QR Buck Switch Control Circuit for Input-Voltage Current Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The QR buck converter circuit experiences errors in load current due to signal delays and changes in input voltage, leading to inaccuracies in inductor current control.
Innovation Solution
A switch control circuit with a current compensation device that adjusts the gate on-time based on an RC resistor and control signal, and includes comparators and logic elements to modify the reference or sensing voltage in response to input voltage changes, thereby compensating for errors in inductor current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If signal delay is present in the comparator to gate terminal path, then the circuit operation is simplified, but the inductor current control precision deteriorates
Solution Approach 1:
The patent applies preliminary action by adjusting the gate on-time before the actual switching operation occurs. The controller pre-calculates and sets the gate on-time duration based on the known signal delay characteristics, so that when the control signal eventually reaches the gate terminal after delay, the switching timing is already optimized for accurate current control. This proactive timing adjustment compensates for the inherent signal delay without requiring complex real-time correction circuits.
2Device complexity
If input voltage changes are not compensated, then the circuit structure remains simple, but the load current accuracy deteriorates
Solution Approach 1:
The patent implements feedback by monitoring the actual input voltage level and using this information to dynamically adjust the gate on-time duration. The controller continuously compares the detected input voltage with reference values and modifies the PWM signal timing accordingly. This closed-loop feedback mechanism ensures that load current accuracy is maintained despite variations in input voltage, without requiring complex hardware compensation circuits.
Solution Approach 2:
The patent applies parameter changes by varying the gate on-time duration as a control parameter in response to input voltage changes. When input voltage increases, the gate on-time is reduced; when input voltage decreases, the gate on-time is increased. This dynamic parameter adjustment allows the system to maintain accurate load current control across different input voltage conditions while keeping the overall circuit structure relatively simple.
3Measurement precision
If gate on-time is adjusted to compensate for voltage changes, then load current accuracy improves, but the control circuit complexity increases
Solution Approach 1:
The patent applies dynamics by implementing a dynamic adjustment mechanism for the gate on-time that automatically adapts to changing input voltage conditions. The control circuit continuously monitors voltage levels and dynamically modifies the PWM signal duration without requiring manual intervention or complex external adjustment circuits. This dynamic behavior enables accurate current control while maintaining control circuit simplicity through automated adaptive adjustment.
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
The solution effectively compensates for errors in load current by adjusting the gate on-time and voltage levels, ensuring accurate inductor current control even with changes in input voltage, thereby improving the precision of the QR buck converter.
Implementation Method 1
a current compensation device configured to adjust a gate on-time based on a RC resistor and a control signal that senses a gate terminal of the control switch
Implementation Method 2
a first comparator configured to compare a drain sensing voltage with a drain sensing reference voltage
Implementation Method 3
an addition device configured to add an output of the current compensation device to a reference voltage
Data Source
AI summary
A switch control circuit and switch control method are provided. The switch control circuit and switch control method compensate an error of a load current that occurs because of the changing of a slope of an inductor current based on the increase and decrease of an input voltage. The switch control circuit includes a current compensation device that adjusts a gate on time based on a RC resistor and a control signal that senses a gate terminal of a control switch. The current compensation device compensates an error that occurs due to a signal delay to a gate terminal by increasing or decreasing a reference voltage or a sensing voltage, according to an increase or a decrease of an input voltage.