STMicroelectronics Double output SMPS for power line application using ALTAIR04-900 primary controller EVLALTAIR900-M1 EVLALTAIR900-M1 Hoja De Datos

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Pin connection
ALTAIR04-900
4/29
Doc ID 18211 Rev 2
2 Pin 
connection 
Figure 2.
Pin connection (top view)
Note:
The copper area for heat dissipation has to be designed under the drain pins
         
N.A.
N.A.   
SOURCE
DRAIN
SOURCE
GND
IREF
ZCD/FB
COMP
Vcc
DRAIN
DRAIN
DRAIN
N.A.
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
N.C.
N.A.
N.A.   
SOURCE
DRAIN
SOURCE
GND
IREF
ZCD/FB
COMP
Vcc
DRAIN
DRAIN
DRAIN
DRAIN
DRAIN
N.A.
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
N.C.
N.A.   
Table 1.
Pin functions 
N.
Name
Function
1, 2
SOURCE
Power section source and input to the PWM comparator. The current flowing in the MOSFET 
is sensed through a resistor connected between the pin and GND. The resulting voltage is 
compared with an internal reference (0.75V max.) to determine MOSFET’s turn-off. The pin 
is equipped with 250 ns blanking time after the gate-drive output goes high for improved 
noise immunity. If a second comparison level located at 1V is exceeded the IC is stopped and 
restarted after Vcc has dropped below 5V.
3
Vcc
Supply voltage of the device. An electrolytic capacitor, connected between this pin and 
ground, is initially charged by the internal high-voltage start-up generator; when the device is 
running the same generator keeps it charged in case the voltage supplied by the auxiliary 
winding is not sufficient. This feature is disabled in case a protection is tripped. Sometimes a 
small bypass capacitor (0.1 µF typ.) to GND might be useful to get a clean bias voltage for 
the signal part of the IC.
4
GND
Ground. Current return for both the signal part of the IC and the gate drive. All of the ground 
connections of the bias components should be tied to a trace going to this pin and kept 
separate from any pulsed current return.
5
IREF
CC regulation loop reference voltage. An external capacitor has to be connected between 
this pin and GND. An internal circuit develops a voltage on this capacitor that is used as the 
reference for the MOSFET’s peak drain current during CC regulation. The voltage is 
automatically adjusted to keep the average output current constant.