Current balancing circuit

Abstract

A current balancing circuit is used for balancing currents flowing through multiple branch circuits and comprises a first branch circuit, a second branch circuit, a current feedback comparison circuit, a positive-negative triangular wave generator, a first multiplexer, a second multiplexer and a grid signal control circuit. The first branch circuit and the second branch circuit are in parallel connection and respectively comprise a first switch and a second switch. Positive-negative triangular waves are compared to grid voltage of the first switch and grid voltage of the second switch by the grid signal control circuit, and input switching between the first multiplexer and the second multiplexer is controlled according to the currents flow through the first branch circuit and the second branch circuit, and then impedance of the first switch and the second switch is adjusted, so that the currents flowing through the first switch and the second switch are balanced. The current balancing circuit is simple. As the impedance is adjusted by adjusting control electrode voltage of the first switch and the control electrode voltage of the second switch, the currents are balanced accurately, and affection caused by temperature and current density is avoided.

Description

technical field [0001] The invention relates to a power supply circuit, in particular to a current balance circuit. Background technique [0002] In a high-power power supply system, in order to provide a large current, it is usually powered by multiple power supplies connected in parallel or a single power supply with multiple current paths, both of which require current sharing. The current sharing method of the multi-power parallel architecture usually adopts an independent pulse width modulation controller, and the current sampling is fed back to the pulse width modulation controller to adjust the output voltage, so as to achieve the purpose of current sharing. However, if the current is sampled by a resistor, the amplified signal is susceptible to common-mode noise interference, and the current is sampled by a current Hall element, which will increase the cost and increase the area required for the design. [0003] Although the single power supply multi-current path ar...

AI Technical Summary

Problems solved by technology

However, if the current is sampled with a resistor, the amplified signal is susceptible to common-mode noise interference, while using a current Hall element to sample the current will increase the cost and increase the area required for the design

[0003] Although the single power supply multi-current path architecture can reduce switching loss, it must overcome the impedance mismatch problem between different current paths

Although the calculation of the impedance of the copper foil can achieve the purpose of current sharing, the impedance of the copper foil is easily affected by the temperature and current density and loses the accuracy of current sharing.

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