Current switching circuit for high-speed current rudder digital-to-analog converter

Abstract

The invention discloses a current switching circuit for a high-speed current rudder digital-to-analog converter, comprising a switch main body circuit, a constant-current circuit which provides a constant flow source for the switch main body switch, a switch drive circuit which provides difference switching signals to the switch main body circuit and a four-phase control signal generating circuit which provides difference control signals for the switch drive circuit. A pre-breakover pull-down MOS (Metal Oxide Semiconductor) tube is adopted in the switch drive circuit , and a clock feedthrough compensation structure is applied to the switch main body circuit, thus overshooting of the difference switching signals is greatly weakened, falling edges of the difference switching signals at the initial stage of hopping become gentle, symmetry of rising and falling edges of the difference switching signals in case of low swing amplitude is improved and clock feedthrough errors resulting from the difference switching signals are effectively reduced. The current switching circuit is especially applicable to the high-speed and high-precision digital-to-analog converter.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits, and in particular relates to a current switch circuit for a high-speed current steering digital-to-analog converter. Background technique [0002] Human needs for more convenient and effective communication methods have promoted the continuous development of information technology, such as modern wireless broadband communication technology, multimedia image processing and digital technology. With the introduction of the system on chip (system on chip, SOC) concept, it is required to integrate all analog signals and digital signals in the same system. High-performance data converter interfaces, including digital-to-analog converters (digital to analog, DAC) and analog-to-digital converters (analog to digital, ADC) have gradually become one of the most challenging modules in these technical research fields. With the increasing demand for bandwidth and information processing capability,...

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Problems solved by technology

[0010] but figure 2 The disadvantage of the current switch circuit is that the symmetry of the rising and falling edges of the differential switching signals S0 and S1 is relatively poor, and the differential switching signal has a large overshoot phenomenon when it jumps from high level to low level

The asymmetry between the rising edge and the falling edge of the signal will cause inter-symbol interference (ISI), which will affect the dynamic characteristics of the digital-to-analog converter. At the same time, the differential switch signal jumps from high level to low level Usually, the overshoot will affect the output feedthrough through the lower-level current switch, and then affect the dynamic characteristics of the high-speed current steering digital-to-analog converter, such as spurious-free dynamic range (SFDR)

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