ALTAIR04-900 Datasheet, PDF (1/29 Pages) STMicroelectronics – Off-line all-primary-sensing switching regulator

ALTAIR04-900
Off-line all-primary-sensing switching regulator
Features
■ Primary side constant voltage operations with
no optocoupler
■ Adjustable and main-independent maximum
output current for safe operations during
overload/short circuit conditions
■ 900 V avalanche rugged internal power section
■ Quasi-resonant valley switching operation
■ Low standby consumption
■ Overcurrent protection against transformer
saturation and secondary diode short circuit
■ SO16 package
Figure 1. Block diagram
SO16N
Applications
■ SMPS for energy metering
■ Auxiliary power supplies for 3-phases input
industrial systems
■ AC-DC adapters
Description
ALTAIR04-900 is a high-voltage all-primary-
sensing switcher intended for operating directly
from the rectified mains with minimum external
parts. It combines a high-performance low-
voltage PWM controller chip and a 900 V
avalanche-rugged power section in the same
package.
+Vi n
+V out
Vc c
Rz cd
ZCD/F B
R fb
Is tar t-up
P ROT ECTION &
FE EDFORWARD
LOGI C
Pr o t
DE MAG
LOGIC
S /H -
+
2.5 V
IFF
3.3 V
R
S
Q
R
Int ernal supply bus
V ref
SUPP LY
& UV LO
B LA NK ING
TIME
Vc
-
+
Iref
+
-
UV LO
STA RT ER
TURN -ON
LOGI C
LE B
S
Q
R
1V
-
I FF
+
R FF
In te r n .
s upply
bus
S
Q
R
UV LO
Pr o t
DRA IN
C OMP
R comp
IR EF
Cr e f
Ccom p
GND
S OURCE
R sens e
January 2011
Doc ID 18211 Rev 2
1/29
www.st.com
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