IRAC1152-350W - International Rectifier

18 Feb 2011

Data Sheet No. PD97152

IRAC1152-350W

Reference Design Kit for IR1152 (Fixed 66kHz Frequency,

One Cycle Control PFC IC with Brown-Out Protection)

REFERENCE DESIGN KIT FEATURES

• IEC61000-3-2 Class D Standards Compliant

• Less than 10% Total Harmonic Distortion (115-

230VAC/350W)

• Universal AC Input Voltage capability

• Fully regulated 388V DC bus

• Full load start-up, no minimum load requirements

• Current loop controlled soft-current limit protection for

overpower limitation at minimum VAC

• High Efficiency Si Superjunction MOSFET boost switch

• Hyper-fast recovery Si boost diode

• On-board Flyback SMPS for 15V VCC supply (option to

disable for external VCC bias supply)

• Single layer PCB illustrating layout best-practices

IR1152 PFC IC FEATURES

• PFC IC with IR proprietary “One Cycle Control”

• Continuous conduction mode boost type PFC

• Fixed 66kHz switching frequency

• Average current mode control

• Input line sensed brownout protection

• DC bus overvoltage protection (Dual & Dedicated)

• DC bus open feedback loop protection

• Cycle-by-cycle peak current limit (DC bus voltage

foldback type)

• Soft-current limit protection

• VCC under voltage lockout

• Programmable soft-start

• Micropower startup & sleep mode (user-initiated)

• 750mA peak gate drive

• Optimized pin-out for single layer PCB layout

Product Summary

AC Input Voltage 85-264VAC

AC Input Line Frequency 47-63Hz

DC Bus Output Voltage 388V +/- 2%

Maximum output power 350W

Minimum Load Requirement None

Power Factor

(115-230VAC/350W) >0.98

Total Harmonic Distortion

(115-230VAC/350W) <10%

Start-up time 60ms

Introduction

IRAC1152-350W is a full function AC-DC reference design showcasing the operation of IR1152 PFC IC in a

continuous conduction mode boost converter for achieving power factor correction, sub-10% harmonic current

distortion and EN61000-3-2 Class D harmonic current limits standard compliance. Designed to be operated from

85-264VAC universal input voltage, IRAC1152-350W delivers 350W continuous output power via a fully regulated

388V DC bus. Thanks to IR1152 PFC IC, the reference design is rendered with a very high level of safety against

system abnormalities such as AC line sag, DC bus voltage loop feedback loss, system overcurrent & overvoltage.

Combining the cost-advantage of single layer PCB and ferrite-core boost inductors with optimized PCB layout, the

IRAC1152-350W reference design is an excellent design example that can be seamlessly imported & integrated

by system designers that require a high-performance PFC stage at the AC-DC front-end of their designs in a

variety of applications.

IRAC1152-350W

Table of Contents

Introduction ......................................................................................................................................................... 1

Description of Hardware & Key Operating Features ........................................................................................... 4

Hardware Installation & Operating Procedure .................................................................................................... 7

Performance Characterization ............................................................................................................................ 9

IRAC1152-350W Schematics ........................................................................................................................... 19

IRAC1152-350W Bill of Materials (BoM) .......................................................................................................... 22

IRAC1152-350W PCB & Component Layout ................................................................................................... 24

List of Figures

Figure 1 IRAC1152-350W test set-up................................................................................................................. 7

Figure 2: IRAC1152-350W external Vcc connection .......................................................................................... 8

Figure 3. Power factor vs. Line/Load Variation of IRAC1152-350W................................................................... 9

Figure 4. Current Harmonics at 85-264VAC, 350W ......................................................................................... 10

Figure 5. Current Harmonics at 85-264VAC, 87.5W (25% of rated power)...................................................... 10

Figure 6. THD at 350W across 85-264VAC for IRAC1152-350W .................................................................... 11

Figure 7. EMI filter stage causes phase-shift in Input Current Waveform (264VAC, 350W) ............................ 13

Figure 8. Power factor vs. Line/Load for modified IRAC1152-350W with single stage EMI filter ..................... 13

Figure 9. 2X AC frequency ripple in DC bus capacitor at 85VAC, 350W ......................................................... 14

Figure 10. 2X AC frequency ripple in DC bus capacitor at 264VAC, 350W ..................................................... 14

IRAC1152-350W

Safety Precautions

ATTENTION:

The ground potential of the IRAC1152-350W is biased to a negative DC bus

voltage potential. In order to be able to safely measure voltage waveform by oscilloscope,

the use of an isolation transformer at the AC input is recommended. Though floating the

ground potential of the scope is often practiced, it is not recommended. Failure to follow

these guidelines so may result in personal injury or death.

ATTENTION:

The IRAC1152-350W system contains dc bus capacitors & capacitors on the

rectified AC line (C6, C9, C10, C21, C22), which take time to discharge after removal of main

supply. Remove and lock out power from the IRAC1152-350W board before you attempt to

disconnect or reconnect wires or perform service. Wait at least one minute after removing

power to discharge the capacitor voltages. Do not attempt to service the reference design

until all capacitor voltages have discharged to zero. Failure to do so may result in bodily injury or death.

ATTENTION:

Only personnel familiar with the IRAC1152-350W system should plan or

implement the installation, start-up, and subsequent maintenance of the system. Failure to

comply may result in personal injury and/or equipment damage.

