MC34262P - Motorola / Freescale Semiconductor

MOTOROLA

SEMICONDUCTOR~

TECHNICAL DATA

Advance Information

Power Factor Controllers

The MC34262, MC33262 series ,are active power factor controllers

specifically designed for use as apreconverter in electronic ballast and

in off-line power converter applications. These integrated circuits feature

an internal start-up timer for stand-alone applications, a one quadrant

multiplier for near unity power factor, zero current detector to ensure

critical conduction operation, transconductance error amplifier, quickstart

circuit for ‘enhanced start-up, trimmed internal bandgap reference,

current sensing comparator, ‘and atotem pole output ideally suited for

Order thie date aheat by MC3426~

MC34262

MC33262 I

\’\$

‘‘J:,*.,

i:kp:.g.>a

POWER FACT,?~,.~*

CONTROLL~+w

t?.s,.*,

,::,:M.,\

SILICON @~~jfHlc

lNTEG~W~lRCUIT

‘t,;~.~‘~

,‘?;\ 1:

driving apower MOSFET. .-,.:$,,,‘t.:,

+i$: :j.~,~

Also included are protective features consisting of an overvoltage .(x,,,‘Ci.+’?,5

\,,.. ,,.,:i~$,.

comparator to eliminate runaway output voltage due to load removal, input ~.,$-.... >+

.,,.;,\~,,...

$.?i{,ekt,~i,!!:;’:,~’

undervoltage lockout with hysteresis, cycle-by-cycle current limiting, ,{+~.f>,..,.,!:3,:.

multiplier output clamp that limits m=imum peak switch current, an RS -+~~k,,‘~.$,~..

‘->,,

,:i:,.

latch for single pulse metering, and a drive output high state clamp for

MOSFET gate protection. These devices are available in dual-in-line and ,R.*:.:t~

>:~

sutiace mount plastic packages. .!}<..*t

\~~i. ~.~i.,~.::

<+,!:.

,.,.,.,J?’

●OvewoltagecomparatorEliminates Runaway Output Voltage *J;,

,,.1,:~.,;,.

.,.%:i$jf,,

.Internal Stad-Up Timer ‘Y,,,>

,:{::i.~*...::~)...

●one Quadrant Multiplier ~,.$:

~>i~ ,

y,--y,i,,.,,,.e$w

.Zero Current Detector *:*,

,,,. ‘-’’”.

.s~~,t~\.:,.i$..*’>.

‘~.$,.,-

●Tflmmed 2% internal Bandgap Reference ,,,

,~;.

,., ?,.

●Totem pole outputwith High State Clamp .

,y~.i’.

“,,......>

.UnderVoltage Lockout with 6.0 Vof Hysteresis ‘J$k‘*..’?:,.>,

,!\k;,:,..,,k\\:,,,~,

\> \.,:C,.!.’U*.*

.Low Start-Up and Operating Current ,..i:.?~,,. ~~.:,

.Supersedes Functionality of SG3561 and @%$Y

..:*<:.>,.‘..:.,‘

.\ ..‘~>h!,,},~:,

simplifiedQl$~~~~a9ram

.:**:“’:?....

———————— ~j__+_— —_— —_ 1

IZeroCurrent

0DetedInput

I,,>,

0Vcc

1“

oDrive Output

1’

=!oCurrentSense

*Tmer, Input

&Overvoltage /4

bgic

Multiplier

Compensation02

PSUFFIX

PLASTIC PACKAGE

CASE 626

8*1

DSUFFIX

PWSTIC PACKAGE

CASE 751

(SO-8)

PIN CONNECTIONS

VoltageFeedback

Input ‘8Vcc

Compensation27Drive Output

Mutiptier Input 36Gnd

Current S?;: 4sZero Current

DetectInput

TopMew)

ORDERING INFORMATION

Temperature

Device Range Package

~s document contains information on a new produti, Specifiwtfons and information herein are subject to change OMotorola, Inc. 199S

without notice.

MAXIMUM RATINGS

Rating

Total Power Supply and Zener Current

Output Current, Source or Sink (Note 1)

Current Sense, Multiplier, and Voltage Feedback Inputs

Zero Current Detect Input

High State Forward Current

Low State ReverseCurrent

Power Dissipation and Thermal Characteristics

PSuffix, Plastic Package, Case 626

Maximum Power Dissipation @TA =700C

Thermal Resistance,Junction-to-Air

DSuffix, Plastic Package, Case 751

Maximum Power Dissipation @TA =700C

Thermal Resistance,Junction-to-Air

Operating Junction Temperature

Operating Ambient Temperature (Note 3)

MC34262

MC33262

Storage Temperature

—

ELECTRICAL CHARACTERISTICS (VCC =12 V(Note 2), for typical values TA ~~2~Q$$r min/max values TA is the operating ambient

temperature range that applies (Note 3), unless othewise noted.) .t~~},+:e’

..> ‘:b~,

Characteristic Symbok~\l, Mln Typ Max Unit

ERROR AMPLIFIER .-’~.’.‘‘,tt,. “

:;$. -\[\

Voltage Feedback InputThreshold

TA =2WC ,,:,4WY’” v

~.’::,i. 2.465 2.5 2.535

TA =Tlow toThigh(Vcc= 12Vto 28 V) ,,,

~,,, 2.44 —2.54 —

Line Regulation (Vcc =12Vto 28 V, TA =25°C) ,1$ ~

,.*$.k;tl,> Regjine ‘—

,. 1.0 10 mV

Input Bias Current (VFB =OV) -i$y:,\‘~’:*, —

.$:J,$:),*,,;*?,. ilB —-0.1 -0.5 PA

Transconductance (TA=25”C) >,>/.:3<*

~*.S., ..~..

