Datasheet

Data Sheet No. PD60184 rev F
For new designs, we recommend
IR’s product IR2166
IR2167(S) & PbF
PFC BALLAST CONTROL IC
Features
• PFC, Ballast Control and Half Bridge Driver in One IC
• Critical Conduction Mode Boost Type PFC
• No PFC Current Sense Resistor Required
• Programmable Preheat Time & Frequency
• Programmable Ignition Ramp
• Programmable Over-Current
• Internal Fault Counter
• End-of-Life Protection
• Lamp Filament Sensing & Protection
•
•
•
•
•
•
•
•
•
Capacitive Mode Protection
Brown-Out Protection
Dynamic Restart
Automatic Restart for Lamp Exchange
Thermal Overload Protection
Programmable Deadtime
Internal 15.6V Zener Clamp Diode on VCC
Micropower Startup (150µA)
Latch Immunity and ESD Protection
Packages
Description
The IR2167 is a fully integrated, fully protected 600V ballast control IC designed to
drive all types of fluorescent lamps. PFC circuitry provides for high PF, low THD and
DC Bus regulation. Externally programmable features such as preheat time & frequency, ignition ramp characteristics, and running mode operating frequency provide a
high degree of flexibility for the ballast design engineer. Comprehensive protection
features such as protection from failure of a lamp to strike, filament failures, low AC
line conditions, thermal overload, or lamp failure during normal operation, as well as
an automatic restart function, have been included in the design. The heart of the
ballast control section is a variable frequency oscillator with externally programmmable
deadtime. Precise control of a 50% duty cycle is accomplished using a T-flip-flop.
20-Lead SOIC
(wide body)
20-Lead
PDIP
Typical Application Diagram
+ Rectified AC Line
D1
L1
R5
RSUPPLY
R4
CBUS
C1
VDC
CPH
CPH
CRAMP
R2
CT
COC
3
RT
4
RUN
5
CT
RDT
ROC
6
DT
7
OC
CCOMP
8
COMP
R6
ZX
19
18
IR2167
RRUN
20
2
RPH
RPH
RT
1
17
16
15
14
13
9
12
10
11
HO
R7
M2
L2
C5
VS
VB
CBS
VCC
DBS
COM
CVCC
CSNUBBER
LO
R8
CS
R9
M3
R12
D3
C7
R11
SD
D2
R10
D4
PFC
VBUS
C3
D5
D6
C6
C4
R3
C2
RCS
R13
R1
M1
- Rectified AC Line
Please note that this datasheet contains advance information that could change before the product is released to production.
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1
IR2167(S) & PbF
Absolute Maximum Ratings
Absolute maximum ratings indicate sustained limits beyond which damage to the device may occur. All voltage parameters are absolute voltages referenced to COM, all currents are defined positive into any lead. The thermal resistance
and power dissipation ratings are measured under board mounted and still air conditions.
Symbol
Min.
Max.
-0.3
625
High side floating supply offset voltage
VB - 25
VB + 0.3
VHO
High side floating output voltage
VS - 0.3
VB + 0.3
VLO
Low side output voltage
-0.3
VCC + 0.3
VPFC
PFC gate driver output voltage
-0.3
VCC + 0.3
IOMAX
Max. allowable output current (HO,LO,PFC) due to external
power transistor miller effect
-500
500
-5
5
High side floating supply voltage
VS
IRT
RT pin current
Units
VCT
CT pin voltage
-0.3
6.5
VDC pin voltage
-0.3
VCC + 0.3
ICPH
CPH pin current
-5
5
IRPH
RPH pin current
-5
5
IRUN
RUN pin current
-5
5
IDT
Deadtime pin current
VCS
Current sense pin voltage
-5
5
-0.3
6.5
ICS
Current sense pin current
-5
5
IOC
Over-current threshold pin current
-5
5
ISD
Shutdown pin current
-5
5
IZX
ICOMP
ICC
DC bus sensing input voltage
-0.3
VCC
PFC inductor current, zero crossing detection input
-5
5
PFC error amplifier compensation current
-5
5
Supply current (note 1)
-20
20
dV/dt
Allowable offset supply voltage slew ratet
-50
50
PD
Package power dissipation @ TA ≤ +25°C
(20 lead PDIP)
—
1.50
(20 lead SOIC)
—
1.25
(20 lead PDIP)
—
85
(20 lead SOIC)
—
90
RthJA
Thermal resistance, junction to ambient
TJ
Junction temperature
-55
150
TS
Storage temperature
-55
150
TL
Lead temperature (soldering, 10 seconds)
—
300
V
mA
VDC
VBUS
2
Definition
VB
V
mA
V
mA
V
mA
V/ns
W
°C/W
°C
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IR2167(S) & PbF
Recommended Operating Conditions
For proper operation the device should be used within the recommended conditions. All voltage parameters are absolute
voltages referenced to COM, all currents are defined positive into any lead
Symbol
Definition
VBS
High side floating supply voltage
VS
Steady state high side floating supply offset voltage
Min.
Max.
VCC - 0.7
VCLAMP
-3.0
600
VCLAMP
Units
V
VCC
Supply voltage
VCCUV+
Note 2
10
mA
0
VCC
V
ICC
Supply current
VDC
VDC lead voltage
ISD
Shutdown lead current
-1
1
ICS
Current sense lead current
-1
1
mA
CT
CT lead capacitance
220
—
pF
RDT
Deadtime resistance
1.0
—
kΩ
IRT
RT lead current (Note 3)
-500
-50
IRPH
RPH lead current (Note 3)
0
450
IRUN
RUN lead current (Note 3)
0
450
IZX
Zero crossing detection lead current
-1
1
TJ
Junction temperature
-40
125
uA
mA
o
C
Electrical Characteristics
VCC = V BS = V BIAS = 14V +/- 0.25V, RT = 16.9kΩ, CT = 470 pF, RPH and RUN leads no connection, V CPH = 0.0V,
RDT = 6.1kΩ, ROC = 20.0kΩ, V CS = 0.5V, VSD = 2.0V, CL = 1000pF, TA = 25 oC unless otherwise specified.
Supply Characteristics
Symbol Definition
Min.
Typ.
Max.
VCCUV+
10.4
11.4
12.5
VUVHYS
IQCCUV
IQCCFLT
VCC supply undervoltage positive going
threshold
VCC supply undervoltage lockout hysteresis
UVLO mode quiescent current
Fault-mode quiescent current
—
—
2.1
250
100
2.1
400
350
IQCC
Quiescent VCC supply current
1.9
3.3
4.5
ICC50K
VCC supply current, f = 48kHz
4.0
5.0
6.0
VCLAMP
VCC zener clamp voltage
14.0
15.6
16.5
Note 2:
Note 3:
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Units Test Conditions
VCC rising from 0V
V
2.0
mA
VCC < VCCUVSD = 5V, CS = 2V or
Tj > TSD
RT no connection, CT
connected to COM
V
ICC = 10mA
µA
Sufficient current should be supplied to the VCC pin to keep the internal 15.6V zener clamp diode on this pin
regulating its voltage.
Due to the fact that the RT pin is a voltage-controlled current source, the total RT pin current is the sum of all