ATTENTION:

The surface temperatures of the IRAC1152-350W board & heatsink may

become hot, which may cause injury. A fan is recommended to cool the board whenever

operating at the full rated power for prolonged periods.

ATTENTION:

The IRAC1152-350W system contains ESD (Electrostatic Discharge) sensitive

parts and assemblies. Static control precautions are required when installing, testing,

servicing or repairing this assembly. Component damage may result if ESD control

procedures are not followed. If you are not familiar with static control procedures, reference

applicable ESD protection handbook and guideline.

ATTENTION:

An incorrectly applied or installed board can result in component damage or

reduction in product life. Wiring errors, supplying an incorrect AC supply, or excessive

ambient temperatures may result in system malfunction.

ATTENTION:

IRAC1152-350W system is shipped with packing materials that need to be

removed prior to installation. Failure to remove all debris and packing materials which are

unnecessary for system installation may result in abnormal operating condition.

IRAC1152-350W

Description of Hardware & Key Operating Features

The key features of the IRAC1152-350W hardware are listed below. The user is referred to IRAC1152-350W

schematics provided later in the document for the following discussions and also to “350W PFC Converter

Design Example” section in IR1152 Application Note AN-1150 where the design and component selection for

IRAC1152-350W is explained in detail in.

AC Input Stage (before bridge rectifier)

• EMI Stage is comprised of a 2 stage EMI filter composed of 3X 0.47uF X-capacitors & 2X common-

mode EMI choke coils with 10mH (16kHz) rated magnetic impedance; There are no Y-capacitors

installed, but they can be installed in sockets C3 & C4 if the user so desires.

• In rush current limitation is provided by a NTC (negative thermal co-efficient) resistor offering 5ohm

impedance at 25C

• A 250V, 6.3A fuse is included for current protection.

Power Stage

• Bridge Rectifier: 600V, 8A bridge rectifier (B1) is employed.

• Boost Inductor: A 600uH, 6A Boost inductor (L1) based on PC40 ferrite magnetic core and EER-

42/42/20 core size is employed. With 600uH of boost inductance, the ripple current factor is about 0.3

(30% current ripple) near peak of AC sinusoid at 85VAC, 350W (DC bus voltage=388V). The user

can substitute this with another inductor in order to adjust the ripple current factor.

• Boost Switch & Gate Drive Circuit: 2X 600V, 20A superjunction MOSFETs (Q3 & Q4) connected in

parallel are employed for boost switch function. The gate drive for MOSFETs is provided by a NPN-

PNP buffer circuit in order to render a tight gate-drive switching loop. It is noted that, since NPN-PNP

buffer is a base-follower circuit, the voltage clamp on GATE output of IR1152 IC is also closely

maintained on the output of the NPN-PNP buffer circuit driving the MOSFETs. The user can also

disable the NPN-PNP buffer circuit & drive the MOSFETs directly using IR1152 IC’s output GATE

driver by implementing the following steps:

i. Un-install jumper J4

ii. Uninstall surface mount resistors R18 & R19

iii. Install jumper J3

iv. Modify IR1152 GATE series resistor R16 (0 ohms in default configuration), if necessary

Localized gate resistor & diode networks (R20, R22, D7 for Q3 & R5, R6, D4 for Q4) is used to

preferentially adjust turn-on & turn-off dV/dt. Turn-on is slower to control reverse recovery behavior of

boost diode. Finally a Schottky diode, D6 between GATE & COM pins of IR1152 is used to clamp any

negative voltage spikes that can cause IC latch-up.

• Boost Diode: A 600V, 8A hyper-fast recovery diode (D5) is employed as boost diode with snubber

circuit (R7, C8) to limit voltage spikes.

• DC Bus Capacitor: 330uF, 450V capacitor (C10) is employed on the DC bus for acceptable ripple at

350W power rating at 388VDC. A 1W, 470kohm bleed resistor (R10) is used across C10 to

discharge the bus voltage.

• Current Sense Resistor: R27 & R28 are sockets allocated for current sense resistor. Dual footprints

are provided for both sockets for flexibility. IRAC1152-350W employs a 50mohm, 5W current sense

resistor in R27 socket (R28 is not populated). The choice of current sense resistor programs the

following:

i. Current level at which cycle-by-cycle peak current protection limit is encountered. When this is

encountered, IR1152 instantaneously pulls the GATE output low.

IRAC1152-350W

ii. Current level (and hence power level) at which soft-current protection limit is invoked at a specific

VAC voltage. When this is encountered, IR1152 limits the duty cycle of the PFC switch which the

causes DC bus voltage to foldback (or droop). This is how IR1152 provides overpower limitation.

The power level at which this protection is encountered increases with increasing VAC. The

current sense resistor employed in IRAC1152-350W is such that the reference design is

guaranteed to deliver 350W at VAC=85VAC without DC bus voltage foldback. At VAC=85VAC,

the DC bus voltage foldback occurs at about 430W output power in IRAC1152-350W.

IRAC1152-350W Default Set-point Typical Level

Cycle-by-Cycle Peak Current Protection Limit 15A

Soft-current Protection Limit at 85VAC 9.8A

CAUTION: If the user attempts to modify the power level of the PCB by changing the current sense

resistor, attention must be paid to the component ratings - semiconductors (bridge rectifier, boost

switch, boost diode), boost inductor, fuse, DC bus capacitor – and system thermal performance (use

a fan to cool heatsink, run at lower ambient temperature etc).

