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Reference Design #0602
IRPLLNR4(rev.B) - A Universal Input Linear Fluorescent Ballast
using the IR2166
By
Cecilia Contenti and Masashi Sekine
Table of Contents Page
Fetures & Description ....................................................................... 2
Characteristics................................................................................... 3
Overview............................................................................................. 3
Schematic Diagram ........................................................................... 4
Bill of Materials................................................................................... 5
Inductor Specs .................................................................................. 6-7
Demo Board Overview ...................................................................... 8
Preheat Mode ..................................................................................... 9
Ignition Ramp Mode .......................................................................... 1 1
Run Mode ........................................................................................... 1 3
Normal Power-Down ......................................................................... 14
Lamp Rwmoval & auto-restart.......................................................... 15
Fault Mode.......................................................................................... 15
Current Mode Configuration............................................................. 19
Design Procedure to adapt the design to different lamp types ..... 20
The IRPLLNR4 is a Universal Input Linear Fluorescent Ballast
using the IR2166
Features
! Drives 1 x 35W TL5 Lamp
! Input V oltage: 80-260V ac
! High Power Factor/Low THD
! High Frequency Operation
! Lamp Filament Preheating
! Lamp Fault Protection with Auto-Restart
! Low AC Line Protection
! End of Lamp Life Shutdown
! IR2166 HVIC Ballast Controller
Description
The IR2166 Demo Board is a high efficiency , high power factor , fixed output electronic ballast designed
for driving rapid start fluorescent lamp types. The design contains an EMI filter, active power factor
correction and a ballast control circuit using the IR2166. This demo board is intended to ease the
evaluation of the IR2166 Ballast Control IC, demonstrate PCB layout techniques and serve as an aid in
the development of production ballast’s using the International Rectifier IR2166.
Ballast Block Diagram
Line
Output Stage
Lamp
Input Bridge
Half - Bridge Driver
Preheat Feedback
Lamp Fault
C
L
EMI Filter PFC
UVLO PFC Control
IR2166
Demo Board Data Sheet
intended for design information only.
Subject to change without prior notice.
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Functional Description
Overview
The IR2166 Demo Board consists of an EMI filter , an active power factor correction section, a ballast
control section and a resonant lamp output stage. The active power factor correction section is a
boost converter operating in critical conduction mode, free-running frequency mode. The ballast
control section provides frequency modulation control of a traditional RCL lamp resonant output
circuit and is easily adaptable to a wide variety of lamp types. The ballast control section also
provides the necessary circuitry to perform lamp fault detection, shutdown and auto-restart.
Electrical Characteristics
Parameter Units Value
Lamp Type 35W TL5
Input Power [W] 38
Lamp running volta ge [Vpp] 600
Run Mode Frequency [kHz] 44
Prehe at Mode Frequency [kHz] 57
Prehe at Time [s] 1
Lamp Prehe at Voltage [Vpp] 660
Ignition Voltage [Vpp] 1700
Input AC Voltage Range [VACrms] 90-260VAC
Powe r Factor 0.995 at 120VA C (rms)
0.971at 220 VAC (rms)
Total Harmonic Distortion [%] <10 at 120 VAC (rms)
<15 at 220 VAC (rms)
Fault Protection Characteristics
Fault Ballast Restart Operation
Line voltage low Deactivates Increase line voltage
Upper filament broken Deactivates Lamp exchange
Lower filament broken Deactivates Lamp exchange
Failure to ignite Deactivates Lamp exchange
Open circuit (no lamp) Deactivates Lamp exchange
End of life Deactivates Lamp exchange
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Schematics Diagram,
IR2166 Single Lamp,
Voltage Mode Heating
Note: Thick traces represent high-frequency, high-current paths. Lead
lengths should be minimized to avoid high-frequency noise problems
L1 C1
BR1
C2
LPFC
MPFC RPFC
DPFC
CBUS
CVDC
RT
CSD1
CT
RPH
DBOOT
CBOOT
RSUPPLY
RHO
RCS
MLS
RLIM
RLO
MHS
DCP2
RSD
CSNUB
RPU
RBUS
L
N
RZX
RV1
GND
CY
CCOMP1
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
IR2166
VBUS
CPH
RT
RPH
CT
COMP
ZX
PFC
LO
COM
VCC
VB
VS
HO
SD
CS
CCS
F1
LRES:B
DCP1
CDC
CRES
CH1
LRES:C
CH2
LRES:A
IC BALLAST
RVDC
REOL1
REOL2
REOL3
REOL4
CEOL
DSD
CSD2
CVCC1
CVCC2
CPH
DCOMP
RDC
CCOMP2
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Bill Of Materials
Lamp type: TL5/35W, Line Input Voltage: 80-260 VAC
Note: Different lamp types require different frequency programming components.