\~..# \9m 80 100 130 who

Output Current ./?%.‘~~’:$’

~;.,,,y10

.V.!,

Source (VFB =2.3 V) ,.,,,~,~i.,,..J,,, N

,::\,,

.,>;? —10

Sink (VFB =2.7 V) —

,,..,, —

,~. 10 —

.*,.

~>:+.~,p~.

Output Voltage Swing ,ti:$.,;

~&,,,;; v

High State (VFB =2.3 V) ,.,,;,:,>.+,\,.S.>:,,:,yt’. vOH(ea)

,.y 5.8 6.4 —

‘~t3

LOW State (VFB =2.7 v) !%. .,.,.; VOL(ea) —1,7 2.4

OVERVOLTAGE COMPARAT~ ‘:~j’ ““

Voltage Feedback lnput~r~eho~ VFB(OV) 1.065VFB 1.08 VFB 1.095 VFB vJ

MULTIPLIER \)i .,,y;~ .

.,-,,,.,.{1”

‘{$\-k.:.~~

,nputThreshow :;”

Input Bias CUrre~!~j,~$~{VFB =OV) IIB —-0.1 -0.5 N

...>\.s,

,,a; ‘Vth(M) 1.05 VOL(EA) 1.2 VOL(EA) —v

‘Pin 30to 2.5 0to 3.5 —

VPin 2Vt~(M) tO vth(M) tO —

(vth(M) +1.0) (vth(M) +1.5)

K0.43 0.65 0.87 IN

ZERO CURRENT DETECTOR

Input Threshold Voltage (~n Increasing) Vth 1.33 1.6 1.67 v

Hysteresis(~n Decreasing) VH 100 200 300 mV

input Clamp Voltage

High State (IDET =+3.0 mA) v

vIH 6.1 6.7 —

Low State (IDET =-3.0 mA) —

VIL 0.3 0.7 1.0

MC34262 ●MC33262

—

ELECTRICAL CHARACTERISTICS (Vcc =12 V(Note 2), for typical values TA =25°C, for rein/m* values TA is the operating ambient

temperature range that appliea (Note 3), unless otherwise noted.)

Characteristic Symbol Min Typ Max Unit

CURRENT SENSE COMPARATOR

Input Bias Current (Vpin 4=OV) IIB 2— -0.15 –1 .0 @

Input Offset Voltage (V~n 2=1.1 V, V~n 3=OV) Vlo —9.0 25 mV

Maximum Current Sense Input Threshold (Note 5) Vth(max) 1.3 1.5 1.8

Delay to Output tpHL~n/out) —200

DRIVE OUTPUT ~...$,,,

4>.

?>iih,’ls$,,**,,$,J.

Output Voltage (VCC =12 V) ..... .,,.:’%:‘v

ir f~}}:

LOW state (lSink =20 mA) .~>i:fi>

vOL —0.3 ., 60,*3

(l~nk =200 mA) ;$~”,..

—2.4 ~~,, “::>,,s:3

High State (lSource =20 mA) vOH 9.8 10.3 e: ‘*’~<*P —

(lsource =200 mA) 7.8 8.4fi. “4$

>$~ —

Output Voltage (VCC =30 V) VO(max) ‘:;wj,{::t

,)h,.,.t~.., v

High State (lsource =20 mA, CL =15 pF) 14 ,$ft;:f~t$”? la

Output Voltage Rise Time (CL =1.0 nF) .::<

tr ::.,,.,,,*~,>.,

—,*, k~>>>:$e~o 120 ns

Output Voltage Fall Tme (CL= 1.0 nF) ,s. .,.....

tf ~~\.-,~%

-,tlj:~k ~... 50 120 ns

Output Voltage with UVLO Activated .,,y

VO(UVLO) ‘$:....*:>.\,.,

y:~.: 0.1 0.5 v

(vcc =7.O V, Isink =1.0 mA) >$.,s,yi$i..\..

,> J*W

$?, ~*:.l

RESTART TIMER ~,$+~‘it.~!‘

\, \/*,y*

.,*.,-,

Restati Tme Delay tDL&$$ “~? 200 620 —~s

UNDERVOLTAGE LOCKOUT ‘.s:~~l>

.,:.:,,,!if,, .

Start-Up Threshold (Vcc Increasing) .,tt~~d) 11.5 13 14.5 v

,$~}.?.<z.:~~~

Minimum Operating Voltage After Turn-On (Vcc Decreasing) ~$~utdown 7.0 8.0 9.0 v

Hysteresis ,~~~.