• Current Monitoring: Jumper J7 is provided for monitoring the inductor current and Jumper J8 is

provided for monitoring the PFC switch current. Current loops (for use with a magnetic current probe)

can be established by uninstalling the onboard jumper wires and installing a current loop of adequate

length to fit the probe.

On-board Flyback SMPS

• An onboard DC-DC Flyback SMPS delivers 16VDC for biasing the VCC pin of IR1152 IC. The

Fyback is configured to supply 16VDC when the VAC voltage is around 35-40VAC. If user desires to

provide IR1152 VCC bias using an external DC supply in order to study the standby & start-up current

requirements of IR1152, then onboard Flyback SMPS can be disconnected by implementing the

following steps:

i. Un-install jumper J13

ii. Though not necessary, un-installing diode D8 is also recommended for safety reasons to fully

disable the Flyback power supply

iii. Input connector J15 can be used for providing external DC supply to bias the VCC pin of IR1152;

please pay attention to the connector biasing as shown in Figure 2. in the Installation and

Operating Instructions section of this document

IR1152 IC Control Circuit

• VFB Pin – The DC bus voltage is programmed using the resistor divider comprised of R8, R23 &

R24. By adjusting R24, the user can modify the DC bus voltage. Increasing R24 will decrease DC

bus voltage. Decreasing R24 will increase DC bus voltage. By default, the overvoltage comparator on

VFB pin programs the overvoltage protection set-point of IRAC1152-350W to 106% of DC Bus

voltage and overvoltage protection reset set-point of IRAC1152-350W to 103% of DC Bus voltage.

IRAC1152-350W Default Set-point Typical Level

DC Bus Regulation Voltage 388V

Overvoltage Protection Set-point (VFB pin) 411V

Overvoltage Protection Reset Set-point (VFB pin) 402V

• OVP Pin – OVP pin resistor divider (R9, R25 & R26) uses the same component values as VFB pin

resistor divider. This programs the overvoltage protection set-point of comparator on OVP pin to be

same as that of VFB pin. This is the recommended configuration & default for IRAC1152-350W.

Thus, the function of OVP pin is two-fold:

i. dedicated pin to monitor DC bus voltage for overvoltage situations

ii. along with overvoltage comparator on VFB pin, the OVP pin provides dual overvoltage

protection i.e. additional redundancy in system overvoltage protection in order to guarantee a

very high level of safety

IRAC1152-350W

IRAC1152-350W Default Set-point Typical Level

Overvoltage Protection Set-point (OVP pin) 411V

Overvoltage Protection Reset Set-point (OVP pin) 402V

CAUTION: The following cautionary statements apply if user attempts to modify value of R24 or R26

in IRAC1152-350W.

o If the modification causes R26<R24, then overvoltage protection set-point & overvoltage

protection reset set-point of OVP pin will be higher than that of VFB pin. This configuration is

acceptable. However, it is noted that the overvoltage protection set-point & overvoltage

protection reset set-point of IRAC1152-350W reference design as a whole is still determined

by the set-points of VFB pin.

o If the modification causes R26>R24, then overvoltage protection set-point & overvoltage

protection reset set-point of OVP pin will be lower than that of VFB pin. This configuration is

generally NOT recommended because the modification may render overvoltage protection

reset set-point of OVP pin to be less than DC bus voltage. This may cause DC bus voltage

regulation issues & undesirable oscillations during system start-up & load transients.

• BOP Pin – Resistors R3, R4 & R12 and capacitor C14 constitute a divide-and-average circuit on the

BOP pin. The choice of resistor divider components (R3, R4 & R12) determines VAC voltage at

which IC exits Brown-out fault condition during system start-up. Decreasing R12 will cause IC to exit

Brown-out fault condition at a higher VAC during start-up (and vice versa). The capacitor C14, which

implements the averaging function, also programs amplitude of 2X AC frequency ripple voltage on

BOP pin. As VAC is decreased, when the valley of VBOP ripple voltage encounters Brown-out

protection threshold then a Brown-out fault condition is immediately triggered. Thus it is VBOP ripple

voltage which determines at what VAC voltage a Brown-out fault condition is triggered during AC line

sag. And by controlling VBOP ripple, the value of C14 determines VAC voltage at which Brown-out

fault condition is triggered. If C14 is increased, VBOP ripple is reduced and Brown-out fault is

triggered at a lower VAC (and vice versa). Diode D2 in BOP circuit is optional.

IRAC1152-350W Default Set-point Typical Level

Brown-out Protection Trigger Threshold during AC line sag (350W) 55VAC

Brown-out Protection Enable Threshold during system start-up (0W) 65VAC

• VCOMP Pin – C12, C13 & R15 are involved in the following functions:

o voltage loop compensation (location of pole & zero in voltage loop feedback response &

phase margin)

o C12 primarily determines the system soft-start time during start-up

The user is recommended to review “Voltage Loop Compensation” section in AN-1150 before

modifying any of these components, since such an explanation is outside the scope of this document.

• ISNS Pin –The VISNS signal from the current sense resistor is filtered using RC network created by

R11 & C11 in order to provide a clean signal to the IR1152 IC.