Item # Qt
y Manufacturer Part Number Description Reference
1 1 In te r n a tiona l Rec tif ie r D F10 S B ridge Re ct ifie r, 1 A 1 0 00V B R1
2 1 Roeders tein W Y 0222M C MB F 0K Cap acitor, 2.2nF 27 5 VA C Y C ap CY
3 1 Dale CW-1 /2 R es istor, 0.5O hm, 1/.2W F1
4 1 Roeders tein F1 772433-2200 Cap acitor, 0.33uF 2 75 VA C C 1
5 1 P anas onic ELF -15N 007 A EM I Inductor, 1X10 mH 0.7A pk L1
6 2 Wima MK P 10 Cap acitor, 0.1uF 40 0 VD C C2, CD C ,
7 1 Panasonic ERZ-V05D471 Transient Suppressor RV1
8 1 Panasonic EEU-EB2W100 Capacitor, 10uF 450VDC 105C CBUS
9 1 B .I. technologies HM00 -01761 PF C Inductor, 1.0m H 2Apk LP F C
10 2 Panasonic EC J-2VB1HC104K Capacitor, 0.1uF SM T 1206 CB OOT , C VCC 2
11 3 Panasonic Capacitor, 0.47uF SMT 1206 CPH, CSD2, CEOL
12 1 Panasonic Capacitor, 1nF SM T 1206 CSD1
13 1 Panasonic Capacitor, 0.68uF SMT 1206 CCO MP1
14 1 Panasonic Capacitor, 0.01uF SMT 1206 CVDC
15 1 P anas onic C apa citor, 2.2uF 50V D C 105 C CV CC 1
16 1 D igi-key Cap acitor, 82 0pF 1K V SM T 1812 CS NU B
17 1 WIMA FK P1 Cap acitor, 3.3nF 1.6KV CR ES
18 1 Panasonic Capacitor, 220pF SMT 1206 CCS
19 2 Cap acitor, 0.1uF 10 0V CH 1, CH 2
20 1 Panasonic ECU-V1H471KBN Capacitor, 820pF SMT 1206 CT
21 2 Digi-key MURS160DICT-ND Diode, 1A 600V, SMT SMB DBOOT, DPFC
22 3 D iodes LL4148 DIC T-ND Diode, 1N 4148 S MT DL3 5 DC P 1, DC P2, DSD
23 1 D iode, 11V Z ener, 500m W D C O M P
24 1 Intern a tiona l R e ctifier IR2 16 6 IC, Balla st D rive r / P F C IC B A L L A S T
25 1 B.I. technologies HM00-01762 Inductor, 4.0m H 3Apk LRES
26 3 International Rectifier IRF 830 Transistor, MOSFE T MP F C , M HS , M LS
27 3 Panasonic ER J-8GEYJ22 Resistor, 22 ohm SM T 1206 RPFC, RLO, RHO
28 1 Panasonic Resistor, 59Kohm SMT1206 RPH
29 1 Res istor, 360K ohm 1/2 watt R SU PP LY
30 2 P anas onic E R J-8G EYJ6 80K Res istor, 680K ohm SM T 120 6 RB US 1, RB US 2
31 2 Res istor, 22K ohm SM T 1206 R T, RZ X
32 1 Panasonic ER J-8GEYJ1K Resistor, 1K ohm SMT 1206 RLIM
33 1 P anas onic Res istor, 1.5 ohm SM T 20 10 RC S
34 1 R es istor, 220K 1/2W R P U
35 1 R es istor, 13K o hm 1% SM T 1206 RV D C
36 1 R esisto r, 100K ohm SM T 1206 RS D
37 3 R es istor, 220K ohm SM T 120 6 RE O L1, REO L2, RE O L3
38 1 R es istor, 1.2K ohm S MT 1206 RE O L4
39 1 WAGO 235-203 Connector, 3 terminal X1
40 1 WAGO 235-207 Connector, 4 terminal X2
Total 56
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Inductor Specs
HORIZONTAL
INDUCTOR SPECIFICATION
CORE SIZE
CORE MATERIAL
GAP LENGTH
Philips 3C85, Siemens N27 or equivalent
WINDING START PIN FINISH PIN TURNS WIRE DIAMETER (mm)
MAIN
ZX
PHYSICAL LAYOUT
TEST
MAIN WINDING INDUCTANCE MIN 0.9 MAX 1.1
MAIN WINDING RESISTANCE
mm
mH mH
MAX 1.5
Ohms
TYPE : LPFC
(TEST FREQUENCY = 50kHz)
NOMINAL INDUCTANCE
MAXIMUM CURRENT
MAXIMUM CORE TEMPERATURE
mH
Apk
ºC100
NOTE : Inductor must not saturate at maximum current and maximum core temperature at given
test frequency.
