pca9635 NXP Semiconductors, pca9635 Datasheet - Page 12

• Manufacturer Part Number: pca9635
• Description: Pca9635 16-bit Fm I2c-bus Led Driver
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9635_5
Product data sheet
7.3.4 GRPPWM, group duty cycle control
A 97 kHz fixed frequency signal is used for each output. Duty cycle is controlled through
256 linear steps from 00h (0 % duty cycle = LED output off) to FFh
(99.6 % duty cycle = LED output at maximum brightness). Applicable to LED outputs
programmed with LDRx = 10 or 11 (LEDOUT0 to LEDOUT3 registers).
Table 8.
Legend: * default value
When DMBLNK bit (MODE2 register) is programmed with logic 0, a 190 Hz fixed
frequency signal is superimposed with the 97 kHz individual brightness control signal.
GRPPWM is then used as a global brightness control allowing the LED outputs to be
dimmed with the same value. The value in GRPFREQ is then a ‘Don’t care’.
General brightness for the 16 outputs is controlled through 256 linear steps from 00h
(0 % duty cycle = LED output off) to FFh (99.6 % duty cycle = maximum brightness).
Applicable to LED outputs programmed with LDRx = 11 (LEDOUT0 to LEDOUT3
registers).
When DMBLNK bit is programmed with logic 1, GRPPWM and GRPFREQ registers
define a global blinking pattern, where GRPFREQ contains the blinking period (from
24 Hz to 10.73 s) and GRPPWM the duty cycle (ON/OFF ratio in %).
duty cycle
duty cycle
Address
12h
GRPPWM - Group brightness control register (address 12h) bit description
Register
GRPPWM
=
=
-------------------------- -
GDC 7:0
-------------------------- -
IDCx 7:0
256
256
Rev. 05 — 22 March 2007
Bit
7:0
Symbol
GDC[7:0]
Access Value
R/W
1111 1111
16-bit Fm+ I
Description
GRPPWM register
PCA9635
2
© NXP B.V. 2007. All rights reserved.
C-bus LED driver
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