Dual power supply system

Abstract

The invention discloses a dual-power supply system. The dual-power supply system comprises a voltage comparator and a low dropout linear regulator, wherein a control signal is generated by the voltage comparator according to a comparison result of a first power supply and a second power supply, low dropout linear voltage stabilizing can be carried out on the first power supply and / or the second power supply by the low dropout linear regulator according to the control signal, and the low dropout linear regulator comprises a first transistor, a second transistor, a first switch, a current mirror circuit and a voltage stabilizing circuit; when the control signal is output by the voltage comparator for controlling a movable end of the first switch to be connected with a fixed end of the first switch, the first transistor is switched on under the action of the current mirror circuit and the second voltage, the second transistor is switched on under the action of the bias voltage generated by the first transistor, and the first power supply can be output to the voltage stabilizing circuit through the first transistor. According to the dual-power supply system disclosed by the invention, the area of a chip and the complexity of a circuit can be reduced, and the design cost is effectively reduced.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to a dual power supply system. Background technique [0002] With the development of technology, more and more chips use dual power supply, which means that the chip can work under either power supply or when both power supplies are present. This requires the power supply circuit to be designed in two sets, that is, each power supply terminal uses its own power supply module, which is then supplied to other circuits. In order to save area, the current dual power supply chip partially multiplexes the voltage regulator circuits used by the two power supplies, specifically as figure 1 shown in . However, since the outputs of the power transistors P4 and P5 of the two power supplies VCC1 and VCC2 are connected together, the reverse flow of current will damage the external circuit and easily cause waste of power consumption. Therefore, four transistors P0-P3 are added to prevent t...

AI Technical Summary

Problems solved by technology

However, since the outputs of the power transistors P4 and P5 of the two power supplies VCC1 and VCC2 are connected together, the current backflow will damage the external circuit and easily cause waste of power consumption.

Therefore, four transistors P0-P3 are added to prevent the current from being poured into the power port, but this increases the chip area

Due to the need to transmit a large enough current, the area of ​​these four transistors will be relatively large, resulting in a waste of chip area. At the same time, more complex processing circuits are required to solve the problem of current backflow, which increases additional overhead.

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