CS5124/6
CS5124/6
High Performance, Integrated Current Mode
PWM Controllers
Description
The CS5124/6 is a fixed frequency
current mode controller designed
specifically for DC-DC converters
found in the telecommunications
industry. The CS5124/6 integrates
many commonly required current
mode power supply features and
allows the power supply designer to
realize substantial cost and board
space savings. The product matrix is
as follows:
CS5124: 400kHz w/V
BIAS
Pin,
195mV first current sense threshold
CS5126: 200kHz w/SYNC Pin,
335mV first current sense threshold
The CS5124/6 integrates the follow-
ing features: Internal Oscillator, Slope
Compensation, Sleep On/Off, Under
Voltage Lock Out, Thermal
Shutdown, Soft Start Timer, Low
Voltage Current Sense for Resistive
Sensing, Second Current Threshold
for Pulse by Pulse Over Current
Protection, a Direct Optocoupler
Interface and Leading Edge Current
Blanking.
The CS5124/6 has supply range of
7.7V to 20V and is available in 8 pin
SO narrow package.
Features
s
Line UVLO Monitoring
s
Low Current Sense
Voltage for Resistive
Current Sensing
s
External Synchronization
to Higher or Lower
Frequency Oscillator
(CS5126 Only)
s
Bias for Start up Circuitry
(CS5124 Only)
s
Thermal Shutdown
s
Sleep On/Off Pin
s
Soft Start Timer
s
Leading Edge Blanking
s
Direct Optocoupler
Interface
s
90ns Propagation Delay
Applications Diagram
s
35ns Driver Rise and Fall
Times
s
Sleep Mode
D1
36-75VIN
L1
10µH
R2
200k
C2
1.5µF,
100V
R1
510k
Q1
ZVN3310A
R4
10Ω
R5
17.4k
CTX15-14514
T1
5VOUT
MBRD360CT
D4
R3
47Ω
Q2
IRFR220
R8
0.39Ω
Package Options
8 Lead SO Narrow
CS5124
BAS16LT1
C1
0.1µF,
100V
C4
0.47µF,
25V
C3
.022µF
R6
1k
C6
R7
30.1k
C5
47µF,
10V
V
CC
BIAS
UVLO
1
Gnd
GATE
V
CC
BIAS
ENABLE
UVLO
SS
C7
0.1µF
Gnd
GATE
IS
U2
I
SENSE
V
FB
.01µF
CS5124
C9
1000pF
SS
C8
1000pF
V
FB
TPS5908
R9
10.0k
ISOLATED
RTN
CS5126
V
CC
UVLO
SYNC
1
Gnd
GATE
48VRTN
I
SENSE
V
FB
48V to 5V, 1A flyback converter using the CS5124
SS
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786
Email: info@cherry-semi.com
Web Site: www.cherry-semi.com
Rev. 3/12/99
1
A
®
Company
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
