Voltage Regulated Pre-Driver Circuit for Signal Slope Control
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Solution Overview
Problem
Existing output circuits face challenges in maintaining a constant power supply voltage, leading to disturbances in the waveform of differential signals due to changes in current consumption, especially during the transition from a standby state to normal operation, resulting in unpredictable output signal slopes and potential noise or ringing.
Innovation Solution
The proposed output circuit includes a regulator that short-circuits nodes to control the voltage differently after transitioning from a standby state to normal operation, using a feedback mechanism with operational amplifiers and transistors to maintain a stable regulator voltage independent of the power supply voltage, ensuring consistent driving capability for pre-drivers and output drivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a voltage control mechanism using an operational amplifier is used to maintain constant power supply voltage, then the power supply voltage stability is improved, but the response time increases and instantaneous voltage drops occur during high current demand transitions
Solution Approach 1:
The patent applies preliminary action by pre-charging a capacitor connected to the power supply voltage input terminal before the pre-driver transitions to normal operation. This stored energy in the capacitor provides immediate voltage support during high current demand, preventing instantaneous voltage drops while the operational amplifier's voltage control mechanism responds. The capacitor acts as a buffer that bridges the response time gap of the feedback control system.
2Power
If the pre-driver starts to draw high current from the power supply circuit during transition to normal operation, then the driving capability is improved, but the power supply voltage instantaneously and largely decreases
Solution Approach 1:
The patent implements beforehand cushioning by providing a capacitor charged to the power supply voltage before the pre-driver begins high current operation. This pre-charged capacitor serves as a cushion that maintains voltage stability during the transition to normal operation, absorbing the instantaneous current demand without causing large voltage drops. The cushioning effect ensures smooth power delivery during the high power consumption phase.
3Stability of the object's composition
If the power supply voltage is changed to maintain constant voltage through voltage control, then the waveform stability is improved, but the circuit complexity increases due to additional control components
Solution Approach 1:
The patent uses an operational amplifier as an intermediary component that compares the power supply voltage with a reference voltage and adjusts the power supply voltage accordingly. This intermediary mechanism maintains waveform stability by ensuring consistent voltage levels for the pre-driver and output driver, while the use of standard operational amplifier circuits keeps the added complexity manageable and predictable.
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 stabilizes the regulator voltage, preventing sudden drops and maintaining desired output signal slopes, thus reducing noise and ensuring reliable signal propagation, even under varying power supply conditions.
Implementation Method 1
an amplifier which performs feedback control on the gate voltage of the first transistor based on the second voltage
Implementation Method 2
a first transistor which is connected between the first node and the second node and supplies a current to the second node based on a gate voltage
Implementation Method 3
a second transistor which controls the gate voltage of the first transistor and short-circuits the first node and the second node based on the control signal
Data Source
AI summary
An output circuit includes first and second nodes, a regulator, a pre-driver, and an output driver. The regulator outputs a second voltage to the second node based on a first voltage applied to the first node. The output driver receives a signal from the pre-driver and outputs a second signal. The regulator short-circuits the first and second nodes while the pre-driver is in a standby state, and controls the second voltage to be different from the first voltage after the pre-driver transitions from the standby state to a normal operation state.