ERJ-8GEYJ22_技术文档

IRPLLNR2

International Rectifier • 233 Kansas Street, El Segundo, CA 90245 USA

IR21571 Ballast Control IC Design Kit

Features

= Drives:

= Input:

1 x 32W T8 Lamp (IRPLLNR2U)

1 x 36W T8 Lamp (IRPLLNR2)

90-140VAC/60Hz (IRPLLNR2U)

185-265VAC/50Hz (IRPLLNR2)

= High Power Factor/Low THD

= High Frequency Operation (42kHz)

= Lamp Filament Preheating

= Lamp Fault Protection with Auto-Restart

= Brownout Protection

= IR21571 HVIC Ballast Controller

Description

The IRPLLNR2 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 IR21571. This demo board is

intended to ease the evaluation of the IR21571 Ballast Control IC, demonstrate PCB layout techniques

and serve as an aid in the development of production ballast’s using the International Rectifier IR21571.

Ballast Block Diagram

EMI Filter

Rectifier

PFC

Half-Bridge

Output Stage

Lamp

Line

PFC Control

IR21571

UVLO

Lamp Fault

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1

Electrical Characteristics

Parameter

Lamp Type

Input Power

Units

Value (IRPLLNR2)

Value (IRPLLNR2U)

36W T8

36

0.300

44

220

0.9

32W T8

32

0.300

44

220

0.6

[W]

[Arms]

[kHz]

[Vrms]

[s]

Input Current

Preheat Mode Frequency

Preheat Mode Lamp Voltage

Preheat Time

Ignition Ramp Mode Frequency

Run Mode Frequency

Lamp Run Current

[kHz]

[Arms]

38

42

0.34

38

42

0.34

Input AC Voltage Range

Input DC Voltage Range

Power Factor

[VACrms] 185..255/50..60Hz

90..140/50..60Hz

100..180

0.99

[VDC]

250..350

0.98

Total Harmonic Distortion

Maximum Output Voltage

[%]

[Vpk]

<15

600

<10

600

Note: Measurements performed with input AC line voltage = 120Vrms (IRPLDIM1U)

230Vrms (IRPLDIM1)

Fault Protection Characteristics

Fault

Line voltage low

Upper filament broken

Lower filament broken

Failure to ignite

Ballast

Restart Operation

Increase line voltage

Lamp exchange

Deactivates

Open circuit (no lamp)

Functional Description

Overview

he IRPLDIM1 Demo Board consists of an EMI filter, an active power factor correction front end, a

ballast control section and a resonant lamp output stage. The active power factor correction section

is a boost converter operating in critical mode conduction, 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 pro-

vides the necessary circuitry to perform closed-loop dimming, lamp fault detection, shutdown and

auto-restart. All functional descriptions refer to the IRPLDIM1 schematic diagram.

2

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IRPLLNR2U Bill Of Materials

Lamp type: T8/32W

Line Input Voltage: 90..140 VAC/50..60 Hz

Note: Different lamp types require different frequency programming components.

