Short Circuit Detection in Asynchronous DC-DC Boost Converters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional asynchronous DC-DC boost converters face challenges in accurately detecting short circuit conditions and protecting components from high short circuit currents, leading to potential burn-out, with existing solutions involving costly and power-consuming short circuit resistors that require precise calibration and additional filtering circuits.
Innovation Solution
A voltage sensing controller is introduced, comprising a circuit with voltage dividers to generate sensed input and output voltages, an offset voltage generator, and a comparator to determine a reference voltage, enabling selective isolation of the input power supply and reducing power loss by eliminating the need for additional short circuit resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a short circuit resistor is used for current sensing, then short circuit detection capability is improved, but power loss increases and cost increases
Solution Approach 1:
The patent extracts the short circuit resistance function from a dedicated physical resistor and relocates it to the MOSFET's inherent on-resistance (Rds(on)). By utilizing the naturally occurring resistance in the switching device, the design eliminates the need for an additional sensing resistor, thereby removing the associated power loss while maintaining short circuit detection capability through voltage monitoring across this inherent resistance.
Solution Approach 2:
The MOSFET device is made multi-functional by using its on-resistance for both switching operation and current sensing purposes. The same component (MOSFET) serves dual roles: as the primary switching element and as the current sensing element through its inherent Rds(on)), eliminating the need for separate dedicated sensing components and reducing overall system power consumption.
2Reliability
If a short circuit resistor is used for current sensing, then short circuit detection capability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the short circuit resistance function from a dedicated physical resistor and relocates it to the MOSFET's inherent on-resistance (Rds(on)). By utilizing the naturally occurring resistance in the switching device, the design eliminates the need for an additional sensing resistor, thereby removing the associated power loss while maintaining short circuit detection capability through voltage monitoring across this inherent resistance.
Solution Approach 2:
The MOSFET device is made multi-functional by using its on-resistance for both switching operation and current sensing purposes. The same component (MOSFET) serves dual roles: as the primary switching element and as the current sensing element through its inherent Rds(on)), eliminating the need for separate dedicated sensing components and reducing overall system power consumption.
3Measurement precision
If a short circuit resistor is precisely calibrated, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The MOSFET's on-resistance (Rds(on)) inherently provides the sensing resistance without requiring external calibration or precision matching. The resistance value is determined by the MOSFET's electrical characteristics and operating conditions, and the control circuit compensates for variations through feedback mechanisms, eliminating the need for costly precision-calibrated resistors while maintaining adequate measurement accuracy for short circuit detection.
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 controller effectively detects short circuits and prevents component burn-out while reducing power loss and costs, using fewer components and simplifying ground routing in the PCB layout, thus enhancing efficiency and cost-effectiveness.
Implementation Method 1
a first voltage divider comprising a first pair of resistors adapted to be connected between the first node and ground and further adapted to generate a sensed input voltage
Implementation Method 2
a second voltage divider comprising a second pair of resistors adapted to be connected between the second node and ground and further adapted to generate a sensed output voltage
Implementation Method 3
a comparator adapted to compare the sensed input voltage with the reference voltage and generate an output signal
Data Source
AI summary
A simple, cost-effective and efficient short circuit protection with simple routing of the ground on the PCB is achieved in an asynchronous DC-DC boost converter wherein a voltage sensing controller selectively isolates an input power supply to a load in the event of a short circuit. The controller alleviates need for additional components by utilizing the circuit for under voltage lockout protection and the circuit for overvoltage protection to generate signals for detecting short circuit. A predetermined offset voltage is added to a sensed output voltage to generate a reference voltage that is compared to a sensed input voltage and an output signal having a high state is generated in the event that the reference voltage is less than the sensed input voltage for selectively disabling the source of input power when the output signal is in the high state.