of the parallel current sources connected to that pin. During the preheat mode, the total current flowing out
of the RT pin consists of the RPH pin current plus the current due to the RT resistor. During the run mode, the
total RT pin current consists of the RUN pin current plus the current due to the RT resistor.
3
IR2167(S) & PbF
Electrical Characteristics (cont.)
VCC = VBS = V BIAS = 14V +/- 0.25V, RT = 16.9kΩ, CT = 470 pF, RPH and RUN leads no connection, V CPH = 0.0V,
RDT = 6.1kΩ, ROC = 20.0kΩ, VCS = 0.5V, VSD = 2.0V, CL = 1000pF, TA = 25 oC unless otherwise specified.
Floating Supply Characteristics
Symbol Definition
IQBS0
ILK
Quiescent VBS supply current
Offset supply leakage current
Min.
—
—
Typ.
0
0
Max.
10.0
50
Units Test Conditions
µA
VHO = VS
VB = VS = 600V
PFC Error Amplifier Characteristics
Symbol Definition
Min.
Typ.
Max.
VBUS
IVBUS
gm
ISOURCE
ISINK
VOH(EA)
V0L(EA)
3.7
—
40
15
5
12.5
—
4.0
—
90
30
30
13.5
0.25
4.3
0.1
130
50
50
14.5
0.4
Min.
Typ.
Max. Units Test Conditions
VBUS sense input threshold
VBUS sense input bias current
Error amplifier transconductance
Error amplifier output current sourcing
Error amplifier output current sinking
Error amplifier output voltage swing (Hi state)
Error amplifier output voltage swing (Lo state)
Units Test Conditions
µmho
µA
V
V
µA
RUN mode operation
VBUS = 3V
VBUS = 5V
VBUS = 3V
VBUS = 5V
PFC Over Voltage Comparator
Symbol Definition
V0V
Over voltage comparator threshold
4.0
4.3
4.5
V
1.7
400
6.0
2.0
300
7.5
2.3
300
9.0
V
mV
V
Typ.
Max.
PFC Zero Current Detector
VZX
ZX lead comparator threshold voltage
VZXhys
ZX lead comparator hysterisis
VZXclamp+ ZX lead clamp voltage (high state)
IZX = 1mA
Oscillator, Ballast Control, I/O Characteristics
Symbol Definition
Min.
Units Test Conditions
RT = 16.9kΩ, RDT =
6.1kΩ, CT=470pF
fosc
Oscillator frequency
41
44
47
VCT+
VCTVRT
tDLO
tDHO
Upper CT ramp voltage threshold
Lower CT ramp voltage threshold
RT lead voltage
LO output deadtime
HO output deadtime
3.6
1.8
1.8
2.0
2.0
4.0
2.0
2.0
2.4
2.4
4.4
2.2
2.2
2.6
2.6
Symbol Definition
Min.
Typ.
Max. Units Test Conditions
ICPH+
CPH lead charging current
ICPHCPH lead discharge current
VCPHIGN CPH lead lgnition mode threshold voltage
VCPHRUN CPH lead run mode threshold voltage
VCPHCLMP CPH lead clamp voltage
2.5
50
3.6
4.7
6
2.8
175
4.1
kHz
V
µsec
Preheat Characteristics
4
5.1
10
3.2
350
4.4
5.5
11.5
µA
nA
VCPH = 0V
VCPH = 0V
V
ICPH = 1µA
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IR2167(S) & PbF
Electrical Characteristics (cont.)
VCC = VBS = VBIAS = 14V +/- 0.25V, RT = 16.9kΩ, CT = 470 pF, RPH and RUN leads no connection, VCPH = 0.0V,
RDT = 6.1kΩ, ROC = 20.0kΩ, VCS = 0.5V, VSD = 2.0V, CL = 1000pF, T A = 25 oC unless otherwise specified.
RPH Characteristics
Symbol Definition
IRPHLK
Open circuit RPH lead leakage current
Min.
Typ.
Max.
—
0.1
—
Min.
Typ.
Max.
—
0.1
—
Max.
Units Test Conditions
µA
VRPH =5V,VRPH =6V
RUN Characteristics
Symbol Definition
IRUNLK
Open circuit RUN lead leakage current
Units Test Conditions
µA
VRUN = 5V
Protection Circuitry Characteristics
Symbol Definition
Min.
Typ.
Units Test Conditions
VSDTH+ Rising shutdown lead threshold voltage
VSDHYS Shutdown lead threshold hysteresis
VSDEOL+ Rising shutdown lead end-of-life threshold
voltage
VSDEOL- Falling shutdown lead end-of-life threshold
voltage
VCSTH+
Over-current sense threshold voltage
VCSTHUnder-current sense threshold voltage
TCS
Over-current sense propogation delay
#FAULT
Number of sequential over-current Fault
cycles
cycles before IC shuts down (IGN Mode)
VVDC+
Low VBUS/rectified line input upper threshold
VVDCLow VBUS/rectified line input lower threshold
TSD
Thermal shutdown junction temperature
4.8
300
2.6
5.25
150
3.0
5.4
100
3.4
0.7
1.0
1.3
1.05
0.14
50
1.2
0.23
350
1.35
0.28
550
nsec
25
4.8
2.7
—
50
5.2
3.1
160
75
5.7
3.5
—
oC
Min.
Typ.
—
—
50
25
0
0
85
45
V
mV
V
Delay from CS to LO
4V < VCPH <5.1V,
cycles cycles @CS > 1.3V
V
Note 4
Gate Driver Output Characteristics
Symbol Definition
VOL
VOH
tr
tf
Note 4:
Low level output voltage (PFC, LO or HO)
High level output voltage (PFC, LO or HO)
Turn-on rise time (PFC, LO or HO)
Turn-off fall time (PFC, LO or HO)
Max.
100
100
200
100
Units Test Conditions
mV
Io = 0
VBIAS - VO, Io = 0
nsec
When the IC senses an overtemperature condition (Tj > 160ºC), the IC is latched off. In order to reset this
Fault Latch, the SD lead must be cycled high and then low, or the VCC supply to the IC must be cycled below
the falling undervoltage lockout threshold (VCCUV-).
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5
IR2167(S) & PbF
Lead Assignments
Pin # Symbol
Pin Assignments
1
20
HO
CPH
2
19
VS
RPH
3
18
VB
RT
4
RUN
5
CT
6
DT
7
OC
8
COMP 9
ZX
6
10
IR2167
VDC
17 VCC
16 COM
15
LO
14
CS
13
SD
12 PFC
11 VBUS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
VDC
CPH
RPH
RT
RUN
CT
DT
OC
COMP
ZX
VBUS
PFC
SD
CS
LO
COM
VCC
VB
VS
HO
Description
DC Bus Sensing Input
Preheat Timing Capacitor
Preheat Frequency Resistor & Ignition Capacitor
Oscillator Timing Resistor
Run Frequency Resistor
Oscillator Timing Capacitor
Deadtime Programming
Over-current (CS+) Threshold Programming
Error Amplifier Compensation
Zero-Crossing, PFC Inductor
Bus Voltage Sense Input
PFC Gate Driver Output
Shutdown Input
Current Sensing Input
Low-Side Gate Driver Output
IC Power & Signal Ground
Logic & Low-Side Gate Driver Supply
High-Side Gate Driver Floating Supply
High Voltage Floating Return
High-Side Gate Driver Output
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IR2167(S) & PbF
State Diagram
Power Turned On
UVLO Mode
1/2-Bridge Off
PFC Off
COMP=0V
IQCC ≅ 150µA
CPH = 0V
SD > 5.1V
(Lamp Removal)
or
VCC < 9.5V
(Power Turned Off)
FAULT Mode
Fault Latch Set
1/ -Bridge Off
2
PFC Off
COMP=0V
IQCC ≅ 150µA
CPH = 0V
