基于PIC16F877A控制boost-buckDC-DC變換器.docx

輸出電壓可設(shè)置的升降壓DC-DC變換器如下圖，設(shè)計(jì)一個(gè)DC-DC變換電路: 要求：1）當(dāng)輸入電壓Ui 在14V16V變化時(shí)，輸出電壓Uo恒壓輸出，Uo穩(wěn)態(tài)相對(duì)誤差不超過(guò)2%，Uo可通過(guò)鍵盤(pán)設(shè)置為1020V間的任意電壓，電壓步進(jìn)長(zhǎng)度0.1V；2）要求用液晶屏顯示輸出電壓和輸出電流，電壓顯示精度到0.1V，電流顯示精度到50mA；要求帶4*4鍵盤(pán)，鍵盤(pán)定義如下：123del456自定義789自定義小數(shù)點(diǎn)0自定義ok3）輸出負(fù)載電流I2范圍01A;4）試計(jì)算電源效率。電路部分：設(shè)計(jì)原理：主電路boost-buck電路，驅(qū)動(dòng)電路，控制電路（pic單片機(jī)控制）。原理概述：boost-buck電路利用開(kāi)關(guān)管的開(kāi)關(guān)，輸出電壓的平均值Uo=ton/(T-ton)Ui=D/(1-D)*ui。D為占空比。用單片機(jī)輸出PWM方波（經(jīng)過(guò)驅(qū)動(dòng)電路放大后）控制MOS管的開(kāi)關(guān)，來(lái)調(diào)節(jié)輸出電壓。將輸出電壓送回PIC單片機(jī)模數(shù)轉(zhuǎn)換模塊，通過(guò)反饋調(diào)節(jié)PWM占空比調(diào)節(jié)電壓，使輸出穩(wěn)定。利用差分運(yùn)放電路，檢測(cè)出輸出電壓與輸出電流的關(guān)系。鍵盤(pán)輸入設(shè)置電壓。外接液晶屏顯示輸出電壓和輸出電流和輸出電流。主電路：驅(qū)動(dòng)電路：控制電路：液晶外圍電路：鍵盤(pán)電路模塊：用multisim仿真如下結(jié)果：設(shè)計(jì)小結(jié)：輸出電流與輸出電壓的關(guān)系U=RI。在程序設(shè)計(jì)中，通過(guò)電壓的輸出在液晶屏上顯示電流的輸出。二程序部分：輸出pwm：#includeunsigned int DRE;_CONFIG(0x2001);void PWM()PR2=39; /頻率25KHz TRISC|=0x04; /RC2置為輸入 CCP1CON=0X0c; /PWM輸出 CCPR1L=0X01; /占空比25% T2CON=0X04; /開(kāi)定時(shí)器TMR2，預(yù)分頻1：1 TMR2IF=0; /清除TMR2中斷標(biāo)志位 void main() while(1) PWM(); DRE=40; /高電平寄存器的值 CCPR1L=DRE/4; /裝入高8位 CCP1CON=(DRE/2)%2; /裝入次低位 CCP1CON=DRE%2; /裝入最低位 while(TMR2IF=0); TRISC=0x00; AD轉(zhuǎn)換：#include_CONFIG(FOSC_XT&WDTE_OFF&LVP_OFF);void AD() TRISA0=1; /RA1設(shè)置為模擬輸入 ADCON1=0x00; /參考電壓電源電壓VDD AD轉(zhuǎn)換周期Fosc/4 ADCON0=0x40; / void delayms(int xms) int i,j ; for(i=0;ixms;i+) for(j=0;j150;j+) ; void main() unsigned int x,y,z,A,B,C; unsigned int Result,Result1,ADRES; while(1); delayms(5);/采樣采樣電壓充電延時(shí) GO=1; while(GO=1); Result=ADRES; x=(Result*5)/256; /取個(gè)位十分位百分位 y=(Result*50)/256)%10; z=(Result*500)/256)%10;Result1=Result/1.2-1.5; A=(Result*5)/256; /取個(gè)位十分位百分位 B=(Result*50)/256)%10; C= (Result*500)/256)%10;液晶屏與鍵盤(pán)：#include#define LCD_EN RC7#define LCD_RW RC6#define LCD_RS RC5unsigned int x,y,z,A,B,C;unsigned char dis0=voltage:;unsigned char dis1=0,1,2,3,4,5,6,7,8,9,.;unsigned char dis2=current:;unsigned char dis3=0,1,2,3,4,5,6,7,8,9,.;unsigned char dis43, dis53; _CONFIG(FOSC_XT&WDTE_OFF&LVP_OFF);void delay (int xms) int i,j; for(i=0;ixms;i+) for(j=0;j150;j+); void write_com() unsigned char