Bootstrap Driver Circuit With Parallel-Series Capacitor Switching
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Solution Overview
Problem
Existing bootstrap driver circuits for high-side switching elements require large capacitance bootstrap capacitors, leading to high cost and chip area, which is inefficient.
Innovation Solution
A driver circuit using a plurality of bootstrap capacitors arranged in parallel during charging and series during control phases to generate high gate-source voltages efficiently, reducing the overall capacitance needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single bootstrap capacitor is used to drive a high-side switching element, then the switching element can be controlled, but the capacitance must be relatively high leading to high cost and chip area
Solution Approach 1:
The single bootstrap capacitor is segmented into multiple smaller bootstrap capacitors (first, second, third, and fourth capacitors). These segmented capacitors are arranged in parallel during charging phases and in series during control phases, enabling the same control functionality with reduced individual capacitance values and reduced total chip area.
2Reliability
If a single bootstrap capacitor is used to drive a high-side switching element, then the switching element can be controlled, but the capacitance must be relatively high leading to high cost
Solution Approach 1:
The single bootstrap capacitor is segmented into multiple smaller bootstrap capacitors (first, second, third, and fourth capacitors). These segmented capacitors are arranged in parallel during charging phases and in series during control phases, enabling the same control functionality with reduced individual capacitance values and reduced total chip area.
3Power
If multiple bootstrap capacitors are used in series to provide high voltage, then the voltage sufficiency is improved, but the capacitance requirement increases
Solution Approach 1:
The circuit dynamically reconfigures the bootstrap capacitors between parallel and series arrangements using switching elements. During charging phases, capacitors are arranged in parallel to minimize total capacitance requirements. During control phases, capacitors are arranged in series to provide sufficient high-side driving voltage. This dynamic reconfiguration resolves the contradiction between voltage requirement and capacitance quantity.
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
The solution provides a compact and efficient driver circuit that reduces the size and cost of bootstrap capacitors while maintaining reliable control of high-side switching elements.
Implementation Method 1
the bootstrap driver circuit typically comprises a bootstrap capacitor for generating the voltage for controlling the high-side switching element
Data Source
AI summary
A driver circuit for controlling a switching element is provided. The driver circuit (200) has a plurality of bootstrap capacitors (210) and a switching unit (211). Furthermore, the driver circuit (200) has a control unit (102) which is configured to control the switching unit (211) in dependence of a control signal (ActHS) to provide a parallel arrangement of the plurality of bootstrap capacitors (210) between a charging voltage (VDD) and a reference voltage, for charging the plurality of bootstrap capacitors (210) during a charging phase; and to provide a serial arrangement of the plurality of bootstrap capacitors (210) between the charging voltage (VDD) and a control port of the switching element (MHS), for controlling the switching element (MHS) during a control phase.