Item #

1

Qt

1

3

5

1

3

2

1

3

5

1

3

1

2

67

Manufacturer

International Rectifier

Roederstein

Wima

Part Number

DF10S

Description

Reference

Bridge Rectifier, 1A 1000V

BR1

2

WY0222MCMBF0K

F1772433-2200

MKP10

Capacitor, 2.2nF 275 VAC Y Cap C1

3

Capacitor, 0.33uF 275 VAC

Capacitor, 0.01uF 400 VDC

Capacitor, 0.01uF SMT 1206

Capacitor, 0.47uF SMT 1206

Capacitor, 0.1uF SMT 1206

Capacitor, 10uF 350VDC 105C

Capacitor, 470pF SMT 1206

Capacitor, 1uF 50VDC 105C

Capacitor, 1.5nF 1KV SMT 1812

Capacitor, 0.1uF 400VDC

Capacitor, 1nF 1KV SMT 1812

Capacitor, 0.01uF 1.6KV

C2

C3

4

5

Panasonic

Vitramon

ECU-V1H103KBM

ECJ-3YB1E474K

ECU-V1H104KBM

EEU-EB2V100

ECU-V1H471KBM

ECE-A1HGE010

1812A152KXE

MKP10

C4, CRAMP, CSTART

6

C5, C6, C13

7

C9,CPH, COC, C10, C11

8

C8

9

CT

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

Total

C12

C14

Wima

C15

Vitramon

1812A102KXE

ECW-H16103JV

ECU-V1H101KBM

LL4148DICT-ND

10BF60

C16

Panasonic

Diodes

C17

Capacitor, 100pF SMT 1206

Diode, 1N4148 SMT DL35

Diode, SMT SMB

CCS

D1, D5, D6

International Rectifier

Diodes

D2, D4

ZMM5250BCT

MC34262

Diode, Zener , 20V SMT DL35

IC, Power Factor Controller

IC, Ballast Driver

D3

Motorola

IC1

International Rectifier

Panasonic

RG-Allen

IR21571

IC2

ELF-15N007A

EMI Inductor, 1X10mH 0.7Apk

PFC Inductor, 2.0mH 2.0Apk

Inductor, 2.0mH 2.0Apk

L1

L2

RG-Allen

L3

International Rectifier

Panasonic

Dale

IRF730

Transistor, MOSFET

M1, M2, M3

ERJ-8GEYJ680K

ERJ-8GEYJ10K

ERJ-8GEYJ12K

ERJ-8GEYJ100K

ERJ-8GEYJ22K

ERJ-8GEYJ22

CW-1/2

Resistor, 680K ohm SMT 1206

Resistor, 10K ohm SMT 1206

Resistor, 12K ohm SMT 1206

Resistor, 100K ohm SMT 1206

Resistor, 22K ohm SMT 1206

Resistor, 22 ohm SMT 1206

Resistor, 0.5 ohm ½ watt

R1, R2, R4, R5, R17

R3

R6

R7

R8, RSTART, RT

R9, R13, R15

R10

Panasonic

Yageo

ERJ-8GEYJ130K

2.2MQBK-ND

CW-1/2

Resistor, 130K ohm SMT 1206

Resistor, 2.2megohm ¼ watt

Resistor, 0.68 ohm ½ watt

Resistor, 5.6K ohm SMT 1206

Resistor, 30K ohm SMT 1206

Resistor, 91K ohm SMT 1206

Resistor, 150K ohm SMT 1206

Resistor, 390K ohm ¼ watt

Resistor, 1K ohm SMT 1206

Resistor, 2.2megohm SMT 1206

Resistor, 100K ohm ¼ watt

Transient Suppressor

R11

R12

Dale

RCS

Panasonic

Yageo

ERJ-8GEYJ5.6K

ERJ-8GEYJ30K

ERJ-8GEYJ91K

ERJ-8GEYJ150K

390KQBK-ND

ERJ-8GEYJ1K

ERJ-8GEYJ2.2M

100KQBK-ND

ERZ-V05D471

ERJ-8GEYJ10

RDT

ROC

RPH

RRUN

R14

Panasonic

Yageo

R16

R18

R19

Panasonic

RV1

Resistor, 10 ohm SMT 1206

R20, R21

4

www.irf.com

IRPLLNR2 Bill Of Materials

Lamp type: T8/36W

Line Input Voltage: 180..255 VAC/50..60 Hz

Note: Different lamp types require different frequency programming components.