?: .vH 3.8 5.0 6.2 v

TOTAL DEVICE ..~~.~s.

. \3’,%,,

~.,

~...

Power Supply Current ‘~”,.,.,<,.

~;>:,p.,.;>:.~,, Icc mA

Stati-Up (Vcc =7.0 V) S,(F*~\%k

.::*:..,:>. “s.’ —0.25 0.4

Operating ,$~1

;.::-h\,,~-:.,~.~,,

‘,.,VI —6.5 12.,\.Y,T,>

Dynamic Operating (50 kHz, CL =1.0 nF#$$#:~! “—9.0 20

Power Supply Zener Voltage (Ice= 25~A}~~’”R’ ~Vz 30 36 —v

A...... .,.. ..-

NOTES: 1. Mwimum package power tiss~a~o~~fi~s must be observed.

2. Adjust VCC above tha sta@~&{q@bld before setting to 12 V.

!:,,‘.~..,?,.’\‘-,.

3, Tlow =O°Cfor MC3426& ‘3 Ttigh = + 85°C for MC34262

=–40”C for w,.~ =+105°C for MC33262

,,,.\ ‘~,*

II I I I I I

m--l !4

!= *---

c1 —I I , I1I

!v~n2=2.0v T

2.2 3.0 3.8

VM,MULTIPUERPIN3INPUTVOLTAGE~

Rn 4Threshold

4.K= V~” 3(Vpin 2- Vth(M))

5. This parameter is measured with VFB =OV, and V~n 3=3.0 V.

Figure 2. Current Sense Input Threshold

versus Multiplier Input, Expanded View

0.08

0.07

0.06

0.05

0.04

0.03

0!02

0.01

-!.12 -0.06 00.08 0.12 0.18 0.24

VM,MULTIPLIERPIN3INPUTVOLTAGE~

MC34262 ●MC33262 MOTOROLA3

—

MOTORO~

4MC34262 ●MC33262 ~.

Figure 9. Zero Current Detector Input Threshold

Voltage versus Temperature

1,7 t

—UpperThreshold Vcc =12V

s~n, Increasing)

— —

01.5

‘- 1.4 — — — — — — -

>5 LowerThreshold

~n, Decreasing)

1.3 I I

--55 -25 0 25 50 75 100 125

TA,AMBIENTTEMPERATURE~C)

Figure 10. Output Saturation Voltage

versus Load Current

0VccHVCC=12V

80 wPulsedLoad

2.0 - -- 120HzRate

SourceSaturation

4.0 —(Loadto Ground) \d

6;0 _,+!.

4.0

(LoadtoVCC)

2.0 ~—

00’ 60 160\,:>::,1NtJ# 240 320

10,OUTPUTLOAD’@,@NT (mA)

,:. ~.:,.,.

—

\$/,,,#,.*

,zA’~@ 13. Supply Current Figure 14. Undervoltage Lockout Thresholds

+x~+$versus Supply Voltage versus Temperature

,,‘,k)>::.,..

16 3* ‘>>. /14

.$\~#,,~.i.~:.~.~+}

,,.s.,.!tt:..

Z:w $?*F? ~‘1!

/z‘3 Stati-UpThreshold

$$,,$; ~: J.8 12 WCCincreasing)

*My~ ———>-— g

8/~g 11

;6.0 ~

nVFB=OV &10

3CurrentSense=OV3

h1 ~9.0

~4.0 Multiplier=OVMrrimumOperatingThreshold

Q1ICL=i.onF >0 WCCDecreasing)

f= 50 kHz 6.0 — —

TA =25°C II I I

n~7.

—“o 10 20 30 40 ‘:55 -25 0 25 50 75 100 125

Vcc, SUPPLYVOLTAGE~TA,AMBIENTTEMPERATURE~C)

—

MC34262 ●MC33262 MOTOROLA 5

FUNCTIONAL DESCRIPTION

Introduction

Wth the goal of exceeding the requirements of legislation

on line-current harmonic content, there is an ever increasing

demand for an economical method of obtaining aunity power

factor. This data sheet describes amonolithic control IC that

was specifically designed for power factor control with

minimal external components. It offers the designer asimple,

cost-effective solution to obtain the benefits of active power

factor correction.

Most electronic ballasts and switching power supplies use

abridge rectifier and a bulk storage capacitor to derive raw

DC voltage from the utility AC line, Figure 15.