• VCC Pin – A 22uF Tantalum surface-mount capacitor and a 1uF ceramic surface mount capacitor

(located as close as possible to VCC & COM pins) are used to provide optimum decoupling for the

VCC bias to IR1152 IC. An 18V zener diode, D3 is used to clamp overvoltage spikes on VCC pin &

protect IR1152 IC.

• COM Pin – A STAR connection point located very close to the COM pin of the IC is used to

individually terminate all the control signal return loops (VCC, VCOMP, VFB, OVP, BOP & power

GND). Please refer to PCB Layout Features section of this document for more information.

• GATE Pin – Please refer to Boost Switch & Gate Drive Circuit section of this document for more

information.

IRAC1152-350W

PCB Layout Best Practices & Noise Suppression Features in IRAC1152-350W

IRAC1152-350W is based on a single layer PCB & jumper connections for cost-reduction purpose. The PCB

layout in IRAC1152-350W, especially control circuitry, is an excellent example that can be studied &

reproduced by the user in his designs in order to achieve clean, noise-free operation in end application. The

following points are noteworthy:

• VCOMP-COM voltage loop:- The VCOMP voltage is the most important control voltage for IR1152

operation. The trace connection from C12 & C13 components in VCOMP-COM control loop to COM

pin must be done in an independent & isolated manner (i.e. it must be a dedicated trace and not

share the ground return loop of any other control circuit such as VFB-COM, VCC-COM etc). This is

very important to achieve a clean VCOMP signal

• COM STAR connection & Dedicated ground return loops:- A STAR connection point located very

close to the COM pin of the IC is used to individually terminate all the control signal ground return

loops (VCC-COM, VCOMP-COM, VFB-COM+OVP-COM, BOP-COM & VISNS-COM i.e. power GND

& ground plane). Each control loop has its own dedicated ground trace which is not shared with

ground return of other loops. This STAR connection ensures that the noise in one control signal loop

does not proliferate into another control loop.

• IR1152 pin-out & ground plane in single layer PCB:- The pin-out arrangement in IR1152 is optimized

for single layer PCB layout to facilitate a ground plane beneath the IC for shielding noise. VCOMP &

COM pins are next to each other for a tight loop. VFB & OVP are located next to each other since

both communicate to DC bus via resistor dividers. VCC & COM are located close to each other to

facilitate placement of 1uF decoupling capacitor in very close proximity to the IC. Careful routing of

the control loops & use of jumper wires to achieve STAR connection also enables a ground plane

beneath IR1152 in IRAC1152-350W. Note that the ground plane does not function as a current

carrying trace to COM pin since it is not a part of any loop i.e. the only connection to the ground plane

is the COM pin to establish ground bias.

• ISNS voltage filtering:- Notice that R11 & C11, which are used for RC filtering the ISNS signal, are

located close to the current sense resistor. This serves to filter the ISNS signal noise near the noise

source (i.e. current sense resistor) rather than near the IC. Also, notice that the noise filter RC circuit

is a dedicated loop by itself in order to prevent noise proliferation.

Hardware Installation & Operating Procedure

The recommended test set-up for IRAC1152-350W is shown in Figure 1.

Power Analyzer

Vin Vin Vout Vout

AC1

AC Prog Source

or Variac

(0 – 265Vac) AC2

(J1) (J6)

ACIN1 +

ACIN2 -

(V out)

DMM V

E-Load

Figure 1 IRAC1152-350W test set-up

IRAC1152-350W

Load Connection

Connect high voltage resistive or electronic load, capable of 350W continuous power to connector J6 as

shown in Figure 1. Pay attention to the polarity of the terminals in the connector. There is no minimum load

requirement for operating IRAC1152-350W. The DC bus voltage is monitored at test-points VOUT and RTN.

Always monitor the DC bus voltage to ensure that the capacitor voltage is discharged completely prior to

adding or removing load connections from the demo board.

AC Input Connection

Connect a 60Hz AC power source, capable of operation up to 264VAC to connector J1 as shown in Figure 1.

The AC input voltage can be monitored at test points AC-IN1 and AC-IN2. Once power is applied to demo

board, potentially lethal high voltages will be present on board and necessary precautions should be taken to

avoid serious injury. The use of an isolation transformer on the AC side is highly recommended, so that all the

control signals on the test points can easily be probed by using regular oscilloscope probes. Though floating

the ground potential of the scope is often practiced, it is not recommended. Failure to follow these guidelines

so may result in personal injury or death.

ATTENTION:

The IRAC1152-350W system contains dc bus capacitors & capacitors on the

rectified AC line (C6, C9, C10, C21, C22), which take time to discharge after removal of main

supply. There is a 470kΩ (R10) bleed resistor on the DC bus capacitor, whose voltage is

monitored at test points VOUT

and RTN. There is a 12kohm (R29) bleed resistor on the output of

the Flyback power supply, whose voltage is monitored at test points VCC and COM. However, there is no

bleed resistor across capacitor C22 located in the Flyback power supply and C6 locating in the main PFC

circuit, both of which sustain the rectified AC voltage. Remove and lock out power from the IRAC1152-350W

board before you attempt to disconnect or reconnect wires or perform service. Wait at least one minute after

removing power to discharge the capacitor voltages. Do not attempt to service the reference design until all

capacitor voltages have discharged to zero. Failure to do so may result in bodily injury or death.