Item #

1

Qt

1

3

5

1

3

2

1

3

5

1

3

1

2

65

Manufacturer

International Rectifier

Roederstein

Wima

Part Number

DF10S

Description

Reference

Bridge Rectifier, 1A 1000V

BR1

2

WY0222MCMBF0K

F1772433-2200

MKP10

Capacitor, 2.2nF 275 VAC Y Cap C1

3

Capacitor, 0.33uF 275 VAC

Capacitor, 0.01uF 400 VDC

Capacitor, 0.01uF SMT 1206

Capacitor, 0.47uF SMT 1206

Capacitor, 0.1uF SMT 1206

Capacitor, 10uF 350VDC 105C

Capacitor, 470pF SMT 1206

Capacitor, 1uF 50VDC 105C

Capacitor, 1.5nF 1KV SMT 1812

Capacitor, 0.1uF 400VDC

Capacitor, 1nF 1KV SMT 1812

Capacitor, 0.01uF 1.6KV

C2

C3

4

5

Panasonic

Vitramon

ECU-V1H103KBM

ECJ-3YB1E474K

ECU-V1H104KBM

EEU-EB2V100

ECU-V1H471KBM

ECE-A1HGE010

1812A152KXE

MKP10

C4, CRAMP, CSTART

6

C5, C6, C13

7

C9,CPH, COC, C10, C11

8

C8

9

CT

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

Total

C12

C14

Wima

C15

Vitramon

1812A102KXE

ECW-H16103JV

ECU-V1H101KBM

LL4148DICT-ND

10BF60

C16

Panasonic

Diodes

C17

Capacitor, 100pF SMT 1206

Diode, 1N4148 SMT DL35

Diode, SMT SMB

CCS

D1, D5, D6

International Rectifier

Diodes

D2, D4

ZMM5250BCT

MC34262

Diode, Zener 20V SMT DL35

IC, Power Factor Controller

IC, Ballast Driver

D3

Motorola

IC1

International Rectifier

Panasonic

RG-Allen

IR21571

IC2

ELF-15N007A

EMI Inductor, 1X10mH 0.7Apk

PFC Inductor, 2.0mH 2.0Apk

Inductor, 2.0mH 2.0Apk

L1

L2

RG-Allen

L3

International Rectifier

Panasonic

Dale

IRF830

Transistor, MOSFET

M1, M2, M3

ERJ-8GEYJ680K

ERJ-8GEYJ10K

ERJ-8GEYJ8.2K

ERJ-8GEYJ100K

ERJ-8GEYJ22K

ERJ-8GEYJ22

CW-1/2

Resistor, 680K ohm SMT 1206

Resistor, 10K ohm SMT 1206

Resistor, 8.2K ohm SMT 1206

Resistor, 100K ohm SMT 1206

Resistor, 22K ohm SMT 1206

Resistor, 22 ohm SMT 1206

Resistor, 1.0 ohm ½ watt

R1, R2, R4, R5, R17

R3

R6

R7

R8, RSTART, RT

R9, R13, R15

R10

Panasonic

Yageo

ERJ-8GEYJ56K

2.2MQBK-ND

CW-1/2

Resistor, 56K ohm SMT 1206

Resistor, 2.2megohm ¼ watt

Resistor, 0.68 ohm ½ watt

Resistor, 5.6K ohm SMT 1206

Resistor, 30K ohm SMT 1206

Resistor, 75K ohm SMT 1206

Resistor, 150K ohm SMT 1206

Resistor, 390K ohm ¼ watt

Resistor, 1K ohm SMT 1206

Resistor, 2.2megohm SMT 1206

Resistor, 100K ohm ¼ watt

Transient Suppressor

R11

R12

Dale

RCS

Panasonic

Yageo

ERJ-8GEYJ5.6K

ERJ-8GEYJ30K

ERJ-8GEYJ75K

ERJ-8GEYJ150K

390KQBK-ND

ERJ-8GEYJ1K

ERJ-8GEYJ2.2M

100KQBK-ND

ERZ-V05D471

ERJ-8GEYJ10

RDT

ROC

RPH

RRUN

R14

Panasonic

Yageo

R16

R18

R19

Panasonic

RV1

Resistor, 10 ohm SMT 1206

R20, R21

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5

Power Factor Correction

The power factor correction section consists of the Motorola Semiconductor MC34262 Power Factor

Controller IC (IC1), MOSFET M1, inductor L2, diode D2, capacitor C8 and additional biasing, sens-

ing and compensation components (see schematic diagram). The IC was chosen for its minimal

component count, low start-up supply current and robust error amplifier. This is a boost topology

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). The design of the power

factor correction section was taken from the Motorola Semiconductor MC34262 data sheet and

information on the operation and design considerations for the MC34262 are contained therein.

Ballast Control

The ballast control section is built around the IR21571 Ballast Control IC, IC2 of the Demo board.

