Power Supply Device Current Comparison Circuit
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Solution Overview
Problem
Power source devices face a conflict between achieving low current consumption and high speed response, as setting a small voltage difference between threshold and normal voltages leads to increased current consumption, while a large difference hinders rapid response to output voltage changes.
Innovation Solution
A power source device with a current comparison type circuit that monitors the output current of a monitor transistor and adjusts the current supplied to an amplifier, allowing for efficient current management and quick response to load changes without requiring precise setting of reference currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the voltage difference between threshold and normal voltages is set to be small, then the response speed to output voltage changes is improved, but the current consumption increases due to erroneous current flow
Solution Approach 1:
The patent changes the detection parameter from voltage difference to output current difference. By monitoring the output current of the monitor transistor instead of the voltage difference at the amplifier input, the system can detect load changes more accurately without suffering from erroneous current flow when the voltage threshold is close to the normal voltage. This parameter transformation resolves the contradiction by enabling fast response while maintaining low current consumption.
2Use of energy by moving object
If the voltage difference between threshold and normal voltages is set to be large, then the current consumption is reduced, but the response speed to output voltage changes is hindered
Solution Approach 1:
The patent transforms the detection mechanism from voltage-based to current-based. The monitor transistor's output current serves as the detection signal, allowing the system to respond quickly to load changes without requiring a large voltage difference threshold. This enables the use of a small voltage threshold (for fast response) while avoiding the erroneous current flow problem that would increase consumption.
3Speed
If the current in the amplifier is increased to achieve high speed response, then the response time is reduced, but the current consumption increases
Solution Approach 1:
The patent divides the current supply into two separate sources: a first current source that provides a small standby current for low power consumption, and a second current source that provides additional current when needed for fast response. The switch controlled by the detection circuit connects the second current source only when a load change is detected, enabling fast response temporarily while maintaining low current consumption during normal operation.
Solution Approach 2:
The patent implements periodic switching of the current supply mode. The detection circuit continuously monitors the output current, and when a change is detected, it switches from the low-current standby mode to the high-current response mode. After the response is complete, it switches back to standby mode. This periodic switching enables the system to achieve fast response when needed while maintaining low current consumption during normal operation.
Data Source
AI summary
A power source device includes an output transistor connected between an input node at which an input voltage can be received and an output node at which an output voltage corresponding to the input voltage can be output according to a control voltage applied to a gate of the output transistor, a first amplifier that includes a first transistor element and a second transistor element having gates to which a first voltage is applied, receives a feedback voltage corresponding to the output voltage, and outputs a second voltage corresponding to a voltage difference between the feedback voltage and a reference voltage, a monitor transistor having a gate to which the first voltage is applied, a first current source that supplies a first current to the first amplifier, and a second current source that supplies a second current to the first amplifier according to a current flowing in the monitor transistor.