ELECTRICAL LAYOUT
BOBBIN PINS
E25/13/7 (EF25) 1
8
1
2
1 6 125
3810
4 strands of AWG 32
4 strands of AWG 32
5mm
5mm
20.05mm
25mm
TOP VIEW
1
2
3
4
8
7
6
5
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HORIZONTAL
INDUCTOR SPECIFICATION
CORE SIZE
CORE MATERIAL
GAP LENGTH
Philips 3C85, Siemens N27 or equivalent
WINDING START PIN FINISH PIN TURNS WIRE DIAMETER (mm)
MAIN
PHYSICAL LAYOUT
TEST
MAIN WINDING INDUCTANCE MIN 3.9 MAX 4.1
MAIN WINDING RESISTANCE
mm
mH mH
MAX 2
Ohms
TYPE : LRES(VOLTAGE MODE)
(TEST FREQUENCY = 50kHz)
NOMINAL INDUCTANCE
MAXIMUM CURRENT
MAXIMUM CORE TEMPERATURE
mH
Apk
ºC100
NOTE : Inductor must not saturate at maximum current and maximum core temperature at given
test frequency.
ELECTRICAL LAYOUT
BOBBIN PINS
CATHODE (1)
CATHODE (2)
E25/13/7 (EF25) 1
8
4
2
5mm
5mm
20.05mm
25mm
TOP VIEW
1
2
3
4
8
7
6
5
1 8 250 4 strands of AWG 32
6 7 10 4 strands of AWG 32
4 5 10 4 strands of AWG 32
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Demo board Overview
This demo-board is designed for single TL5/35W Lamp, voltage mode heating (JV1 and JV2 mounted,
JC1 and JC2 not mounted). TL5 lamps are becoming more popular due to their lower profile and
higher lumen/ watt output. These lamps, however , can be more difficult to control due to their higher
ignition and running voltages. A typical ballast output stage using current-mode filament heating
(filament placed inside L-C tank) will result in excessive filament current during running. The output
stage has therefore been configured for voltage-mode filament heating using secondary windings off
of the resonant inductor LRES. The lamp has been placed outside the under-damped resonant circuit
loop, which consist of LRES and CRES. The filament heating during preheat can be adjusted with the
capacitors CH1 and CH2. The result is a more flexible ballast output stage necessary for fulfilling the
lamp requirements. The DC blocking capacitor, CDC, is also placed outside the under-damped
resonant circuit loop such that it does not influence the natural resonance frequency of LRES and
CRES. The snubber capacitor , CSNUBB, serves as charge pump for supplying the IR2166.
The IR2166 Ballast Control IC is used to program the ballast operating points and protect the ballast
against conditions such as lamp strike failures, low DC bus, thermal overload or lamp failure during
normal operations. It is also used to regulate the DC bus and for power factor control allowing high
power factor and low harmonic distortion.
Power Factor Correction Section
The power factor correction section contained in the IR2166 forms the control for a boost topology
circuit operating in critical conduction mode. This topology is designed to step-up and regulate the
output DC bus voltage while drawing sinusoidal current from the line (low THD) which is “in phase”
with the AC input line voltage (HPF).
