PCA9531 Philips Semiconductors (Acquired by NXP), PCA9531 Datasheet - Page 9

• Manufacturer Part Number: PCA9531
• Description: 8-bit I2C Led Dimmerthe PCA9531 is an 8-bit i C And Smbus I/o Expander Optimized For Dimming Leds in 256 Discrete Steps For Red/green/blue (RGB) Color Mixing And Back Light Applications. The PCA9531 Contains an Internal Oscillator With Two User Progr
• Manufacturer: Philips Semiconductors (Acquired by NXP)

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 Nov 10
8-bit I
Figure 14. High value resistor in parallel with the LED
Note: LED0 to LED5 are used as LED drivers
DD
LED6 and LED7 are used as regular GPIOs.
2
when the LED is off. Figure 14 shows a high value resistor in parallel with the LED. Figure 15 shows V
C LED dimmer
DD
DD
I
2
C/SMBus MASTER
in the DC characteristics table.
when the I/O is used to control LEDs
V
5 V
DD
LEDx
SDA
SCL
LED
IN
is about 1.2 V less than V
100 k
V
DD
Figure 13. Typical application
RESET
A2
A1
A0
V
SDA
SW02086
SCL
SS
DD
PCA9531
IN
. The supply current , I
V
DD
at or above V
9
LED0
LED1
LED2
LED3
LED4
LED5
LED6
LED7
DD
through a resistor as shown in Figure 13. Since the LED acts as a
DD
Figure 15. Device supplied by a lower voltage
and prevents additional supply current consumption when
DD
, increases as V
V
3.3 V
DD
LEDx
5 V
LED
IN
becomes lower than V
5 V
DD
less than the LED supply
PCA9531
GPIO
SW02041
Product data
SW02087
DD
and is