TLC6C5712-Q1_15 Datasheet, PDF (56/64 Pages) Texas Instruments – TLC6C5712-Q1 12-Channel, Full-Diagnostic, Constant-Current-Sink LED Driver With 8-Bit Dot Correction

TLC6C5712-Q1
SLVSCO9A – AUGUST 2015 – REVISED AUGUST 2015
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Typical Applications (continued)
8.2.1.1 Design Requirements
For this design example, use the parameters listed in Table 55.
Table 55. Design Parameters
DESIGN PARAMETER
I_{(LED_FULLRANGE)} ⁽¹⁾
I_(LED) ⁽²⁾
EXAMPLE VALUE
20 mA
16 mA
8.2.1.2
(1) I_{(LED_FULLRANGE)} is the maximum LED current allowed.
(2) I_(LED) is the required output driving current for this application.
Detailed Design Procedure
This design has multiple TLC6C5712-Q1 devices connected by a SPI daisy chain. Use Equation 5 to calculate
the reference resistor value.
R_(IREF)
=
V_(IREF)
I_{(LED _ FULLRANGE)}
´ K_(OUT)
=
1.229 V
0.02 A
´ 500
= 30.725 kW
(5)
Use Equation 6 to calculate the dot correction for each channel.
Dot
correction
=
16
20
´
256
-1
=
204,
(0xCC)
(6)
8.2.1.3 Application Curves
Figure 107. PWM Delay and Output Rise Time
CH3: PWM0, CH4: OUT0
Figure 108. PWM Delay and Output Fall Time
CH3: PWM0, CH4: OUT0
8.2.2 Parallel Channels for Driving Higher Current
In some applications, capability to drive higher current is needed. To deliver higher current while maintaining
adjacent-short detection capability, channels with odd numbers can be shorted together; similarly, channels with
even numbers can be shorted together. If odd and even numbers are shorted together, the device reports a false
error during adjacent-pin short detection.
56
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