CL8801K6-G Supertex, CL8801K6-G Datasheet - Page 4

• Manufacturer Part Number: CL8801K6-G
• Description: LED Lighting Drivers SEQUENTIAL LED DRVR 13W
• Manufacturer: Supertex

Specifications of CL8801K6-G

• Rohs: yes
• Maximum Supply Current: 410 uA
• Output Current: 200 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-40
• Minimum Operating Temperature: - 40 C
• Power Dissipation: 13 W

Overview
Designing a driver to meet particular requirements may be
a difficult task considering the number of design variables
(16): tap current (4), number of series-connected LEDs per
segment (4), and the number of parallel-connected LEDs
per segment (4). Manually selecting values will provide light,
but the chosen values may be far from optimal in regards to
efficiency, LED utilization, line regulation, etc.
Contact your nearest Supertex Field Applications Engineer
for design assistance. MathCAD and Excel worksheets are
available by contacting [e-mail].
I
employed to increase reliability, performance, and cost. The
following sections briefly describe these circuits.
Transient Protection
Since the driver circuits have no need for capacitors that
could otherwise absorb transient energy, nor is there a need
for EMI filters that would block transients, the full burden of
transient protection is borne by the protection circuit. The
two-stage approach in the following schematics provide
2.5kV protection, both pulse and ring per EN 61000-4-5 and
EN 61000-4-12, six hits each.
100 to 120VAC Transient Protection
230VAC Transient Protection
Zener Substitution
Zeners may be substituted for LEDs in the bottom stages.
The last 1 or 2 stages contribute little to light output - they
are mainly to off-load the adjacent upstream regulator at
high line voltages to minimize losses. Zener substitution
advantages include minimizing unlit LEDs at low line for
better light uniformity, better line regulation at high line,
fewer LEDs for lower cost and less PCB area, and fewer
Doc.# DSFP-CL8801
B121712
n addition to configuring the driver, several circuits may be
AC Line
AC Line
275VAC
22
22
10mm
150VAC
10mm
440VDC
33
1.5kW
4
board-to-board connections. Disadvantages include slight-
ly reduced efficiency at high line, and additional heat load
on the driver board.
Phase Dimming
As with any light load, the LED lamp might not draw
enough current to assure proper dimmer operation. This
is especially true for 230VAC dimmers. Triacs used in dim-
mers require a minimum latching current when triggered
to place the triac in the latched-on state. Once latched, a
minimum holding current is required to maintain the triac in
the on state. Latching current is many times greater than
the holding current, and is the main concern with dimmer
compatibility.
Higher latching current can be provided by a simple series
RC network across the AC line. A short time constant pro-
vides a current spike at the turn-on edge.
Less common is inadequate holding current. The minimum
dimmer holding current is typically 10-20mA. Tap1 at 60mA
(max) exceeds the minimum.
Flicker
Twice per AC line cycle the line voltage crosses zero volts,
during which time there is no light output.
The circuit below can provide 5-10% valley fill. It has little
effect on input current waveshape (THD, PF) and efficiency.
Power Boost
Higher output power can be achieved by off-loading a por-
tion of the power dissipation from the CL8801 to exter-
nal FETs. The circuit below drops most of the tap voltage
across the FETs, thereby shifting the bulk of the dissipation
to the FET.
AC Line
Protection
Transient
to LEDs
TAP2
200k
100 - 200nF
500
15V
to LEDs
Supertex inc.
TAP3
www.supertex.com
Rectifier
Bridge
CL8801