VCC = 15.6V
VCC > 11.4V (UV+)
and
VDC > 5.1V (Bus OK)
and
SD < 4.9V (Lamp OK)
and
TJ < 160C (Tjmax)
TJ > 160C
(Over-Temperature)
CS > OC Threshold
For 55 cycles
(Failure to Strike Lamp
or Hard Switching)
or
TJ > 160C
(Over-Temperature)
CS > OC Threshold
(Over-Current or Hard Switching)
or
CS < 0.2V
(No-Load or Below Resonance)
or
TJ > 160C
(Over-Temperature)
or
SD < 1V or SD > 3V (End-of-Life)
VCC < 9.5V
(VCC Fault or Power Down)
or
VDC < 3.0V
(dc Bus/ac Line Fault or Power Down)
or
SD > 5.1V
(Lamp Fault or Lamp Removal)
PREHEAT Mode
1/
-Bridge @ fPH
2
PFC Enabled
CPH Charging @ IPH = 3µA
RPH = 0V
RUN = Open Circuit
CS Disabled
CPH > 4.0V
(End of PREHEAT Mode)
IGNITION RAMP Mode
fPH ramps to fMIN
CPH Charging @ IPH = 1µA
RPH = Open Circuit
RUN = Open Circuit
CS OC Threshold Enabled
CPH > 5.1V
(End of IGNITION RAMP)
RUN Mode
fMIN Ramps to fRUN
CPH Charges to 10V Clamp
RPH = Open Circuit
RUN = 0V
CS 0.2V Threshold Enabled
SD 1.0V and 3.0V Thresholds Enabled
All values are typical
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7
IR2167(S) & PbF
Functional Block Diagram
3.0V
18 VB
VDC 1
5.1V
S
Q
R
Q
PULSE
FILTER &
LATCH
LEVEL
SHIFT
20 HO
1.0uA
19 VS
CPH 2
9.5V
5.1V
S
4.0V
4.0V
RPH 3
Q
R1
R2 Q
2.0V
T
Q
R
Q
17 VCC
15 LO
IRT
RT 4
15.6V
16 COM
2.0V
RUN 5
Q
ICT = IRT
CT 6
DT 7
Q
S
Q
R
D
0.2V
14 CS
CLK
Q
R
7.6V
FAULT COUNTER
50uA
OVERTEMP
DETECT
UNDERVOLTAGE
DETECT
OC 8
13 SD
7.6V
2.0V
7.6V
VBUS 11
4.0V
VCC
4.3V
GM
12 PFC
hi
COMP 9
S
4.0V
Q
R1
S
Q
R
Q
R2 Q
3.0V
S
Q
R
Q
S
Q
WATCHDOG
TIMER
R1
R2 Q
ZX 10
1.0V
7.6V
8
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IR2167(S) & PbF
BALLAST CONTROL SECTION
TIMING DIAGRAMS
NORMAL OPERATION
15.6V
UVLO+
UVLO-
VCC
7.6V
5.1V
4.0V
VCPH
2.0V
VRPH
2.0V
VRUN
FREQ
fSTART
fPREHEAT
fRUN
fMIN
HO
LO
CS
Over-Current Threshold
CT
HO
LO
CS
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PH
IGN
UVLO
RUN
UVLO
CT
CT
HO
LO
CS
HO
LO
CS
9
IR2167(S) & PbF
BALLAST CONTROL SECTION
TIMING DIAGRAMS
FAULT CONDITION
15.6V
UVLO+
UVLO-
VCC
7.6V
5.1V
4.0V
VCPH
2.0V
VRPH
2.0V
VRUN
FREQ
fSTART
fPH
fRUN
fIGN
SD
5.2V
2V
HO
LO
CS
CS
10
PH
IGN
LO
SD > 5.1V
HO
FAULT
CT
PH
IGN
UVLO
RUN
UVLO
CT
CT
HO
LO
CS
HO
LO
CS
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IR2167(S) & PbF
6
4
5.5
EOL+
3
EOL+, EOL- (V)
SD(Preheat, Ignition) (V)
3.5
5
4.5
2.5
2
EOL-
1.5
1
0.5
4
0
-25
0
25
50
75
100
125
-25
0
Temperature (°C)
25
50
75
100
125
Temperature (°C)
SD+ Threshold vs Temperature (IR2167)
(Preheat, Ignition)
EOL+, EOL- Threshold vs Temperature (IR2167)
(Run Mode)
200
100
175
tRISE LO, t FALL LO (nS)
150
tDEAD ( S)
10
220pF
470pF
1
1nF
tRISE
125
100
75
50
tFALL
3.3nF
25
10nF
0.1
0
1
10
RDT (KΩ)
tDEAD vs RDT (IR2167)
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100
-25
0
25
50
75
100
125
Temperature (°C)
tRISELO, tFALLLO vs Temperature (IR2167)
11
IR2167(S) & PbF
5
15
13
VBUS+
VCCUV +, V CCUV - (V)
VBUS+, V BUS- (V)
4.5
4
VBUS3.5
VCCUV+
11
VCCUV-
9
7
3
-25
0
25
50
75
100
5
125
-25
0
Temperature (°C)
25
50
75
100
125
Temperature (°C)
VBUS Threshold vs Temperature (IR2167)
VCCUV +, VCCUV - vs Temperature (IR2167)
10
8
8
VCPH (IGN , RUN ) (V)
4
VDC+, VDC- (V)
VRUN
6
VIGN
2
4
VDC-
2
0
0
-25
0
25
50
75
100
Temperature (°C)
VCPH (IGN,
12
VDC+
6
RUN)
vs Temperature (IR2167)
125
-25
0
25
50
75
100
125
Temperature (°C)
VDC+, VDC- vs Temperature (IR2167)
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IR2167(S) & PbF
CT=220pF, RDT=5.6K
1000000
30
CT=470pF, RDT=2.7K
25
CT=1nF, RDT=1.2K
Frequency (Hz)
ILK ( A)
20
15
10
100000
5
0
-25
0
25
50
75
100
125
10000
1000
10000
Temperature (°C)
100000
RT (Ω)
Frequency vs RT (IR2167)
ILK vs Temperature (IR2167)
tDEAD=1µsec
10
80
125°C
70
9
60
75°C
50
IQBS (uA)
ICC (mA)
8
7
25°C
40
30
6
20
-25°C
5
10
4
10000
100000
Frequency (Hz)
ICC vs Frequency (IR2167)
1000000
0
0
4
8
12
16
20
VBS (V)
IQBS vs VBS vs Temperature (IR2167)
RDT=5.6KΩ, CT=220pF
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13
IR2167(S) & PbF
1000000
90
C T=220pF,R DT=11K
C T=470pF,R DT=6.2K
C T=1nF,RD T=3K
80
C T=4.7nF,RD T=1K
70
100000
Tj (°C)
Frequency (Hz)
C T=10nF,R DT=1K
10000
60
50
40
30
1000
1000
10000
100000
20
10000
100000
Frequency (Hz)
1000000
RT (Ω)
Frequency vs RT (IR2167)
14
Tj vs Frequency (IR2167 DIP)
Driving IRF820's, VBUS=400V
IC driven by square wave
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IR2167(S) & PbF
Functional Description
Under-voltage Lock-Out Mode (UVLO)
The under-voltage lock-out mode is defined as the state the
IC is in when VCC is below the turn-on threshold of the IC.
(To identify the different modes of the IC, refer to the State
Diagram shown on page 7 of this document). During undervoltage lock-out mode, the HO, LO and PFC driver outputs
are low and the CT pin is connected to COM through resistor RDT to disable the oscillator. Also, the internal supply to
the RT pin circuitry is shut off and pins CPH, RUN, DT and
COMP are internally pulled to COM. The IR2167 undervoltage lock-out mode is designed to maintain a very low
supply current of less than 200µA, and to guarantee the IC
is fully functional before the high side, low side and PFC
drivers are activated. Figure 1 shows an efficient supply
using the start-up current of the IR2167 together with a charge
pump from the ballast stage (RSUPPLY, CVCC, DCP1 and
DCP2).
+ VBUS
+ rectified AC Line
R1
RSupply
VDC
R2
C1
1
CPH
2
RPH
19
3
4
RUN
5
CT
6
DT
7
OC
8
COMP
18
IR2167
RT
ZX
20
17
16
15
14
13
9
12
10
11
R3
HO
Half-bridge
output
VS
VB
CBS
VCC
DBS
COM
CVCC
LO
by the IC. The value of (RSUPPLY) is chosen to provide 2X
the maximum start-up current to guarantee ballast start-up
at low line input voltage. Once the capacitor voltage on the
VCC pin reaches the start-up threshold, the SD lead is below 5.1 volts and VVDC is greater than 5.1V, the IC turns on
and LO and HO begin to oscillate. PFC does not begin to
