Power Circuit Overvoltage Protection via Voltage Clamp and Charge Pump
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Solution Overview
Problem
Existing power circuitry in electronic devices is vulnerable to damage during overvoltage events due to the susceptibility of gate control circuitry to overheating, which can disable the device even if it protects the ICs from damage.
Innovation Solution
A power circuitry configuration that includes a voltage clamp, charge pump, and current limiting resistor to isolate IC components from high supply voltage, with control circuitry powered by a startup voltage to actively manage the power transistor and regulate voltage to the load during overvoltage events, ensuring only discrete components are exposed to high voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power transistor with gate control circuitry is used to protect ICs from overvoltage, then IC components are protected from damage, but the gate control circuitry itself is vulnerable to overheating and damage during overvoltage events
Solution Approach 1:
The circuit divides the power protection function into separate components: the power transistor handles the main power switching, while the charge pump and voltage clamp are segmented to specifically protect the gate control circuitry. This segmentation allows each component to be optimized for its specific function and protects the control circuitry from overvoltage damage.
Solution Approach 2:
A charge pump circuit is introduced as an intermediary between the supply voltage and the gate control circuitry. The charge pump generates the gate drive voltage and includes a voltage clamp that limits the maximum voltage to a safe level, thereby protecting the gate control circuitry from overvoltage events while still enabling proper transistor control.
2Reliability
If the gate control circuitry is damaged during an overvoltage event, then the power transistor remains off and ICs are protected, but the electronic device is disabled until repair or replacement
Solution Approach 1:
The voltage clamp circuit provides beforehand cushioning by limiting the voltage to the gate control circuitry to a safe level before an overvoltage event can cause damage. This preventive measure ensures that even during severe overvoltage events, the control circuitry remains intact and the device stays operational.
Solution Approach 2:
The circuit implements feedback through the charge pump that continuously monitors and regulates the gate voltage. When an overvoltage condition is detected, the voltage clamp activates to limit the voltage, and the charge pump adjusts accordingly to maintain proper gate control, ensuring continuous safe operation of the power transistor.
3Reliability
If a voltage clamp is added to protect the charge pump during overvoltage events, then the charge pump is protected, but an additional component is introduced into the circuit
Solution Approach 1:
The voltage clamp function is merged with the charge pump circuit, allowing the same component to perform both charge pumping and voltage clamping functions. This integration protects the charge pump from overvoltage events without requiring a completely separate voltage clamp circuit, thereby reducing overall device complexity.
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 configuration effectively protects IC components from overvoltage damage while allowing the electronic device to continue operating by regulating voltage, preventing device disablement and potential fires.
Implementation Method 1
A voltage clamp is connected in parallel with a charge pump, wherein the voltage clamp limits an input voltage of the charge pump
Implementation Method 2
A current limiting resistor couples a supply voltage to the voltage clamp and to the charge pump
Implementation Method 3
A power transistor couples the supply voltage to a load, wherein a gate of the power transistor is controlled by an output of the charge pump
Data Source
AI summary
Power circuitry is disclosed for protecting an electronic device during an overvoltage event. A voltage clamp is connected in parallel with a charge pump, wherein the voltage clamp limits an input voltage of the charge pump. A current limiting resistor couples a supply voltage to the voltage clamp and to the charge pump. A power transistor couples the supply voltage to a load, wherein a gate of the power transistor is controlled by an output of the charge pump during a power-on operation. When the supply voltage exceeds a threshold thereby activating the voltage clamp, the current limiting resistor limits a current flowing through the voltage clamp.