Constant-Current Control Circuit for Independent Parallel Loads
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Solution Overview
Problem
Existing constant-current driving circuits consume excessive resources, occupy large areas on PCB boards, and lack integration due to the use of multiple operational amplifiers and PMOS transistors for independent control of load elements.
Innovation Solution
A constant-current control circuit with a load module, controller, and constant-current control module, utilizing operational amplifiers and divided resistors to independently control multiple load units without increasing device count, allowing for compact integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-channel DAC signals are used to control multiple load elements independently, then independent control capability is improved, but the number of operational amplifiers and PMOS transistors increases, leading to larger PCB area and reduced integration
Solution Approach 1:
The patent applies multi-functionality by designing a single operational amplifier to serve multiple load elements through shared control signals. The operational amplifier's output is distributed to multiple PMOS transistors, each controlling a different load element, allowing one amplifier to perform what would traditionally require multiple amplifiers. This reduces the total number of electrical elements while maintaining independent control capability through the shared signal distribution architecture.
2Reliability
If PMOS transistors are added to ensure complete cut-off of power supply, then reliability of load element cut-off is improved, but the number of electrical elements increases and integration is reduced
Solution Approach 1:
The patent combines the cut-off function with the existing PMOS transistors used for load control, eliminating the need for separate PMOS transistors dedicated solely to cut-off. The same PMOS transistors that control load elements are configured to provide complete power supply cut-off when needed, merging two functions into a single component set. This reduces the total number of electrical elements while maintaining reliable cut-off performance.
3Productivity
If multiple operational amplifiers are used to process multi-channel DAC signals, then signal processing capability is improved, but PCB area occupation increases
Solution Approach 1:
The patent implements multi-functionality by configuring a single operational amplifier to process multiple channels of DAC signals simultaneously. The amplifier's output is distributed to multiple PMOS transistors, each controlling a different load element. This allows one operational amplifier to perform the signal processing function that would traditionally require multiple amplifiers, significantly reducing PCB area occupation while maintaining full signal processing capability for all channels.
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 circuit achieves independent control of load units with reduced device count, maintaining constant current through load elements, and preventing micro-bright jitter, thus enhancing integration and efficiency.
Implementation Method 1
an operational amplifier constant-current driving circuit shown in FIG. 1 mainly uses a 'voltage following characteristic' of an operational amplifier, that is, a circuit characteristic that voltages of two input pins 2 and 3 of the operational amplifier are equal
Data Source
AI summary
Disclosed are a constant-current control circuit and a method for constant-current control. The circuit includes: a load module, including a plurality of load units connected in parallel; a controller, connected to each load unit of the load units and configured to output a first level signal to the load unit; and a constant-current control module, connected to the controller and further connected to each load unit of the load units via at least one divided resistor, configured to receive a first voltage signal sent by the controller, and generate a second level signal and a second voltage signal according to the first voltage signal and output the second level signal and the second voltage signal to the load module.