oscillate until the IC reaches Preheat Mode.
Preheat Mode Startup Mode
The IR2167 enters Preheat mode when VCC exceeds
the UVLO positive-going threshold. Before Preheat mode
begins, the CPH and RPH pins are connected to COM. (See
Figure 3). As Preheat begins, the external capacitor CPH is
charged up by an internal 3µA current source. CPH
determines the preheat time which continues until the voltage
on the CPH pin charges to 4.0V. Preheat mode is defined as
the state the IC is in when the lamp filaments are being heated
to their correct emission temperature. This is necessary for
maximizing lamp life and reducing the required ignition
voltage. At the onset of Preheat Mode, CVCC begins to
discharge due to the increase in IC operating current (Figure
2) above the available current through resistor RSUPPLY.
However, the half-bridge output also begins to oscillate and
the charge pump, consisting of CSNUBBER, DCP1 and DCP2,
supply the current to charge capacitor CVCC and thus the
voltage to the IC. The VCC voltage supplied to the IC is
VC1
CVCC
DISCHARGE
CSNUBBER
DCP1
VUVLO+
DCP2
R4
VHYST
VUVLOCS
SD
INTERNAL VCC
ZENER CLAMP VOLTAGE
DISCHARGE
TIME
RCS
CHARGE PUMP
OUTPUT
PFC
VBUS
RSUPPLY & CVCC
TIME
CONSTANT
t
VBUS return
Figure 1: Start-up and supply circuitry
The VCC capacitor (CVCC) is charged by current through
supply resistor (RSUPPLY) minus the start-up current drawn
www.irf.com
Figure 2: Supply Capacitor (CVCC) voltage
limited by the internal 15.6V zener clamp. C VCC and
CSNUBBER must be selected such that enough supply current
15
IR2167(S) & PbF
is available over all ballast operating conditions. Bootstrap
diode (DBS) and supply capacitor (CBS) comprise the supply
voltage for the high-side driver circuitry. To guarantee that
the high-side supply is charged up before the first pulse on
HO, the first pulse from the output drivers comes from the
LO pin.
The Preheat mode oscillation frequency of the half-bridge
output is determined by the parallel combination of RPH and
RT with the values of CT, RDT and an internal circuit as
CPH
CPH
3.0uA
2
COMP1
turns off and CRAMP begins to charge. CRAMP determines
the time it takes for the oscillator to ramp down from the
Preheat frequency to the Ignition Mode frequency. Once
the voltage on the RPH lead reaches 2.0V, external resistor
RPH has no effect on the frequency that is now determined
by external components RT, CT and RDT. This is the minimum frequency. By this time, the oscillator will have ramped
down toward the resonance of the load circuit causing the
lamp to ignite.
QUICK
RESTART
LOGIC
9.5V
5.1V
COMP2
RPH
CRAMP
RT
RPH
RRUN
RT
RDT
Q
R2 Q
M1
IRT
4
2.0V
RUN
CT
CT
S
R1
2.0V
4.0V
3
4.0V
DT
5
M2
ICT = IRT
6
7
Fault signal
Figure 3: Oscillator section block diagram with external component connection
shown in Figure 3. Note that at the onset of Preheat mode
the initial startup frequency is much higher than the preheat
frequency. The half-bridge output frequency then ramps
down from this initial start-up frequency to the Preheat mode
frequency. This is to ensure that the instantaneous voltage
across the lamp during the first few cycles of operation
does not exceed the strike potential of the lamp.
Ignition Mode
Run Mode
When the voltage on the CPH pin reaches 5.1V, the IC enters Run mode. At this time, the output of COMP1 (figure 3)
goes high which turns M2 on and pulls the RUN pin to COM.
The frequency is now controlled by external components RT,
RRUN, CT and RDT. In certain cases it is necessary to have
the run frequency higher than the ignition frequency to control the power used by the load. Figure 4 shows the ballast
control sequence explained in the previous paragraphs.
When the CPH pin charges up to 4.0V, ignition mode begins.
At this time, the output of COMP2 (figure 3) goes low, M1
16
www.irf.com
IR2167(S) & PbF
frequency
fStart
fPH
fRun
fmin
t
5V
VCPH
2V
VRPH
Figure 5: Oscillator Waveforms
This falling portion of the sawtooth waveform is referred to
as deadtime, during which both HO and LO outputs are low.
The deadtime can be programmed by means of the external
RDT resistor.
2V
VRUN
Preheat mode
Ignition Run mode
Ramp
mode
Figure 4: IR2167 Ballast Control Sequence
The control sequence used in the IR2167 allows the Run
mode operating frequency of the ballast to be higher than
the ignition frequency (i.e., fstart > fph > frun > fign). This
control sequence is recommended for lamp types where the
ignition frequency is too close to the run frequency to ensure
proper lamp striking for all production resonant LC component tolerances (please note that it is possible to use the
IR2167 in systems where fstart > fph > fign > frun, simply by
leaving the RUN pin open).
The heart of this controller is an oscillator that
resembles those found in many popular PWM voltage
regulator ICs. In its simplest form, this oscillator consists of
a timing resistor and capacitor connected to ground. The
voltage across the timing capacitor CT is a sawtooth, where
the rising portion of the ramp is determined by the current in
the RT lead, and the falling portion of the ramp is determined
by an external deadtime resistor RDT. The oscillograph in
Figure 5 illustrates the relationship between the oscillator
capacitor waveform and the gate driver outputs.
www.irf.com
The RT input is a voltage-controlled current source, where
the voltage is regulated to be approximately 2.0V. In order
to maintain proper linearity between the RT pin current and
the CT capacitor charging current, the value of the RT pin
current should be kept between 50µA and 500µA. The RT
pin can also be used as a feedback point for closed loop
control.
PFC Section
In most AC to DC power converters it is necessary to have
the circuit act as a pure resistive load to the AC input line
voltage. To achieve this, active power factor correction (PFC)
