Output Transistor Gate Control for Stable Signal Slew Rates
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Solution Overview
Problem
Existing signal transmitting apparatuses face challenges in maintaining consistent output signal conditions across varying power supply voltages, leading to fluctuations in signal levels and increased radiation noise.
Innovation Solution
A signal transmitting apparatus with a charge-discharge circuit that adjusts the gate voltage of an output transistor using a control input signal, where the range of the control input signal's low level is adjusted based on the power supply voltage, and the charge and discharge currents are varied to maintain consistent output slew rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply voltage varies, then the output signal levels fluctuate, but maintaining consistent output signal conditions requires adjusting control parameters
Solution Approach 1:
The patent implements dynamic adjustment of the control input signal's low level range based on the detected power supply voltage. The signal generation circuit modifies the control signal characteristics in real-time according to voltage variations, enabling the output transistor to maintain consistent output signal levels across different power supply conditions without requiring fixed control parameters
Solution Approach 2:
The patent changes the control signal parameters (specifically the low level range) in response to power supply voltage variations. By detecting the actual voltage and adjusting the control signal's voltage range accordingly, the system compensates for power supply fluctuations and maintains stable output signal conditions across a wide voltage range
2Speed
If the charge and discharge currents are increased to maintain output slew rates, then radiation noise increases
Solution Approach 1:
The patent dynamically adjusts the charge and discharge currents based on the power supply voltage level. By detecting the voltage and proportionally adjusting the currents, the system maintains consistent output slew rates across different voltage conditions while avoiding excessive current values that would generate harmful radiation noise
Solution Approach 2:
The patent implements a feedback mechanism where the power supply voltage is detected and used to adjust the control input signal and charge/discharge currents. This closed-loop control ensures that the output slew rate remains consistent while minimizing radiation noise by optimizing the current values according to actual operating conditions
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 approach ensures consistent output signal conditions across a wide range of power supply voltages, minimizing radiation noise and maintaining compliance with communication standards while optimizing signal quality.
Implementation Method 1
a capacitor connected between a gate of the output transistor and the output terminal
Implementation Method 2
a backcurrent prevention diode between the output terminal and the application end of the power supply voltage, having a forward direction from the application end of the power supply voltage toward the output terminal
Data Source
AI summary
An output terminal is connected to the application end of a power supply voltage via a pull-up resistor and a backcurrent prevention diode. An output transistor is provided between the output terminal and a ground. A capacitor is connected between the gate of the output transistor and the output terminal. A charge-discharge circuit charges and discharges the gate of the output transistor during a first level period and during a second level period of a control input signal to turn on and off the output transistor and thereby generates an output signal corresponding to an input signal at the output terminal. A signal generation circuit causes a change in the level of the control input signal when the level of an original input signal is changed. Here, a range in which the control input signal has a second level is adjusted according to the power supply voltage.