PCA9550 Philips Semiconductors, PCA9550 Datasheet - Page 8

• Manufacturer Part Number: PCA9550
• Description: 2-bit I2C LED driver with programmable blink rates
• Manufacturer: Philips Semiconductors

Philips Semiconductors
APPLICATION DATA
Minimizing I
When the I/Os are used to control LEDs, they are normally connected to V
diode, when the LED is off the I/O V
specified as ∆I
Designs needing to minimize current consumption, such as battery power applications, should consider maintaining the I/O pins greater than or
equal to V
voltage by at least 1.2 V. Both of these methods maintain the I/O V
the LED is off.
2003 May 02
2-bit I
Figure 13. High value resistor in parallel with the LED
DD
2
when the LED is off. Figure 13 shows a high value resistor in parallel with the LED. Figure 14 shows V
C LED driver with programmable blink rates
DD
DD
in the DC characteristics table.
when the I/O is used to control LEDs
V
DD
LEDx
I
LED
IN
2
C/SMBus MASTER
is about 1.2 V less than V
5 V
100 kΩ
SDA
SCL
V
DD
Figure 12. Typical application
SW02086
DD
IN
. The supply current, I
at or above V
8
DD
through a resistor as shown in Figure 12. Since the LED acts as a
RESET
A0
V
SDA
SCL
SS
DD
PCA9550
Figure 14. Device supplied by a lower voltage
and prevents additional supply current consumption when
V
DD
DD
, increases as V
LED0
LED1
V
3.3 V
DD
LEDx
5 V
IN
LED
becomes lower than V
5 V
DD
less than the LED supply
PCA9550
SW00929
Product data
SW02087
DD
and is