CS51021 Datasheet, PDF (1/9 Pages) Cherry Semiconductor Corporation – Enhanced Current Mode PWM Controller

CS51021/CS51023
CS51022/CS51024
Enhanced Current Mode
PWM Controller
Description
Features
The CS51021/22/23/24 Fixed
Frequency PWM Current Mode
Controller family provides all neces-
sary features required for AC-DC or
DC-DC primary side control.
Several features are included elimi-
nating the additional components
needed to implement them external-
ly. In addition to low start-up cur-
rent (75µA) and high frequency
operation capability, the CS51021/
22/23/24 family includes overvolt-
age and undervoltage monitoring,
externally programmable dual
threshold overcurrent protection,
current sense leading edge blank-
ing, current slope compensation,
accurate duty cycle control and an
externally available 5V reference.
The CS51021 and CS51023 feature
bidirectional synchronization capa-
bility, while the CS51022 and
CS51024 offer a sleep mode with
100µA maximum IC current con-
sumption. The CS51021/22/23/24
family is available in a 16 lead nar-
row body SO package.
Device
CS51021
CS51022
CS51023
CS51024
Sleep/Synch
Synch
Sleep
Synch
Sleep
V_CC Start/Stop
8.25V/7.7V
8.25V/7.7V
13V/7.7V
13V/7.7V
Typical Application Diagram
VIN (36V to 72V)
PGND
51k
BAS21
100
1µF
SYNC/SLEEP
11V
22µF
FZT688
18V
0.1µF
200K,1%
10
24.3K
1%
100:1
10K
4:1
0.01µF
4700pF
10K
22K
51K
330pF
0.01µF
VC
VREF
VCC
UV
COMP
OV
VFB
RTCT
ISET
SLOPE
SYNC/
SLEEP
CSS
LGnd U1
GATE
ISENSE
PGnd
2.49K,1%
BA521
10
IRF6345
6.98k, 6.98k, 100
1% 1% _100p 62
470pF
100pF
10
MBRB2060CT
10
680pF
2:5
VOUT
(5V/5A)
100µF 100µF
SGND
0.1µF 5.1K
TL431
1000pF
2K, 1%
180
1K
2K,1%
10K
MOC81025
1K
s 75µA Max. Startup Current
s Fixed Frequency Current
Mode Control
s 1MHz Switching Frequency
s Undervoltage Protection
Monitor
s Overvoltage Protection
Monitor with
Programmable Hysteresis
s Programmable Dual
Threshold Overcurrent
Protection with Delayed
Restart
s Programmable Soft Start
s Accurate Maximum Duty
Cycle Limit
s Programmable Slope
Compensation
s Leading Edge Current
Sense Blanking
s 1A Sink/Source Gate Drive
s Bidirectional Synchronization
(CS51021/23)
s 50ns PWM Propagation
Delay
s 100µA Max Sleep Current
(CS51022/24)
Package Options
16 Lead SO Narrow
GATE ¹
I_SENSE
SLEEP
or SYNC
SLOPE
UV
OV
R_TC_T
I_SET
V_C
PGnd
V_CC
V_REF
LGnd
SS
COMP
V_FB
36-72V to 5V, 5A DC-DC Convertor
Rev. 2/22/99
Consult factory for other package options.
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: [phone] Fax: [phone]
Email: [e-mail]
Web Site: www.cherry-semi.com
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