DC-DC Converter Bias Current Control for False Trigger Prevention
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Solution Overview
Problem
Existing switch mode DC-DC converters are prone to false triggers due to bias current variations, requiring complex additional circuitry to prevent them, which increases costs.
Innovation Solution
An electronic device with a switch mode DC-DC converter that adjusts bias current based on load conditions using pulse width modulation (PWM) and pulse frequency modulation (PFM) modes, reducing bias current gradually when load decreases and increasing it quickly when load increases, with slopes of opposite signs and varying absolute values to prevent mode changes and maintain robust control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If bias current is reduced to lower power consumption, then power consumption decreases, but false triggers increase
Solution Approach 1:
The bias current is made dynamic rather than static, automatically adjusting its magnitude based on operating conditions. The circuit switches between high bias current mode (for stability during transients) and low bias current mode (for power savings during steady-state), resolving the contradiction by adapting the bias current level to the specific operational context rather than using a fixed value
Solution Approach 2:
The bias current parameter is changed based on detected operating conditions. The circuit monitors parameters such as output voltage stability and load changes, and accordingly adjusts the bias current magnitude to prevent false triggers while minimizing power consumption during normal operation
2Reliability
If bias current is increased to prevent false triggers, then reliability improves, but power consumption increases
Solution Approach 1:
The bias current is made dynamic rather than static, automatically adjusting its magnitude based on operating conditions. The circuit switches between high bias current mode (for stability during transients) and low bias current mode (for power savings during steady-state), resolving the contradiction by adapting the bias current level to the specific operational context rather than using a fixed value
Solution Approach 2:
The bias current is applied periodically or in pulses rather than continuously. The circuit activates high bias current only when needed (during mode transitions or transient conditions) and reduces it during stable operation, achieving both reliability and power efficiency through temporal modulation of the bias current
3Speed
If bias current changes quickly to respond to load changes, then response speed improves, but false triggers increase
Solution Approach 1:
The bias current adjustment rate is made dynamic, with the circuit capable of both rapid changes (for quick load response) and controlled changes (to prevent false triggers). The system adapts the rate of bias current change based on the severity and type of load variation detected
Solution Approach 2:
The circuit incorporates damping or filtering mechanisms that cushion abrupt bias current changes. Before the bias current fully responds to load changes, the circuit applies controlled rate-of-change limits or intermediate transition stages to prevent oscillations and false triggers while maintaining overall fast response capability
Data Source
AI summary
The invention relates to an electronic device and a method for DC-DC conversion using a comparator for generating an output signal for driving a power switch of a switch mode DC-DC converter. The electronic device is configured to reduce a bias current of the comparator with a first slope in response to a decreasing load and to increase the bias current of the comparator with a second slope in response to an increasing load, wherein the second slope is steeper than the first slope.