The IR21571 contains an oscillator, a high voltage half-bridge gate driver and lamp fault protection

circuitry. A block diagram of the IR21571 IC is shown in figure 1 and a state diagram of the IR21571

is shown in figure 2. Following is a breakdown of the operation of the ballast in all of the different

modes of operation.

3.0V

14

16

VB

1

VDC

CPH

S

R

Q

PULSE

FILTER &

LATCH

LEVEL

SHIFT

HO

5.1V

1.0uA

15 VS

2

7.6V

5.1V

4.0V

T

S

Q

4.0V

2.0V

13

VCC

R1

R2

R

3

4

5

RPH

RT

11 LO

I_RT

15.6V

2.0V

12

COM

CS

RUN

0.2V

Q

D

CLK

R

I_CT= I_RT

10

7.6V

9

6

7

CT

DT

Q

S

R

Q

OVER-

TEMP

DETECT

50uA

7.6V

UNDER-

VOLTAGE

DETECT

8

OC

SD

7.6V

2.0V

Figure 1: IR21571 Block Diagram

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Power Turned On

UVLO Mode

¹/₂-Bridge Off

µ

I_QCC150 A

CPH = 0V

Oscillator Off

VCC < 9.5V

(VCC Fault or Power Down)

VCC > 11.4V (UV+)

SD > 2.0V

(Lamp Removal)

or

VCC < 9.5V

(Power Turned Off)

and

or

VDC > 5.1V (Bus OK)

VDC < 3.0V

(dc Bus/ac Line Fault or Power Down)

and

SD < 1.7V (Lamp OK)

or

and

SD > 2.0V

T_J< 140C (T_jmax

)

(Lamp Fault or Lamp Removal)

FAULT Mode

T_J> 140C

(Over-Temperature)

PREHEAT Mode

Fault Latch Set

¹/₂-Bridge Off

I_QCC150µA

CPH = 0V

¹/₂-Bridge @ f_PH

CPH Charging @ I_PH= 1µA

RPH = 0V

RUN = Open Circuit

CS Disabled

VCC = 15.6V

Oscillator Off

CPH > 4.0V

(End of PREHEAT Mode)

CS > CS+ Threshold

(Failure to Strike Lamp

or Hard Switching)

or

T_J> 140C

(Over-Temperature)

IGNITION RAMP Mode

f_PHramps to f_MIN

CPH Charging @ I_PH= 1µA

RPH = Open Circuit

RUN = Open Circuit

CS+ Threshold Enabled

CS > CS+ Threshold

(Over-Current or Hard Switching)

CPH > 5.1V

(End of IGNITION RAMP)

or

CS < 0.2V

(No-Load or Below Resonance)

or

RUN Mode

T_J> 140C

(Over-Temperature)

f_MINRamps to f_RUN

CPH Charges to 7.6V Clamp

RPH = Open Circuit

RUN = 0V

CS- Threshold Enabled

Figure 2: IR21571 State Diagram

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7

Startup Mode

When power is initially applied to the ballast, the voltage on the VCC pin of IC2 (IR21571) begins to

charge up. The voltage for IC2 is derived from the current supplied from the rectified AC line through

startup resistor R14. During this initial startup when the VCC voltage of IC2 is below its rising under-

voltage lock-out threshold (11.4V), IC2 is in its UVLO and also its micro-power mode. The micro-

power mode of the IC2 allows the use of a large value,

low wattage startup resistor (R14). When the voltage

on IC2 reaches the rising under-voltage lockout thresh-

old, the oscillator is enabled (this assumes that there

are no fault conditions) and drives the half-bridge out-

put MOSFETs (M2 and M3). When the half-bridge is

oscillating, capacitor C16, diodes D5 and D6 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 C12 to the VCC clamp volt-

age (approx. 15.6V) of IC2. The voltage for IC1 is de-

rived from the current supplied from another snubber/

charge pump circuit formed by capacitor C14 and di-

odes D1 and D3. When the rising under-voltage lock-

out threshold of IC1 is reached, it starts to oscillate

and drive MOSFET M1 to boost and regulate the bus

Figure 3: Top trace: Half-bridge output voltage

voltage to 400 VDC. An oscillograph of the startup of

Middle trace: VCC of IC2

the VCC of IC1, VCC of IC2 and half-bridge output

voltage are shown in Figure 3. (For a complete de-

Bottom trace: VCC of IC1

scription of the operation of IC1, refer to the Motorola Semiconductor MC34262 data sheet.)