can be implimented which, for an AC input line voltage,
produces an AC input line current. It is also important to
produce a sinusoidal input current which has a low total
harmonic distortion (THD) and a high power factor (PF) (See
Figure 6).
.
17
IR2167(S) & PbF
Figure 7: Inductor Current
Figure 6: Input Voltage & Current
PF=0.96, THD=22%
The approach used in the IR2167 is classified as running in
critical conduction mode, in which the inductor current
discharges to zero with each switching cycle. There is no
need to sense the rectified AC line input voltage because it
is already sinusoidal. Therefore, the inductor current will
naturally follow the sinusoidal voltage envelope as the PFC
MOSFET is turned on and off at a much higher frequency
(>10KHz) than the line input frequency (50 to 60Hz). The
circuit compares the DC Bus voltage to a fixed reference
voltage to determine the on-time of the PFC MOSFET. The
off-time is determined by the time it takes the LPFC current
to drop to zero. This zero current level is detected by a
secondary winding in LPFC that is connected to the ZX pin.
The result is a system where the switching frequency is freerunning and constantly changing from a high frequency near
the zero crossing of the AC input line voltage, to a lower
frequency at the peaks. (See Figures 7, 8 & 9).
Figure 8: Boost Inductor Envelope & Line Voltage
ILPFC
0
PFC
pin
0
ZX
pin
0
near peak region of
rectified AC line
near zero crossing region
of rectified AC line
Figure 9: Boost FET On Time vs Line Input
18
www.irf.com
IR2167(S) & PbF
As the external capacitor on the COMP pin begins to charge,
the PFC MOSFET on time duration increases. The gain of
OTA1 is at its maximum value (See Figures 10 & 11).
Maximum gain is desireable to raise the Bus voltage to its
nominal value as quickly as possible. When the voltage at
the VBUS pin reaches 3V, the gain of OTA1 decreases to its
Run Mode
Signal
MOSFET is turned on with minimum on time and LPFC is
shorted to ground and begins charging. The PFC MOSFET
then turns off and LPFC begins to discharge into the DC
BUS capacitor.
COMP4 has a 4.3V threshold with hysteresis so that if
the voltage at the VBUS pin overshoots the 4.3V threshold,
From Fault
Detection Circuitry
VBUS 11
COMP4
OTA1
VCC
4.0V
4.3V
GM
hi
COMP1
RS2
4.0V
COMP2
RS1
3.0V
M1
S Q
R1
R2 Q
C1
12 PFC
RS3
COMP5
COMP 9
S
Q
R
Q
WATCHDOG
TIMER
M2
S
Q
RS4
R
Q
S Q
R1
R2 Q
COMP3
ZX 10
7.6V
1.0V
Figure 10: PFC Section
nominal value. The BUS voltage continues to increase to its
nominal value at which time the voltage measured at the
VBUS pin equals 4V. The gain of OTA1 now increases to
its maximum value and remains there until the Run mode.
This is necessary because if VBUS overshoots its nominal
value, the circuit can react quickly to correct the error. Also,
during ignition, there is a sudden increase in load current
which can cause the Bus voltage to sag. With maximum
gain, OTA1 can quickly restore the DC Bus voltage to its
nominal value.
When the AC line voltage is applied to the ballast, VCC
rises to 15V. The PFC section is not enabled until the beginning of the Preheat mode of operation. By not enabling the
PFC section until the beginning of the Preheat mode, the
DC Bus voltage in the ballast is not yet boosted to its nominal running value. This helps alleviate the initial flash of the
lamp when the half-bridge driver section first begins to switch.
When the PFC circuit is first enabled, (See Figure 10),
the voltage at the VBUS and COMP pins is low. The PFC
www.irf.com
the PFC MOSFET will not turn on again until the voltage at the
VBUS pin drops to approximately 4.0V. This effectively limits
ths maximum bus voltage to approximately 8% greater than
the regulated level.
In some instances, the line voltage may be too
high. This causes the AC rectified line current to directly
charge the DC Bus capacitor without being boosted. Since
the current never drops to zero, the ZX pin never goes high
and the PFC MOSFET never turns on. The Watch Dog Timer
circuit provides a pulse to turn on the PFC MOSFET if no
pulse is detected at the ZX pin for 500mS. This enables the
PFC circuitry to regulate the DC Bus voltage at its nominal
value
19
IR2167(S) & PbF
VVBUS
4.3
4.0
3.0
0
DRIVE
SIGNALS
6.0
5.1
5.0
4.0
VCPH
2.0
0
6.0
4.0
VCOMP
2.0
0
Note 1
ICOMP
0
Note 1
RESULTANT
SIGNALS
Note 1
Note 1
1000
gm
(max)
200
0
QUICK
START
MODE
POWER
UP
MODE
POWER
BOOST
MODE
RUN
MODE
Note 1: ICOMP in these regions is the output
saturation current of the OTA Error amplifier
Figure 11: PFC Timing Sequence
20
www.irf.com
IR2167(S) & PbF
PFC Over-Current Protection (optional)
In case of fast on/off interruptions of the mains input voltage
or during normal lamp ignition, the DC bus voltage level can
decrease below the instantaneous rectified line voltage.
Should this occur, the PFC inductor current and PFC MOSFET
current can increase to high levels causing the PFC inductor
to saturate and/or the PFC MOSFET to become damaged.
During fast on/off interruptions of the input mains voltage, the
DC bus can drop during the time when the mains voltage is
interrupted (off). Since VCC is still above UVLO-, the IC will
continue to operate and will increase the COMP pin voltage to
increase the PFC MOSFET on-time due to the dropping of the
DC bus. When the mains voltage returns again quickly, (before
VCC reaches UVLO-), the on-time of the PFC MOSFET is too
long for the given mains voltage level resulting in high PFC
inductor and MOSFET currents that can saturate the inductor
and/or damage the PFC MOSFET (Figure 12).
During lamp ignition, the DC bus can drop below the rectified
AC line voltage causing current to conduct directly from the
output of the rectifier, through the PFC inductor and diode, to
the DC bus capacitor. This results in a low-frequency offset
