High-Side Driver Circuit That Holds Relay State During MCU Reset
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Solution Overview
Problem
In electric vehicles, the potential for unexpected microcontroller resets during driving can cause abrupt switching off of relays, leading to safety hazards and premature wear of relay components.
Innovation Solution
A drive circuit incorporating a high-side driver module and a delay module, where the delay module outputs a preset duration signal to maintain the high-side driver module in its previous state during a control module reset, preventing abrupt state changes and ensuring safety by keeping the relay in its intended on or off state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a relay is used as a switch controlled by a microcontroller, then the relay can be switched on/off for vehicle control, but the microcontroller may reset during driving causing abrupt switching off and safety hazards
Solution Approach 1:
The delay module is pre-configured with a preset duration time value that is longer than the expected microcontroller reset duration. When the control signal changes during reset, the delay module maintains the original state for the preset duration, preventing abrupt switching before the microcontroller recovers.
Solution Approach 2:
The delay module acts as an intermediary between the control module and the high-side driver module. It receives the control signal and introduces a time delay, outputting a delayed control signal that prevents direct transmission of abrupt state changes during microcontroller reset periods.
2Loss of time
If the relay switches off abruptly during microcontroller reset, then the control state changes immediately, but this causes premature wear of relay components
Solution Approach 1:
The delay module is pre-configured with a preset duration that extends beyond the microcontroller reset period. This preliminary timing configuration ensures that the relay state is maintained during the reset window, preventing unnecessary switching cycles that would accelerate relay wear.
Solution Approach 2:
The delay module provides a cushioning effect by maintaining the relay in its current state during the microcontroller reset period. This protective delay prevents the relay from experiencing abrupt on/off transitions during vulnerable reset intervals, thereby extending relay component life.
3Speed
If the control signal is transmitted directly without delay, then the system responds quickly to control changes, but the relay state cannot be maintained during microcontroller reset
Solution Approach 1:
The delay module serves as an intermediary that selectively delays control signals only during microcontroller reset periods. During normal operation, signals pass through with minimal delay, maintaining fast response. During reset, the delay module holds the state, ensuring stability when needed.
Solution Approach 2:
The delay module is pre-configured with a preset duration longer than the microcontroller reset time. This preliminary timing setup allows the system to maintain relay state stability during reset without permanently slowing down the control response speed during normal operation.
Data Source
AI summary
Embodiments of this application relate to the field of electricity, and disclose a drive circuit. In some embodiments of this application, the drive circuit includes a high-side driver module and a delay module, the delay module is configured to output a delay signal of preset duration to the high-side driver module in a case that a control module is being reset; and the high-side driver module is configured to: according to the delay signal of preset duration, remain in a first state within the preset duration, the first state being the same as a second state; where the second state is a working state of the high-side driver module before the control module is reset, and the second state includes being on or off.