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GM384X Datasheet, PDF (1/8 Pages) Gamma Microelectronics Inc. – Low Start-Up and Operating Current | |||
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GM3842A, GM3843A
GM3844A, GM3845A
CURRENT MODE PWM CONTROLLER
Description
Features
GM384XA series is high performance with fixed-
frequency current mode PWM controllers. They
are specially designed for off-Line and DC-to-DC
converter applications with minimum external
components. These devices feature a trimmed
oscillator for precise duty cycle control, a
temperature compensated reference, high gain
error amplifier, current sensing comparator, and
high current totem pole output which is suitable
for driving MOSFETs.
ïµ Low Start-Up and Operating Current
ïµ Automatic Feed Forward Compensation
ïµ Current Mode Operating Frequency up to
500KHz
ïµ Trimmed Oscillator Discharge Current for
Precise Duty Cycle Control
ïµ Latching PWM for Cycle-By-Cycle
Current Limiting
The under voltage lock-out (U.V.L.O.) is
designed to operated with 0.17mA typ. start-up
current, allowing an efficient bootstrap supply
voltage design. The U.V.L.O. thresholds for the
AMC3842A/44A are 16V (on) and 10V (off)
which are ideal for off-line applications. The
corresponding typical threshold for the
GM3843A/45A is 8.4V (on) and 7.6V (off). The
GM3842A/43A can operated within 100% duty
cycle and the GM3844A/45A can operated within
50% duty cycle.
ïµ Under Voltage Lockout with Hysteresis
ïµ High Current totem Pole Output Stage
Available Options
Application
Device
GM3842A
GM3843A
GM3844A
GM3845A
Start-UP
Voltage
16V
8.4V
16V
8.4V
Hysteresis
Max. Duty
Cycle
6V
0.8V
6V
0.8V
< 100%
< 100%
< 50%
< 50%
C Off-line flyback or forward converters
N DC-to DC buck boost converter
Monitor Power Supply
O
N
GP O
O
G
C
C
UNW M
U
N
TDR P
T
D
P
P
U
U
G
T
T
www.gammamicro.com.tw 1
N
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