of current in the PFC inductor. Since the zero-crossing
detection circuit only detects the high-frequency zerocrossing of the inductor current, the PFC MOSFET will turn
on again each cycle before the inductor current has reached
zero. This causes the PFC to work in a continuous conduction
mode and the sum of the low-frequency and high-frequency
components of current can saturate the PFC inductor and/
or damage the PFC MOSFET.
To protect against these conditions, a current sense resistor
(RS) can be inserted between the source on the PFC MOSFET
and ground, and a diode (D4) connected from the top of this
current-sensing resistor to the VBUS pin (Figure 13).
Rectified
AC line
HO
VBUS
1
16
2
15
3
14
VS
CPH
RT
RPH
4
D4
CT
5
1N4148
RS
1Ω
COMP
98-0265
VB
VCC
13
COM
12
Device
Ground
LO
7
6
11
7
10
8
9
CS
ZX
SD/EOL
PFC
High
Current
Ground
Figure 12, High PFC inductor current during fast mains on/off
(upper trace: DC Bus, 100V/div; middle trace: AC line input voltage,
100V/div; lower trace: PFC inductor current 1A/div).
www.irf.com
13, External over-current protection circuit
21
IR2167(S) & PbF
Should high currents occur, the voltage across the currentsensing resistor (RS) will exceed the 4.3V over-voltage
protection threshold at the VBUS pin and the PFC MOSFET
will turn off safely limiting the current. The watch-dog timer
will then restart the PFC as normal (Figure 14). The current
sensing resistor value should be selected such that the
over-current protection does not false trip during normal
operation over the entire line voltage range and load range.
A current-sensing resistor value, for example, of 1.0 W will
set the over-current protection threshold to about 5 A peak.
when the DC bus drops during ignition (the 3V reset on the
VBUS pin does not become active until RUN mode). For
these reasons, the ballast designer should perform these
mains interrupt and ignition tests carefully to determine the
robustness of their final design and to decide if this additional
over-current protection circuit is necessary.
Figure 14, PFC inductor current limited using over-current
protection circuit (upper trace: DC Bus, 100V/div; middle
trace: AC line input voltage, 100V/div; lower trace: PFC inductor
current 1A/div).
The effect that these line and load conditions have on the
performance of the ballast depends on the saturation level
of the PFC inductor, the selection of the PFC MOSFET, the
DC bus capacitor value, the maximum on-time limit set by
DZCOMP, and, how fast VCC decreases below UVLO-
22
www.irf.com
IR2167(S) & PbF
Lamp Protection & Automatic Restart Circuitry Operation
+VBUS
R1
R2
VDC
3.0V
1
C1
5.1V
1.0uA
2
CPH
9.5V
S
Q
R
Q
from oscillator
section
QUICK
RESTART
LOGIC
5.1V
4.0V
T
Q
R
Q
Q2
R3
Q
D
Q
S
Q
R
DT 7
14
8
ROC
COC
R
R4
FAULT
COUNTER
50uA
OC
Q
UNDERVOLTAGE
DETECT
OVERTEMP
DETECT
RCS
CS
0.2V
CLK
7.6V
C3
3V
1meg
R6
SD
R7
13
1V
7.6V
C2
5.1V
from upper
lamp cathode
VCC
2V
7.6V
R5
C4
from lower
lamp cathode
Figure 15: Lamp Protection & Automatic Restart circuitry block diagram with external component connection
Sensing the AC Line Voltage
The first of these protection pins senses the voltage on the
AC line by means of an external resistor divider (R1, R2 and
capacitor C1) and an internal comparator with hysterisis.
When power is first supplied to the IC at system startup,
three conditions are required before oscillation is initiated:
1.) the voltage on the VCC pin must exceed the rising
undervoltage lockout threshold (11.5V), 2.) the voltage at
the VDC pin must exceed 5.1V, and 3.) the voltage on the
SD pin must be below approximately 4.85V. If a low ac line
condition occurs during normal operation, or if power to the
ballast is shut off, the ac line will collapse prior to the VCC of
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the chip (assuming theVCC is derived from a charge pump
off of the output of the half-bridge). In this case, the voltage
on the VDC pin will shut the oscillator off, thereby protecting
the power transistors from potentially hazardous hard switching. Approximately 2V of hysterisis has been designed into
the internal comparator sensing the VDC pin, in order to
account for variations in the ac line voltage under varying
load conditions. When the ac line recovers, the chip restarts from the beginning of the control sequence, as shown
in timing diagram (See Figure 16).
23
IR2167(S) & PbF
ment, the ballast automatically restarts the lamp in the proper
manner.
In the Run mode there are two additional thresholds
enabled on the SD pin: 1V and 3V. These thresholds form a
window and during normal lamp running the voltage
appearing at the SD pin is maintained within these two levels.
As a lamp nears its end-of-life, its running voltage will
increase and the signal applied to the SD pin detects this by
exceeding the window threshold width. The oscillator is
disabled, both gate driver outputs are pulled low, and the
chip is put into the micropower mode.
5
VDC
3
4
CT
8
+ rectified
AC Line
CPH
VDC
CPH
15
RPH
5
CT
DT
HO-VS
6
7
COMP
ZX
19
4
RUN
OC
2
3
RT
15
20
18
IR2167
LO
1
17
16
15
14
8
13
9
12
10
+ VBUS
HO
VS
VB
RGHS
CBLOCK
VCC
DBOOT
COM
CVCC
RSupply
CSNUBBER
D1
SD
CRES
D2
LO
CS
LRES
CBS
R3
RGLS
R5
D3
R6
R4
PFC
VBUS
C2
C4
11
RCS
R7
C3
RUN mode
Low VDC
Restart
Figure 16: VDC lead fault and auto restart
VBUS return
Figure 17: Lamp presence detection circuit connection
(shaded area)
Lamp Presence and End-of-Life Detection
The second protection pin, SD, is used for both shutdown
and end-of-life detection. The SD pin would normally be
connected to an external circuit that senses the presence
of the lamp(s) and the voltage appearing across the lamp(s).
An example circuit for a single lamp is shown in Figure 17.
During all modes of operation if the SD pin exceeds 5.1V
