欢迎访问ic37.com |
会员登录 免费注册
发布采购

UC3844 参数 Datasheet PDF下载

UC3844图片预览
型号: UC3844
PDF下载: 下载PDF文件 查看货源
内容描述: 高性能电流模式控制器 [HIGH PERFORMANCE CURRENT MODE CONTROLLERS]
分类和应用: 控制器
文件页数/大小: 14 页 / 380 K
品牌: MOTOROLA [ MOTOROLA ]
 浏览型号UC3844的Datasheet PDF文件第6页浏览型号UC3844的Datasheet PDF文件第7页浏览型号UC3844的Datasheet PDF文件第8页浏览型号UC3844的Datasheet PDF文件第9页浏览型号UC3844的Datasheet PDF文件第11页浏览型号UC3844的Datasheet PDF文件第12页浏览型号UC3844的Datasheet PDF文件第13页浏览型号UC3844的Datasheet PDF文件第14页  
UC3844, 45 UC2844, 45  
Figure 19. Adjustable Reduction of Clamp Level  
Figure 20. Soft–Start Circuit  
V
CC  
V
in  
7(12)  
5.0V  
+
ref  
5.0V  
ref  
8(14)  
R
R
+
8(14)  
R
R
Bias  
+
Bias  
+
+
+
7(11)  
6(10)  
5(8)  
Q1  
Osc  
Osc  
T
+
4(7)  
2(3)  
T
+
4(7)  
V
Clamp  
S
1.0mA  
2R  
+
1.0mA  
2R  
S
Q
+
Q
R
+
R2  
R
EA  
+
EA  
2(3)  
1(1)  
R
Comp/Latch  
R
1.0V  
1.0V  
3(5)  
1(1)  
t
C
R
S
R1  
5(9)  
5(9)  
3600C in µF  
Soft–Start  
1.67  
2
R
R
2
V
1
Clamp  
–3  
+ 0.33 x 10  
V
Clamp  
I
pk(max)  
R
+ R  
R
1
2
S
R
R
+ 1  
Where: 0  
V
1.0 V  
Clamp  
1
Figure 21. Adjustable Buffered Reduction of  
Figure 22. Current Sensing Power MOSFET  
Clamp Level with Soft–Start  
V
CC  
R
I
r
S
pk DS(on)  
V
V
in  
CC  
V
5 ≈  
V
(12)  
Pin  
in  
r
+ R  
DM(on)  
S
7(12)  
If: SENSEFET = MTP10N10M  
+
R
= 200  
5.0V  
ref  
S
+
+
5.0V  
ref  
Then: V  
SENSEFET  
5 = 0.075 I  
pk  
+
pin  
8(14)  
4(7)  
R
R
+
D
Bias  
+
+
(11)  
(10)  
(8)  
+
S
7(11)  
6(10)  
5(8)  
Q1  
Osc  
G
T
K
T
M
+
V
Clamp  
S
S
Q
1.0mA  
2R  
+
R
Q
+
R
Power Ground  
To Input Source  
Return  
+
Comp/Latch  
EA  
2(3)  
1(1)  
Comp/Latch  
R
R2  
(5)  
R
1.0V  
3(5)  
S
1/4 W  
R
S
Control CIrcuitry  
Ground:  
To Pin (9)  
5(9)  
–3  
MPSA63  
C
R1  
1.67  
2
R
R
2
V
1
Clamp  
+ 0.33 x 10  
R
+ R  
R
R
1
2
Virtually lossless current sensing can be achieved with the implement of a SENSEFET  
power switch. For proper operation during over current conditions, a reduction of the  
+ 1  
1
V
I
clamp level must be implemented. Refer to Figures 19 and 21.  
Clamp  
pk(max)  
I
Where: 0  
V
V
1.0 V  
pk(max)  
Clamp  
C
R
S
R
R
C
1
2
t
= – In  
1 –  
Softstart  
3V  
R
+ R  
Clamp  
1 2  
Figure 23. Current Waveform Spike Suppression  
V
CC  
V
in  
7(12)  
+
5.0V  
ref  
+
+
+
7(11)  
6(10)  
5(8)  
Q1  
T
S
Q
R
+
R
Comp/Latch  
3(5)  
The addition of the RC filter will eliminate  
instabilitycaused by the leading edge spike on  
the current waveform.  
C
R
S
10  
MOTOROLA ANALOG IC DEVICE DATA