Diode-Free Waveform Shaping Circuit for Temperature-Stable Voltage
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Solution Overview
Problem
Waveform shaping circuits that use diodes are affected by temperature fluctuations, leading to unstable target constant voltage settings, which impacts the accuracy of output pulse signals.
Innovation Solution
A waveform shaping circuit that excludes diodes, utilizing a capacitor, a first impedance element, and a switch circuit without diodes, with a switch control circuit that adjusts the switch state based on the input pulse signal to maintain a target constant voltage during both high and low voltage periods, ensuring the output pulse signal's peak-to-peak voltage is consistent with the input's AC component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diode is used in the waveform shaping circuit to set the target constant voltage, then the circuit can perform waveform shaping, but the target constant voltage fluctuates according to temperature due to diode forward voltage characteristics
Solution Approach 1:
The invention extracts and removes the diode component from the waveform shaping circuit. By eliminating the diode, the circuit no longer suffers from temperature-dependent forward voltage fluctuations, thereby resolving the contradiction between achieving waveform shaping and maintaining temperature-stable target constant voltage.
Solution Approach 2:
The invention substitutes the diode-based voltage setting mechanism with an alternative approach using a capacitor and impedance element network. This replacement eliminates reliance on the diode's electrical characteristics, which are temperature-sensitive, and achieves waveform shaping through passive components with more stable temperature characteristics.
2Manufacturing precision
If a diode is used to set the forward voltage for waveform shaping, then the positive peak value can be clamped, but the forward voltage fluctuates with temperature causing target constant voltage to fluctuate
Solution Approach 1:
The invention removes the diode from the circuit entirely, eliminating the source of voltage fluctuation. The waveform shaping and voltage clamping functions are achieved through a capacitor and impedance element configuration that does not rely on temperature-sensitive semiconductor characteristics.
Solution Approach 2:
The invention changes the fundamental operating parameters of the waveform shaping circuit by replacing active diode-based clamping with passive RC (resistor-capacitor) network-based shaping. This parameter change transitions the circuit from relying on diode forward voltage characteristics to using RC time constants, which are more stable across temperature variations.
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 reliably sets the output pulse signal's voltage at a constant level unaffected by temperature, reducing noise interference and maintaining signal integrity across temperature variations.
Implementation Method 1
a capacitor with one end connected to an input to which an input pulse signal is input and the other end connected to an output
Implementation Method 2
a first impedance element that has one end, which is connected to the other end of the capacitor, and the other end, to which a target constant voltage is applied, and supplies the target constant voltage to the other end of the capacitor
Data Source
Figure 1~2
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Figure 5~6
AI summary
A waveform shaping circuit is configured without including a diode that is affected by temperature. The waveform shaping circuit includes: a capacitor 42c with one end into which a differential signal Vd0 is inputted and another end connected to an output 42b; an impedance element 42d that has one end connected to the other end of the capacitor 42c and another end into which a target constant voltage Vtg is applied; a switch circuit SC that is constructed of a series circuit with an impedance element 42e and a switch 42f without including a diode, has one end connected to the output 42b, and has another end into which the target constant voltage Vtg is applied; and a switch control circuit SWC that shifts the switch 42f into an on state during a low voltage period in an AC component of the differential signal Vd0 and shifts the switch 42f to an off state during a high voltage period of the AC component. The waveform shaping circuit shapes the differential signal Vd0 into a single-ended signal Vd whose peak-to-peak voltage is equivalent to a peak-to-peak voltage of the AC component and whose voltage during a low voltage period is the target constant voltage Vtg, and outputs from the output 42b.