com ; /聲明寫(xiě)指令 LCD_RS=0; LCD_RW=0; LCD_EN=0; PORTD=com; delay(5); LCD_EN=1; delay(5); LCD_EN=0;void write_date() unsigned char date; LCD_RS=1; LCD_RW=0; LCD_EN=0; PORTD=date; delay(5); LCD_EN=1; delay(5); LCD_EN=0; void init() TRISD=0x00; TRISC&=0x1f; write_com(0x38); delay(5); write_com(0x0c); delay(5); write_com(0x06); delay(5); write_com(0x01); delay(5); void display() unsigned char j; dis40=dis1x; dis41=dis110; dis42=dis1y; dis43=dis1z; write_com(0xc8); for(j=0;j=3;j+) write_date(dis5j); delay(1); unsigned char k; dis50=dis3A; dis51=dis310; dis52=dis3B; dis53=dis3C; write_com(0xc8); for(k=0;k=3;k+) write_date(dis4k); delay(1); void main() unsigned char i; init(); write_com(0x80); /顯示第1行 for(i=0;i=8;i+) write_date(dis0i); delay(1); write_com(0x80+0x40);/顯示第2行 for(i=0;i=8;i+) write_date(dis2i); delay(1); #include#include#define LCD_EN RC7#define LCD_RW RC6#define LCD_RS RC5unsigned int x,y,z,A,B,C;unsigned char dis0=voltage:;unsigned char dis1=0,1,2,3,4,5,6,7,8,9,.;unsigned char dis2=current:;unsigned char dis3=0,1,2,3,4,5,6,7,8,9,.;unsigned char dis43, dis53; _CONFIG(FOSC_XT&WDTE_OFF&LVP_OFF);void delay (int xms) int i,j; for(i=0;ixms;i+) for(j=0;j150;j+); void write_com() unsigned char com ; /聲明寫(xiě)指令 LCD_RS=0; LCD_RW=0; LCD_EN=0; PORTD=com; delay(5); LCD_EN=1; delay(5); LCD_EN=0;void write_date() unsigned char date; LCD_RS=1; LCD_RW=0; LCD_EN=0; PORTD=date; delay(5); LCD_EN=1; delay(5); LCD_EN=0; void init() TRISD=0x00; TRISC&=0x1f; write_com(0x38); delay(5); write_com(0x0c); delay(5); write_com(0x06); delay(5); write_com(0x01); delay(5); void display() unsigned char j; dis40=dis1x; dis41=dis110; dis42=dis1y; dis43=dis1z; write_com(0xc8); for(j=0;j=3;j+) write_date(dis5j); delay(1); unsigned char k; dis50=dis3A; dis51=dis310; dis52=dis3B; dis53=dis3C; write_com(0xc8); for(k=0;k=3;k+) write_date(dis4k); delay(1); void main() unsigned char i; init(); write_com(0x80); /顯示第1行 for(i=0;i=8;i+) write_date(dis0i); delay(1); write_com(0x80+0x40);/顯示第2行 for(i=0;i=8;i+) write_date(dis2i); delay(1); #define KEYBOARD_PORT_DIR TRISB /鍵盤(pán)掃描方向端口#define KEYBOARD_PORT PORTB /鍵盤(pán)掃描端口#define NO_KEY 0xFF /無(wú)按鍵_CONFIG(0x3FFF);unsigned char L,O;char scankeypad(); /獲取44鍵盤(pán)值char getkeyvalue(); /獲取某按鍵的值 voi