Ballast Control Section
The ballast control section of the IR2166 Ballast Control IC contains an oscillator , a high voltage half-
bridge gate driver and lamp fault protection circuitry. Please, refer to the datasheet of this IC for the
block diagram and the state diagram. Following is a breakdown of the operation of the ballast in all of
the different modes of operation.
Startup Mode
When power is initially applied to the ballast, the voltage on the VCC pin of the IR2166 begins to
charge up. The voltage for the IR2166 is derived from the current supplied from the rectified AC line
through startup resistor RSUPPLY. During this initial startup when the VCC voltage of the IR2166 is
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below its rising under-voltage lock-out threshold, it is in its UVLO and also its micro-power mode. The
micro-power mode of the IR2166 allows the use of a large value, low wattage startup resistor
(RSUPPLY). When the voltage on the IR2166 reaches the rising under-voltage lockout threshold
(11.5V), the gate driver oscillator is enabled (this assumes that there are no fault conditions) and
drives the half-bridge output MOSFETs (MHS and MLS). When the half-bridge is oscillating, capaci-
tor CSNUB, diodes DCP1 and DCP2 form a snubber /charge pump circuit which limits the rise and
fall time at the half-bridge output and also supplies the current to charge capacitor CVCC2 to the
VCC clamp voltage (approx. 15.6V) of IR2166. When the rising under-voltage lockout threshold of
the IR2166 is reached, the power factor control oscillator starts to oscillate and drive MOSFET MPFC
to boost and regulate the bus voltage to 400 VDC.
Preheat Mode
When the ballast reaches the end of the UVLO mode, the Preheat mode is entered. At this point the
ballast control oscillator of the IR2166 has begun to operate and the half-bridge output is driving the
resonant load (lamp) circuit.
There is an initial startup
frequency that is much
higher than the steady
state Preheat mode fre-
quency that lasts for only
a short duration. This is
done to ensure that the
initial voltage appearing
across the lamp at the
startup of oscillation does
not exceed the minimum
lamp ignition voltage. If, at
the initiation of oscillation
of the half-bridge, the volt-
age across the lamp is
large enough, a visible
flash of the lamp occurs
which should be avoided.
This in effect is a cold
strike of the lamp, which
could shorten the life of
the lamp.
Figure 1: Lamp filament current during Preheat and Ignition Ramp (500mA / div)
(crossed lamps)
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The ballast control section oscillator of the IR2166 is similar to oscillators found in many popular
PWM voltage regulator ICs and consists of a timing capacitor and resistor connected to ground.
Resistors RT and RPH program a current which determines the ramp up time of capacitor CT. The
downward ramping time of CT is the dead time between the switching off of the LO (HO) and the
switching on of the HO (LO) pins on the IR2166. The Preheat mode frequency of oscillation is
determined from the parallel between RT and RPH. It is selected such that the voltage appearing
across the lamp is below the minimum lamp ignition voltage while supplying enough current to preheat
the lamp filaments to the correct emission temperature within the Preheat mode period. The preheat-
ing of the lamp filaments is performed with a constant voltage during the Preheat mode. The wave-
form in Figure 1 shows the lamp filament current while Figure 2 shows lamp filament voltage during
the normal Startup, Preheat and Ignition Ramp modes of the ballast.
Figure 2: Lamp filament voltage during preheat and Ignition Ramp
(crossed lamps)
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I
Figure 3 shows a plot of the half-bridge oscillation frequency as a function of time for all of the normal
modes of operation: Preheat mode, Ignition Ramp mode and Run mode.
f
osc
t
preheat ignition run
f
Preheat
f
Run
f
Ignition
The duration of the Preheat mode as well as the mode of operation of the ballast are determined by
the voltage on the CPH pin of the IR2166. At the completion of the UVLO mode, Preheat mode is
entered and an internal current source is activated at the CPH pin of the IR2166, which begins to
charge up capacitor CPH. The ballast remains in the Preheat mode until the voltage on the CPH pin
exceeds the Ignition Ramp mode threshold (10V).