VCC Supply Connection (if necessary)

If user desires to provide IR1152 VCC bias using an external DC supply in order to study the standby & start-

up current requirements of IR1152, then onboard Flyback SMPS can be disconnected by implementing the

following steps:

i. Un-install jumper J13

ii. Though not necessary, un-installing diode D8 is also recommended for safety reasons to fully disable

the Flyback power supply from the

iii. Input connector J15 can be used for providing external DC supply to bias the VCC pin of IR1152; Pay

attention to the polarity of the terminals in the connector as shown in Figure 2.

OPTIONAL EXTERNAL VCC SUPPLY

Disconnect

Connect 15VDC

Figure 2: IRAC1152-350W external Vcc connection

IRAC1152-350W

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

0 50 100 150 200 250 300 350 400

Output Power (W)

Power Factor

85VAC

115VAC

230VAC

264VAC

Power-up

Once all the connections are made the system can be powered up. There is no minimum load requirement

during power-up and the system can be powered-up at any load from 0W to 350W.

If the AC line is increased gradually:

• the onboard Flyback power supply will establish the VCC bias supply of 16VDC at around 35-40VAC

• the PFC converter will start boosting as soon as the IC exits the Brown-out fault condition during

start-up - around an AC voltage of 65-70VAC at 0W load and at an AC voltage of 70-75VAC under

the presence of any load.

If an external DC power supply is used for the VCC bias, then there is no strict biasing sequence for VAC and

DC supply. It is OK to supply either voltage first.

Performance Characterization

DC Bus Voltage Regulation

DC bus voltage variation is less than 0.2% across line (85-264VAC) & load (0-350W). There is absolutely no

minimum load requirement to maintain voltage regulation.

DC Bus voltage (in V) variation in IRAC1152-350W

Power Factor

IRAC1152-350W delivers power factor greater than 0.98 at 350W, 115-230VAC. At light load condition, there

is some drop in power factor which is primarily due to X-capacitors in EMI filter. By reducing the X-capacitors

in the EM filter stage, the light load performance can be improved. This is demonstrated later in this

document.

Figure 3. Power factor vs. Line/Load Variation of IRAC1152-350W

350W

262.5W

175W

87.5W

35W

85VAC

389.10 389.13 389.15 389.19 389.24 389.51

115VAC

389.15 389.17 389.19 389.20 389.26 389.59

180VAC

389.18 389.22 389.24 389.26 389.34 389.68

230VAC

389.21 389.24 389.26 389.31 389.45 389.69

264VAC

389.21 389.26 389.29 389.37 389.54 389.69

IRAC1152-350W

Input Current Harmonics

0.0001

0.001

0.01

0.1

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39

Harmonic Order (#)

Harmonic Current Amplitude (A)

85VAC Input, 350W Output

264VAC Input, 350W Output

Class D Limits (350W)

Figure 4. Current Harmonics at 85-264VAC, 350W

0.0001

0.001

0.01

0.1

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39

Harmonic Order (#)

Harmonic Current Amplitude (A)

85VAC Input, 87.5W Output

264VAC Input, 87.5W Output

Class D Limits (87.5W)

Figure 5. Current Harmonics at 85-264VAC, 87.5W (25% of rated power)

IRAC1152-350W

0 50 100 150 200 250 300

AC Input Voltage (VAC)

Total Harmonic Distortion (%)

Total Harmonic Distortion

IRAC1152-350W delivers less than 10% of Total Harmonic Distortion at the rated 350W output power.

Figure 6. THD at 350W across 85-264VAC for IRAC1152-350W

IRAC1152-350W

Steady-state Input Current Waveforms (Ch 2: Input Voltage, Ch1: Input Current)

85VAC, 350W 115VAC, 350W

230VAC, 350W 264VAC, 350W

IRAC1152-350W

Effect of EMI Filter stage (X-capacitors) on Input Current

The X-capacitors (C1, C2 & C5) in EMI filter causes a phase shift in input current with respect to the input AC

voltage and “current steps” at VAC zero-crossings. This is more obvious at lower current amplitudes (such as

at 264VAC, 350W condition). Notice however that the inductor current being regulated by the IC maintains

very good symmetry with respect to the AC input voltage indicating that power factor correction stage is

operating normally.

Figure 7. EMI filter stage causes phase-shift in Input Current Waveform (264VAC, 350W)

As mentioned earlier, the X-capacitors in the EMI stage contribute to drop in power factor at light load

conditions. By reducing to a single stage EMI filter (remove C1, C2 & L1), the power factor at light load can be

greatly improved. This is depicted in Figure 8 below.

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

0 50 100 150 200 250 300 350 400

Output Power (W)

Power Factor

85VAC

115VAC

230VAC

264VAC

Figure 8. Power factor vs. Line/Load for modified IRAC1152-350W with single stage EMI filter

IRAC1152-350W

DC Bus Capacitor Ripple Voltage

The sizing of the DC bus capacitor, load condition, AC input voltage frequency etc determine the 2X AC

frequency ripple in the DC bus capacitor. The DC bus capacitor ripple in IRAC1152-350W at 350W is less

than 10V as seen in Figure 9 and 10.

