Driver Circuit Backflow Prevention and Voltage Boosting
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Solution Overview
Problem
Existing driver circuits face challenges in minimizing the on-resistance of output MOS transistors while preventing reverse current flow from the booster circuit to the power supply terminal, especially when the boosted voltage exceeds breakdown voltages.
Innovation Solution
Incorporating a backflow prevention circuit with a body diode and a Dickson-type booster circuit, which includes MOS transistors and capacitors, to control the input voltage and generate a boosted voltage that is applied to the gate of the output transistor, thereby reducing on-resistance and preventing reverse current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a booster circuit is used to boost input voltage to reduce on-resistance of the output MOS transistor, then the on-resistance decreases and current handling capability improves, but reverse current may flow from the booster circuit to the power supply terminal side
Solution Approach 1:
A body diode is introduced as an intermediary component between the power supply terminal and the booster circuit. This body diode acts as a one-way valve for current flow, allowing normal operation current to pass through while blocking reverse current from flowing back to the power supply terminal, thus resolving the contradiction between using a booster circuit for low on-resistance and preventing reverse current harm
2Reliability
If the boosted voltage is increased to further reduce on-resistance, then the current handling capability improves, but the voltage may exceed breakdown voltage limits causing damage
Solution Approach 1:
An input-voltage control circuit is implemented that continuously monitors the input voltage to the booster circuit and provides feedback control. When the input voltage approaches or exceeds the breakdown voltage limit, the control circuit automatically adjusts or interrupts the voltage input, preventing damage while allowing optimal voltage to be applied for minimum on-resistance operation
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 effectively decreases the on-resistance of the output MOS transistor and prevents reverse current flow, even when the boosted voltage approaches breakdown voltages, ensuring the reliability and efficiency of the driver circuit.
Implementation Method 1
a first body diode formed in the first transistor and having an anode connected to the first terminal of the first transistor and a cathode connected to a second terminal of the first transistor
Implementation Method 2
a first transistor having a first terminal to which the input voltage is applied via the power supply terminal, the first transistor being configured to turn on to output the input voltage to the input-voltage control circuit when the control signal is in the enabled state
Implementation Method 3
The booster circuit receives the input voltage outputted from the input-voltage control circuit and boosts the input voltage to generates a boosted voltage
Data Source
AI summary
According to an embodiment, an input-voltage control circuit outputs an input voltage when a control signal is in an enabled state. A backflow prevention circuit includes a first transistor and a first body diode. The first transistor turns on to output the input voltage to the input-voltage control circuit when the control signal is in the enabled state. The first body diode is formed in the first transistor and having an anode connected to the first terminal of the first transistor and a cathode connected to a second terminal of the first transistor. The booster circuit receives the input voltage outputted from the input-voltage control circuit and boosts the input voltage to generates a boosted voltage. The boosted voltage is outputted from the driver circuit and supplied to the control terminal of an external output transistor.