Ignition Ramp Mode
At the completion of the Preheat mode the ballast switches to the Ignition Ramp mode and the
frequency ramps down to the run frequency . Resistor RPH is no longer connected directly in parallel
with resistor RT so the run frequency is determined only with R T. During this ramping downward of
the frequency , the voltage across the lamp increases in magnitude as the frequency approaches the
Figure 3: Oscillator frequency versus time, normal operating conditions
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resonant frequency of the LC load circuit until the lamp ignition voltage is exceeded and the lamp
ignites. The maximum ignition voltage that can be generated is determined from the value of RCS, but
in any case the ignition frequency must be higher than the run frequency. Figure 4 shows the
ramping of voltage appearing across the lamp.
Figure 4: Ignition Ramp (crossed lamps)
During the Ignition Ramp mode the voltage on the CPH pin of the IR2166 continues to ramp up until
the voltage at the CPH pin of the IR2166 exceeds the Run mode threshold (13V). Over-current
sensing is also enabled at the beginning of the Ignition Ramp mode. A full explanation of the function-
ality of the over-current sensing is in the section on Fault Mode.
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Run Mode
During the Run mode the frequency is shifted to the run frequency . The run frequency is determined
only by RT. The 1-3V window comparator in the SD pin is enabled at the beginning of the Run mode.
The full explanation of the functionality of the under-current sensing and end-of-life sensing is in the
section on Fault Mode.
The Run mode frequency is that at which the lamp is driven to the lamp manufacturer’s recom-
mended lamp power rating. The running frequency of the lamp resonant output stage for selected
component values is defined as,
where,
L= Lamp resonant circuit inductor (L3) (H)
C= Lamp resonant circuit capacitor (C14) (F)
PLamp = Lamp running power (W)
VLamp = Lamp running voltage amplitude (V)
fLC P
CV LC P
CV
V
V
LC
run Lamp
Lamp
Lamp
Lamp
DCbus
Lamp
=−
+−
−−
1
212124
12
2
2
2
22
2
22
ππ
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Figure 5 shows the voltage appearing across the lamp during Startup, Preheat, Ignition Ramp and
Run modes.
Figure 5: Preheat, Ignition Ramp and Run V oltage in the lamp
Normal Power-Down
A normal power down occurs when the AC line voltage is disconnected from the ballast. When this
occurs the voltage on the VBUS pin of the IR2166 drops below the line fault threshold (3V). The value
of the zener diode in the COMP pin and of the RSUPPLY resistor are chosen to discharge VCC
below the power down threshold (9.5V) then the AC line falls below a minimum value (that can be set
with the value of DCOMP and RVBUS) to have latched shutdown. The ballast control oscillator is
stopped, the half-bridge driver outputs (LO and HO) are turned off and the IR2166 goes into its
UVLO/micro-power mode and the bus voltage collapses.
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Lamp Removal and Auto-restart
Resistors RPU, RSD and capacitor CSD1 form a divider/filter network which is used to detect an
open lower lamp filament and/or lamp replacement. Under normal conditions, the voltage across
CSD1 is close to zero. However, if the lower filament becomes open or the lamp is removed, the
voltage at the SD pin increases above the 5V threshold for the SD pin of the IR2166 and signals a
lamp removal condition, which in turn sends the ballast into UVLO mode. The ballast remains in the
UVLO mode until the lamp replacement is performed. If the lamp is replaced with a lamp with a good
lower filament, the voltage on the SD pin of the IR2166 drops back below the threshold and the ballast
will go through a restart. Line voltage cycling is also used to restart the ballast for all lamp fault
conditions. The ballast will go through a full Preheat, Ignition Ramp and Run mode sequence anytime
a restart is performed. Note that the SD pin of the IR2166 is active during all modes of operation.
Fault Mode
Fault mode is when the ballast driver is shutdown due to the detection of a lamp fault. Note that when
the ballast is in this Fault mode the power factor correction section of the ballast is also shutdown and
the bus voltage will drop to the non-boosted/unregulated level. There are several lamp fault conditions
that can put the ballast into the Fault mode.
