Current sharing circuit of isolated current-sharing bus and power supply circuit

Abstract

The invention discloses a current sharing circuit of an isolated current sharing bus and a power supply circuit, and the current sharing circuit comprises a current sampling isolation amplification circuit, a second isolation circuit, and a current sharing control processing circuit which is connected with the second isolation circuit and the current sampling isolation amplification circuit. The second isolation circuit is used for isolation between an output power ground and a current-sharing circuit ground, the current-sharing control processing circuit is used for carrying out current-sharing control processing so as to output current-sharing signals, and the current sampling isolation amplification circuit is used for sampling and amplifying current signals and simultaneously isolating from a sampling ground. The power supply circuit comprises a current sharing circuit which is used for carrying out current sharing among multiple power supplies when the multiple switching power supplies are used in parallel. The sampling end of the current sharing circuit is isolated from the sampling ground, and the output end of the current sharing circuit is isolated from the control ground, so that the independence of the current sharing circuit is ensured, the mutual influence between the circuits is avoided, and the current sharing precision is improved.

Description

technical field [0001] The invention relates to the technical field of switching power supplies, in particular to a current sharing circuit and a power supply circuit of an isolated current sharing bus. Background technique [0002] At present, in the parallel use of switching power supplies, sampling current is used to control the output current. One of the sampling currents is sampling at the primary side of switching power supplies, and the other is sampling at the secondary After a series of circuit processing, the duty cycle of the power device of the switching power supply is controlled, so as to realize the control of the output current of each power supply in the parallel application. [0003] In the prior art, neither the primary sampling nor the secondary sampling, the current sharing control circuit is not isolated from the power ground. [0004] Specifically, such as figure 1 , 2 shown, where figure 1 in the secondary sampling current, figure 2 where is the...

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Problems solved by technology

[0007] In this case, the ground of the current sharing bus (share) cannot be isolated from the power ground. When the loads are different, the power circuit will generate line loss on the power ground network, which will affect the accuracy of current sharing. When multiple machines are used in parallel, The output power ground may interfere with the normal operation of the current sharing circuit, resulting in abnormal operation

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