H-Bridge Buck-Boost Current Sensing With Dual Detection Resistors
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Solution Overview
Problem
Current buck-boost circuits in voltage converters face high costs and significant detection latency in inductor current sensing due to the use of current sensors like Hall elements, limiting their application range and increasing the risk of damage from delayed overcurrent protection.
Innovation Solution
A voltage conversion circuit with a detection circuit comprising first and second detection resistors and an H-bridge structure, allowing inductor current detection through resistor voltage sampling, which reduces costs and latency by ensuring current detection accuracy regardless of boost or buck conversion modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current sensor (Hall element) is used to detect inductor current, then current detection accuracy is improved, but detection latency increases and cost increases
Solution Approach 1:
The patent extracts the current detection function from the expensive Hall element current sensor and implements it using simple detection resistors combined with voltage sampling circuits. The detection resistors are integrated into the existing H-bridge circuit paths, allowing current detection without requiring separate current sensor components, thereby reducing both cost and detection latency while maintaining adequate detection accuracy.
Solution Approach 2:
The patent creates a voltage copy of the current signal by measuring the voltage drop across detection resistors. Instead of directly measuring current with a Hall element, the system copies the current information through voltage measurements (V=IR), which can be processed faster and with lower latency, while the voltage sampling circuits accurately reproduce the current waveform characteristics.
2Measurement precision
If a current sensor (Hall element) is used to detect inductor current, then current detection accuracy is improved, but cost increases
Solution Approach 1:
The patent replaces expensive current sensors with inexpensive detection resistors and voltage sampling circuits. The detection resistors are standard low-cost components that can be easily integrated into the circuit board, eliminating the need for costly Hall elements while providing sufficient detection capability for overcurrent protection and control functions.
Solution Approach 2:
The patent extracts the current detection function from dedicated current sensor components and implements it using basic circuit elements (resistors and voltage sampling circuits) that are already present or easily added to the power conversion circuit, thereby dramatically reducing component costs while maintaining detection functionality.
3Loss of time
If detection resistors are used instead of current sensors, then cost and latency are reduced, but detection accuracy may be affected
Solution Approach 1:
The patent implements voltage sampling circuits that continuously monitor the voltage drops across detection resistors and provide feedback signals to the control system. This feedback mechanism ensures accurate current detection by maintaining a direct relationship between the measured voltage and the actual inductor current, enabling precise overcurrent protection and control while achieving fast response times.
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 proposed solution effectively reduces detection costs and latency in inductor current sensing, enhancing the accuracy and safety of voltage converters by enabling real-time current monitoring and overcurrent protection.
Implementation Method 1
a first detection resistor R1 and a second detection resistor R2... separately perform voltage sampling on a first resistor voltage of the first detection resistor R1 and a second resistor voltage of the second detection resistor R2
Data Source
Figure 1
Figure 2a~2b
Figure 2c~2d
AI summary
This application discloses a voltage conversion circuit, a voltage converter, and an electronic device. The voltage conversion circuit mainly includes a detection circuit having a first detection resistor and a second detection resistor, and a buck-boost circuit of an H-bridge structure. The first detection resistor is connected between one input end of the buck-boost circuit and one bridge arm of the H-bridge structure, the second detection resistor is connected between one output end of the buck-boost circuit and the other bridge arm of the H-bridge structure, and the detection circuit may output a current detection signal based on resistor voltages of the first detection resistor and the second detection resistor. This application implements detection of an inductor current, and further helps reduce detection costs of the inductor current and shorten a detection latency of the inductor current.