Preheat Mode

When the ballast reaches the end of the UVLO mode, the Preheat mode is entered. At this point the

oscillator of IC2 has begun to operate and the half-bridge output is driving the resonant load (lamp)

circuit. The oscillator section of IC2 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 and resistor RDT deter-

mines the ramp down time. The downward ramping time of CT is the deadtime between the switch-

ing off of the LO (HO) and the switching on of the HO (LO) pins on IC2. The Preheat mode frequency

of oscillation 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 preheating of the lamp filaments is performed with

a constant current during the Preheat mode. The waveform in Figure 4 shows the lamp filament

current while Figure 5 shows lamp filament voltage during the normal Startup, Preheat, Ignition

Ramp and Run modes of the ballast.

8

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Figure 4: Lamp filament current during Startup,

Figure 5: Lamp filament voltage during Startup,

Preheat, Ignition Ramp and Run (500mA/div)

Preheat, Ignition Ramp and Run

Figure 6 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. As shown in Figure 6 there

is an initial startup frequency that is much higher than the steady state Preheat mode frequency that

lasts for only a short duration. Components CSTART and RSTART are used to program this initial

startup frequency. This is done to insure 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 oscil-

lation of the half-bridge, the voltage 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. An oscillograph of the lamp voltage at startup is shown in Figures 7 and 8 (next page).

Figure 7 shows the lamp voltage without the high initial startup frequency while Figure 8 shows the

lamp voltage with the high initial frequency startup.

f_osc

f_Preheat

f_Run

f_Ignition

t

preheat

ignition

run

Figure 6: Oscillator frequency versus time, Normal operating conditions

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9

Figure 7: Typical lamp voltage at startup;

= f

Figure 8: Improved lamp voltage at startup;

> f

f

Startup

P reheat

The duration of the Preheat mode as well as which mode of operation the ballast is operating in is

determined by the voltage on the CPH pin of IC2. At the completion of the UVLO mode, Preheat

mode is entered and an internal current source is activated at the CPH pin of IC2 which begins to

charge up capacitor CPH. The ballast remains in the Preheat mode until the voltage on the CPH

pin of IC2 exceeds the Ignition Ramp mode threshold (4V).

Ignition Ramp Mode

At the completion of the Preheat mode (4V < CPH

pin < 5.1V) the ballast switches to the Ignition Ramp

mode and the frequency ramps down to the ignition

frequency. The frequency ramping is accomplished

by turning off the internal open drain MOSFET on

the RPH pin of IC2 (see Figure 1, IR21571 block

diagram). Resistor RPH is no longer connected di-

rectly in parallel with resistor RT. The shift in frequency

does not occur in a step function but rather with an

exponential decay because of capacitor CRAMP in

series with resistor RPH to ground. The duration of

this frequency ramp is determined by the time con-

stant of the RC combination of capacitor CRAMP

and resistor RPH. The minimum frequency of oscil-

lation occurs at the end of this ramp and is deter-

mined by resistor RT and capacitor CT. During this

ramping downward of the frequency, the voltage

Figure 9: Upper trace: voltage on capacitor

CRAMP during Ignition Ramp mode

Lower trace: Lamp voltage during Ignition

across the lamp increases in magnitude as the

frequency approaches the resonant frequency of

the LC load circuit until the lamp ignition voltage

Ramp mode.

10

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is exceeded and the lamp ignites. Figure 9 shows the ramping of voltage appearing across the lamp

and also the voltage on capacitor CRAMP. Note that the sudden drop in lamp voltage indicates that

the lamp has ignited. Also note that the voltage on capacitor C12 is still increasing at the point when

the lamp has already ignited meaning the frequency is still ramping down to the final minimum

ignition frequency. This minimum frequency corresponds to the absolute maximum ignition voltage

required by the lamp under all conditions.

