Soft-Start Switching Power Converter Dynamic Resistance Control
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Solution Overview
Problem
Conventional switching power converters require a longer start-up time and consume more power due to high resistance in the resistor network, which slows down the charging of capacitors and increases overall power consumption.
Innovation Solution
The soft-start switching power converter incorporates a transformer with a primary and secondary winding, a switch controlled by a control signal, and a soft-start circuit that adjusts the voltage level to reduce start-up time and power consumption by using a lower resistance path for charging, allowing the feedback voltage to reach a preset starting voltage more quickly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high resistance resistors are used in the voltage converter circuit, then the circuit can provide voltage division and capacitor charging functions, but the start-up time increases significantly
Solution Approach 1:
The patent applies dynamics by making the resistance value changeable during operation. A control circuit dynamically adjusts the resistance of the first resistor based on the voltage level detected at the control terminal of the switch. During start-up, the resistance is kept high to enable proper voltage division and capacitor charging. Once the voltage reaches a certain level, the control circuit reduces the resistance to accelerate the charging process, thus resolving the contradiction between needing high resistance for voltage division and needing low resistance for fast start-up.
2Reliability
If high resistance resistors are used in the voltage converter circuit, then the circuit can maintain voltage levels, but power consumption increases
Solution Approach 1:
The control circuit dynamically adjusts the resistance value based on operating conditions. When the output voltage is low, the resistance is maintained at a higher value to ensure proper voltage division and stable operation. When the voltage reaches acceptable levels, the resistance is reduced to minimize power consumption. This dynamic adjustment allows the circuit to maintain voltage levels when needed while reducing energy waste during normal operation.
Solution Approach 2:
The patent changes the resistance parameter of the first resistor based on the voltage detection results. The control circuit monitors the voltage at the control terminal and adjusts the resistance accordingly - maintaining high resistance for voltage stability during start-up, then reducing resistance to lower power consumption during steady-state operation. This parameter change strategy resolves the contradiction between voltage maintenance and energy efficiency.
3Loss of time
If the capacitor charging current is increased to reduce start-up time, then the start-up speed improves, but power consumption increases
Solution Approach 1:
Instead of using a fixed high current for capacitor charging, the patent employs dynamic resistance adjustment. The control circuit monitors the voltage level and adjusts the resistance in real-time. During the initial phase, higher resistance limits the current to reduce power consumption. As the voltage builds up, the resistance is reduced to increase charging current and accelerate start-up. This dynamic approach achieves fast start-up without sustained high power consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design reduces start-up time to approximately 0.1 seconds and decreases power consumption by using lower resistance components, resulting in a more efficient switching process.
Implementation Method 1
The second secondary winding, based on the conduction and nonconduction of the first switch and a turns ratio of the primary winding to the second secondary winding, generates an induced current that is associated with the rectified voltage
Data Source
AI summary
A soft-start switching power converter includes a voltage converting circuit and a soft-start circuit. The voltage converting circuit includes a transformer, and a first switch which includes a first terminal connected to the transformer, a second terminal providing a trigger signal, and a control terminal receiving a control signal, and which is controlled to switch between conduction and nonconduction, such that the transformer generates a feedback voltage. The soft-start circuit receives the trigger signal, generates the control signal according to the trigger signal, and determines whether or not to clamp the control signal at a preset voltage level based on the trigger signal.