A Bidirectional Constant Current Source Device Based on Double Negative Feedback Control

Abstract

The invention relates to a bi-directional constant current source device based on dual negative feedback control, and belongs to the technical field of electronic technique. The bi-directional constant current source device structurally comprises a front panel (10), a current setting module (1), an output control module (5), a power output module (6) and a first feedback module (7), and is characterized by further structurally comprising a subtracter module (2), a PID module (3), a limited current setting module (4), a second feedback module (8) and a display driver module (9). The bi-directional constant current source device adopts the dual negative feedback structure, thereby having the characteristics of being high in output current stability, high in safety, wide in range of usage occasions and the like, the limited current setting function is achieved, and output current dual-directional regulation can be further realized.

Description

technical field [0001] The present invention belongs to the technical field of electronic technology. In particular, it relates to a high stability bidirectional constant current source device based on double negative feedback control. Background technique [0002] The constant current source has important applications in many occasions such as optical fiber communication, LED lighting, and laser drive. In some occasions, such as laser drive, the output current stability of the constant current source is very important, and the instability of the output current will cause Affect the life of the laser and the output optical power. Commonly used measures to improve current stability are: 1. Using the nonlinear magnetization principle of magnetic saturation reactor to improve stability; 2. Connecting a large resistance in series in the load circuit (relative to the load resistance); 3. Realizing the current through the negative feedback network Automatic stabilization. Among...

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Problems solved by technology

Among these schemes, the first scheme is greatly affected by the device itself and has limited improvement in stability; the second scheme can effectively reduce the impact of changes in load resistance due to a large resistor connected in series in the load circuit. The influence of the output current, but due to the existence of the large resistance of the load circuit, the output current is very small, generally only in the milliampere level, and most of the power is dropped on the large resistance, which also makes the efficiency extremely low; the third scheme Due to the automatic adjustment function of the negative feedback network itself, the output current can be automatically stabilized without being affected by load changes, so it is currently the most effective way to improve current stability. However, in the currently disclosed technologies, generally Adopting a single linear feedback network, the biggest disadvantage of this scheme is that once the feedback network fails, the system will be in an open-loop working state, the output current will increase sharply, and it is easy to damage the load and the circuit itself. Another disadvantage is the use of The occasion is limited, and it can only be applied to the occasion where the load responds linearly to the current. In some specific occasions, if the load responds to the current with a delay or lead, this constant current source based on a single linear feedback network will lose automatic stabilization capability

In addition, most of the current common constant current sources are unidirectional output. When bidirectional current is required in some occasions (such as heating or cooling of temperature control devices), its use will be limited.

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