The lamp fault conditions detected include:
hard-switching detection, over-current
detection (CS pin) and end of life detec-
tion (SD pin). Resistor RCS in the source
lead of the low side MOSFET (MHS)
serves as the current sensing point for
the half-bridge, which is used to detect
these lamp fault conditions. In operation
when the half-bridge is oscillating, a volt-
age appears across RCS whenever the
low side MOSFET, MHS, is turned on or
the high side MOSFET, MLS, is turned
off. The magnitude of this voltage directly
relates to the current in the lamp reso-
nant circuit. Figure 6 shows the voltage
which appears across resistor RCS dur-
ing normal Run mode conditions. Also
shown in Figure 6 are the gate drive sig-
nals for the low side MOSFET (LO pin)
and the high side MOSFET (HO-VS pin). Figure 6: Normal Run mode; Upper trace CS: voltage across
RCS, Middle trace: LO pin voltage, Lower trace: HO-VS pin
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During the Preheat mode the voltage across resistor RCS is not measured. However, at the end of
Preheat mode (the beginning of the Ignition Ramp mode) the hard-switching and over-current detec-
tion are enabled. During RUN mode, If at any time thereafter the voltage magnitude across resistor
RCS rises above the over-current threshold (1.3V), a lamp fault condition is signaled and the half-
bridge output MOSFETs’, (MHS and MLS) are turned off and the ballast goes into Fault mode. During
Ignition, a lamp fault condition is signaled only after 10 cycles to avoid triggering this protection in the
case of a current transient that can happen during normal ignition. An over-current condition can
occur if the lamp fails to ignite or the lamp is broken (an open circuit cathode or broken lamp).
Figure 7 shows the voltage across resistor RCS and the voltage appearing across the lamp when the
ballast detects a failure to ignite the lamp and goes into Fault mode. Figure 8 shows the voltage
appearing across the lamp during the tail end of the Preheat mode and the Ignition Ramp mode for a
failure of the lamp to ignite condition. If a cathode is broken (open circuit) the half-bridge output
hard-switches and each time the low side MOSFET (MHS) is turned on a large current pulse occurs
and thus a large voltage pulse occurs across resistor RCS signaling a fault, Figure 9 shows this
hard-switching condition. Figure 10 shows the lamp voltage during the Preheat mode and beginning
of Ignition Ramp mode for this hard-switching condition when the lamp fault condition is detected.
The ballast will remain in Fault mode until either the line voltage is reset or a lamp replacement is
performed.
Figure 7: Failure of lamp to ignite condition
(lamp filaments good): Upper trace: voltage
across RCS, Lower trace: lamp voltage
Figure 8: Failure of lamp to ignite condition
(lamp filaments good): Lamp voltage during
end of Preheat and Ignition Ramp modes
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Figure 9: Hard-switching condition (upper
filament open): Upper trace: voltage across
RCS, Middle trace: LO pin voltage,
Lower trace: HO-VS pin voltage
Figure 10: Hard-switching condition (upper
filament open): Lamp voltage during Preheat
mode and beginning of Ignition Ramp mode
when lamp fault is detected
The components REOL1, REOL2, REOL3, REOL4, CEOL are used for end of life protection. The
end-of-life window comparator is enabled at the beginning of the Run mode. In case of end-of-life the
voltage on pin SD of the IR2166 will fall outside the range of the internal window comparator 1-3V
causing it to go to Fault mode (fig. 11).
CSD1
REOL
REOL4
CEOL
CRES
SD
2V
A
Inside the
IR2167
0V
2V
in A
in the SD pin
Figure 1 1: End-of-Life circuit
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The value of REOL4 is changed so that the lamp voltage during normal running produces a signal
with 1.5 Vppk at the point (A) were the capacitor CEOL connects it to the SD pin. For a T5/35W
lamp 1.2Kohm at REOL4 provides the correct voltage.
The SD pin is internally biased at 2V with 1Mohm impedance and therefore at the SD pin a signal
varying between 1.25V and 2.75V will normally be present due to the AC coupling of the 100nF
capacitor (CEOL).
During end of life the lamp voltage may increase either symmetrically (AC end of life, due to a
similar deterioration in both cathode) or asymmetrically (DC end of life, due to a deterioration only
in one cathode). This circuit has the advantage of detecting both failure modes.
The peak to peak voltage at the SD pin will increase (with 2V DC offset) in either case until the
positive peak exceeds 3V and/or the negative peak drops below 1V , therefore triggering the window
comparator shutdown. The threshold of end of life can be adjusted by changing the value of REOL4
(usually 30% Vlamp is required).
Figure 12 shows the voltage in the SD pin and the voltage on the lamp in these 4 cases: no end of
life, DC end of life (upper cathode deteriorated and lower cathode deteriorated) and AC end of life
(both filaments deteriorated in the same way).
