Voltage Regulator Feedback Protection for Bond Wire Disconnection
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Solution Overview
Problem
Conventional voltage regulators experience excessive output voltage when the bonding wire of the feedback voltage port is broken, leading to inaccurate output voltage regulation.
Innovation Solution
Incorporation of a disconnection protection circuit with a MOS transistor that detects and responds to the disconnection of the bonding wire, controlling the output transistor to stabilize the output voltage by adjusting the feedback voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective resistor is connected in series with voltage dividing resistors to limit output voltage when feedback bonding wire is broken, then output voltage can be limited to a predetermined voltage, but the output voltage becomes higher than the desired voltage value
Solution Approach 1:
A disconnection protection circuit is introduced as an intermediary between the feedback voltage port and the voltage dividing resistors. This circuit includes a detection transistor that monitors the feedback voltage and a control transistor that adjusts the effective resistance of the voltage dividing network. When disconnection is detected, the control transistor activates to modify the voltage division ratio, thereby compensating for the protective resistor's voltage drop and maintaining accurate output voltage regulation.
Solution Approach 2:
The invention dynamically changes the resistance parameters of the voltage dividing network based on the operational state. A control transistor is added to the voltage dividing circuit, allowing the resistance values to be adjusted between two states: normal operation mode and disconnection protection mode. This parameter change enables the circuit to compensate for the protective resistor's effect and maintain precise output voltage control even when the feedback bonding wire is broken.
2Manufacturing precision
If a feedback voltage port is connected to the output port to ensure output voltage accuracy under large output current, then output voltage accuracy is improved, but the feedback voltage port becomes susceptible to output current and bonding wire voltage drop
Solution Approach 1:
The feedback path is segmented into two separate ports: an output port for current carrying and a feedback voltage port for voltage sensing. The feedback voltage port is connected to the output port through a low-current path that includes the protective resistor and voltage dividing resistors, allowing it to sense the actual output voltage without being significantly affected by the high output current and associated voltage drops in the main power path.
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
Prevents excessive voltage generation at the output port by stabilizing the output voltage in case of bonding wire disconnection, ensuring accurate voltage regulation without interfering with normal operation.
Implementation Method 1
a disconnection protection circuit which includes a first MOS transistor containing a gate connected to the voltage adjustment port, and detects a disconnection of a bonding wire of the voltage adjustment port
Implementation Method 2
an error amplifier circuit for controlling a gate voltage of the output transistor based on the reference voltage and the feedback voltage
Implementation Method 3
voltage dividing resistors which are connected between a voltage adjustment port and a ground port, divide an adjustment voltage received at the voltage adjustment port, and output a feedback voltage
Data Source
AI summary
A voltage regulator includes: an output transistor containing a source connected to an input port and a drain connected to an output port; voltage dividing resistors which are connected between a voltage adjustment port and a ground port, divide an adjustment voltage received at the voltage adjustment port, and output a feedback voltage; a reference voltage circuit which outputs a reference voltage; an error amplifier circuit which controls a gate voltage of the output transistor based on the reference voltage and the feedback voltage; and a disconnection protection circuit which includes a first MOS transistor containing a source connected to the output port and a gate connected to the voltage adjustment port, and detects a disconnection of a bonding wire of the voltage adjustment port.