MAX16806 Maxim Integrated Products, MAX16806 Datasheet - Page 11

• Manufacturer Part Number: MAX16806
• Description: (MAX16805 / MAX16806) EEPROM-Programmable
• Manufacturer: Maxim Integrated Products

www.DataSheet4U.com
DataSheet U .com
The dimming feature can be used for LED brightness
adjustment (see the Typical Operating Circuits ) and
theater dimming. If the external PWM signal is used,
theater dimming can be achieved by varying the PWM
duty cycle.
ments theater dimming with a DC input signal.
The MAX16806 features dual-function inputs, TFP/SCL
and TFN/SDA. In programming mode, TFP/SCL and
TFN/SDA serve as the I
face. TFP/SCL and TFN/SDA also serve as inputs for
analog signals generated by an external temperature
sensor such as the MAX6613.
The MAX16805 does not offer dual-function inputs. SCL
and SDA are used only to communicate with the
MAX16805 through the I
The MAX16806 offers a momentary switch (SW) that
overrides the analog dimming signal by latching the
output current to 100% duty cycle. The MAX16806
does not override external PWM signal at DIM or dim-
ming caused by thermal or LED current foldback. To
latch the output current into a 100% duty cycle, press
SW once. To restore the initial duty cycle determined
by the DC level at DIM, press SW again. The
MAX16806 provides a minimum of 1mA of wetting cur-
rent to the momentary switch.
The MAX16805/MAX16806 enter a thermal shutdown in
the event of overheating. This typically occurs in over-
load or output short-circuit conditions. When the junc-
tion temperature exceeds T
internal thermal protection circuitry turns off the pass
device. The MAX16805/MAX16806 recover from ther-
mal shutdown once the junction temperature drops by
+23°C (typ). This feature allows self-protection by ther-
mally cycling in the event of a short-circuit or overload
condition.
The MAX16805/MAX16806 feature an I
interface consisting of a bidirectional serial data line
(SDA) and a serial clock line (SCL). SDA and SCL facili-
tate bidirectional communication between the
MAX16805/MAX16806 and the master device at rates
up to 400kHz. The master (typically a microcontroller)
initiates data transfer on the bus and generates SCL.
4
EEPROM-Programmable, High-Voltage, 350mA
Thermal Sensor Inputs/I
Figure
Momentary Switch Interface (SW)
______________________________________________________________________________________
2 shows a simple circuit that imple-
Overtemperature Protection
LED Drivers with LED Current Foldback
2
2
(TFP/SCL and TFN/SDA)
C interface.
C serial communication inter-
J
= +155°C (typ), the
Digital Interface
2
2
C, 2-wire serial
C Interface
Both SCL and SDA remain high when the interface is
not busy. A master controller signals the beginning of a
transmission with a START condition by transitioning
SDA from high to low while SCL is high. The master
controller issues a STOP condition by transitioning the
SDA from low to high while SCL is high, when it finishes
communicating with the slave. The bus is then free for
another transmission
Figure
Figure
SDA
SCL
THEATER
DIMMING
SIGNAL
V
IN
CONDITION
START
2. Theater Dimming Light
3. I
S
2
C Communication Start and Stop Conditions
DIM
IN
EN
MAX16805
MAX16806
(Figure
Start and Stop Conditions
GND
3).
OUT
CS+
CS-
V5
+5V REG
0.1µF
CONDITION
STOP
R
LEDs
SENSE
P
11