Figure 15, Uncorrected Power Factor Circuit

Retiifiers Converter

~_— —_T ~—— —_T

L————d L—_—_J

This simple rectifying circuit draws power from the line

when the instantaneous AC voltage exceeds the capacitor

voltage. This occurs near the line voltage peak and results

in ahigh charge current spike, Hgure 16.”.Since power is

only taken near the line voltage peaks, the resulting spikes

of current are extremely nonsinusoidal with ahigh content

of harmonics. This results in apoor power factor condit~~

where the apparent input power is much higher than th~?~i

power. power factor ratios of 0.5 to 0.7 are Commd$i$

Power factor correction can be achieved with,,~~’+~e of

either apassive or an active input circuit. P~;* @rcuits

.i.w+t,,\::?{::>,

usually contain ,acombination of large capaq~~~ductors,

and rectifiers that operate at the AC line ‘~~wncy. Active

circuits incorporate some form of ahi~Q,W~,@ncy switching

converter for the power processing, ~~th $e boost convetier

being the most popular topoloq#~BVe 17.. Since active

input circuits operate at afre$~~~much higher than that

of the AC line, they are sm~$r~~ghter in weight, and more

eficient than apassive ampit tid~ yields similar results, Wth

proper control of the ~fw~tier, almost any complex load

~>.:~<

.,,,...

,\&

can be made to appear resistive to the AC line, thus

significantly reducing the harmonic current content.

Figure 16. Uncorrected Power Factor

input Waveforms

.-.

—

,>*

\~$~

*{$,*

~&~b34262, MC33262 are high performance, critical

~#@,ti@tion, current-mode power factor controllers

‘?~+~$ffi~ally designed for use in off-line active preconvetiers.

.~;sVhese devices provide the necessary features required to _

significantly enhance poor power factor loads by keeping the

AC line current sinusoidal and in phase with the line voltage. _

Operating Description

The MC34262, MC33262 contain many of the building

blocks and protection features that are employed in modern

high performance current mode power supply controllers.

There are, however, two areas where there is amajor

difference when compared to popular devices such as the

UC3842 series. Referring to the block diagram in Hgure 19,

note that amultiplier has been added to the current sense

loop and that this device does not contain an oscillator. The

reasons for these differences will become apparent in the

following discussion. Adescription of each of the functional

blocks is given below.

.?~iy$i,:,~~

.ji,,o.

.,:,} ~.. Figure 17. Active Power Factor Correction Preconvetier

~~t$b>. .

PFCPreconverter Convetier

➤––~_ ———

~.1 ~_––_ 1

Hgh

t_Frequency /

.:*>’

J*:. 7Bypass IMC34362 Load

Capacitor J

L——_____

—

MOTOROLA

6MC34262 .MC33262

Error Amplifier

An Error Amplifier with access to the inverting input and

output is provided. The amplifier is atransconductance type,

—meaning that it has high output impedance with controlled

voltage-to-current gain. The amplifier features atypical gm

—of 100 pmhos (Figure 5). The noninvefling input is internally

biased at 2.5 V+2.070 and is not pinned out. The output

voltage of the power factor convetier is typically divided down

and monitored by the invetiing input. The maximum input

bias current is –0.5 wA, which can cause an output voltage

error that is equal to the product of the input bias current

and the value of the upper divider resistor R2. The Error Amp

output is internally connected to the Multiplier and is pinned

out (Pin 2) for external loop compensation. Typically, the

bandwidth is set below 20 Hz, so that the amplifier’s output

voltage is relatively constant over agiven AC line cycle. In

effect, the error amp monitors the average output voltage

of the converter over several line cycles. The Error Amp

output stage was designed to have arelatively constant

transconductance over temperature. This allows the

designer to define the compensated bandwidth over the

intended operating temperature range. The output stage can

sink and source 10 WAof current and is capable of swinging

from 1.7 Vto 6.4 V, assuring that the Multiplier can be driven

over its entire dynamic range.

Akey feature to using atransconductance type amplifier,

is that the input is allowed to move independently with

respect to the output, since the compensation capacitor is

connected to ground. This allows dual usage of of the Voltage

monitored with respect to the Voltage Feedback Input

threshold. The Multiplier is designed to have an extremely

linear transfer curve over awide dynamic range, OVto 3.2 V

for Pin 3, and 2.0 Vto 3.75 Vfor Pin 2, Figure 1. The Multiplier

output controls the Current Sense Comparator threshold as

the AC voltage traverses sinusoidally from zero to peak line,

Figure 18. This has the effect of forcing the MOSFET on-time

to track the input line voltage, resulting in afixed Drive Output

on-time, thus making the preconvetier load appear,?,~o be

resistive to the AC line. An approximation of thaj:@&qnt

Sense Comparator threshold can be calculat~,$~~m the

following equation. This equation is accurate .Wj%@er the

given test condition stated in the elect:c~:~$,

Asignificant reduction in line “~r@t” distortion can be

attained by forcing the preco~~r t~ switch as the AC line

voltage crosses through g$~Yhe forced switching is

achieved by adding a,@~trb%d amount of offset to the

Multiplier and Curren%+~.N#e Comparator circuits, The

.... .>:* ~$“

equation shown belW’a&ounts for the built-in offsets and

is accurate to ,Wn t~h percent. Let Vth(M) =1.991 V

,.*,.~..~.

