l6590a STMicroelectronics, l6590a Datasheet - Page 2

• Manufacturer Part Number: l6590a
• Description: Fully Integrated Power Supply
• Manufacturer: STMicroelectronics

L6590A
DESCRIPTION (continued)
The MOSFET is source-grounded, thus it is possible
to build flyback, boost and forward converters.
The device is meant to work with secondary feed-
back for tight tolerance of the regulated output volt-
age.
The internal fixed oscillator frequency and the inte-
grated non dissipative start-up generator minimize
the external component count and power consump-
tion.
The device is equipped with a standby function that
automatically reduces the oscillator frequency from
65 to 22 kHz under light load conditions to enhance
BLOCK DIAGRAM
PIN CONNECTIONS (Top view)
2/19
(6,7,8)
GND
DRAIN
COMP
DRAIN
(1)
THERMAL
N.C.
START-UP
S.DOWN
Vcc
STANDBY
+
-
CURRENT
OVER
65/22 kHz
OSC
SUPPLY
& UVLO
efficiency (P
mains).
Internal protections like cycle-by-cycle current limit-
ing, latched output overvoltage protection, mains un-
dervoltage
generate a 'robust' design solution.
The IC uses a special leadframe with the ground pins
(6, 7 and 8) internally connected in order for heat to
be easily removed from the silicon die. An heatsink
can then be realized by simply making provision of
few cm
close to the high-voltage one is not connected to
ease compliance with safety distances on the PCB.
PWM
COMP
BROWNOUT
(4)
VOLTAGE
OVER
1 mA
2
+
of copper on the PCB. Furthermore, the pin
-
VREF
GND
GND
GND
BOK
+
-
in
protection
2.5V
< 1W @ P
BOK
V CC
(5)
(3)
out
and
= 0.5W with wide range
thermal
shutdown