(approximately 150mV of hysterisis is included to increase
noise immunity), signaling either a lamp fault or lamp removal, the oscillator is disabled, both gate driver outputs are
pulled low, and the chip is put into the micropower mode.
Since a lamp fault would normally lead to a lamp exchange,
when a new lamp is inserted in the fixture, the SD pin would
be pulled back to near ground potential. Under these conditions a reset signal would restart the chip from the beginning of the control sequence, as shown in the timing diagram in Figure 18. Thus, for a lamp removal and replace-
24
www.irf.com
IR2167(S) & PbF
R OC = VCS+ ,
55E - 6
5
SD
or
VCS + = 55E - 6 ⋅ ROC
4
CT
rectified
AC line
8
VDC
CPH
CPH
RPH
RT
LO
RUN
CT
DT
15
HO-VS
OC
COMP
RUN mode
SD mode
Restart
Figure 18: SD lead fault and auto restart
Half-Bridge Current Sensing and Protection
The third pin used for protection is the CS pin, which is normally connected to a resistor in the source of the lower power
MOSFET, as shown in Figure 19. The CS pin is used to
sense fault conditions such as failure of a lamp to strike,
over-current during normal operation, hard switching, no
load, and operation below resonance. If any one of these
conditions is sensed, the fault latch is set, the oscillator is
disabled, the gate driver outputs go low, and the chip is put
into the micropower mode. The CS lead performs its sensing functions on a cycle-by-cycle basis in order to maximize
ballast reliability.
For the over-current, failure-to-strike, and hard switching fault
conditions, an externally programmable, positive-going CS+
threshold is enabled at the end of the preheat time. The level
of this positive-going threshold is determined by the value of
the resistor ROC. The value of the resistor ROC is determined
by the following formula:
www.irf.com
ZX
20
2
19
3
4
5
6
7
8
9
ROC 10
18
IR2167
15
1
17
16
15
14
13
12
+VBUS
HO
VS
Q1
RGHS
1
/2 Bridge output
VB
CBOOT
VCC
DBOOT
RSUPPLY
D1
LO
SD
R
CVCC
COM
CS
CSNUBBE
Q2
RGLS
D2
R3
PFC
VBUS
11
RCS
VBUS return
Figure 19: Half-bridge current sensing circuit connection
(shaded area)
For the under-current and under-resonance conditions, there
is a negative-going CS- threshold of 0.2V which is enabled
at the onset of the run mode. The sensing of this CSthreshold is synchronized with the falling edge of the LO
output.
Figures 20, 21 and 22 are oscillographs of fault conditions.
Figure 20 shows a failure of the lamp to strike, Figure 21
shows a hard switching condition and Figure 22 shows an
under-current condition.
25
IR2167(S) & PbF
CS
CS
VS
VS
Figure 22: Operation below resonance
upper trace CS 200 mV/div
lower trace VS 200V/div
Figure 20: Failure of lamp to strike
upper trace CS 1V/div
lower trace VS 200V/div
SD
CS
CPH
VS
Figure 21: Hard switching condition
upper trace CS 2V/div
lower trace VS 200V/div
26
VS
Figure 23: Auto restart for lamp replacement
upper trace SD/EOL 5V/div
middle trace CPH 5V/div
lower trace VS 200V/div
www.irf.com
IR2167(S) & PbF
Recovery from such a fault condition is accomplished by
cycling either the SD pin or the VCC pin. (See Figure 23).
When a lamp is removed, the SD pin goes high, the fault
latch is reset, and the chip is held off in an unlatched state.
Lamp replacement causes the SD pin to go low again,
reinitiating the startup sequence. The fault latch can also be
reset by the undervoltage lockout signal, if VCC falls below
the lower undervoltage threshold.
Bootstrap Supply Considerations
Power is normally supplied to the high-side circuitry by means
of a simple charge pump from VCC, as shown in Figure 24.
this CMOS circuitry is very low (typically 45µA in the onstate), the majority of the drop in the VBS voltage when Q1
is on occurs due to the transfer of charge from the bootstrap
capacitor to the gate of the power MOSFET.
Design Equations
Note: The results from the following design equations can
differ slightly from experimental measurements due to IC
tolerances, component tolerances, and oscillator over- and
under-shoot due to internal comparator response time.
Step 1: Program Maximum Ignition Voltage
rectified
AC
line
VDC
CPH
RPH
20
2
19
3
4
RUN
5
CT
6
DT
7
OC
8
COMP
18
IR2167
RT
ZX
1
17
16
15
14
13
9
12
10
11
+V BUS
HO
VS
Q1
R GHS
1/
VB
C BOOT
VCC
DBOOT
RSUPPLY
COM
SD
Bridge
output
C SNUBBER
D1
CVCC
LO
CS
2
Q2
R GLS
D2
I CT = I RT =
R3
PFC
RCS
VBUS
VBUS
A high voltage, fast recovery diode DBOOT (the so-called
bootstrap diode) is connected between VCC (anode) and
VB (cathode), and a capacitor CBOOT (the so-called
bootstrap capacitor) is connected between the VB and VS
leads. During half-bridge switching, when MOSFET Q2 is
on and Q1 is off, the bootstrap capacitor CBOOT is charged
from the VCC decoupling capacitor, through the bootstrap
diode DBOOT, and through Q2. Alternately, when Q2 is off
and Q1 is on, the bootstrap diode is reverse-biased, and the
bootstrap capacitor (which ‘floats’ on the source of the upper
power MOSFET) serves as the power supply to the upper
gate driver CMOS circuitry. Since the quiescent current in
2.0V
RT
The value of this current should be kept between 50 µA and
500 µA. The value for CT is computed as follows:
return
Figure 24 : Typical bootstrap supply connection
with VCC charge pump from half-bridge output
(shaded area)
www.irf.com
Maximum lamp voltage is required during ignition. This will
vary depending on the type of lamp, but 1600V is typical for
a T8 lamp. As the frequency decreases from the preheat
frequency to the resonant frequency, the voltage across the
lamp increases. During ignition, only RT along with CT and
DT determine the frequency. R PH and R RUN are not
connected to COM at this time. The value of RT should be
chosen so that the desired ignition voltage is reached. The
RT pin current and timing capacitor charging current are both
approximately:
CT =
1
RT
 1


