Boost DC-DC Converter Low Voltage Actuation
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Solution Overview
Problem
Conventional boost DC—DC converters require an input voltage higher than the lowest voltage necessary for actuation due to the forward drop voltage of Schottky diodes, making it difficult to initiate operation without excessive power supply voltage.
Innovation Solution
Incorporating a switching device, such as a p-channel MOS transistor, and a voltage detection circuit that controls power supply to the booster circuit, allowing operation at lower input voltages by using stored energy and hysteresis to manage the switching state based on detected voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Schottky diode is used for rectification in the boost DC-DC converter, then the converter can prevent reverse current flow, but the forward drop voltage of the diode increases the required input voltage for actuation
Solution Approach 1:
The patent removes the Schottky diode from the circuit and replaces it with a P-channel MOS transistor switching device. This extraction of the problematic component eliminates the forward drop voltage issue while maintaining the reverse current prevention function through the MOS transistor's inherent body diode and control logic.
Solution Approach 2:
The patent changes the electrical parameters of the switching device from a diode with fixed forward drop characteristics to a MOS transistor with controllable on-resistance. By controlling the gate voltage of the MOS transistor, the circuit can achieve lower voltage drop and improved efficiency while maintaining the necessary rectification function.
2Use of energy by moving object
If the power supply voltage is reduced to match the lowest actuation voltage of the booster circuit, then the input voltage requirement is minimized, but the forward drop voltage of the Schottky diode prevents proper operation
Solution Approach 1:
The patent introduces a storage capacitor as an intermediary energy storage element between the power supply and the booster circuit. This capacitor accumulates energy when the MOS transistor is on and releases it when the MOS transistor is off, enabling the booster circuit to operate reliably even when the input voltage is at or near its minimum actuation voltage.
Solution Approach 2:
The patent uses the voltage detection circuit to preliminarily assess whether sufficient voltage is available before attempting to actuate the booster circuit. This preliminary detection prevents failed actuation attempts and ensures that the booster circuit only starts when the input voltage is adequate, improving reliability without requiring excessive voltage margin.
3Use of energy by moving object
If a switching device is added to control power supply to the booster circuit, then the input voltage requirement is reduced, but the device complexity increases
Solution Approach 1:
The P-channel MOS transistor switching device performs multiple functions: it acts as a switch to control power flow, provides a low-resistance path when on, and its body diode provides reverse current protection. This multi-functionality reduces the need for separate components, thereby limiting the increase in overall circuit complexity while achieving the voltage reduction goal.
Solution Approach 2:
The patent combines the switching function, rectification function, and power control function into a single integrated circuit block. By merging these functions into one unit rather than using separate discrete components, the overall device complexity is minimized while still achieving the desired voltage reduction and operational control.
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
Enables the boost DC—DC converter to be actuated at a power supply voltage lower than conventional systems, reducing the required input voltage by approximately 0.1 V-0.25 V and maintaining operation with lower input voltages.
Implementation Method 1
a storage capacitor (106) for storing electric power as stored electric power in such a manner that the stored electric power is capable of operating the booster circuit (102) for a predetermined length of time even when electric power is stopped being supplied to the power supply terminal (112)
Implementation Method 2
a voltage detection circuit (105) for detecting a voltage at the power supply terminal (112) of the booster circuit (102) to control an on/off state of the switching device (104) according to a result of the detection of the voltage
Implementation Method 3
a switching device (104) provided between the power supply (101) and a power supply terminal (112) of the booster circuit (102) for controlling supply of the electric power to the power supply terminal (112) of the booster circuit (102)
Data Source
AI summary
Provided is a boost DC-DC converter where electric power to be supplied to a booster circuit is supplied from a power supply and from boosted electric power of the booster circuit which can be actuated at a low voltage. The boost DC-DC converter has a structure in which: a switching device is provided between the power supply and a boosted output of the booster circuit; a storage capacitor for storing electric power to be inputted to the booster circuit and for operating the booster circuit for a predetermined length of time using the stored electric power is additionally provided; and in a case where the booster circuit can generate boosted electric power even when the switching device is turned off, the switching device is turned off.