TCA6507_10 Datasheet, PDF (11/32 Pages) Texas Instruments – LOW-VOLTAGE 7-BIT I2C AND SMBus LED DRIVER WITH INTENSITY CONTROL AND SHUTDOWN

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TCA6507
LOW-VOLTAGE 7-BIT I²C AND SMBus LED DRIVER
WITH INTENSITY CONTROL AND SHUTDOWN
SCPS164B – MAY 2007 – REVISED NOVEMBER 2007
A1
B1
C1
D
A2
B2
C2
E
F or ALD
100%
Intensity
0%
Figure 7. LED Intensity Per Bank
Approximately 25%
Approximately 75%
V_OH
I/O port
Voltage
V_OL
8 ms 2 ms
8 ms 6 ms
Figure 8. Output Port Voltage vs LED Intensity, Maximum Intensity = 100%
50%
Intensity
0%
Approximately
12.5%
Approximately 37.5%
V_OH
I/O port
Voltage
V_OL
8 ms 1 ms
8 ms 4 ms
8 ms 3 ms
Figure 9. Output Port Voltage vs LED Intensity, Maximum Intensity = 50%
The One-Shot / Master Intensity register (register 9) (see Table 16) is an 8-bit register with three functions.
Bits 0–3 set the master intensity value (ALD). It is a binary number between 0 and 15.
Bits 4–5 determine whether the maximum intensity of PWM0 and PWM1 is set by the programmed F value
(BRIGHT_F0 or BRIGHT_F1) or the master ALD value. The default value for these bits is 0. Bit 4 supports
PWM0 and bit 5 is for PWM1. If bit 4 (or bit 5) is 0, the maximum intensity value for PWM0 (or PWM1) is set by
the F value. If bit 4 (or bit 5) is 1, the maximum intensity value for PWM0 (or PWM1) is set by the master ALD
value. This allows the user to vary the brightness of all LEDs by changing a single register.
Bits 6–7 determine whether each PWM operates in normal or one-shot mode. Bit 6 supports PWM0 and bit 7 is
for PWM1. If bit 6 (or bit 7) is 0, PWM0 (or PWM1) operates in the normal mode where the LEDs goes through
the full intensity cycle defined by Table 15 and Figure 7. If bit 6 (or bit 7) is 1, PWM0 (or PWM1) operate in the
one-shot mode. In this mode, the LEDs can be used to create a single-shot lighting effect where the LED
intensity is valid for a particular segment of the cycle shown in Table 15 and Figure 7.
Copyright © 2007, Texas Instruments Incorporated
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