Figure 9. 2X AC frequency ripple in DC bus capacitor at 85VAC, 350W

Figure 10. 2X AC frequency ripple in DC bus capacitor at 264VAC, 350W

IRAC1152-350W

Start-up Current Waveforms at 100% load

The maximum time for system start-up, about 60msec, is encountered when IRAC1152-350W is powered up

at minimum input voltage (85VAC) and maximum output power (350). The soft-start feature of the IC allows

for a linear ramp in the VCOMP voltage, which allows a smooth build-up of AC input RMS current admitted

into the PFC converter and DC bus capacitor voltage. Note that, prior to entering the soft-start mode, the IC is

held under a Brown-out fault condition until VBOP exceeds the Brown-out Protection Enable threshold of

1.7V. Since the PFC voltage loop is a slow loop, the converter goes through a period where the DC bus

voltage is under hysteretic OVP condition (between 103% and 106% of regulation voltage set-point) before

the VCOMP voltage stabilizes near the steady stage voltage value.

85VAC, 350W 115VAC, 350W

230VAC, 350W 264VAC, 350W

IRAC1152-350W

No Load Start-up Current Waveforms

85VAC, 0W 115VAC, 0W

230VAC, 0W 264VAC, 0W

IRAC1152-350W

Load Step Waveforms

• No-Load to Full-Load

Under a 0W to 300W load step at 115VAC, the maximum DC bus voltage undershoot is about 49V; the

undershoot at 230Vac is 22V.

115VAC, 0W to 300W load step 230VAC, 0W to 300W load step

• Full-load to No-Load

300W to 0W negative load step waveforms are presented below. In all cases, the OVP protection feature is

encountered until the DC bus capacitor voltage discharges back to the regulation voltage.

115VAC, 300W to 0W load step 230VAC, 300W to 0W load step

IRAC1152-350W

IRAC1152-350W Brown-Out Protection

At power up, if AC input voltage is lower than 75Vac, the BOP protection will hold the output of IR1152.

Output voltage stays at the peak of input voltage. When AC input exceeds 75Vac, BOP voltage exceeds the

BOP enable threshold. IR1152 starts Power Factor correction and V

BOP

voltage drops to 2/

of its original

value. The hysteresis of the BOP prevents any bouncing between On and Off.

IRAC1152-350W

IRAC1152-350W Schematics

1 2 3 4

4321

CON3

250VAC/6.3A R2

N/C

470k/1W C3

N/C

470n/275VAC

N/C

C1470n/275VAC

RT1

THERMISTOR 2

3 4

AC+

AC-

AC-IN1

AC-IN2

JT1

AC-IN1

JT2

AC-IN2

470n/275VAC

IRAC1152-350W EMI Filter Stage

IRAC1152-350W

12345678

87654321

BRIDGE

470n/500V

C5 470n/275VAC

C14 300n

C15 1uf/25v

C13

10n

C12

0.56u

C11

1000p

C16

1uf/25v C17

N/C

C18N/C

470n/630v

100P/1kv

1N4148

R12

100K

R11

100

R27

0.01/3W

R15

1.1k

R13

0 ohm

R18

R16

470 ohm

R17

10K

R20

R21

10k

R19

R23

499K R25

499K

R22

R24

13K

1 R10

470k/2w

499K R9

499K

150/2W

500uHY

+C7

22uf/25v

+C10

330uf/450v

IRFP22N60K

1N4148

FMMT619TA

FMMT720TA

COM

COMP

ISNS

BOP

4OVP/EN 5

VFB 6

VCC 7

GATE 8

IR1152

21 J7

JUMPER

2 1

J8 JUMPER

21 J4

21 J3

1N5407-TP

R26

13K

R28

0.01/3w

D3 18V Zener

10BQ040

VCCCOM

Vout

GND

AC+

AC-

CON2

Vbus

8ETX06

2 1

JUMP2

J11

JUMP2

2 1

J10

JUMP2

J12

JUMP2

R38

10K

JT3

VCC

JT4

COM

J15

CON2

JT5

ISNS

JT7

GATE

JT8

OVP 1

JT9

VFB

JT6

BOP

IRAC1152-350W Boost PFC Stage

IRAC1152-350W

1 2 3 4

4321

+C22

22uf/400v

1N4007

R30

1.5M R31

R35

47/1/8W

R34

R33

21K

R32

100

R37

2K/1/8W

PC817A

D14

BZX79/15V

D10

P6KE150A

D13

UF4003

BYV26-200

D11

1N4007

D12

1N5255/28V

C25

100n/50v

C23

10n/1kv

C21

22uf/50V

C24

1uf/60v

C20

N/C

C19

2.2n/250vAC

EN/UV

BP/M

4S5

U3 TNY278P

TRANS7

R36

390/1/8W

L4 SHORT

R29

12K/1W

21 J13

Vbus

GND

VCC

COM1

J14

IRAC1152-350W Flyback SMPS Stage

IRAC1152-350W

IRAC1152-350W Bill of Materials (BoM)

NO.

NO.NO.

