What are the categories of current sources? You will know after reading these

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What are the categories of current sources? You will know after reading these [Copy link]

The internal resistance of the current source is large relative to the load impedance, and fluctuations in the load impedance will not change the current. It is meaningless to connect a series resistor in the current source loop because it will not change the load current or the voltage on the load. Such resistors should be simplified on the schematic diagram. The load impedance only makes sense when connected in parallel to the current source, and it is a shunt relationship with the internal resistance.

　　Due to many reasons such as internal resistance, an ideal current source does not exist in the real world, but such a model is very valuable for circuit analysis. In fact, if the current fluctuation of a current source is not obvious when the voltage changes, we usually assume that it is an ideal current source.

　　Let's take a look at the classification of current sources.

　　1. Adjustable current source

　　A DC current source (the main parameters are output current, rated output power, etc.) with adjustable output current is called an adjustable current source.

　　2. Pulse current source

　　The pulse current mirror circuit uses high-speed field effect transistors to replicate and multiply the constant current source current, reduce the impact of the pulse current source output load on the previous stage deep negative feedback part, improve the stability of the circuit, and use the analog multiplexer to control the current mirror gate to pass the pulse signal to the pulse current, thereby outputting a pulse current.

　　Simulation experiments show that the proposed pulse current source operates stably and reliably. The amplitude, repetition frequency and pulse width of the output pulse current can be adjusted numerically. The current amplitude is stable and the pulse front is steep, which can meet different laser driving and testing requirements.

　　3. High-precision current source

　　A high-precision current source circuit is proposed. Through V/I conversion, the bandgap reference voltage generated by the bandgap reference voltage circuit, which is independent of temperature and power supply voltage, is converted into a high-precision reference current that is independent of temperature and voltage. The required mirror current is generated through a high-precision current mirror structure, which effectively suppresses the influence of changes in temperature, power supply voltage, load impedance and interference on the current source.

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