Switching Power Supply Control Circuit Using Boost Inductor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing switching power supply control circuits require a large bootstrap capacitor, which is difficult to integrate into a chip, increasing circuit area and design cost.
Innovation Solution
A switching power supply controlling circuit that uses a boost circuit to provide driving power for the upper transistor, eliminating the need for a bootstrap pin or capacitor by utilizing parasitic inductance and bond-wire inductance as energy storage, and includes auxiliary circuits to control the transistors' states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bootstrap capacitor is used to drive the upper transistor, then the upper transistor can be driven to on state, but the capacitor size is large and difficult to integrate into chip, increasing circuit area
Solution Approach 1:
The patent extracts the energy storage function from the traditional bootstrap capacitor and relocates it to the parasitic inductance of the bond wire connecting the control chip to the switching power supply. This eliminates the need for a separate bootstrap capacitor component, reducing circuit area while maintaining the ability to drive the upper transistor to on state.
Solution Approach 2:
The patent utilizes the parasitic inductance that inherently exists in the bond wire connection as the energy storage element. Instead of adding a separate component, the system uses the self-existing parasitic inductance to generate the bootstrap voltage, making the system self-sufficient and eliminating additional circuit area requirements.
2Ease of operation
If a bootstrap capacitor is used, then the upper transistor can be controlled, but it increases design cost and complexity
Solution Approach 1:
The patent removes the bootstrap capacitor from the circuit and extracts its energy storage function to the parasitic inductance of the bond wire. This simplifies the circuit structure by eliminating unnecessary components and reducing design complexity while preserving full transistor control capability.
Solution Approach 2:
The bond wire, which originally serves only as a connection element, is made to serve multiple functions: it provides electrical connection and simultaneously acts as an energy storage inductor. This multi-functionality reduces the total number of components needed and simplifies the overall circuit design.
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 reduces the need for a bootstrap capacitor, allowing for a more compact and cost-effective integration of the switching power supply control circuit within a chip while maintaining control over the transistors' states.
Implementation Method 1
a boost circuit, an input terminal of the boost circuit is connected to an input terminal of the switching power supply, the boost circuit output a first voltage
Implementation Method 2
the boost circuit may include a first inductor, a switch transistor, a rectification transistor and a first capacitor; a first terminal of the first inductor may be connected to an input terminal of the switching power supply
Data Source
AI summary
This invention provides a switching power supply controlling circuit, the switching power supply comprises an upper transistor and a lower transistor, the switching power supply controlling circuit comprises a boost circuit, an input terminal of the boost circuit is connected to an input terminal of the switching power supply, the boost circuit output a first voltage to control a working state of the boost circuit, driving the upper transistor to be in an on state. The switching power supply controlling circuit adopts a boost circuit to provide a driving power for the upper transistor, and there is no need to set a bootstrap pin or a bootstrap capacitor.