Bias-Capacitor Output Stage Circuit for Low-Kickback DAC Switching
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Solution Overview
Problem
Conventional output stage circuits face issues with high power consumption due to standby currents and lack of effective current limitation mechanisms, as well as kick back interference when coupled or decoupled from power voltage.
Innovation Solution
An output stage circuit incorporating a current source circuit, output switch circuit, bias capacitor, and bias switch circuit, which uses bias voltage to charge capacitors during specific intervals to manage current flow and mitigate kick back interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional output stage circuits use components with standby currents to ensure current availability, then current response speed is improved, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by pre-charging bias capacitors (CB1, CB2) to specific voltages before the output switch needs to conduct. This allows the current source circuit to immediately provide the correct bias voltage when the output switch turns on, eliminating the need for standby currents while ensuring fast current response. The capacitors are charged in advance during non-conduction periods.
Solution Approach 2:
The patent extracts the standby current requirement by replacing continuous current flow with periodic capacitor charging. Instead of maintaining constant standby currents in bias circuits, the design uses capacitors to store bias voltage temporarily, eliminating continuous power consumption while maintaining current availability when needed.
2Use of energy by moving object
If conventional output stage circuits reduce standby currents to lower power consumption, then power consumption is improved, but current limitation capability deteriorates
Solution Approach 1:
The patent implements feedback by using the output voltage to control the bias voltage generation. The bias capacitors are charged to voltages that are functions of the output voltage, creating a feedback mechanism that automatically adjusts the current source circuit's operation. This ensures proper current limitation is maintained even with reduced standby currents, as the feedback loop continuously monitors and adjusts the bias conditions.
Solution Approach 2:
The patent changes the operating parameters by using variable bias voltages generated from output voltage samples. Instead of fixed standby currents, the bias voltage parameters are dynamically adjusted based on the output conditions, allowing the circuit to maintain proper current limitation capability while consuming less power in normal operation.
3Speed
If output stage circuit switches are turned on and off rapidly for high-frequency operation, then operating frequency is improved, but kick back interference increases
Solution Approach 1:
The patent applies preliminary action by pre-charging the bias capacitors to the exact voltages needed before the output switch transitions. This eliminates voltage transients and kick-back interference during switching operations, allowing rapid on-off cycling at high frequencies without generating harmful interference. The capacitors are charged in advance during the non-conduction period.
Solution Approach 2:
The bias capacitors act as intermediaries between the power supply and the current source circuit. They absorb and smooth out voltage transients during switching operations, preventing kick-back interference from propagating through the circuit. This mediation allows high-frequency switching without generating harmful interference.
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 proposed solution reduces standby current consumption and effectively controls output current size, minimizing kick back interference and enabling high-frequency square wave generation suitable for high-speed applications.
Implementation Method 1
at least one bias capacitor, coupled to the current source circuit; and a bias switch circuit, configured to receive a bias voltage, comprising at least one bias switch, coupled to the bias capacitor and the current source circuit, wherein the bias voltage charges the bias capacitor when the bias switch circuit is conducted
Data Source
AI summary
An output stage circuit, comprising: a current source circuit; an output switch circuit, comprising at least one output switch, coupled to the current source circuit, wherein an output current flows through a target circuit when the output switch circuit is conducted; at least one bias capacitor, coupled to the current source circuit; and a bias switch circuit, configured to receive a bias voltage, comprising at least one bias switch, coupled to the bias capacitor and the current source circuit, wherein the bias voltage charges the bias capacitor when the bias switch circuit is conducted. The present invention further discloses a DAC applying the output stage circuit and a TOF system applying the DAC. The conventional kick back issue can be improved by the mechanism provided by the present invention.