~*!,~,‘..,.*,...~

Z@Cur&nt Detector

~F$~~& MC34262 operates as acritical conduction current

%wo:~e controller, whereby output switch conduction is

Feedback Input pin by the Error Amplifier and by the

Overvoltage Comparator. ‘:q$~~”~ated by the Zero Current Detector and terminated when

~li:3)y\;!.,,\alN>

Overvoltage Comparator “::% \he peak inductor current reaches the threshold level

—,,%

,., established by the Multiplier output. The Zero Current

An overvoltage Comparator is incorporated to e~~~inate

the possibility of runaway output voltage. This con~[;o~~an

—occur during initial startup, sudden load remoy~:~!@uring

output arcing and is the result of the low ban@~@h~~at must

be used in the Error Amplifier control loop:{~~&t@emoltage

Comparator monitors the peak ou~~~~~dltage of the

converter, and when exceeded, iqwmtely terminates

MOSFET switching. The compa~~r~~shold is internally

set to 1.08 Vref. In order to,lQN~&:,# false triPPin9 during

normal operation, the value ~~ t~ “output filter capacitor C3

must be large enough tqW~p#e peak-to-peak ripple less

than 16% of the aver~~q~:~C output. The Overvoltage

Comparator input t~~$jve ~utput turn-off propagation delay

is typically 400 ns$$W:@arison of startup overshoot without

and with the ~Xohage Comparator circuit is shown in

Figure 23. $i:$~~~‘

~u,tip~*S~*J‘:*...

Aslpgl$’~uadrant, two input multiplier is the critical

el@-$~~lRat enables this device to control power factor. The

.,#&~~~tiave rectified haversines are monitored at Pin 3with

“~xt to ground while the Error Amp output at pin 2is

..:$

—

Detector initiates the next” on-time by setting the RS Latch

at the instant the inductor current reaches zero. This critical

conduction mode of operation has two significant benefits,

First, since the MOSFET cannot turn-on until the inductor

current reaches zero, the output rectifier reverse recovery

time becomes less critical, allowing the use of an inexpensive

rectifier. Second, since there are no deadtime gaps between

cycles, the AC line current is continuous, thus limiting the

peak switch to twice the average input current.

The Zero Current Detector indirectly senses the inductor

current by monitoring when the auxiliary winding voltage

falls below 1.4 V. To prevent false tripping, 200 mV of

hysteresis is provided. Hgure 9shows that the thresholds

are well-defined over temperature. The Zero Current

Detector input is internally protected by two clamps. The

upper 6.7 Vclamp prevents input overvoltage breakdown

while the lower 0.7 Vclamp prevents substrate injection.

Current limit protection of the lower clamp transistor is

provided in the event that the input pin is accidentally

shorted to ground. The Zero Current Detector input to Drive

Output turn-on propagation delay is typically 320 ns.

MC34262 ●MC33262 MOTOROLA

...?

Hgure 18. Inductor Current and MOSFET

Gate Voltage Waveforms

,’/i\/HT1

~n I

‘1 Offl uu

Current Sense Comparator and RS Latch

The Current Sense Comparator RS Latch configuration

used ensures that only asingle pulse appears at the Drive

Output during agiven cycle. The inductor current is

convetied to avoltage by inserting aground-referenced

sense resistor R7 in series with the source of output switch

Q1. This voltage is monitored by the Current Sense Input

and compared to alevel derived from the Multiplier output.

The peak inductor current under normal operating conditions

is controlled by the threshold voltage of Pin 4where:

lL(pk )=Pin 4Threshold

R7 ,\J:$‘

.l\t.i,tt,,

.$:sk

Abnormal operating conditions occur during prec~~&e~

startup at extremely high line or if output volta~,,4~Sfng

is lost. Under these conditions, the Multipli$$~~~t and

Current Sense threshold will be internally c.~~~$’to 1.5 V.

Therefore, the maximum peak switch cur~~w limited to:

.,<*es

1.5 Y*$$$;329$

‘pk(m~) = ~ .,}

,,J:\.,,\*>\*,.&\

An internal RC filter has bee~~irr~{ed to attenuate any

highfrequency noise that @~t~&’fpresent on the CUrrent

waveform. This filter h,~lp#’$$@ucethe AC line current

distortion especially,, &# the zero crossings. Wth the

component values s~~~~ Figure 20, the Current Sense

Comparator thres~~~~~t the peak of the haversine varies

from 1.1 Vat{9~t~ to 100 mV at 268 Vat. The Current

Sense lnpy~:,m?~rke Output turn-off propagation delay is

typically I*s ti~h 200 ns.

.~,<,,i,s.

,l)*,:,.X:*’$’

,.,.,.,

~$~hdog timer function was added to the IC to

elim~ate the need for an external oscillator when used in

stand-alone applications. The Timer provides ameans to

automatically start or restart the preconvetier if the Drive

Output has been off for more than 620 ps after the inductor

current reaches zero. The restart time delay versus —

temperature is shown in Figure 8. —

Undervoltage Lockout and Quickstart

An Undervoitage Lockout comparator has been

incorporated to guarantee that the IC is fully functional

before enabling the output stage. The positive power su~ly

terminal (VCC) is monitored by the UVLO comparat~~~w

the upper threshold set at 13 Vand the lower thr#Wat

8.0 V. In the stand-by mode, with VCC at 7.0 Vh~~~{W~red

supply current is less than 0.4 mA. This large fi#*”~sis and

low start-up current allow the impleme~~h:~f efficient

bootstrap stati-up techniques, making,p~$j+~avices ideally

suited for wide input range off-line pre~nV$fier applications.

