MAX16821BEVKIT+ Maxim Integrated Products, MAX16821BEVKIT+ Datasheet - Page 20

• Manufacturer Part Number: MAX16821BEVKIT+
• Description: KIT EVAL FOR MAX16821B
• Manufacturer: Maxim Integrated Products

Specifications of MAX16821BEVKIT+

• Current - Output / Channel: 660mA
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 28V
• Features: Dimmable
• Voltage - Input: 7 ~ 24V
• Utilized Ic / Part: MAX16821
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Boost:
The crossover frequency of the inner current loop is
given by:
High-Power Synchronous HBLED
Drivers with Rapid Current Pulsing
Figure 10. Low-Side Buck LED Driver with PWM Dimming
20
f
C
______________________________________________________________________________________
V
LED
R
=
C10
R9
R10
C9
CF
V
RAMP
≤
R
C11
R6
C8
R9
R7
S
A
V
×
×
2
R
V
V
× ×
RAMP
S
LED
π
17
18
19
15
16
20
21
×
CLP
OVI
DIFF
EAOUT
EAN
CSN
CSP
L
(
V
SGND
14
I.C.
LED
×
22
×
f
34 5
SW
−
.
SENSE- SENSE+
OUTV
13
R3
23
V
×
×
IN
L
g
)
RT/SYNC
m
×
C3
12
24
g
×
MAX16821A
MAX16821B
MAX16821C
m
R
R4
SGND
CF
V
EN
11
25
CC
V
C7
IN
MODE
10
26
IN
ON/OFF
C6
CLKOUT
For adequate phase margin at crossover, place the zero
formed by R
crossover frequency. The pole formed by R
is added to eliminate noise spikes riding on the current
waveform and is placed at the switching frequency.
Even though the MAX16821A/MAX16821B/MAX16821C
do not have a separate PWM input, PWM dimming can
be easily achieved by means of simple external circuitry.
See Figures 10 and 11.
V
27
9
CC
C5
SGND
V
PGND
28
8
DD
N.C.
N.C.
BST
LX
DL
DH
4
CF
7
6
5
3
2
1
and C
R5
CZ
D2
C4
at least 3 to 5 times below the
Q1
Q2
7V TO 28V
PWM DIM
V
IN
R1
L1
PWM Dimming
C2
Q3
R2
CF
V
LED
LED
STRING
and C
CP