6脚电源IC资料及代换

荆州市胡振华资料----- 6PIN电源芯片的功能引脚及代换注意事项
2013年1月6日
LD7535,CR6848,CR6850,CR6853,OB2263,OB2262,SG6848,
GR8836,NE1102可以完美代换
RS2051可以和OB2263做代换,功率做到60W.RS2030和
ACT30做代换
代换总结：
所有6脚IC引脚都是一样的功能，在代换的时候检查3脚是否有接电路，如果没，在3脚对地接一只
100K电阻，用OB2263代换，电路即可工作。

特别注意
如果在3脚没有外围电路的情况下用OB2263代换
会引起炸机，如果忘记这点你就悲剧了，重来吧。

典型应用电路
5
3 6 2 1 4
4
3
2
1
TOP MARK YYWWPP
5
6
7 8 pp
2
3
1 6
5 4 YW P 36
引脚功能
DIP-8 (TOP VIEW)
SOT-26 (TOP VIEW)
OUT
VCC
CS
GND COMP OTP
Pin Descriptions
PIN SOT-26 PIN DIP-8
名称
功能
1
8
GND
Ground
2
7
COMP
Voltage feedback pin (same as the COMP pin in UC384X). Connect a photo-coupler to close the control loop and achieve the regulation.
3
5
OTP
Pull this pin below 0.95V to shutdown the controller into latch mode until the AC
resume power-on. Connecting this pin to ground with NTC will achieve OTP protection. Keep this pin float to disable the latch protection.
4 4 CS Current sense pin, connect it to sense the MOSFET current
5 2 VCC Supply voltage pin
6
1
OUT
Gate drive output to drive the external MOSFET
O U T
G N D
C O M P
N C
V C C
N C
O T P
C S
芯片内部方框图
Fig. 15
Fig. 17
A pull-high resistor is embedded internally and can be eliminated externally.
A 230nS leading-edge blanking (LEB) time is included in the input of CS pin to prevent the false-trigger from the current spike. In the low power application, if the total pulse width of the turn-on spikes is less than 230nS and the negative spike on the CS pin below -0.3V, the R-C filter is free to eliminate. (As shown in Fig.16).
However, the total pulse width of the turn-on spike is determined according to output power, circuit design and PCB layout. It is strongly recommended to adopt a smaller R-C filter (as shown in Fig. 17) for larger power application to avoid the CS pin being damaged by the negative turn-on spike.
Output Stage and Maximum Duty-Cycle
An output stage of a CMOS buffer, with typical 300mA driving capability, is incorporated to drive a power MOSFET directly. And the maximum duty-cycle of LD7536 is limited to 75% to avoid the transformer saturation.
Voltage Feedback Loop
The voltage feedback signal is provided from the TL431 at the secondary side through the photo-coupler to the COMP pin of the LD7536. Similar to UC3842, the LD7536 would carry a diode voltage offset at the stage to feed the voltage divider at the ratio of RA and RB, that is,
Fig. 16
V -(PWM COMPARATOR ) =
RB
RA + RB
⨯ (V COMP - V F )
C5
F1 3.15A/250V L
L1 120uH L2 22mH
330P/1206 R3
R1
2.2MEG/1206
R2
2.2MEG/1206
N
CX1 0.22uF
BR1
KBP206
C4 82uF/400V
R9 51K/1206 C6
NC
102pF/1206 R10
T1A
RM8
C1
51R/1206
D5 20120
C7 470uF/25V
C8
470uF/25V
C10 104P/0805
19V / 2.1A
+Vo
R5
620K/1206
D1
R6
620K/1206
51k/1206
R11 22R/1206
D2 PR1007
U1A
R32
DZ2/6.8V
ZENER1 RTN
R4
0/0805 GS1002FL
SMD
R31
330/0805
5.6k/0805
T1B
C11 4.7u/50V
C12
104P/0805
2 COMP
5 VCC
OUT 6
R12B 10R/0805
D6 D4148
R12
Q1
2SK3562
IC432
R25
1K/0805
R29 4.3k/0805
C16 R28
62K/0805
R30 /0805
PC817B
3.3nF/0805 LD7536
CS 4
200R/0805
C13 3 OTP
GND
R13
100R/0805 C13 1 100P/0805
C14
100PF/0805
R16A R16 1.4/1206 R16B 1.4/1206
CY1 1.4/1206
102P
473p/0805 --- 40W (19V /2.1A )
典型电源适配器电路图。