一种基于 PI 控制的数字低压差稳压器高速可调节模型

A high-speed adjustable model of digital Low Drop Out regulators based on PI controller

摘要:

数字低压差线性稳压器由于可以在低电源电压下工作而被广泛使用。在数字低压差线性稳压器中，其利用模数转换器和积分器进行稳压操作。但是当负载出现瞬态电压变化，其稳定时间将会很长。在PI控制系统中，积分系数大的电路建立时间很短，会产生过冲，然后输出才会稳定。积分系数小的模型输出可以直接稳定，但是建立时间太长。提出了一种高速可调节电路模型，目的是利用电压传感器和时间数字转换器(TDC)，并在电路中加入2种不同积分系数的积分器。首先利用电压传感器和时间数字转换技术(TDCT)实现模数转换以得到数字信号。随后判断数字信号与基准电压，在误差很大时，控制电路选择大积分系数，输出到PI控制；误差小时，控制电路选择小的积分系数，这样可以使电路结合不同积分系数电路的优点，从而达到同时缩短电路建立时间和稳定时间的目的。

Abstract:

The Digital Low Drop-Out(DLDO) regulators are widely used because it can operate at low supply voltage. In the DLDO regulators, the Analog-Digital-Converter and shift register are employed to regulate the voltage. However, when the load has a transient voltage change, it will be stabilized for a long time. In addition, in the PI control system, the circuit with a large integral coefficient has a short setup time, but overshoot will occur before the output is stable. Although the output of the model with a small integration coefficient can be directly stabilized, the setup time is too long. A high-speed adjustable circuit model is proposed, using a voltage sensor and a Time Digital Converter(TDC), and adding two kinds of integrators with different integral coefficients into the circuit. Firstly, the voltage sensor and Time Digital Conversion Technology(TDCT) are utilized to realize the analog-to-digital conversion to obtain the digital signal. When judging the error of digital signal compared with the reference voltage to be large, the control circuit chooses large integral coefficient to output to PI control. When the error is small, the control circuit chooses small integral coefficient, so that the circuit can combine the advantages of the circuits with different integral coefficients to shorten the circuit setup time and the stabilization time at the same time.