PCA9532 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2016. All rights reserved.
Product data sheet Rev. 4.1 — 22 August 2016 13 of 31
NXP Semiconductors
PCA9532
16-bit I
2
C-bus LED dimmer
8. Application design-in information
8.1 Minimizing I
DD
when the I/Os are used to control LEDs
When the I/Os are used to control LEDs, they are normally connected to V
DD
through a
resistor as shown in Figure 14
. Since the LED acts as a diode, when the LED is off the
I/O V
I
is about 1.2 V less than V
DD
. The supply current, I
DD
, increases as V
I
becomes
lower than V
DD
and is specified as I
DD
in Table 13 “Static characteristics”.
Designs needing to minimize current consumption, such as battery power applications,
should consider maintaining the I/O pins greater than or equal to V
DD
when the LED is off.
Figure 15
shows a high value resistor in parallel with the LED. Figure 16 shows V
DD
less
than the LED supply voltage by at least 1.2 V. Both of these methods maintain the I/O V
I
at or above V
DD
and prevents additional supply current consumption when the LED is off.
LED0 to LED12 are used as LED drivers.
LED13 to LED15 are used as regular GPIOs.
Fig 14. Typical application
PCA9532
LED0
LED1
SDA
SCL
RESET
5 V
I
2
C-BUS/SMBus
MASTER
002aae522
SDA
SCL
V
DD
A2
A1
A0
V
SS
5 V
10 kΩ
LED2
LED3
LED4
LED5
LED14
LED15
GPIOs
10 kΩ10 kΩ
LED6
LED7
LED8
LED9
LED10
LED11
LED12
LED13
