PMOS transistor substrate selection circuit

Abstract

The invention belongs to the technical field of integrated circuits and relates to a PMOS transistor substrate selection circuit. The PMOS transistor substrate selection circuit comprises a reference current source circuit, a comparator circuit and a high-voltage selection circuit. The PMOS transistor substrate selection circuit is characterized in that the voltage source with a higher voltage is automatically selected from two voltage sources to supply the voltage to a PMOS transistor, the higher voltage is used as a substrate level, and electric leakage generated at the substrate end when the PMOS transistor is switched off is avoided.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits, and relates to a PMOS tube substrate selection circuit, which is suitable for various chip systems with dual power supply inputs, and is especially suitable for mobile devices with dual power supplies such as mobile phones and portable computers. Background technique [0002] PMOS transistor substrate selection circuits are widely used in analog circuit modules, especially in circuits with dual power supplies, such as charger circuits, DC / DC boost circuits and boost charge pump circuits. [0003] figure 1 It is a schematic circuit diagram of a substrate selection circuit in the prior art. The structure of the substrate selection circuit is simple, as figure 1 As shown, the PMOS transistors P1 and P2 are selection and driving transistors. The source of P1 is connected to the power supply voltage V1, the gate is connected to the power supply voltage V2, the source of P2 is connected t...

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Problems solved by technology

[0005] The object of the present invention is to provide a PMOS transistor substrate selection circuit, which overcomes the disadvantages that the substrate selection circuit cannot make a correct selection when V1 and V2 are close to each other or when one of the voltages between V1 and V2 does not exist in the prior art.

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