Power Clamping Circuit Temperature Compensation
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Solution Overview
Problem
Traditional power clamping circuits are susceptible to temperature variations, leading to inefficiencies in system voltage regulation due to changing breakdown voltages of Zener diodes and threshold voltages of transistors, which affect operating efficiency.
Innovation Solution
A power clamping circuit with temperature compensation is designed using a combination of diodes and resistors with specific temperature coefficients, a comparator, and a transistor, where resistance ratios are adjusted to balance and cancel out positive and negative temperature coefficients, ensuring a system voltage with a substantially zero temperature coefficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional power clamping circuit uses a Zener diode or transistors, then power clamping can be achieved, but the circuit becomes susceptible to temperature variations causing voltage instability
Solution Approach 1:
The patent changes the parameters of the clamping circuit by using a transistor whose threshold voltage has a negative temperature coefficient to compensate for the positive temperature coefficient of the Zener diode breakdown voltage. By adjusting the transistor's threshold voltage parameter, the circuit achieves temperature compensation and stabilizes the clamping voltage across temperature variations.
Solution Approach 2:
The patent creates a composite clamping structure by combining a Zener diode and a transistor in a specific configuration. The Zener diode provides breakdown voltage clamping while the transistor provides temperature compensation, creating a composite system that achieves both voltage clamping and temperature stability that neither component could achieve alone.
2Productivity
If transistors M1-MM are used for power clamping, then clamping action occurs when voltage exceeds threshold, but threshold voltages increase as temperature decreases causing excessive voltage reduction at high temperatures
Solution Approach 1:
The patent changes the voltage parameter by selecting a transistor with a negative temperature coefficient threshold voltage to offset the positive temperature coefficient of the Zener diode. This parameter selection ensures that the total clamping voltage remains stable across temperature variations, preventing excessive voltage reduction at high temperatures that would harm operating efficiency.
3Reliability
If temperature compensation is added to the power clamping circuit, then voltage stability improves, but circuit complexity increases
Solution Approach 1:
The patent merges the temperature compensation function with the existing power clamping function by using the same transistor that performs clamping action. The transistor serves dual purposes: providing the clamping action through its threshold voltage and simultaneously providing temperature compensation through its negative temperature coefficient, thereby adding temperature stability without significantly increasing circuit 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
The circuit effectively stabilizes the system voltage across varying temperatures, maintaining it within a narrow range (4.94-4.96V) despite temperature changes from -40°C to 150°C, thereby improving power clamping efficiency and broadening its application range.
Implementation Method 1
a first diode having an anode and a cathode, the cathode coupled to a ground, for generating a voltage with a negative temperature coefficient
Implementation Method 2
a resistor with a positive temperature coefficient
Implementation Method 3
a comparator having a negative input terminal coupled to the anode of the first diode and a positive input terminal coupled to the resistor with the positive temperature coefficient
Implementation Method 4
a transistor having a gate coupled to an output terminal of the comparator, a drain coupled to the system voltage and a source coupled to the ground
Data Source
AI summary
A power clamping circuit with temperature compensation is disclosed. The power clamping circuit, for a system voltage, includes a first diode, a resistor with a positive temperature coefficient, a second diode, a comparator including a negative input terminal coupled to an anode of the first diode and a positive input terminal coupled to the resistor with the positive temperature coefficient, a transistor including a gate coupled to an output terminal of the comparator, a drain coupled to the system voltage and a source coupled to the ground, a first resistor, a second resistor, a third resistor, a fourth resistor, and a fifth resistor.