Switching Driving Circuit with Dynamic Reference Voltage Compensation
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Solution Overview
Problem
Typical switching driving circuits fail to maintain a consistent driving current for target circuits, such as displays, due to variations in input and output voltages, leading to issues with applying desired full-wave rectified voltage and achieving desired brightness.
Innovation Solution
A switching driving circuit with a controller and compensation circuit that compares sensing voltage with a reference voltage, regulating the reference voltage based on variations in input and output voltages to maintain a constant driving current, using a switch, sensing resistor, and a voltage divider with capacitors and resistors to ensure stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a typical switching driving circuit uses a fixed reference voltage for controlling the switch, then the circuit structure is simple, but the driving current cannot be maintained consistently when input or output voltage varies
Solution Approach 1:
The patent implements a feedback mechanism where the sensing voltage (proportional to driving current) is compared with a reference voltage to generate control signals for the switch. The controller adjusts the switch duty cycle based on the difference between sensing voltage and reference voltage, creating a closed-loop feedback system that maintains consistent driving current despite input or output voltage variations.
Solution Approach 2:
The patent makes the reference voltage dynamic by adjusting it according to the detected output voltage level. When output voltage changes, the reference voltage is相应ly adjusted to maintain the proper relationship between reference voltage and sensing voltage, enabling the control system to adapt to different operating conditions and maintain consistent driving current.
2Illumination intensity
If the switching driving circuit adjusts the driving current to compensate for voltage variations, then the brightness consistency improves, but the control complexity increases
Solution Approach 1:
The controller uses feedback from the sensing voltage (which reflects the actual driving current) to adjust the switch control signals. By continuously comparing sensing voltage with reference voltage and adjusting the duty cycle accordingly, the system maintains consistent driving current and thus consistent brightness of light-emitting devices, while using a relatively simple control mechanism based on PWM modulation.
Solution Approach 2:
The patent changes the control parameter from fixed reference voltage to dynamically adjusted reference voltage based on output voltage detection. This parameter change enables the control system to adapt to different operating conditions and maintain proper control relationships, achieving consistent brightness without requiring complex control algorithms.
Data Source
AI summary
A switching driving circuit includes a switch configured to switch a current supplied to a target circuit, a sensing resistor connected to the switch, a controller configured to control the switch by comparing a sensing voltage applied to the sensing resistor with a reference voltage, and a compensation circuit configured to regulate the reference voltage based on an amount of variation of an input voltage input into the target circuit and an output voltage output from the target circuit.