits the charging current to a preset value when the resistor is shorted or opened, thereby stabilizing the switching frequency.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If frequency jitter technology is adopted to suppress electromagnetic interference, then electromagnetic compatibility is improved, but switching frequency stability deteriorates when external resistors are shorted or opened
Why choose this principle:
The patent implements a feedback mechanism where the oscillator monitors the charging current through the variable resistor and automatically adjusts to maintain frequency within a safe range. When the resistor is shorted or opened, the feedback loop detects the abnormal condition and prevents drastic frequency changes, thus resolving the contradiction between EMI suppression and system stability.
Principle concept:
If frequency jitter technology is adopted to suppress electromagnetic interference, then electromagnetic compatibility is improved, but switching frequency stability deteriorates when external resistors are shorted or opened
Why choose this principle:
The patent changes the operating parameters of the oscillator by introducing a variable resistor that can be adjusted to modify the charging current. This allows the system to adapt the switching frequency to different operating conditions while maintaining stability through the current limiting module, which constrains the frequency parameter within safe boundaries even when the resistor fails.
Application Domain
Data Source
AI summary:
The oscillator incorporates a charging current generating circuit with a variable resistor and a current limiting module, which limits the charging current to a preset value when the resistor is shorted or opened, thereby stabilizing the switching frequency.
Abstract
Disclosed are a switching converter and an oscillator thereof. The oscillator includes a charging current generating circuit and a clock signal generator circuit, which is used for generating a clock signal according to a charging current provided by the charging current generating circuit. The charging current generating circuit includes a variable resistor and a current limiting module. The current limiting module is used for limiting a current value of the charging current to a preset current value when the variable resistor is shorted or opened, thus avoiding drastic change of a switching frequency of the circuit when the external variable resistor is shorted or opened, so as to improve system stability.