CPC9909 Clare, Inc., CPC9909 Datasheet - Page 8

• Manufacturer Part Number: CPC9909
• Description: High Efficiency, Off-line, High Brightness Led Driver
• Manufacturer: Clare, Inc.

CPC9909
2.10 Linear Dimming
A linear dimming function can be implemented by
applying a DC control voltage to the LD pin. By varying
this voltage from 0V to V
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
Figure 3 Typical Linear Dimming Application Circuit
2.11 PWM Dimming
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
Figure 4 Buck Driver for PWM Dimming Application Circuit
2.12 Combination Linear and PWM Dimming
A combination of linear and PWM dimming techniques
can be used to achieve a large dimming ratio.
8
90 - 265V
12 - 30V
AC Input
DD
V
CS(high)
IN
. This function is useful if the
Fuse F2
HB LEDs
350mA
rms
NTC1
DC
2A
0.27Ω
10μF
50V
R1
, the user can adjust
Q1
AC
AC
BR1
D1 Schottky
+
-
220μH
4.7mH
40V
BYV26B
L1
D1
0.1μF
400V
V
CS
GND
GATE
C1
www.clare.com
IN
IXTA8N50P
0.56Ω
CPC9909
R4
22μF
400V
PWMD
C1
V
LD
R
DD
0.1μF
50V
T
user requires LED current of a particular level, and
there is no exact R
a voltage higher than the current sense threshold
voltage to the LD pin will not change the output current
due to the fixed internal threshold setting. When the
LD pin is not used, it should be connected to V
the PWM gate driver output pin GATE. The signal can
be generated by a microcontroller or a pulse generator
with a duty cycle proportional to the amount of desired
light output.
402kΩ
V
CS
GND
GATE
IN
CPC9909
402kΩ
PWMD
R1
CPC1001N*
*Optional Isolation
V
LD
R
DD
2.2μF
T
16V
C1
ASMT-Mx00
900mA Max
HB LEDs
T
value available. Note that applying
0.1μF
25V
C1
Monitor
PWM
LD
51kΩ
5.0kΩ
RA1
R2
DD
.
R01