Half-Bridge Driver Floating Voltage Detection for Bootstrap Protection
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Solution Overview
Problem
Existing half-bridge driver circuits face challenges in efficiently detecting and managing the floating voltage levels in high-voltage applications, leading to potential overvoltage events and inefficiencies in the bootstrap charging process.
Innovation Solution
A half-bridge driver circuit with an integrated floating level detector circuit that includes a first comparator circuit with hysteresis and a negative transient detection circuit, along with a current limiter, to accurately monitor and manage the floating reference voltage, ensuring reliable and efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional comparator circuit is used to detect floating reference voltage, then voltage detection function is achieved, but power consumption increases and circuit complexity increases
Solution Approach 1:
The patent extracts the essential detection function from a conventional comparator circuit and implements it using a simplified detector circuit comprising a resistor, capacitor, and logic circuit. This extraction removes unnecessary complexity and power consumption while retaining the core voltage detection capability.
Solution Approach 2:
The patent employs a simplified detector circuit that uses inexpensive, simple components (resistor, capacitor, logic gates) instead of a complex comparator circuit. This disposable-like approach prioritizes functional adequacy over precision, reducing power consumption and complexity while achieving sufficient detection performance.
2Measurement precision
If a conventional comparator circuit is used to detect floating reference voltage, then voltage detection function is achieved, but device complexity increases
Solution Approach 1:
The patent extracts the essential detection function from a conventional comparator circuit and implements it using a simplified detector circuit comprising a resistor, capacitor, and logic circuit. This extraction removes unnecessary complexity and power consumption while retaining the core voltage detection capability.
Solution Approach 2:
The detector circuit is segmented into simple functional blocks: a resistor for voltage division, a capacitor for timing/filtering, and logic circuits for threshold comparison. This segmentation avoids the need for a complex integrated comparator while achieving the same detection function through discrete simple components.
3Ease of operation
If bootstrap architecture is used to generate floating supply voltage, then high-side switch driving is enabled, but overvoltage events may occur reducing reliability
Solution Approach 1:
The detector circuit continuously monitors the floating reference voltage before overvoltage conditions can develop. By detecting voltage transitions in advance, the system can take preventive action (such as disabling the bootstrap pump or clamping the voltage) to prevent overvoltage events, thereby maintaining reliability while enabling high-side switch driving.
Solution Approach 2:
The detector circuit provides real-time feedback on the floating reference voltage status to the control logic. This feedback mechanism enables the system to adjust its operation dynamically, preventing overvoltage conditions while maintaining the bootstrap architecture's ability to drive the high-side switch.
4Productivity
If floating reference voltage is not properly detected, then circuit operation continues, but system efficiency decreases due to undetected overvoltage events
Solution Approach 1:
The detector circuit continuously monitors the floating reference voltage before overvoltage conditions can develop. By detecting voltage transitions in advance, the system can take preventive action (such as disabling the bootstrap pump or clamping the voltage) to prevent overvoltage events, thereby maintaining reliability while enabling high-side switch driving.
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 provides rapid and precise detection of voltage transitions, preventing overvoltage events and optimizing the bootstrap charging process, thereby enhancing the efficiency and reliability of high-voltage half-bridge switching circuits.
Implementation Method 1
a second node (104) configured to be connected via a capacitor (CB) to said first node (102a)
Implementation Method 2
a first circuit (30) including a first diode (300) having an anode connected to said further supply voltage (VCC) and a cathode connected to a first decoupling node (C2D), wherein a first parasitic capacitance (CP1) is associated with said first diode (300)
Implementation Method 3
A half-bridge driver circuit with a detector circuit that includes a comparator with hysteresis to monitor voltage drops and currents
Data Source
AI summary
A half-bridge driver circuit is provided. The circuit includes a detector circuit that generates a signal indicating whether a floating reference voltage is greater than a second supply voltage. The detector circuit includes a first circuit, a second circuit and combinational logic circuit. A first comparator circuit of the first circuit monitors a voltage drop at a resistance and sets a first control signal to a first logic level when the monitored voltage drop is smaller than a first threshold. A second comparator circuit of the second circuit monitors a current provided by an output transistor of a current mirror and sets a second control signal to a first logic level when the monitored current is greater than a second threshold. The combinational logic circuit asserts the signal when the first control signal has the respective first logic level or the second control signal has the respective first logic level.