MXHV9910B Clare, MXHV9910B Datasheet - Page 8

• Manufacturer Part Number: MXHV9910B
• Description: IC LED DRIVER HIGH BRIGHT 8-SOIC
• Manufacturer: Clare
• Type: HBLED Driverr

Specifications of MXHV9910B

• Topology: AC DC Offline Switcher, PWM, Step-Down (Buck)
• Number Of Outputs: 1
• Internal Driver: No
• Type - Primary: Backlight
• Type - Secondary: High Brightness LED (HBLED), RGB
• Frequency: 51kHz ~ 77kHz
• Voltage - Supply: 8 V ~ 450 V
• Voltage - Output: 7.8V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Operating Temperature: -40°C ~ 85°C
• Internal Switch(s): No
• Efficiency: 90%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output / Channel: -

MXHV9910
The inductor peak current rating is given by:
The MXHV9910 uses an internal gate drive circuit to
turn on and off an external power MOSFET. The gate
driver can drive a variety of MOSFETs. For a typical
off-line application, the total MOSFET gate charge will
be less than 25nC.
Figure 5 Typical Linear Dimming Application Circuit
Pulse width modulation dimming can be implemented
by driving the PWMD pin with a low frequency square
wave signal in the range of a few hundred Hertz. The
PWMD signal controls the LED brightness by gating
the PWM gate driver output pin GATE.
Figure 6 Buck Driver for PWM Dimming Application Circuit
8
2.2.7 Gate Output Drive
2.2.9 PWM Dimming
I
Lmax
=
90 - 265V
AC Input
I
12 - 30V
LED
V
Fuse F2
HB LEDs
IN
×
350mA
rms
NTC1
2A
[
DC
1
+
0.27Ω
(
10μF
50V
R1
0.5 r
AC
AC
Q1
×
BR1
iout
D1 Schottky
+
-
4.7mH
BYV26B
220μH
)
L1
40V
]
D1
0.1μF
400V
C1
www.clare.com
V
CS
GND
GATE
IXTA8N50P
0.56Ω
IN
R4
MXHV9910
400V
22μF
C1
PWMD
0.1μF
50V
V
LD
R
DD
A linear dimming function can be implemented by
applying a DC control voltage to the LD pin. By varying
this voltage, the user can adjust the current level in the
LEDs, which in turn will increase or decrease the light
intensity. The control voltage to the LD pin can be
generated from an external voltage divider network
from V
LED current at a particular level and there is no exact
R
higher than the current sense threshold voltage at the
LD pin will not change the output current due to the
fixed threshold setting. When the LD pin is not used, it
should be connected to V
The signal can be generated by a microcontroller or a
pulse generator with a duty cycle proportional to the
amount of desired light output. When PWMD is low,
gate drive is off; when PWMD is high, gate drive is
enabled.
T
sense
2.2.8 Linear Dimming
402kΩ
V
CS
GND
GATE
IN
DD
value available. Note that applying a voltage
MXHV9910
. This function is useful if the user requires a
402kΩ
PWMD
R1
CPC1001N*
*Optional Isolation
V
LD
R
DD
2.2μF
T
16V
C1
900mA Max
ASMT-Mx00
HB LEDs
0.1μF
25V
C1
DD
PWM
Monitor
.
LD
51kΩ
5.0kΩ
RA1
R2
R01