Switch Drive Circuit High-Side Stop Logic Level Stability
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Solution Overview
Problem
Conventional switch drive circuits for intelligent power modules (IPMs) often fail to establish a reliable stop logic level in high-side circuits, leading to erroneous activation of high-side switching elements due to unstable power supply conditions and noise interference.
Innovation Solution
A switch drive circuit that includes a high-side power supply section, a latch circuit, a high-side driver, a low-side driver, and a high-side switch control circuit with a constant-current source, resistor, and a three-terminal switch to set and release a stop established state, ensuring accurate logical level fixation and prevention of high-side switching element activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power supply circuits are used for high-side switching, then device complexity is reduced, but reliability deteriorates due to unstable stop logic level and erroneous switching activation
Solution Approach 1:
The patent introduces an intermediary circuit between the power supply and the high-side switching element. This intermediary includes a control circuit that generates a stop logic level signal and a power supply circuit that provides power based on this signal. The intermediary acts as a mediator that ensures the stop logic level is properly established before power is supplied, preventing erroneous activation while maintaining circuit functionality.
Solution Approach 2:
The patent implements preliminary action by establishing the stop logic level before supplying power to the high-side switching element. The control circuit first generates and stabilizes the stop logic level signal, then the power supply circuit provides power only after this preliminary condition is met. This preliminary establishment of logical level ensures reliability before operation begins.
2Measurement precision
If simple power supply control is used, then ease of operation is improved, but measurement precision deteriorates in determining accurate logical levels
Solution Approach 1:
The patent implements feedback mechanisms where the control circuit monitors the logical level status and adjusts power supply accordingly. The control circuit receives feedback about the current state of the high-side switching element and ensures the stop logic level is properly established. This feedback loop maintains measurement precision of logical levels while automating the control process to preserve ease of operation.
Data Source
AI summary
A switch drive circuit includes a high-side power supply section, a latch circuit, a high-side driver, a low-side driver, and a high-side switch control circuit. The latch circuit latches a logical level of a high-side switching signal at the time of performing switching of a high-side switch. The high-side driver drives the high-side switch by the high-side switching signal outputted from the latch circuit. The low-side driver drives a low-side switch by a low-side switching signal. The high-side switch control circuit sets, at the time of stopping the switching of the high-side switch, a stop established state in which the logical level of the high-side switching signal is fixed at a stop logic level, and releases the stop established state at the time of performing the switching of the high-side switch.