Semiconductor Power Supply Control Circuit with Adjustable Switching Frequency
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Solution Overview
Problem
Existing AC-DC converters struggle to dynamically change switching frequency to reduce noise and accommodate smaller transformer sizes, while also efficiently managing standby power consumption and output ripple.
Innovation Solution
A semiconductor device with a clock generating circuit, voltage/current control circuit, and internal power supply voltage control circuit that allows for external setting of switching frequency and feedback terminal voltage, enabling latch stop or gate stop modes to prioritize power consumption or ripple reduction based on system needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the switching frequency is fixed to control output voltage according to feedback voltage characteristics, then the output voltage control is stable, but the switching frequency cannot be changed to reduce noise or to use a smaller transformer
Solution Approach 1:
The patent applies dynamics by making the switching frequency adjustable rather than fixed. The clock generating circuit includes an oscillating circuit with changeable frequency that generates clock signals based on external resistance values connected to the ADJ terminal. This allows the switching frequency to be dynamically changed according to system requirements for noise reduction or transformer size optimization, while maintaining stable output voltage control through the feedback mechanism.
2Object-affected harmful factors
If the switching frequency is changed to reduce noise, then noise reduction is achieved, but the control of output voltage according to feedback voltage characteristics is compromised
Solution Approach 1:
The patent applies parameter changes by allowing the switching frequency parameter to be adjusted through external resistance connections to the ADJ terminal. The oscillating circuit's frequency can be changed based on these external parameters, enabling noise reduction through frequency adjustment while the feedback voltage characteristics maintain output voltage control stability. The system changes the frequency parameter dynamically without compromising the fundamental control mechanism.
3Volume of stationary object
If a smaller transformer is used to reduce apparatus size, then the device size is reduced, but the switching frequency cannot be optimized for the smaller transformer
Solution Approach 1:
The patent applies dynamics by enabling the switching frequency to be adjusted according to the transformer size and characteristics. When a smaller transformer is used to reduce apparatus size, the switching frequency can be optimized through external resistance connections to the ADJ terminal, allowing the system to adapt to the different magnetic characteristics and inductance values of smaller transformers, thereby maintaining efficient operation.
4Adaptability or versatility
If the feedback terminal voltage is fixed to control switching element turn-off, then the control is simple, but the power consumption and ripple cannot be optimized based on system needs
Solution Approach 1:
The patent applies parameter changes by allowing the feedback terminal voltage threshold for switching element turn-off to be adjusted based on system requirements. The internal power supply voltage control circuit can set different voltage thresholds, enabling optimization of power consumption and output ripple characteristics. External resistance connections influence the operating mode, allowing the system to adapt between different optimization goals without increasing fundamental circuit complexity.
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
Enables flexible switching frequency control to address noise and size constraints, while allowing for external setting of feedback voltage to manage power consumption and ripple, enhancing the efficiency and adaptability of the power supply control semiconductor device.
Implementation Method 1
an oscillating circuit in which a frequency can be changed and which generates a clock signal to provide timing to periodically turn on the switching element
Implementation Method 2
a voltage converting transformer including a primary side winding, a secondary side winding and an auxiliary winding
Implementation Method 3
voltage which is converted by electric current-voltage conversion with the resistance
Data Source
AI summary
A semiconductor device, for controlling a power supply which generates and outputs a driving pulse, includes: a clock generating circuit with an oscillating circuit in which a frequency can be changed and which generates a clock signal; a voltage/electric current control circuit which provides timing to turn off a switching element; a setting terminal to provide setting information from outside; a switch between a first power supply terminal and a second power supply terminal; and an internal power supply voltage control circuit which controls the switch. When voltage of the setting terminal is lower than a first voltage value, the device advances to a first stop mode in which output of a driving pulse is stopped. When voltage of the setting terminal is higher than the first voltage value, the device advances to a second stop mode in which the output of the driving pulse is stopped.