A constant current source circuit with current monitoring

Abstract

The invention provides a constant-current source circuit with current monitoring capability. The constant-current source circuit comprises a basic constant-current source circuit, a current detection circuit, a voltage conditioning circuit, a comparison circuit, a signal retaining circuit, a power supply control circuit and a power conversion circuit, wherein the power conversion circuit is used for providing working voltages to the other circuits; the current detection circuit is used for converting output currents of the basic constant-current source circuit into voltage signals and providing the voltage signals to the voltage conditioning circuit; the voltage conditioning circuit is used for conditioning the voltage signals and then outputting the voltage signals to the comparison circuit; the comparison circuit is used for comparing conditioned voltages with a preset voltage and sending an on / off control signal to the signal retaining circuit; the signal retaining circuit is used for outputting the signal to the power supply control circuit; the power supply control circuit is used for controlling the power conversion circuit to perform power supply or power breakdown on the basic constant-current source circuit. The constant-current source circuit can be used for monitoring the output currents of a constant-current source in real time, and cutting off the power supply of the constant-current source when the output current exceeds a set value, thus cutting off the output current of the constant-current source so as to avoid damages on electric equipment.

Description

technical field [0001] The invention belongs to the field of constant current source circuits, and in particular relates to a constant current source circuit with current monitoring. Background technique [0002] Constant current source circuits are widely used in the fields of path detection, charging circuits, and device measurement. The constant current source circuit is introduced. The bipolar transistor constant current source circuit is one of them. It is composed of transistors, Zener tubes, resistors, etc. It has a simple structure and is widely used. In the titled "Constant Current Source Circuit for GPS Equipment" (Chinese Patent Application No.: 201220728351) and the title "Constant Current Source for Temperature Measurement Circuit" (Chinese Patent Application No. 201210535034), the use of this type of circuit in GPS is introduced. equipment and temperature measuring equipment applications. However, the constant current source used in the above literature canno...

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Problems solved by technology

However, the constant current source used in the above literature cannot monitor the output current in real time when it is working. If the output current of the constant current source deviates from the design value due to device failure, it will continue to monitor the output current when the output current is larger than the design value. If current is applied to electrical equipment, it will cause damage to electrical equipment in current-sensitive applications, such as device measurement, charging circuits, etc.

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