Half-Bridge Driver Circuit with Integrated Current Measurement
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Solution Overview
Problem
Current half-bridge driver circuits in automotive applications lack the capability to directly sample motor phase currents, requiring external systems to synchronize measurements with control signals, which can be complex and inefficient.
Innovation Solution
A half-bridge driver circuit with integrated measurement terminals connected to shunt resistors, an analog-to-digital converter, and a synchronization circuit that generates trigger signals based on control signals to acquire digital samples of motor phase currents, allowing for direct measurement and synchronization within the driver circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external systems are used to synchronize measurements with control signals, then motor phase current measurement capability is achieved, but system complexity and measurement efficiency deteriorate
Solution Approach 1:
The patent combines the measurement function with the driver circuit by integrating measurement terminals directly into the driver. The measurement terminals are electrically connected to the internal nodes between the high-side and low-side switches, allowing the driver circuit itself to provide measurement capabilities without requiring separate external measurement systems.
Solution Approach 2:
The driver circuit performs self-measurement by providing measurement terminals that allow the system to monitor its own internal state. The measurement terminals are connected to internal nodes within the driver, enabling the circuit to self-diagnose and provide feedback about its operating condition without external intervention.
2Measurement precision
If external systems are used to synchronize measurements with control signals, then current measurement is possible, but measurement efficiency and directness deteriorate
Solution Approach 1:
The measurement function is merged with the driver circuit operations. The measurement terminals are synchronized with the switching operations internally, eliminating the need for external synchronization mechanisms and improving measurement efficiency.
Solution Approach 2:
The measurement terminals act as intermediaries that provide direct access to internal circuit nodes. These terminals enable direct measurement of switch node voltages and currents without requiring external probes or measurement equipment, thereby improving measurement directness and efficiency.
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
Enables efficient and direct sampling of motor phase currents within the driver circuit, simplifying the measurement process and improving the accuracy of motor control in automotive applications.
Implementation Method 1
two measurement terminals connected to terminals of shunt resistors
Implementation Method 2
analog-to-digital converter, and a synchronization circuit that generates trigger signals
Data Source
AI summary
A half-bridge driver circuit includes an amplifier configured to generate a measurement signal indicative of a current flowing through a shunt resistor. A processing circuit is configured to selectively acquire a sample of the measurement signal in response to a trigger signal. A synchronization circuit is configured to determine a first value indicative of the switch-on duration of a high side control signal, determine a second value indicative of the switching period of the high side control signal, compute a third value based on the first and second values, generate a third signal based on the third value when the next switching period of the high side control signal starts, start a second counter in response to the third signal, compare the count value of the second counter with a reference value to generate a fourth signal, and generate the trigger signal as a function of the fourth signal.