Digital control constant current source device with threshold voltage preprocessing function

Abstract

The invention relates to a digital control constant current source device with the threshold voltage preprocessing function. As a preprocessing measure for high-power N-channel-field-effect-transistor threshold voltage is added, the initial grid voltage of a power field-effect transistor is suitably improved; as the technical scheme is adopted, and compared with the prior art, the digital control constant current source device with the threshold voltage preprocessing function has the advantages that the conducting speed of the power field-effect transistor is increased, the driving efficiency of a power-field-effect-transistor driving circuit is improved, the dynamic response performance of a power digital control constant current source is improved, and the digital control constant current source device has the quite-large practical advantage; in addition, the digital control constant current source device can also flexibly adjust the initial grid voltage loaded to the power field-effect transistor according to the use condition to be suitable for the application requirements of various different power field-effect transistors; common electron components are adopted for achievement, the components are easy to purchase, and the digital control constant current source device has good application prospects.

Description

technical field [0001] The invention relates to the fields of instrumentation and electronic measurement, in particular to a numerically controlled constant current source device with the function of turning on voltage preprocessing, which can be widely used in instrumentation or equipment such as switching power supply, linear power supply, electronic load and DC resistance measurement. Background technique [0002] Numerical control constant current source is a commonly used electronic circuit, which is widely used in power electronic equipment aging, linear power supply, switching power supply, electronic load, overcurrent detection and other occasions. [0003] Common numerically controlled constant current sources are attached figure 1 As shown, the circuit with the operational amplifier as the core forms a deep negative feedback, and uses a high-power N-channel enhanced insulated gate field-effect transistor as a current conversion element to meet the requirements of h...

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Problems solved by technology

Due to the turn-on voltage U GS(th) The existence of the circuit, the initial period of time when the circuit is turned on is the effect of the output current of the operational amplifier on charging the capacitance of the field effect tube. This part of energy is only to overcome the turn-on voltage U in the transfer characteristic curve of the field effect tube. GS(th) The impact of the field effect tube leads to the slow conduction speed of the field effect tube, the driving efficiency of the field effect tube drive circuit is low, and the dynamic response performance of the high-power constant current source is particularly reduced.

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