基于PIC16F877A控制boost-buckDC-DC变换器

输出电压可设置的升降压DC-DC变换器如下图，设计一个DC-DC变换电路:要求：1）当输入电压Ui在14V~16V变化时，输出电压Uo恒压输出，Uo稳态相对误差不超过2%，Uo可通过键盘设置为10~20V间的任意电压，电压步进长度0.1V；2）要求用液晶屏显示输出电压和输出电流，电压显示精度到0.1V，电流显示精度到50mA；要求带4*4键盘，键盘定义如下：123del456自定义789自定义小数点0自定义ok3）输出负载电流I2范围0~1A;4）试计算电源效率。一电路部分：设计原理：主电路boost-buck电路，驱动电路，控制电路（pic单片机控制）。原理概述：boost-buck电路利用开关管的开关，输出电压的平均值Uo=ton/(T-ton)×Ui=D/(1-D)*ui。D为占空比。用单片机输出PWM方波（经过驱动电路放大后）控制MOS管的开关，来调节输出电压。将输出电压送回PIC单片机模数转换模块，通过反馈调节PWM占空比调节电压，使输出稳定。利用差分运放电路，检测出输出电压与输出电流的关系。键盘输入设置电压。外接液晶屏显示输出电压和输出电流和输出电流。主电路：驱动电路：控制电路：液晶外围电路：键盘电路模块：用multisim仿真如下结果：设计小结：输出电流与输出电压的关系U=RI。在程序设计中，通过电压的输出在液晶屏上显示电流的输出。〈二〉程序部分：输出pwm：#includepic.hunsignedintDRE;__CONFIG(0x2001);voidPWM(){PR2=39;//频率25KHzTRISC|=0x04;//RC2置为输入CCP1CON=0X0c;//PWM输出CCPR1L=0X01;//占空比25%T2CON=0X04;//开定时器TMR2，预分频1：1TMR2IF=0;//清除TMR2中断标志位}voidmain(){while(1){PWM();DRE=40;//高电平寄存器的值CCPR1L=DRE/4;//装入高8位CCP1CON5=(DRE/2)%2;//装入次低位CCP1CON4=DRE%2;//装入最低位while(TMR2IF==0);TRISC=0x00;}}AD转换：#includepic.h__CONFIG(FOSC_XT&WDTE_OFF&LVP_OFF);voidAD(){TRISA0=1;//RA1设置为模拟输入ADCON1=0x00;//参考电压电源电压VDDAD转换周期Fosc/4ADCON0=0x40;//}voiddelayms(intxms){inti,j;for(i=0;ixms;i++)for(j=0;j150;j++);}voidmain(){unsignedintx,y,z,A,B,C;unsignedintResult,Result1,ADRES;while(1);{delayms(5);//采样采样电压充电延时GO=1;}while(GO==1);{}Result=ADRES;x=(Result*5)/256;//取个位十分位百分位y=((Result*50)/256)%10;z=((Result*500)/256)%10;Result1=Result/1.2-1.5;A=(Result*5)/256;//取个位十分位百分位B=((Result*50)/256)%10;C=((Result*500)/256)%10;}液晶屏与键盘：#includepic.h#defineLCD_ENRC7#defineLCD_RWRC6#defineLCD_RSRC5unsignedintx,y,z,A,B,C;unsignedchardis0[]=voltage:;unsignedchardis1[]={'0','1','2','3','4','5','6','7','8','9','.'};unsignedchardis2[]=current:;unsignedchardis3[]={'0','1','2','3','4','5','6','7','8','9','.'};unsignedchardis4[3],dis5[3];__CONFIG(FOSC_XT&WDTE_OFF&LVP_OFF);voiddelay(intxms){inti,j;for(i=0;ixms;i++){for(j=0;j150;j++);}}voidwrite_com(){unsignedcharcom;//声明写指令LCD_RS=0;LCD_RW=0;LCD_EN=0;PORTD=com;delay(5);LCD_EN=1;delay(5);LCD_EN=0;}voidwrite_date(){unsignedchardate;LCD_RS=1;LCD_RW=0;LCD_EN=0;PORTD=date;delay(5);LCD_EN=1;delay(5);LCD_EN=0;}voidinit(){TRISD=0x00;TRISC&=0x1f;write_com(0x38);delay(5);write_com(0x0c);delay(5);write_com(0x06);delay(5);write_com(0x01);delay(5);}voiddisplay(){unsignedcharj;dis4[0]=dis1[x];dis4[1]=dis1[10];dis4[2]=dis1[y];dis4[3]=dis1[z];write_com(0xc8);for(j=0;j=3;j++){write_date(dis5[j]);delay(1);}unsignedchark;dis5[0]=dis3[A];dis5[1]=dis3[10];dis5[2]=dis3[B];dis5[3]=dis3[C];write_com(0xc8);for(k=0;k=3;k++){write_date(dis