DC/DC Converter Charging Transistor for Fast Startup and Low Power
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Solution Overview
Problem
Existing DC/DC converters face challenges in reducing power consumption and shortening startup time due to inefficiencies in the control circuit's power supply voltage generation, which affects the overall efficiency and reliability of the converter.
Innovation Solution
The proposed DC/DC converter incorporates a current limiting circuit with a charging transistor and a current source to control the charging current, allowing for immediate charging of the power supply capacitor when the voltage is low and reducing current consumption when the voltage exceeds a threshold, thereby shortening startup time and lowering power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a resistor and capacitor are used to charge the power supply voltage, then the circuit is simple, but the startup time cannot be shortened and power consumption cannot be reduced
Solution Approach 1:
The patent applies dynamics by making the charging current dynamic rather than fixed. The charging transistor's conductivity is dynamically adjusted based on the power supply voltage level: when voltage is low, the transistor provides high conductivity for rapid charging; when voltage approaches the threshold, conductivity decreases to reduce current consumption. This dynamic adjustment resolves the contradiction between simple structure and performance requirements.
Solution Approach 2:
The patent changes the parameter of charging current based on voltage conditions. By using the charging transistor to modulate current magnitude according to voltage level, the system transitions from a fixed parameter approach (resistor-capacitor) to a variable parameter approach, enabling both rapid startup and reduced power consumption without increasing circuit complexity significantly.
2Loss of time
If the charging current is increased to shorten startup time, then the startup time is reduced, but the power consumption increases
Solution Approach 1:
The charging transistor provides dynamic current control, allowing the system to use high current only when necessary (during initial charging phase) and reduce current when the voltage approaches the threshold. This temporal differentiation of current magnitude resolves the contradiction between startup speed and power consumption.
Solution Approach 2:
The charging process occurs in distinct phases: an initial high-current phase for rapid voltage buildup, followed by a reduced-current phase as the voltage approaches the threshold. This periodic variation in current magnitude allows the system to achieve fast startup while minimizing overall power consumption.
3Use of energy by moving object
If the resistance is decreased to reduce power consumption, then the power consumption is reduced, but the startup time increases
Solution Approach 1:
Rather than using a fixed low resistance, the patent employs a dynamic resistance control mechanism through the charging transistor. The transistor's effective resistance is high during initial charging (enabling fast startup) and automatically decreases as voltage rises (reducing power consumption). This dynamic behavior resolves the contradiction that plagues fixed-resistance designs.
Solution Approach 2:
The system changes the charging parameter (current magnitude) based on the voltage state. The charging transistor responds to voltage changes by adjusting its conductivity, thereby changing the effective charging resistance. This parameter change allows the system to achieve both fast startup and low power consumption, overcoming the trade-off inherent in fixed-resistance designs.
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 enables a DC/DC converter that can start quickly and reduce power consumption, improving efficiency and reliability by optimizing the power supply voltage generation and current management.
Implementation Method 1
a charging transistor, which is a N-channel Metal Oxide Semiconductor Field Effect Transistor (MOSFET), disposed between the high voltage terminal and the power supply terminal
Implementation Method 2
a current limiting circuit, for limiting a charging current flowing from the high voltage terminal through the charging transistor to the power supply terminal
Implementation Method 3
the capacitor Co2 is charged by the input voltage VIN via a resistor R11, so as to elevate the power supply voltage VCC
Data Source
AI summary
A direct current (DC)/DC converter capable of lowering power consumption and capable of being started in a short time is provided. A voltage generated at a second output capacitor is input to a power supply terminal. An input voltage is input to a high voltage terminal. A charging transistor is a N-channel Metal Oxide Semiconductor Field Effect Transistor disposed between the high voltage terminal and the power supply terminal and applied with a bias so that the charging transistor is normally on. In a first state, in which the voltage of the power supply terminal is lower than a specified first threshold voltage, a current limiting circuit limits a charging current flowing from the high voltage terminal to the power supply terminal, and in a second state in which the voltage is higher than a second threshold voltage, the current limiting circuit lowers the charging current substantially to zero.