Bridge Circuit Control for Inductive Load Discharge
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Solution Overview
Problem
Existing electrical circuits for controlling bridge circuits driving inductive loads face challenges in safely and effectively discharging energy accumulated in the loads during active phases, particularly when failures occur or unexpected stopping happens, leading to potential overvoltage and electromagnetic interference issues.
Innovation Solution
An electrical circuit with a voltage pulse detector, internal control logic, and validation gates that control high-side and low-side switches to manage energy discharge through closed low-side switches, even in failure conditions, reducing the need for protective measures and minimizing electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protective measures such as filtering capacitors are added to protect the power supply from voltage pulses, then the reliability of the power supply is improved, but the device complexity and volume increase
Solution Approach 1:
The patent converts the harmful voltage pulse generated by inductive load discharge into a useful control signal. The voltage pulse detector captures the pulse and transforms it into a validation signal that automatically triggers the low-side switch to close, creating a beneficial feedback mechanism that eliminates the need for external protective capacitors and complex protection circuits
2Reliability
If filtering capacitors with larger capacitance are used to reduce voltage pulses, then the power supply protection is improved, but the volume and footprint of the device increase
Solution Approach 1:
The patent replaces the passive mechanical/electrical filtering approach (large capacitors) with an active control system. The voltage pulse detector and validation gate circuitry actively respond to voltage pulses by controlling switch states, substituting the need for large energy-storing capacitors with a smarter, more compact control mechanism
3Reliability
If the low-side switch is controlled to close in response to voltage pulse to discharge accumulated energy, then the safety of the inductive load is improved, but the device complexity increases due to additional control circuitry
Solution Approach 1:
The system performs self-service by using the voltage pulse itself as the trigger signal. The voltage pulse detector automatically detects the pulse and the validation gate automatically enables the low-side switch closure, creating a self-regulating safety mechanism that doesn't require external control signals or complex external protection circuits
4Object-affected harmful factors
If validation gate is used to control low-side switch based on voltage pulse detector output, then the electromagnetic interference is reduced, but the device complexity increases
Solution Approach 1:
The validation gate serves as an intermediary element between the voltage pulse detector and the low-side switch control. It mediates the control signal by enabling or disabling the switch based on the detected voltage pulse, providing a clean interface that reduces electromagnetic interference while maintaining necessary control functionality
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
This solution enhances safety by ensuring controlled energy discharge and reduced power dissipation, minimizing the impact of failures and electromagnetic interferences, and allows for reduced filtering capacitors and protection measures, effectively managing voltage pulses and maintaining system reliability.
Implementation Method 1
a voltage pulse detector adapted to detect a voltage pulse on the supply voltage supplying the bridge circuit
Implementation Method 2
the at least one low-side switch of the bridge circuit is closed in case of such a voltage pulse under the condition that the validation gate is controlled by the internal control logic to connect through the output of the voltage pulse detector to the low-side control output
Data Source
Figure 1
Figure 2
AI summary
The invention concerns an electrical circuit (1) adapted to control a bridge circuit (2) for driving an inductive load (3). The electrical circuit comprises a voltage pulse detector (16, 17), at least one high-side control output (11, 12) adapted to control a high-side switch (5, 6) of the bridge circuit (2) connecting the inductive load (3) with the supply voltage (9), at least one low-side control output (13, 14) adapted to control a low-side switch (7, 8) of the bridge circuit (2) connecting the inductive load (3) with ground (10), an internal control logic (15) controlling the high- and low-side control outputs (11 to 14) and one validation gate (19) per low-side control output (13, 14). The internal control logic (15) controls the at least one validation gate (19) to connect through when the supply voltage (9) falls below a supply voltage threshold, thereby connecting the respective low-side control output (13, 14) with the output of the voltage pulse detector (16, 17).