AAT4295 Datasheet, PDF (9/16 Pages) Advanced Analogic Technologies – Single/Dual RGB Controller

Control
AAT4295/97
Single/Dual RGB Controller
Control
2Ω
S1 to S6
S1 to S6
Figure 1: Switch Input Circuit.
The state of each switch is controlled via the
EN/SET pin using AnalogicTech's S²Cwire inter-
face. To enable a respective switch, a series of
clocked pulses should be applied to the EN/SET
pin. The number of pulses clocked will determine
the switch configuration based on the truth table
given in Table 1. At the end of the serial pulse data
set, the EN/SET set pin should be held high to latch
the clocked data and enable the desired switch
configuration. When the device is enabled with the
EN/SET held to a logic high state, the quiescent
current consumption will typically increase to 3µA
at normal ambient room temperatures. If output
sequencing of the switches is not necessary, all of
the switches may be turned on simultaneously on
the first rising edge of the EN/SET pin by simply
pulling the EN/SET to a logic high level. The
default configuration for one clock pulse is to
enable all switches to the "on" state. However, if
output sequencing is desired, a series of pulses on
the EN/SET pin will set the outputs to the desired
state (refer to Table 2 for output settings). For LED
lighting applications, the EN/SET line may be
clocked at rates up to 1MHz, allowing the user to
not only control brightness, but (in the case of color
RGB LEDs) color as well.
Figure 2: Simplified Equivalent Model.
Output Settings
The ON/OFF state of the MOSFET switches is
controlled by the EN/SET serial data input. An
internal control counter is clocked on the rising
edge of the EN/SET pin, and is decoded into the 8
possible states of the MOSFET for the AAT4295
(see Table 1) and 64 possible states for the
AAT4297 (see Table 2). The counter rolls over
after 8 clocks and the table repeats.
Clock
1
2
3
4
5
6
7
8
OUT3
on
on
on
on
off
off
off
off
OUT2
on
on
off
off
on
on
off
off
OUT1
on
off
on
off
on
off
on
off
Table 1: AAT4295 EN/SET Settings.
4295.2006.03.1.3
9