An internal 36 Vclamp has been a~.ed f~m VCC to ground

to protect the IC and capac~~~~~. from an overvoltage

condition. This feature is ,@[* ‘if external circuitry is

used to delay the statiu~%~t~~ preconverter. The supply

current, startup, and m~~ voltage characteristics are

shown in Figures.ll~,~n’~*84.

AQuickstati ~~~.has been incorporated to optimize

converter sta~ti~$~uring initial start-up, compensation

capacitor ~# ~~i~be discharged, holding the error amp

output belo+~:jheMultiplier threshold. This will prevent Drive

Outp~#$kwitcfiYngand delay bootstrapping of capacitor C4

by,,$Wd*6. If Pin 2does not reach the multiplier threshold

~q~rej>4 discharges below the lower UVLO threshold, the

,l~m~~tier will “hiccup” and experience asignificant start-up

~ray. The Quickstati circuit is designed to precharge Cl to

#1“.7 V, Figure 7. This level is” slightly below the Pin 2—

Multiplier threshold, allowing immediate Drive Output

switching and bootstrap operation when C4 crosses the —

upper UVLO threshold.

Drive Output

The MC34262/MC33262 contain asingle totem-pole

output stage specifically designed for direct drive of power

MOSFETS.The Drive Output is capable of up to ~500 mA

peak current with atypical rise and fall time of 50 ns with

a1.0 nF load. Additional internal circuity has been added

to keep the Drive Output in asinking mode whenever the

Undervoltage Lockout is active. This characteristic

eliminates the need for an external gate pull-down resistor.

The totem-pole output has been optimized to minimize

cross-conduction current during high speed operation. The

addition of two 10 Qresistors, ,one in series with the

source output transistor and one in series with the sink

output transistor, helps to reduce the cross-conduction

current and radiated noise by limiting the output rise and

fall time. A16 Vclamp has been incorporated into the

output stage to limit the high state VOH. This prevents

rupture of the MOSFET gate when VCC exceeds 20 V.

MOTOROLA

8MC34262●MC33262

APPLICATIONS INFORMATION

The application circuits shown in Figures 19, 20 and 21 nominal line. Figures 20 and 21 are universal input

—reveal that few external components are required for apreconverter examples that operate over acontinuous input

complete power factor preconverter. Each circuit is apeak voltage range of 90 Vac to 268 Vat. Figure 20 provides an

detecting current-mode boost converter that operates in

—output power of 175 W(400 Vat 440 mA) while Figure 21

critical conduction mode with afixed on-time and variable provides 450 W(400 Vat 1.125 A). Both circuits have an

off-time. Amajor benefit of critical conduction operation is observed worst-case power factor of approximately 0.989.

that the current loop is inherently stable, thus eliminating the The input current and voltage waveforms of Figure 20 are

need for ramp compensation. The application in Figure 19 shown in Figure 22 with operation at 115 Vac and 2* Vat. .

operates over an input voltage range of 90 Vac to 138 Vac The data for each of the applications was genqr~~&&ith

and provides an output power of 80 W(230 Vat 350 mA) the test set-up shown in Figure 24. ,$:~.~’\‘~:,.

:>.:.+!~~<’,;.

with an associated power factor of approximately 0.998 at .,;~.

~::.*\,ii.+,~.*\!

.Y+ $’,

—

,>>

i,~”,,,.,-$>\.~,,)},

,~, e+~ *

Table 1. Design Equations #3 ,>a.:$~

.~:j~:.+:..’~,.i

,$.,;,‘~$.,.)..

Calculation . ...

Formula ~o{&&%~

Required Converter Output Power Po =Vo 10 Calculate the maximu~$~~iredoutput power.

. ...8.x.

2fi Po Calculated at th$.@~~~& required AC line voltage

Peak Inductor Current lL(pk) =for output regu@~@:1~8t the efficiency q=0.92 for

qvaC(LL) low line op*@~?’~$

Lp:(%-vac(LL))~vac(LL)2

Let th~~jtchi$~ cycle t=40 ps for universal input

Inductance (85~oWV&c) operation and 20 KSfor fixed input

,$(~,~~~t~ Vat, or 184 to 276 Vat) operation.

tivo Po ,.,

$- ,,:.t.~,,.~~

*,,..:.!.

....

.4’ ‘~&theory the on-time ton is constant. In practice ton

2PO Lp ,1r\5.’.<\

Switch On-Time bn =*<*V, tends to increase at the AC line zero crossings due

‘.*,.,

~vac2 J “$’*i tO the charge on CapaCitOr C5. Let vaC =vaC(LL) fOr

,::,,, ,~,

‘::’&.,>

‘*\’:.$:,).. initial ton and toff calculations.