During the Ignition Ramp mode the voltage on the CPH pin of IC2 continues to ramp up until the

voltage at the CPH pin of IC2 exceeds the Run mode threshold (5.1V). Over-current sensing is also

enabled at the beginning of the Ignition Ramp mode. A full explanation of the functionality of the

over-current sensing is in the section on Fault Mode.

Run Mode

At the end of the Ignition Ramp mode (CPH pin

> 5.1V) the ballast switches to the Run mode at

which point the frequency is shifted to the run

frequency. The run frequency is determined by

the parallel combination of resistors RT and

RRUN and capacitor CT. Resistor RRUN is

connected in parallel by turning on the internal

open drain MOSFET connected to the RUN pin

of IC2 (see Figure 1, IR21571 block diagram).

The sensing of under-current conditions is also

enabled at the beginning of the Run mode. The

full explanation of the functionality of the under-

current sensing is in the section on Fault Mode.

Figure 10 shows the functionality of the CPH,

RPH and RUN pins of IC2 during Startup, Pre-

heat, Ignition Ramp and Run modes.

Figure 10: Top trace: CPH pin IC2

Middle trace: RPH pine IC2

Bottom trace: RUN pin IC2

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,

2

(3)

DCbus

2V

2

1−

2

Lamp

1

P

1

P

Lamp

V

π

run

f =

− 2

+

− 2

− 4

2

Lamp

2π LC

CV ²

LC

CV ²

L C²

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11

where,

L

C

P

= Lamp resonant circuit inductor (L3)

= Lamp resonant circuit capacitor (C14)

= Lamp running power

(H)

(F)

(W)

Lamp

V

= Lamp running voltage amplitude

(V)

Figure 11 shows the voltage appearing across the lamp while Figure 12 shows the current flowing

through the lamp during Startup, Preheat, Ignition Ramp and Run modes.

Figure 11: Lamp voltage during Startup, Preheat,

Ignition Ramp and Run

Figure 12: Lamp current during Startup, Preheat,

Ignition Ramp and Run (100mA/div.)

Normal Powerdown

A Normal Powerdown occurs when the AC line voltage is disconnected from the ballast. When this

occurs the voltage on the VDC pin of IC2 drops below the line fault threshold (3V) and IC2 shuts

down in a controlled fashion. The oscillator is stopped, the half-bridge driver outputs (LO and HO)

are turned off and capacitors CPH, CRAMP, CSTART and CT are discharged. IC2 also goes into its

UVLO/micro-power mode and the bus voltage begins to collapse.

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 which can put the ballast into the Fault mode. The lamp fault conditions detected include:

near/below resonance (under-current) detection, hard-switching detection and over-current detec-

tion. Resistor RCS in the source lead of the low side MOSFET (M3) 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 voltage appears across RCS whenever the low side MOSFET, M3, is

12

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turned on or the high side MOSFET, M2, is turned off. The magnitude of this voltage directly relates

to the current in the lamp resonant circuit. Figure 13 shows the voltage which appears across resis-

tor RCS during normal Run mode conditions while Figure 14 shows the voltage appearing across the

lamp during the end of Preheat mode, Ignition Ramp mode and the beginning of Run mode. Also

shown in Figure 13 are the gate drive signals for the low side MOSFET (LO pin) and the high side

MOSFET (HO-VS pin).

Figure 13: Normal Run mode, Upper trace: voltage

across RCS, Middle trace: IC2 LO pin voltage,

Lower trace: IC2 HO-VS pin voltage

Figure 14: Normal lamp ignition: Lamp voltage during

the end of Preheat mode, Ignition Ramp mode

and the beginning of the Run mode

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. If at any time thereafter the voltage magnitude across resistor RCS rises above the

over-current (CS+) threshold of the CS pin of IC2, a lamp fault condition is signaled and the half-

bridge output MOSFETs’, (M2 and M3) are turned off and the ballast goes into Fault mode. This can

happen if the lamp fails to ignite or if the upper filament is open. For failure to ignite the lamp, the

current in the half-bridge increases and thus the voltage across resistor RCS increases above the

over-current threshold signaling a fault. Figure 15 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. The CS+ threshold is determined by resistor ROC. An internal current source of 50uA is

connected to the OC pin of IC2 which when applied to resistor ROC sets a voltage at the OC pin.

