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| PCA9552 Datasheet, PDF (10/21 Pages) NXP Semiconductors – 16-bit I2C LED driver with programmable blink rates | |||
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Philips Semiconductors
16-bit I2C LED driver with programmable blink rates
Product data sheet
PCA9552
APPLICATION DATA
5V
5V
SDA
SCL
I2C/SMBus MASTER
10 k⦠(3Ã)
SDA
SCL
RESET
A2
A1
A0
VSS
VDD LED0
LED1
LED2
LED3
LED4
LED5
LED6
LED7
LED8
LED9
LED10
LED11
LED12
LED13
LED14
LED15
PCA9552
Note: LED0 to LED12 are used as LED drivers
LED13 to LED15 are used as regular GPIOs.
Figure 13. Typical application
GPIOs
SW00930
Minimizing IDD when the I/O is used to control LEDs
When the I/Os are used to control LEDs, they are normally connected to VDD through a resistor as shown in Figure 13. Since the LED acts as a
diode, when the LED is off the I/O VIN is about 1.2 V less than VDD. The supply current, IDD, increases as VIN becomes lower than VDD and is
specified as âIDD in the DC characteristics table.
Designs needing to minimize current consumption, such as battery power applications, should consider maintaining the I/O pins greater than or
equal to VDD when the LED is off. Figure 14 shows a high value resistor in parallel with the LED. Figure 15 shows VDD less than the LED supply
voltage by at least 1.2 V. Both of these methods maintain the I/O VIN at or above VDD and prevents additional supply current consumption when
the LED is off.
VDD
3.3 V
5V
VDD
LEDx
LED
100 kâ¦
SW02086
Figure 14. High value resistor in parallel with the LED
VDD
LEDx
LED
SW02087
Figure 15. Device supplied by a lower voltage
2004 Oct 01
10
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