2V
3V
1V
2V
3V
1V
2V
3V
1V
2V
3V
1V
0V
Vspec
0V 0V
0V
Vspec + 30%
-Vspec - 30%
Vspec + 30%
-Vspec - 30%
SD pin Voltage
Lamp Voltage
Vspec = VpK in the spec of the lamp
Figure 12: V oltage in the SD pin and voltage on the lamp
in these 4 cases: no end of life, DC end of life and AC end of life.
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Current mode configuration
The same PCB can be config-
ured for current mode heating.
It is needed to remove the
Jumpers JV1 and JV2 and to
introduce the Jumpers JC1
and JC2. It could be also usefull
to add a resistor RDC in paral-
lel to CDC because in this con-
figuration after initial start-up
you could have some striations
(visible dark rings) on the lamps
for a short period (a few min-
utes) particularly when the lamp
has been off for some time and
is cold. The value should in the
order of 100kOhm 0.5W.
We suggest the use of the Bal-
last Designer software to deter-
mine the values of the compo-
nents to use in this configura-
tion.
Note: Thick traces represent high-frequency, high-current paths. Lead
lengths should be minimized to avoid high-frequency noise problems
CRES
LRES
CDC
L1 C1
BR1
C2
LPFC
MPFC RPFC
DPFC
CBUS
L
N
RV1
GND
CY
F1
CSD1
RSUPPLY
RCS
MLS
MHS
DCP2
RSD
CSNUB
RPU
CCS
DCP1
CVDC
RT
CT
RPH
DBOOT
CBOOT
RHO
RLO
CCOMP1
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
IR2166
VBUS
CPH
RT
RPH
CT
COMP
ZX
PFC
LO
COM
VCC
VB
VS
HO
SD
CS
IC BALLAST
RVDC
CVCC1 CVCC2
RBUS
CPH
RZX RLIM
CSD2
REOL1
REOL2
REOL3
REOL4
CEOL
DSD
DCOMP
RDC
CCOMP2
www.irf.com RD-0602 20
Design Procedure to adapt the design to different lamp types
To adapt the design to different types of lamps you need to adjust the values of: LPFC, MPFC, MLO,
MHO, CPH, RT, RPH, RCS, CT, REOL4, CRES and LRES. Do not change any others values!
1) Use the Ballast Designer Software to set the values of LRES, CRES, LPFC, MPFC, MLO and
MHO, CT, and to set the starting values of CPH, RT, RPH, RCS and LPFC.
Cross both lamps (i.e. connect a filament or resistor to each lamp cathode position but not a good
lamp) and measure the lamp voltage at ignition using a storage oscilloscope.
1) Set RCS to get the right maximum ignition voltage (decrease RCS to increase the ignition voltage)
Cross both lamps (i.e. connect a filament or resistor to each lamp cathode position but not a
good lamp) and measure the lamp voltage at ignition using a storage oscilloscope.
Connect both lamps correctly and measure the input power
2) Set RT to set the power on the lamp (increase RT to decrease the frequency and increase
the power on the lamp)
3) Set RPH to set the right preheat frequency (increase RPH to decrease the preheat fre-
quency and increase the preheat current)
In the case of voltage mode heating, increase CH1 and CH2 to increase the preheat voltage (use 6-7
turns in the secondary of LRES).
4) Select CPH to set the preheat time (increase CPH to increase the preheat time)
5) V erify the value of LPFC at each limit of the line/load range:
maximum input voltage: If the COMP pin becomes less than 400mV the PFC will not operate
in a stable manner and it is necessary to increase LPFC.
minimum input voltage: If the PFC does not operate in a stable manner and audible noise can
be heard from LPFC, it is necessary to decrease LPFC.
6) Set ROL4 to set the End of life protection to a percentage of the lamp voltage. For example, to
set the protection threshold to 30% of the lamp voltage:
The value of REOL4 is chosen to have the SD pin varying between 2-0.7V and 2+0.7 during
normal operations and exceeding the window comparator limits (less than 1V or more than 3V)
with 30% change in the voltage of the lamp.
(Fine tuning of this threshold can be done by trying different REOL4 values on the test bench)
Data and specifications subject to change without notice. 3/30/2006
