Input/output interface circuit for wide I/O power supply voltage range

Abstract

The invention provides an input / output interface circuit for a wide I / O power supply voltage range; the input / output interface circuit at least comprises the following units: an I / O PAD end; an input drive circuit used for transmitting an off-chip device input signal of the I / O PAD end to the inner side chip; an output drive circuit used for transmitting a chip inner output signal to the off-chip device through the I / O PAD end. When the I / O PAD end input voltage is the I / O power supply voltage or higher than the I / O power supply voltage tolerance voltage, the input / output interface circuit can use the input drive circuit and / or output drive circuit to realize normal signal transmission without electric leakage, thus allowing the I / O power supply voltage of the input / output interface circuit to be within the wide I / O power supply voltage range. The input / output interface circuit can work in the wide I / O power supply voltage range, and can work under a condition in which the I / O PAD end input voltage is higher than the I / O power supply voltage tolerance voltage.

Description

Technical field [0001] The invention relates to the technical field of large-scale integrated circuit design, and is suitable for SOC (System On Chip, system on chip), and particularly relates to an input and output interface circuit used for a wide I / O power supply voltage range. Background technique [0002] The integrated circuit chip is connected with the outside world through the input and output interface (Input / Output interface). The I / O interface receives the input signal of the off-chip device and transmits it to the chip, and can also receive the internal output signal of the chip to drive the off-chip device . In integrated circuits, signals are generally connected to the outside world through input and output buffer stages and I / O PAD (I / O pressure solder joints). The function of input and output buffer stages is to match on-chip signals with off-chip signals. [0003] Due to the wide variety of off-chip devices and different interface standards, the I / O interface circ...

AI Technical Summary

Problems solved by technology

However, for the existing I / O interface circuit, the I / O interface circuit designed with the function of input voltage tolerance (such as 5V input voltage tolerance) can only be used when the I / O power supply voltage is relatively high (such as 3.3 V), the input buffer stage of the I / O interface circuit can work normally

And when the I / O power supply voltage is less than 3.3V (for example, 1.8V), the input buffer stage of the existing I / O interface circuit cannot work normally

The reason is that some transistors that constitute the input buffer stage require a certain voltage for their own conduction, resulting in a certain voltage drop in the input voltage of the I / OPAD terminal, which makes the input buffer stage unable to drive and transmit the input signal of the off-chip device to the inside of the chip.

As a result, the existing I / O interface circuit can only work in a relatively narrow I / O power supply voltage range, its application is limited, and it cannot meet the needs of a wide variety of off-chip devices with different interface standards

In addition, in the output buffer stage of some existing I / O interface circuits, when the input voltage of the I / O PAD terminal is equal to 5V (input voltage tolerance), leakage often occurs in the circuit, resulting in unnecessary power consumption loss

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