NO. PART TYPE

PART TYPEPART TYPE

PART TYPE PART DESCRIPTION

PART DESCRIPTIONPART DESCRIPTION

PART DESCRIPTION MANUFACTURER & PART# QTY

QTYQTY

QTY DESIGNATOR

DESIGNATORDESIGNATOR

DESIGNATOR

1 BN PCB PCB, IR1152-350W_V4.0 1

2 Bridge RECT BRIDGE GPP 600V 8A GBU YJ GBU806 1 B1

3 Discrete Capacitor CAP THR, 0.47UF 250/275VAC ECQ-UL Panasonic ECQ-U2A474ML

DIGIKEY P10734-ND 3 C1,C2,C5

4 Electrolytic Capacitor CAP THA, 330uF AL ELEC 450V 20%---40*35*10 SAMWHA HE 450V 330UF 35*40 P=10

JIANGHAI HE 450V 330UF 35*40 P=10 1 C10

5 Chip Capacitor CAP SMT, 1000pF 1206 CER 50V 10% X7R 1 C11

6 Chip Capacitor CAP SMT, 0.56uF 1206 CER 50V 10% X5R 1 C12

7 Chip Capacitor CAP SMT, 10000pF 1206 CER 50V 10% X7R 1 C13

8 Chip Capacitor CAP SMT, 0.1uF 1206 CER 50V 10% X7R 2 C14,C25

9 Chip Capacitor CAP SMT, 1uF 1210 CER 50V 10% X5R 2 C15,C16

10 Discrete Capacitor

CAP THR,

2.2nF 400V, 20%, Disc Y1

Cera-Mite 440LD22 1 C19

11 Electrolytic Capacitor CAP THR, 22uF, AL ELEC, 50V (2mmLS)---

11.5*5*2.5 1 C21

12 Electrolytic Capacitor CAP THR, 22 µF, 400 V, Electrolytic, Low ESR, 901

mΩ, (20 x 16×7.5) 1 C22

13 Discrete Capacitor

CAP THR,

10 nF, 1 kV, 20%, Disc Ceramic

Vishay/Sprague 562R5HKMS10 1 C23

14 Electrolytic Capacitor CAP THR, 1uF,ELEC 50V 20%---11*5*2 105 °C 1 C24

15 Discrete Capacitor CAP THR, 0.47uF CER 630V 10% Panasonic ECQ-E6474KF

DIGIKEY EF6474-ND 2 C6,C9

16 Tantalum capacitor CAP SMT, 22uF 7343-31 TANT 35V 20% PANASONIC EEJ-L1VD226R

DIGIKEY P11302CT-ND 1 C7

17 Discrete Capacitor

CAP THR, 100PF 1KVDC CERAMIC SL/GP 5% LS=5mm

Panasonic ECC-D3A101JGE

DIGIKEY P10804-ND 1 C8

18 Diode DIODE, RECTIFIER GPP 800V 3A DO-201AD DIODES 1N5407-T

DIGIKEY 1N5407DICT-ND 1 D1

19 Diode DIODE, TVS 150V 600W 5% UNI AXL MOUSER 625-P6KE150A-E3 1 D10

20 Diode DIODE, STANDARD 1N4007 50V 1A DO-41---DO-

41 YJ--1N4007 2 D8,D11

21 Diode DIODE, Zener Diode 36V MOUSER 512-1N5258B 1 D12

22 Diode DIODE, GPP FAST 1A 200V DO-41 Fairchild UF4003

DIGIKEY UF4003-ND 1 D13

23 Diode DIODE, ZENER 15V 1W 5% DO-41 DIODES 1N4744A-T

DIGIKEY 1N4744ADICT-ND 1 D14

24 Diode DIODE SMT, FAST SWITCHING 100V 5uA 500mW

MINI-MELF DL-35 DIODES INC LL4148

DIGIKEY LL4148DITR-ND 3 D2,D4,D7

25 Diode DIODE SMT, ZENER 500MW 18V SOD-123 DIODES BZT52C18-7-F

DIGIKEY BZT52C18-FDICT-ND 1 D3

26 Diode DIODE, HYPERFAST 600V 8A TO-220AC DIGIKEY 8ETX06PBF-ND 1 D5

27 Diode DIODE SMT, SCHOTTKY 40V 1A SMB DIGIKEY 10BQ040-ND 1 D6

28 Diode DIODE, GPP 3A 200V HI EFF DO-201AE DIGIKEY EGP30D-TPCT-ND 1 D9

29 Fuse base 2 F1

30 Connector CONN, HDR, 3P, 2 J1,J6

31 Wire WIRE, 24 AWG,AWM1007 0.25 J2,J4,J5,J9,J10,J11,J12,J13

,J14,J17,L4

32 Wire WIRE, 16 AWG,AWM1007 0.08 J7,J8

33 Connector CONN, HDR, 1x2, 0.100" PITCH, 0.025 SQ POST,

TIN (0.135"/0.380") KEYED MOLEX 22-23-2021

DIGIKEY WM4200-ND 1 J15

34 Test point KEYSTONE 5007

DIGIKEY 5007K-ND 7

35 Inductor EMI Common Mode Choke 7A 10mH TNC KOREA CV507100BS 2 L1,L2

36 Inductor

600uH Boost Inductor custom designed by Precision

Inc

Precision 019-4894-01R proto-2 1 L3

37 NPN Transistor DIODE SMT, NPN 50V 2000MA SOT-23 Zetex FMMT619TA

DIGIKEY FMMT619CT-ND 1 Q1

38 PNP Transistor DIODE SMT, PNP -40V -1500MA SOT-23 Zetex FMMT720TA

DIGIKEY FMMT720CT-ND 1 Q2

39 MOSFET TRANS, MOSFET N-CHAN 600V 20A TO-247 Fairchild FCH20N60

DIGIKEY FCH20N60-ND 2 Q3,Q4

40 Discrete resistor RES, MF 470K-OHM 1W 5% 2 R1,R10

41 Chip Resistor RES SMT, 100-OHM 1/4W 1% 1206 1 R11

42 Chip Resistor RES SMT, 100K-OHM 1/4W 5% 1206 1 R12

43 Chip Resistor RES SMT, 0-OHM 1/4W 5% 1206 3 R13,R16,R19

44 Chip Resistor RES SMT, 1.1K-OHM 1/4W 1% 1206 1 R15

45 Chip Resistor RES SMT, 10K-OHM 1/4W 1% 1206 3 R17,R21,R38

46 Chip Resistor RES SMT, 5.1-OHM 1/4W 1% 1206 1 R18

IRAC1152-350W

NO.