IS.,,:*.,*.::,<,~

ton ‘JS[~~~‘“ The off-time toff is greatest at the peak of the AC line

t~ff =

Switch Off-Time ,,Fvo ?:’ voltage and approaches zero at the AC line zero

,,,~%,lSin el -‘ crossings. Theta (e) represents the angle of the AC

line voltage.

.,~

~,~~1~.~~.>~$?,ky

~.,?,.;l,

~,t’; The minimum switching frequency occurs at the peak

Switching Frequency .i~f{~:= +of the AC line voltage. As the AC line voltage traverses

.:.$,.>,~.s\.‘>.$,.bn +toff from peak to zero, tofi approaches zero producing an

$; .<.;’,,%6.‘“

“.,.. .,~\\+

-..~.? increase in switching frequency.

..,,.,..>,.

.& ..::,}

.8 Set the current sense threshold VCS to 1.0 Vfor

+$:1..2..

.:$}*~-’ Vcs

Peak Switch Current $!+, :,. R7=— universal input (85 to 265 Vat) operation and to

,..$?J(JZ),

)+~>..,?,.,.!.,

?.! ?+ lL(pk) 0.5 Vfor fixed input (92 to 138 Vat, or 184 to 276

,,;,+.

..-,

~e:..~ Vat) operation. Note that VCS must be <1.4 V.

~:~~,),

t~:,:.,, Set the multiplier input voltage VM to 3.0 Vat high

~h;g? Vac 6

Multiplier Input Vo[@& ~VM =

()

line. Empirically adjust VM for the lowest distortion

‘.$ ‘*):~$ —+1 over the AC line voltage range whi[e guaranteeing

,y,,\.,‘t:, ‘., R3

,,:, w!,,,,l?: start-up at minimum line.

+$i.’*+* ‘“’

,.r&.,*

()

R2 The llB R1 error term can be minimized with adivider

Conv~~&~Qu&ut Voltage VO=Vref ~+1 -IIBRI current in excess of 50 @.

~.~,.

J+:. $.

..,.

~.’~~’‘.\,:h;.f.’

,,*:..,$ The calculated peak-to-peak ripple must be less than

“:@vetier Output

AVO(p-p)=lO/-

16% of the average DC output voltage to prevent false

$Wak to Peak tripping of the Overvoltage Comparator. Refer to the

Ripple Voltage Overvoltage Comparator text. ESR is the equivalent

series resistance of C3

BW=~ The bandwidth is typically set to 20 Hz. When operating

Error Amplifier Bandwidth at high AC line, the value of Cl may need to be

increased. (See Figure 25)

Thefollowing convertercharacteristicsmust bechosen

VO —Desiredoutput voltage

—10 —Desiredoutput current

Vac —AC RMSopereting tinevoltage

—Vac(LL) —AC RMSMiniMUM requiradoperating line voltagefor output regulation

AVo —Converteroutput peak-to-peakripplevoltage

MC34262 *MC33262 MOTOROLA9

2.2M

0.01 m

C2 ~R3

Figure 19.80 WPower Factor Controller

100k

R6 t1N493

——— ———_— —_ —________ _

[MC34262 .

!,’ ZeroCurrent <36V~

1?V‘7 —

*1.4V -I

iCurrent Sense /h 20k -14

Comparator

... .-, ,,1

—

1.OM

Ilk

—

,(>. Q, ~a

A~j~*B’input

*,*+).:,.>. DC Output

:,<: !’

,,ta.$,;$~:i;~$i‘Current Harmonic Distotiion VA Ifund)

Vrms Pin PF ~,, lf~d THD 2357Vo(p-p) Vo 10 Po nrA)

90 85.9 o.*9’”~.’’o93 2.6 0.08 1.6 0.84 0.95 4.0 230.7 0.350 80.8 94.0

100 85.3 ~fi’%~.99&’ 0.85. 2.3 0.13 1.0 1.2 0.73 4.0 230.7 0.350 80.8 94.7

110 ~~,~$~~~&ga 0.77 2.2 0.10 0.58 1.5 0.59 4.0 230.7 0.350 80.8 94.9

120 ,~:~:~s o,gg8 0.71 3,0 0.09 0.73 1.9 0.58 4.1 230.7 0.350

“~:;$4:4 80.8 95.3

1~Q,~..k 0.997 0.65 3,9 0.12 1.7 2.2 0.61 4.1 230.7 0.350 80.8

.y,i~~, ~ ~84.1 95.7

0.996 0.62 4.6 0.16 2.4 2.3 0.60 4.1 230.7 0.350 80.8 96.0

$$~-ta wastaken with the test set-up shown in Hgure 24,

!;.2$..:,},.,-.-’s..

