High-Side Transistor Drive Circuit With Pulse Level Shifting
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Solution Overview
Problem
High-side transistor drive circuits in applications like DC/DC converters and motor drive circuits face high power consumption due to significant stable-state current, even at high voltage levels, necessitating a reduction in power consumption.
Innovation Solution
A high-side transistor drive circuit design incorporating a level shift circuit and a buffer, featuring a pulse generator, open drain circuit, current mirror circuits, and latch circuits to generate pulses based on input signal edges, reducing stable-state current and power consumption by minimizing current flow through high breakdown voltage elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional high-side transistor drive circuit is used, then the transistor can be driven properly, but power consumption is high due to significant stable-state current
Solution Approach 1:
The patent applies periodic action by using pulse signals to drive the high-side transistor instead of continuous voltage application. The level shift circuit generates pulses only during switching transitions (rising and falling edges), keeping the transistor in a stable state for extended periods without continuous current flow, thereby reducing power consumption while maintaining reliable transistor operation.
Solution Approach 2:
The patent extracts the continuous current path by introducing high-impedance states in the level shift circuit. The circuit is designed to remove the connection between the bootstrap capacitor and the gate during stable periods, eliminating the stable-state current that causes high power consumption, while still allowing proper transistor driving during switching transitions.
2Strength
If high breakdown voltage elements are used in the drive circuit, then high voltage operation is enabled, but chip area increases
Solution Approach 1:
The patent segments the circuit into different voltage domains: the bootstrap capacitor and level shift circuit operate at high voltage to drive the high-side transistor, while the pulse generator and logic circuits operate at lower voltages. This segmentation allows using high breakdown voltage elements only where necessary (in the high-voltage path), reducing the overall chip area compared to designing the entire circuit for high voltage.
Solution Approach 2:
The patent introduces an intermediary level shift circuit that translates low-voltage pulse signals into high-voltage gate drive signals. This intermediary stage allows the use of smaller, lower-voltage elements for signal generation and control, while only the essential high-voltage components (bootstrap capacitor, level shift transistors) need to handle high breakdown voltages, optimizing chip area.
Data Source
AI summary
The present disclosure relates to a high-side transistor drive circuit, a switching circuit and a controller of a DC/DC converter. A pulse generator generates a first pulse that becomes high level for a certain period of time in response to a first edge of an input signal and a second pulse that becomes high level for a certain period of time in response to a second edge of the input signal. An open drain circuit has a first output node that becomes low level in response to the first pulse and a second output node that becomes low level in response to the second pulse. A first current mirror circuit folds back a first current flowing through the first output node of the open drain circuit. A second current mirror circuit folds back a second current flowing through the second output node of the open drain circuit.