Control system of resistive segmented digital-to-analog converter

Abstract

The invention relates to a control system of a resistive segmented digital-to-analog converter. An MSB resistor string is divided into three groups, meanwhile, switches corresponding to the three groups of resistors are also divided into three groups, the group most sensitive to changes in the power supply voltage and temperature is controlled by a set of switches, i.e., the first switch group, the first switch group is controlled by a control voltage generated by a control signal bootstrap circuit, meanwhile a logic timing sequence generation circuit is introduced to ensure that the output signal of the digital-to-analog converter is continuous and to improve the performance degradation of the control signal bootstrap circuit due to power leakage at low frequency.

Description

technical field [0001] The invention relates to a digital-to-analog converter, in particular to a control system for a resistance segmented digital-to-analog converter with stable performance. Background technique [0002] figure 1 Shown is a schematic diagram of the structure of the existing resistance segmented DAC (digital-to-analog converter). The resistance segmented DAC of the traditional structure takes a 12-bit DAC as an example. In this example, the upper 7 bits are called MSB (Most Significant Bit) , the number of MSB resistors is 128; the lower five bits are called LSB (least significant bit), and the number of LSB resistors is 32. In practical applications, according to the different requirements of the system, the number of bits of the MSB resistor can be selected from 4 to 8 bits, and the corresponding number of bits of the LSB resistor can be selected from 8 to 4 bits. The traditional segmented DAC considers matching, and the MSB resistor string and the LSB ...

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Problems solved by technology

But in many applications now, the range of power supply voltage changes is quite large, and sometimes the power supply voltage will change in the range of 2V ~ 5V or even lower or higher.

When encountering low voltage and low temperature and the transistor is at the slow process corner, the threshold voltage of the transistor will increase significantly at low temperature, which makes the on-resistance Rsw very large when the switch in the middle of the MSB resistor string is turned on. Large, it will cause significant deterioration to the performance of the circuit. Simply increasing the width-to-length ratio of the transistor to reduce Rsw will lead to a very large switch area and a high cost

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