This voltage is the CS+ threshold of IC2. Figure 16 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 the upper filament is open, the half-bridge output hard-switches and each time the low

side MOSFET (M3) is turned on a large current pulse occurs and thus a large voltage pulse occurs

across resistor RCS signaling a fault, Figure 17 shows this hard-switching condition. Figure 18 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 cycled or a lamp replacement is performed.

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13

Figure 15: Failure of lamp to ignite condition (lamp

filaments good): Upper trace: voltage across

RCS, Lower trace: lamp voltage

Figure 16: Failure of lamp to ignite condition (lamp

filaments good): Lamp voltage during the end

of Preheat and Ignition Ramp modes

Figure 17: Hard-switching condition (upper filament

open): Upper trace: voltage across RCS,

Middle trace: IC2 LO pin voltage,

Figure 18: Hard-switching condition (upper filament open):

Lamp voltage during Preheat mode and beginning of

Ignition Ramp mode when lamp fault is detected

Lower trace: IC2 HO-VS pin voltage

At the completion of the Ignition Ramp mode (beginning of the Run mode) the near/below resonance

(under-current) detection is also enabled. Near/below resonance detection is performed by synchro-

nously sensing the voltage across resistor RCS, which relates to the current flowing in the low side

MOSFET (M3), just prior to the turn off of M3. If this voltage is lower than the near/below resonance

threshold (CS- = 0.2V) of the CS pin of IC2, a lamp fault condition is signaled and the ballast goes

into Fault mode. This could occur if the frequency of oscillation becomes too close to the resonant

14

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frequency of the load circuit and the current in the load circuit commutates to close to zero. Figure 19

shows a near/below resonance condition where the voltage on resistor RCS falls below the 0.2V

threshold on the CS pin of IC2.

Resistors R17, R18 and capacitor

C13 form a divider/filter network

which is used to detect an open lower

lamp filament and/or lamp replace-

ment. Under normal conditions, the

voltage across C8 is approximately

zero volts. However, if the lower fila-

ment becomes open or the lamp is

removed, the voltage across C13 in-

creases above the 2V threshold for

the SD pin of IC2 and signals a lamp

fault condition which in turn puts the

ballast into Fault mode. The ballast

remains in the Fault mode until the

line voltage is cycled or a lamp re-

placement is performed. If the lamp

is replaced with a lamp with a good

lower filament, the voltage on the SD

Figure 19: Near/Below Resonance conditions

pin of IC2 is pulled back below the

2V threshold and the ballast will go

through a restart. Line voltage cycling

Upper trace: voltage across RCS

Lower trace: half-bridge output voltage

is also used to restart the ballast for all lamp fault conditions. The ballast will go through a full

Preheat, Ignition Ramp and Run modes any time a restart is performed. Note that the SD pin of IC2

is active during all modes of operation.

Another way that the ballast can go into Fault mode is if the AC line voltage falls below approximately

170Vrms. Resistors R11, R12 and capacitor C9 form a voltage divider/filter network which is con-

nected to the VDC pin of IC2 and is used to determine if the line voltage falls below permissible

levels. This happens when the line voltage is cycled or possibly a brownout condition occurs. The

VDC pin of IC2 senses a fault if the voltage at the pin falls below 3 volts and shutdown of the ballast

occurs. The ballast remains shutdown until the voltage at the VDC pin rises above 5.1 volts. At this

time if there are no other fault conditions the ballast will go through a full Preheat, Ignition Ramp and

Run mode. As in the case of the SD pin of IC2, the VDC pin of IC2 is active during all modes of

operation of the ballast.

IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245 Tel: (310) 252-7105

Data and specifications subject to change without notice. 10/28/2000

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15

Data Sheets

Lighting Ballast Control IC - Designer’s Manual

16

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型号：	ERJ-8GEYJ22
厂家：	Infineon
描述：	High Power Factor/Low THD
文件：	总16页 (文件大小：355K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

ERJ-8GEYJ22 [INFINEON]

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