CPC9909NE Clare, CPC9909NE Datasheet - Page 7
CPC9909NE
Manufacturer Part Number
CPC9909NE
Description
IC LED DRVR HIGH BRIGH SOIC-8EP
Manufacturer
Clare
Type
HBLED Driverr
Datasheet
1.CPC9909N.pdf
(10 pages)
Specifications of CPC9909NE
Mfg Application Notes
CPC9909 Design Considerations
Constant Current
Yes
Topology
AC DC Offline Switcher, PWM
Number Of Outputs
1
Internal Driver
Yes
Type - Secondary
High Brightness LED (HBLED)
Frequency
30kHz ~ 120 kHz
Voltage - Supply
12 V ~ 550 V
Voltage - Output
7.8V
Mounting Type
Surface Mount
Package / Case
8-SOIC (3.9mm Width) Exposed Pad, 8-eSOIC. 8-HSOIC
Operating Temperature
-40°C ~ 85°C
Internal Switch(s)
No
Efficiency
90%
Operating Supply Voltage
8 V to 550 V
Maximum Power Dissipation
2.5 W
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
Minimum Operating Temperature
- 40 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Current - Output / Channel
-
Lead Free Status / Rohs Status
Details
Other names
CLA328
The switching frequency is determined by:
Where:
•
•
In general, switching frequency selection is based on
the inductor size, controller power dissipation, and the
input filter capacitor.
The typical off-line LED driver switching frequency, f
is between 30 kHz and 120 kHz.
This operating range gives the designer a reasonable
compromise between switching losses and inductor
size. The internal off-time one-shot has an accuracy of
±20%. The figure below shows the R
selection for the desired off-time.
2.8 Inductor Design
The inductor value is defined by the LED/inductor
ripple current, minimum off time, and the output
voltage. The minimum off time is determined by the
duty cycle and switching frequency. The duty cycle is
given by:
Where:
•
•
R01
D = duty cycle
t
V
average LED current.
V
off
LEDstring
in(min)
45
40
35
30
25
20
15
10
5
0
D
F
= Off-time
0
S
=
=
V
------------------------- -
is the minimum DC input voltage.
1 D
------------ -
V
LEDstring
t
–
is the LED string voltage at the desired
off
in min
500
(
)
1000
R
T
vs Off-Time
R
1500
T
(KΩ)
t
off
2000
(μS)
T
resistor
2500
3000
www.clare.com
S
,
The minimum inductor value for a given ripple current
is:
Where:
•
The inductor peak current is given by:
2.9 Gate Output Drive
The CPC9909 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.
ΔI
L
I
L
LPeak
= Ripple Current
MIN
=
=
I
V
------------------------- -
LED
LEDstring
ΔI
+
L
0.5ΔI
L
×
t
off
CPC9909
7