欢迎访问ic37.com |
会员登录 免费注册
发布采购

LM555 参数 Datasheet PDF下载

LM555图片预览
型号: LM555
PDF下载: 下载PDF文件 查看货源
内容描述: 定时器 [Timer]
分类和应用:
文件页数/大小: 12 页 / 392 K
品牌: NSC [ National Semiconductor ]
 浏览型号LM555的Datasheet PDF文件第4页浏览型号LM555的Datasheet PDF文件第5页浏览型号LM555的Datasheet PDF文件第6页浏览型号LM555的Datasheet PDF文件第7页浏览型号LM555的Datasheet PDF文件第8页浏览型号LM555的Datasheet PDF文件第10页浏览型号LM555的Datasheet PDF文件第11页浏览型号LM555的Datasheet PDF文件第12页  
Applications Information (Continued)  
PULSE POSITION MODULATOR  
This application uses the timer connected for astable opera-  
tion, as in Figure 10, with a modulating signal again applied  
to the control voltage terminal. The pulse position varies with  
the modulating signal, since the threshold voltage and hence  
the time delay is varied. Figure 11 shows the waveforms  
generated for a triangle wave modulation signal.  
DS007851-16  
FIGURE 12.  
Figure 13 shows waveforms generated by the linear ramp.  
The time interval is given by:  
DS007851-14  
VBE 0.6V  
FIGURE 10. Pulse Position Modulator  
DS007851-17  
V
= 5V  
Top Trace: Input 3V/Div.  
CC  
TIME = 20µs/DIV. Middle Trace: Output 5V/Div.  
DS007851-15  
R
1
R
2
R
E
= 47kΩ  
= 100kΩ  
= 2.7 kΩ  
Bottom Trace: Capacitor Voltage 1V/Div.  
V
= 5V  
Top Trace: Modulation Input 1V/Div.  
Bottom Trace: Output 2V/Div.  
CC  
TIME = 0.1 ms/DIV.  
R
R
= 3.9kΩ  
= 3kΩ  
C = 0.01 µF  
A
B
FIGURE 13. Linear Ramp  
C = 0.01µF  
FIGURE 11. Pulse Position Modulator  
LINEAR RAMP  
When the pullup resistor, RA, in the monostable circuit is re-  
placed by a constant current source, a linear ramp is gener-  
ated. Figure 12 shows a circuit configuration that will perform  
this function.  
9
www.national.com