− td 


 2 fign

And the ignition mode frequency is:
f IGN =
RT =
1
2(RT CT + td )
1
CT
 1


− td 


 2 fign

27
IR2167(S) & PbF
Deadtime is equal to:
250
td = 0.69 ⋅ RDT ⋅ CT
The following graphs, figures 25 and 26, illustrate the
relationship between the effective resistance (i.e. the parallel
combination of resistors which programs the CT capacitor
charging current) and the operating frequency.
200
CT=220pF, RDT=5.6K
CT=470pF, RDT=2.7K
CT=1nF, RDT=1.2K
150
FREQ
(KHz)
100
150
FREQ
(KHz)
50
CT=220pF,RDT=11K
CT=470pF,RDT=6.2K
CT=1nF,RDT=3K
100
0
0
5
10
15
20
25
30
35
40
RT (KΩ)
Figure 26: fOSC vs effective RT
(tDEAD=1.0µsec)
50
Figure 27 illustrates the relationship between deadtime vs
RDT.
0
0
5
10
15
20
25
30
35
40
10
RT (KΩ)
Figure 25: fOSC vs effective RT
(tDEAD=2.0µsec)
tDEAD
(usec)
CT = 220 pF
CT = 470 pF
CT = 1 nF
1
0.1
1
10
100
RDT (KΩ)
Figure 27: Deadtime vs RDT
28
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IR2167(S) & PbF
Step 2: Program Maximum Ignition Current
Step 4: Program preheat time
The ignition current should be limited to the rating of the
lamp resonant inductor and the half-bridge MOSFETS. The
saturation current of the lamp resonant inductor should be
much lower than the current rating of the MOSFETS. Under
worst case conditions, the lamp resonant inductor should
not be allowed to saturate. This current is controlled by the
CS pin and the OC pin. The OC lead has an internal 50µA
current source. This current through external resistor ROC
determines the threshold on the CS pin.
The preheat time is determined by external capacitor CPH.
The preheat time required for a 4:1 hot to cold ratio can be
observed by measuring the voltage across the filaments.
The preheat time is calculated as follows:
ROC =
VCS +
or
55E − 6
VCS + = 55 E − 6 −
If the current through external resistor RCS exceeds a
predetermined value, the IC shuts off.
Step 3: Program Preheat Frequency
The preheat frequency is determined by the parallel
combination of RPH and RT along with CT and RDT. The
frequency should be chosen so that the voltage across the
lamp is much lower than the ignition voltage but still provides
adequate heating of the filaments. During preheat, the current
through the filaments is constant. However, as the filaments
heat up, their resistance increases. This results in an
increase in the voltage measured across the filaments, which
indicates the hot to cold ratio.
f PH =
RPH
tPH = 4.0 E 6 ⋅ CPH
The IR2167 is held in preheat until CPH is charged to 4.0V.
Step 5: Program the ignition mode time
The difference in time between the preheat mode and the
run mode is the ignition mode. The rate at which the frequency changes from preheat to run is determined by external resistor RRAMP.
Step 6. Program the run frequency
The run mode begins when external resistor RPH is charged
to 5.1V. At this time, the run frequency is determined by the
parallel combination of RT and RRUN along with RDT and
CT. The run frequency can be programmed above or below
the ignition frequency. fRUN is determined by the following
equation:
f RUN =
1
 R ⋅R

2 ⋅  T PH ⋅ CT + td 
 RT + RPH

 1



 2 f − td 
ph


=

1  1

1−
−
td

RT ⋅ CT  2 f ph

1
CT
RRUN
1
 R ⋅R

2 ⋅  T RUN ⋅ CT + td 
 RT + RRUN

 1


− td 
 2 f RUN

=


1
1

1−
− td 
RT ⋅ CT  2 f RUN

1
CT
4:1 is an acceptable ratio for proper heating
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29
IR2167(S) & PbF
Component Selection Tips
Connecting the IC Ground (COM) to the Power Ground
Supply Bypassing and pc Board Layout Rules
Both the low power control circuitry and low side gate driver
output stage grounds return to this lead within the IC. The
COM lead should be connected to the bottom terminal of the
current sense resistor in the source of the low side power
MOSFET using an individual pc board trace, as shown in
Figure 29. In addition, the ground return path of the timing
components and VCC decoupling capacitor should be connected directly to the IC COM lead, and not via separate
traces or jumpers to other ground traces on the board.
Component selection and placement on the pc board is extremely important when using power control ICs. VCC should
be bypassed to COM as close to the IC terminals as possible with a low ESR/ESL capacitor, as shown in Figure 28.
IR2167
pin 1
CVCC
(surface
mount)
CBOOT
(surface
mount)
(surface
DBoot
mount)
IR2167 pin 1
CVCC
(surface
mount)
CVCC (through hole)
CVCC (through hole)
timing
component
s
RCS (through hole)
VBUS return
Figure 28: Supply bypassing PCB layout example
Figure 29: COM lead connection PCB layout example
A rule of thumb for the value of this bypass capacitor is to
keep its minimum value at least 2500 times the value of the
total input capacitance (Ciss) of the power transistors being
driven. This decoupling capacitor can be split between a
higher valued electrolytic type and a lower valued ceramic
type connected in parallel, although a good quality electrolytic (e.g., 10µF) placed immediately adjacent to the VCC
and COM terminals will work well.
These connection techniques prevent high current ground
loops from interfering with sensitive timing component operation, and allows the entire control circuit to reject common-mode noise due to output switching.
In a typical application circuit, the supply voltage to the IC is
normally derived by means of a high value startup resistor
(1/4W) from the rectified line voltage, in combination with a
charge pump from the output of the half-bridge. With this
type of supply arrangement, the internal 15.6V zener clamp
diode from VCC to COM will determine the steady state IC
supply voltage.
30
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IR2167(S) & PbF
Caseoutline
IR2167S
20-Lead SOIC (wide body)
www.irf.com
(MS-013AC) 01-3080 00
31
IR2167(S) & PbF
Caseoutline
IR2167 - 20 Lead PDIP
32
(MS-001AD) 01-3079 00
www.irf.com
IR2167(S) & PbF
LEADFREE PART MARKING INFORMATION
Part number
Date code
IRxxxxxx
YWW?
Pin 1
Identifier
?
P
MARKING CODE
Lead Free Released
Non-Lead Free
Released
IR logo
?XXXX
Lot Code
(Prod mode - 4 digit SPN code)
Assembly site code
Per SCOP 200-002
ORDER INFORMATION
Basic Part (Non-Lead Free)
20-Lead SOIC IR2167 order IR2167S
20-Lead PDIP IR2167 order IR2167
Leadfree Part
20-Lead SOIC IR2167 order IR2167SPbF
20-Lead PDIP IR2167 order IR2167PbF
IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245 Tel: (310) 252-7105
Data and specifications subject to change without notice. 1/29/2006
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33