STCS1A STMicroelectronics, STCS1A Datasheet - Page 12

• Manufacturer Part Number: STCS1A
• Description: 1.5A MAX CONSTANT CURRENT LED DRIVER
• Manufacturer: STMicroelectronics

8
8.1
Figure 15. Reverse polarity condition
8.2
12/19
Application information
Reverse polarity protection
STCS1A must be protected from reverse connection of the supply voltage. Since the current
sunk from V
protect the chip. Care must be taken for the whole application circuit, especially for the
LEDs, in fact, in case a negative voltage is applied between V
voltage will be applied to the LED string that must have a total breakdown voltage higher
than the negative applied voltage in order to avoid any damage.
Thermal considerations
The STCS1A is able to control a LED current up to 1.5 A and able to sustain a voltage on
the drain pin up to 40 V. Those operating conditions are however limited by thermal
constraints, the thermal resistances shown in the
in particular R
circuit board under the pad. DFN8 and PowerSO-8 have an exposed die attach pad which
enhances the thermal conductivity enabling high power application.
The power dissipation in the device can be calculated as follow:
P
basing on this and on the thermal resistance and ambient temperature, the junction
temperature can be calculated as:
T
A typical application could be:
J
D
= R
– Input voltage: 12 V;
– 3 white LEDs with an typical V
= (V
thJA
DRAIN
x P
CC
- V
thJA
D
pin is in the range of 450 µA a small diode connected to V
V
V
V
V
+ T
IN
IN
IN
IN
FB
depends on the copper area and the number of layers of the printed
A
) x I
BAT46
BAT46
or similar
or similar
or similar
or similar
+
+
+
+
LED
+ (V
CC
x I
CC
F
=3.6 V;
PWM
PWM
PWM
PWM
EN
EN
EN
EN
V
V
V
V
)
CC
CC
CC
CC
DISC
DISC
DISC
DISC
SLOPE
SLOPE
SLOPE
SLOPE
Thermal data
GND
GND
GND
GND
DRAIN
DRAIN
DRAIN
DRAIN
FB
FB
FB
FB
IN
section are the typical ones,
and GND, a negative
CC
is able to