Research And Design Of DPWM Technology For Digital DC-DC Switching Power Supply

With the rapid development of digital chips,the traditional analog switching power supply design for its power supply is becoming more and more stretched.It is urgent to reform the switching power supply and realize the digitalization of the switching power supply to meet the power supply needs of various chips.This article mainly introduces the basic structure and principle of the digital switching power supply,explains the main structure of the digital switching power supply,and focuses on analyzing the performance parameters and limit cycle phenomena of the DPWM module in the digital feedback loop;on this basis,this article introduces several common DPWM technologies,Conduct behavior-level modeling through principle analysis and experimental simulation,summarize the advantages and disadvantages and applicability of each method,and give the simulation waveforms of the six types of DPWM design methods summarized in this article to corroborate;Since then,this paper has designed a new type of second-order delay chain hybrid DPWM with reference to the rolling subtraction algorithm.Its clock frequency is 62.5Mhz and switching frequency is 1Mhz.Through the algorithm,a 7ns and 3ns delay unit is used to achieve a 1ns precision PWM output,thereby outputting 10-bit precision PWM waveform.At the same time,through in-depth research on the technology,the coding module Decoder is supplemented and improved,and the corresponding compensation mechanism is added,which can not only effectively reduce the average error rate,but also apply to the extreme case where the PID high bit is all 0.The algorithm error rate is reduced to 0.05%.The final simulation results show that: under normal operation and extreme conditions,this technology can achieve the purpose of using low-resolution modules to achieve high-resolution PWM output,reflecting the rationality and superiority of the algorithm.This paper further studies the application of DPWM technology and builds a mixed digital-analog switching power management system.Use the MPI interface technology to achieve instant communication between the DPWM output and the external MPU;use the segmented sampling technology of the power drive tube and the operational amplifier to achieve precise control of the system's output current and output voltage.Based on this,using Cadence to simulate and verify the specific circuit,the results show that: the current sampling module function is normal,the response speed is fast,under the accuracy requirement of 20 uA / A,the error rate is within ± 5%;at the same time,the voltage monitoring module functions normally,in When the input voltage is 20 V,the overvoltage lockout starts the power supply protection.At the same time,the circuit has a 0.6V hysteresis window to avoid oscillation at the reversal point and improve circuit stability.Finally,this paper uses 0.18 um BCD process to achieve the overall topology,layout design of important circuit modules,and Hspice for system back-end simulation.The simulation results show that the entire system can output 2.5V voltage stably under the input of 12 V,and its output ripple is not greater than 200mV;after the sampling current samples the output current by 1/50000,it can also effectively follow the current when the DPWM waveform is inverted The sampling error rate is about 3.36%,which meets the design requirements.