4[k]);delay(1);}}voidmain(){unsignedchari;init();write_com(0x80);//显示第1行for(i=0;i=8;i++){write_date(dis0[i]);delay(1);}write_com(0x80+0x40);//显示第2行for(i=0;i=8;i++){write_date(dis2[i]);delay(1);}}#includepic.h#includepic.h#defineLCD_ENRC7#defineLCD_RWRC6#defineLCD_RSRC5unsignedintx,y,z,A,B,C;unsignedchardis0[]=voltage:;unsignedchardis1[]={'0','1','2','3','4','5','6','7','8','9','.'};unsignedchardis2[]=current:;unsignedchardis3[]={'0','1','2','3','4','5','6','7','8','9','.'};unsignedchardis4[3],dis5[3];__CONFIG(FOSC_XT&WDTE_OFF&LVP_OFF);voiddelay(intxms){inti,j;for(i=0;ixms;i++){for(j=0;j150;j++);}}voidwrite_com(){unsignedcharcom;//声明写指令LCD_RS=0;LCD_RW=0;LCD_EN=0;PORTD=com;delay(5);LCD_EN=1;delay(5);LCD_EN=0;}voidwrite_date(){unsignedchardate;LCD_RS=1;LCD_RW=0;LCD_EN=0;PORTD=date;delay(5);LCD_EN=1;delay(5);LCD_EN=0;}voidinit(){TRISD=0x00;TRISC&=0x1f;write_com(0x38);delay(5);write_com(0x0c);delay(5);write_com(0x06);delay(5);write_com(0x01);delay(5);}voiddisplay(){unsignedcharj;dis4[0]=dis1[x];dis4[1]=dis1[10];dis4[2]=dis1[y];dis4[3]=dis1[z];write_com(0xc8);for(j=0;j=3;j++){write_date(dis5[j]);delay(1);}unsignedchark;dis5[0]=dis3[A];dis5[1]=dis3[10];dis5[2]=dis3[B];dis5[3]=dis3[C];write_com(0xc8);for(k=0;k=3;k++){write_date(dis4[k]);delay(1);}}voidmain(){unsignedchari;init();write_com(0x80);//显示第1行for(i=0;i=8;i++){write_date(dis0[i]);delay(1);}write_com(0x80+0x40);//显示第2行for(i=0;i=8;i++){write_date(dis2[i]);delay(1);}}#defineKEYBOARD_PORT_DIRTRISB//键盘扫描方向端口#defineKEYBOARD_PORTPORTB//键盘扫描端口#defineNO_KEY0xFF//无按键__CONFIG(0x3FFF);unsignedcharL,O;charscankeypad();//获取4×4键盘值chargetkeyvalue();//获取某按键的值voiddelay(intxms){inti,j;for(i=0;ixms;i++)for(j=0;j150;j++);}constcharccode[16][2]={{0xEE,1},{0xED,2},{0xEB,3},{0xE7,'L'},{0xDE,4},{0xDD,5},{0xDB,6},{0xD7,'+'},{0xBE,7},{0xBD,8},{0xBB,9},{0xB7,'-'},{0x7E,'.'},{0x7D,0},{0x7B,'*'},{0x77,'O'}};charscankeypad()//获取4*4键盘扫描码{charkey4H=0,key4L=0,scancode=0;TRISD=0xF0;//低四位输出，高四位输入PORTD=0x00;//低四位输出0asm(nop);asm(nop);//待输出信号稳定key4H=PORTD;//读取高四位key4H=key4H&0xF0;//将低四位屏蔽if(key4H!=0xF0)//有按键按下{delay(20);key4H=PORTD;//重读if(key4H!=0xF0){TRISD=0x0F;PORTD=0x00;asm(nop);asm(nop);key4L=PORTD;//读取高四位key4L=key4H&0x0F;//将高四位屏蔽if(key4L!=0x0F)//有按键按下{scancode=key4H|key4L;//高四位与低四位组成键盘扫描码while(PORTD!=0x0F);//按键未松开等待return(scancode);}}}returnNO_KEY;}charGetkeyvalue()//获取扫描码{charkeyvalue=0,c=0;keyvalue=scankeypad();if(keyvalue!=NO_KEY){while(keyvalue!=ccode[c][0]){//比较描码与当前数组元素是否相等c++;}return(ccode[c][1]);//返回序号对应值}return(NO_KEY);}voidmain(){i