NO.NO.

NO. PART TYPE

PART TYPEPART TYPE

PART TYPE PART DESCRIPTION

PART DESCRIPTIONPART DESCRIPTION

PART DESCRIPTION MANUFACTURER & PART# QTY

QTYQTY

QTY DESIGNATOR

DESIGNATORDESIGNATOR

DESIGNATOR

47 Chip Resistor RES SMT, 1.5-OHM 1/4W 1% 1206 2 R5,R20

48 Chip Resistor RES SMT, 3.9-OHM 1/4W 1% 1206 2 R6,R22

49 Chip Resistor RES SMT, 1M-OHM 1/4W 1% 1210 4 R8,R9,R23,R25

50 Chip Resistor RES SMT, 26.1K-OHM 1/4W 1% 1206 2 R24,R26

51 Discrete resistor RES, 50m-ohm CURRENT SENSE RESISTOR 5W HMR KOREA 50mohm,MPR-5R(S)

series,TWO LEAD TYPE 1 R27

52 Chip Resistor RES SMT, 3M-OHM 1/4W 1% 1206 2 R3,R4

53 Discrete resistor RES, CF 12K-OHM 1W 5% 1 R29

54 Discrete resistor RES, CF1.5M-OHM 1/2W 5% 1 R30

55 Chip Resistor RES SMT, 1.0K-OHM 1/4W 1% 1206 1 R31

56 Discrete resistor RES, CF 100-OHM 1/4W 5% 1 R32

57 Chip Resistor RES SMT, 21K-OHM 1/4W 1% 1206 1 R33

58 Discrete resistor RES, CF 20-OHM 1/4W 5% 1 R34

59 Chip Resistor RES SMT, 47-OHM 1/4W 1% 1206 1 R35

60 Chip Resistor RES SMT, 390-OHM 1/4W 1% 1206 1 R36

61 Chip Resistor RES SMT, 2.0K-OHM 1/4W 1% 1206 1 R37

62 Discrete resistor RES, MF 150-OHM 2W 5% 1 R7

63 Discrete resistor CURRENT LIMITER INRUSH 6A STEADY STATE DIGIKEY KC004L-ND 1 RT1

64 Transformer EE25V Switch transformer SANTRONICS SNX-1380 1 T1

65 IC IC, PFC Control IC IR1152---SO-8 IR IR1152S 1 U1

66 Diode DIODE, PHOTOCOUPLER TRAN OUT 4-DIP SHARP--PC817X2 1 U2

67 IC IC, SWITCH OFF-LINE 10/28W TNY278PN---8P

DIP Power Integrations TNY278PN

DIGIKEY 596-1094-5-ND 1 U3

68 - UNINSTALLED PARTS - - C17,C18,C20,C3,C4,R2,R28,

69 Fuse FUSE 6.3A/250V 5X20MM FAST DIGIKEY F953-ND 1 F1

70 Fuse Cover Vinyl Fuse Cover DIGIKEY 3527CK-ND 1

71 Heatsink HEATSINK, IRAC1152-350W Heatsink for Boost

FET/Diode---160mm length AAVID 78195(160mm) 1

72 Heatsink HEATSINK, IRAC1152-350W Heatsink for Bridge

rectifier---76mm length AAVID 78195(76mm) 1

73 Clip HEATSINK CLIP, Aavid MAX Clip 03 for TO-247 for

Q3, Q4 & B1 AAVID MAX03(406097)

MOUSER 532-MAXCLIP03 3

74 Clip HEATSINK CLIP, Aavid MAX Clip 01 for TO-220 for

D5 AAVID MAX01(406098)

MOUSER 532-MAXCLIP01 1

75 Screw 5

76 Spring Washer 5

77 Washer 5

78 Standoff 5

79 Insulation Pad For D5 (TO-220) 1

80 Insulation Pad For Q3 & Q4 (TO-3P, 25X19) 2

81 Screw 5

82 Standoff HW, SPACER, M3 x 18mm,NYLON---M3*18 5

83 Label LABEL, 22.86x6.35 1

84 Anti-static Bag 400x300 1

IRAC1152-350W

IRAC1152-350W PCB & Component Layout

The information provided in this document is believed to be accurate and reliable. However, International Rectifier assumes no responsibility

for the consequences of the use of this information. International Rectifier assumes no responsibility for any infringement of patents or of

other rights of third parties which may result from the use of this information. No license is granted by implication or otherwise under any

patent or patent rights of International Rectifier. The specifications mentioned in this document are subject to change without notice. This

document supersedes and replaces all information previously supplied.

For technical support, please contact IR’s Technical Assistance Center

http://www.irf.com/technical-info/

WORLD HEADQUARTERS:

233 Kansas St., El Segundo, California 90245

Tel: (310) 252-7105

Mouser Electronics

Authorized Distributor

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IRAC1152-350W