MAX16834ATP/V+T Maxim Integrated Products, MAX16834ATP/V+T Datasheet - Page 11

• Manufacturer Part Number: MAX16834ATP/V+T
• Description: IC LED DRIVR HIGH BRIGHT 20-TQFN
• Manufacturer: Maxim Integrated Products
• Type: HBLED Driverr

Specifications of MAX16834ATP/V+T

• Topology: PWM, SEPIC, Step-Down (Buck), Step-Up (Boost)
• Number Of Outputs: 1
• Internal Driver: No
• Type - Primary: Automotive, Backlight
• Type - Secondary: High Brightness LED (HBLED), RGB
• Frequency: 100kHz ~ 1MHz
• Voltage - Supply: 4.75 V ~ 28 V
• Mounting Type: Surface Mount
• Package / Case: 20-TQFN Exposed Pad
• Operating Temperature: -40°C ~ 125°C
• Internal Switch(s): Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Current - Output / Channel: -
• Efficiency: -
• Lead Free Status / Rohs Status: Details

Figure 2. Boost LED Driver
The LED current is programmed using the voltage on
REFI and the LED current-sense resistor R10 (see
Figure 2). The current is given by:
where V
are in ohms. The regulation voltage on the LED current-
sense resistor must not exceed 0.3V to prevent activa-
tion of the LED short-circuit protection circuit.
In the boost converter (Figure 2), the average inductor
current varies with the line voltage. The maximum aver-
age current occurs at the lowest line voltage. For the
boost converter, the average inductor current is equal
to the input current.
High-Power LED Driver with Integrated High-Side LED
Current Sense and PWM Dimming MOSFET Driver
V
IN
REF
R1
R2
I
is 3.7V and the resistors R5, R6, and R10
LED
Programming the LED Current
=
______________________________________________________________________________________
R
10
×
V
C1
(
REF
R
6
R5
R3
C4
C2
C5
+
Boost Configuration
×
R
R
5
5
)
×
R6
9 9
.
( )
IN
UVEN
HV
SC
RT/SYNC
V
REFI
SGND
A
LV
REF
CC
MAX16834
PWMDIM
DIMOUT
SENSE+
COMP
NDRV
OVP+
PGND
CLV
FLT
CS
Calculate maximum duty cycle using the below equation.
where V
volts, V
volts (approximately 0.6V), V
supply voltage in volts, and V
source voltage of the MOSFET Q1 in volts when it is on.
Use an approximate value of 0.2V initially to calculate
D
cycle can be calculated once the power MOSFET is
selected based on the maximum inductor current.
Use the following equations to calculate the maximum
average inductor current IL
current ripple ΔI
amperes:
MAX
. A more accurate value of the maximum duty
D
ON
LED
is the forward drop of the rectifier diode D1 in
R7
C7
is the forward voltage of the LED string in
OFF
D
Q1
MAX
C6
L
, and the peak inductor current IL
=
L1
R8
V
D1
V
LED
LED
+
AVG
INMIN
+
FET
R4
R9
V
V
D
Q2
D
, peak-to-peak inductor
−
is the average drain to
−
V
is the minimum input
V
INMIN
FET
C3
R10
LED+
LED-
C8
LEDs
P
11
in