Supertex inc.
Sequential Linear LED Driver
Features
►
►
►
Minimal component count
(base config: CL8801 + 4 resistors + diode bridge)
No magnetics, no capacitors
Up to 7.5W output (13W w/ heat sink)
CL8801
General Description
►
>110Lm/W using efficient LEDs
►
85% electrical efficiency
►
>0.95 power factor
►
<30% THD line current
►
Low conducted EMI w/o filters
►
85% LED luminous utilization
►
Phase dimmer compatible with an RC network
The CL8801 is designed to drive a long string of inexpensive,
low current LEDs directly from the AC mains. A basic driver
circuit consists of the CL8801, four resistors, and a bridge
rectifier. Two to four additional components are optional for
various levels of transient protection. No capacitors, EMI
filters, or power factor correction circuits are needed.
A string of series/parallel LEDs is tapped at four locations.
Four linear current regulators sink current at each tap and
are sequentially turned on and off, tracking the input sine
wave voltage. Voltage across each regulator is minimized
when conducting, providing high efficiency. Output current
at each tap is individually resistor-adjustable. Cross-
regulation, as the CL8801 switches from one regulator to
the next, provides smooth transitions. The current waveform
can be tailored to optimize for input voltage range, line/load
regulation, output power/current, efficiency, power factor,
THD, dimmer compatibility, and LED utilization.
With the addition of an RC network, the driver is compatible
with phase dimming.
Applications
►
Fluorescent tube retrofit
►
Incandescent & CFL bulb replacement
►
General LED lighting
Typical Application Circuit
transient
protection
AC
Mains
BIAS
GND
TAP1
TAP2
TAP3
TAP4
CL8801
SET1
SET2
SET3
SET4
Doc.# DSFP-CL8801
D031914
Supertex inc.
www.supertex.com
CL8801
Ordering Information
Part Number
CL8801K63-G
CL8801K63-G M935
Package Options
33-Lead (6x6) QFN
33-Lead (6x6) QFN
Packing
490/Tray
2000/Reel
GND
GND
GND
GND
GND
1
Pin Configuration
TAP1
TAP2
TAP3
33
-G denotes a lead (Pb)-free / RoHS compliant package
TAP4
BIAS
NC
NC
GND
GND
GND
GND
GND
GND
GND
GND
GND
ESD Sensitive Device
GND
GND
GND
Absolute Maximum Ratings
Parameter
V
BIAS
, V
TAP1
V
TAP2–4
V
SET1–4
Operating junction temperature
Storage temperature, T
S
Value
–0.5V to +550V
NC
NC
NC
NC
NC
SET1
SET2
SET3
–0.5V to +320V
4.0V
-55ºC to +125ºC
-65°C to +150°C
33-Lead QFN
(top view)
Absolute Maximum Ratings are those values beyond which damage to the device
may occur. Functional operation under these conditions is not implied. Continuous
operation of the device at the absolute rating level may affect device reliability. All
voltages are referenced to device ground.
Product Marking
8801
LLLLLL
YYWW
AAACCC
L = Lot Number
YY = Year Sealed
WW = Week Sealed
A = Assembler ID
C = Country of Origin
= “Green” Packaging
Typical Thermal Resistance
Package
33-Lead QFN
θ
ja1
24
O
C/W
θ
jc2
2.5
O
C/W
Notes:
1. 1.0oz Cu 4-layer board, 3x4” PCB with thermal pad and thermal via array.
2. Junction to exposed heat slug.
33-Lead QFN
Recommended Operating Conditions
Sym
Parameter
TAP1
I
OUT
Output current
TAP2
TAP3
TAP4
TAP1
V
OUT
V
BIAS
Output voltage
Applied BIAS voltage
TAP2-4
TAP1-4
Note:
(1) Voltage capability is determined by power dissipation (V × I).
Min
-
-
-
-
-
-
-
-
Typ
-
-
-
-
-
-
-
-
Max
60
90
200
200
400
300
(1)
440
Units Conditions
mA
---
Non-conducting
V
V
Non-conducting
Conducting
---
Doc.# DSFP-CL8801
D031914
2
Supertex inc.
www.supertex.com
SET4
NC
CL8801
Overview
board-to-board connections. Disadvantages include slight-
Designing a driver to meet particular requirements may be ly reduced efficiency at high line, and additional heat load
a difficult task considering the number of design variables on the driver board.
(16): tap current (4), number of series-connected LEDs per
segment (4), and the number of parallel-connected LEDs
Phase Dimming
per segment (4). Manually selecting values will provide light, As with any light load, the LED lamp might not draw
but the chosen values may be far from optimal in regards to enough current to assure proper dimmer operation. This
efficiency, LED utilization, line regulation, etc.
is especially true for 230VAC dimmers. Triacs used in dim-
mers require a minimum latching current when triggered
Contact your nearest Supertex Field Applications Engineer to place the triac in the latched-on state. Once latched, a
for design assistance. MathCAD and Excel worksheets are minimum holding current is required to maintain the triac in
available by contacting apps@supertex.com.
the on state. Latching current is many times greater than
the holding current, and is the main concern with dimmer
I
n addition to configuring the driver, several circuits may be compatibility.
employed to increase reliability, performance, and cost. The
Higher latching current can be provided by a simple series
following sections briefly describe these circuits.
RC network across the AC line. A short time constant pro-
vides a current spike at the turn-on edge.
Since the driver circuits have no need for capacitors that
Less common is inadequate holding current. The minimum
could otherwise absorb transient energy, nor is there a need
dimmer holding current is typically 10-20mA. Tap1 at 60mA
for EMI filters that would block transients, the full burden of
(max) exceeds the minimum.
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.
500
100 to 120VAC Transient Protection
22
Transient Protection
AC Line
Transient
Protection
Bridge
Rectifier
100 - 200nF
AC Line
150VAC
10mm
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.
33
230VAC Transient Protection
22
AC Line
275VAC
10mm
440VDC
1.5kW
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
Zener Substitution
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.
Power Boost
to LEDs
to LEDs
200k
TAP2
15V
TAP3
Doc.# DSFP-CL8801
D031914
4
Supertex inc.
www.supertex.com
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