~~,~#w$.*Coilcrafl N2881-A

Pdmay 62 turns of # 22 AWG

*:. Seconday 5turns of # 22 AWG

Core: Coilcraft PT2510, EE 25

Gap 0.072’ total for aprimay inductance (Lp) of 320 pH

Heateink =AAVID Engineering Inc. 590302 B03600, or 593002B03400

—

MOTOROM

10 MC34262 ●MC33262

—

Figure 20.175 WUniversal Input Power Factor Controller

dl~c5

—

D2 D4

90fa:66 RFI

Filter D1 ~D3

1.3M

100k

RR 41N4934

——————————————————— -

L“

—

1.6M

10k

Power Factor Controller Test Data

Dc output

Current Harmonic Distoflion PA lf~nd)

Vrms THD 2357Vo(p.p) Vo 10 Po np~)

90 1q3.33$&$#991 2.15 2.8 0.18 2.6 0.55 1.0 3.3 402.1 0.44 176.9 91.5

.. .. 1.59 1.6 0.10 1.4 0.23 0.72 3.3 402.1 0.44 176.9 93.1

1.2 0.12 1.3 0.65 0.80 3.3 402.1 0.44 176.9 94.0

~:,~~j.: 184.9 0.998 1.03 2.0 0.10 0.49 1.2 0.82 3.4 402.1 0.44 176.9 95.7

“h ‘:%40 182.0 0.993 0.76 4.4 0.09 1.6 2.3 0.51 3.4 402.1 0.44 176.9 97.2

:,,,

~+i:. ,

‘“;’’”‘~”*$T268

,t.a,,.

,\.>,.,,,., 180.9 0.989 0.69 5.9 0.10 2.3 2.9 0.46 3.4 402.1 0.44 176.9 97.8

.,!,,~

‘......,1.,~,,,,,

?+~,\

<t,!.y$,l ,, *This data wae taken with the test set-up ehown in Hgure 24.

.\ ,.$+.“

j..,,.~x......

~:>::, T=Coilcrafi N2880-A

Primay 78 turns of # 16 AWG

Seconday 6turns of # 16 AWG

Core CoilcraftPT4215,EE42-15

Gap: 0.104” total for aprima~ inductance (Lp) of 870 ~H

Heatsink =AAVID Engineering Inc. 590302B03600

MC34262 ●MC33262 MOTOROW11

2*C5 10Ok

D2 D: ———-— ——— ——---,—--— ——n R: IN4934

.MP*A9E9 D6

loi II

0.01L12k T

331

.m -

L–d ‘

–––––––___b:-=

<,. ...

.J,~&e Input DC Output

.Jy‘

,* ::;.::,

~.;:~. Current Harmonic ~qOfiiOn~~Ifund)

..:*.,..,”,:..$,

.,t~+.’!>i~,~;kx‘,e

v~~~ ~“ PF +>, ~nd THD 2:3“;:<’” 5,7 Vo(p-p) Vo 10 Po qyA)

90 ‘489.5 ,~[d~$ “‘6.53 2.2 0;10 .’;’”::1,;5;.,;-:, 0.25 0.83 8.8 395.5 1.14 450.9 92.1

120 4753p” ,. 0.9M 3.94 2.5 0.12- 6.29: 0!62 0.52 8.8 395.5 1.14 450.9 94.9

.:*~,;,,..,:.,,,,~+.,

138 ,a$7$6s@b.998 3.38 2.1 0.06 0,70 1.1 0.41 8.8 395.5 1.14 450.9 95.8

580 <~~&~~i 0.998 2.57 4.1 0.21 2.0 1.6 0.71 8.9 395.5 1.14 450.9 97.3

,g$&$f’’$;@60.1 0.996 1.91 4.8

,. 0.74 4.3 2.2 0.63 6.9 395.5 1.14

,,~\~6@ “459.1 0.995 1.72 58 450.9 98.0

0.10 5.0 2.5 0.61 6.9 395.5 1.14 450.9 98.2

~~w was takenwith the taat set-up shownin figure 24.

.;;:;*:,..>>

~,~+.$,T=Coilcraft P3657-A

~~:~+. Primay 38 turns Litzwire, 1300atrandaof #48 AWG, Kerrigan-Lewis,CMcago,IL.

,.+, Seconday 3turnsof # 20 AWG

cOre: CoilCraftPT4220,EE42.20

Gap 0.180” total for aprimay inductance(LP)of 190 ~H

Heatsink=AAVID EngineeringInc.604953B04000 Etiruaion

,.,,..,. ,,

.. . .- ..

.,........ ..,,.,...

,:. .. . ,,

MOTOROM

12 MC34262 ●MC33262

—

Hgure 22. Power Factor.&orrected Input Waveforms

(figure 20 CMcuit)

504

400

—

,’

Input =i15 Vat, Output= 175 WInput ❑230 Vat, Output= 175 W

An RFI filter is required for best performance when connecting the preconverfer dhectly to the AC line. The filter attenuates the level of high

frequency switching that appears on the AC tine current waveform. Figures 19 and 20 work well with commercially available two stage filters such as

the Delta Electronics 03DPCG5. Shown above is asingle stage test ‘filter that can easily be constructed with four AC line rated capacitors and a

—common-mode transformer. Coilcrafi CMT3-28-2 was used fo test Hgursa 19 and 20. It has aminimum inductance of 28 mH and a mwimum current

rating of 2.0 A. Coilcraft CMT4-I 7-9 was used to test Rgure 21. It has aminimum inductance of 17 mH and a muimum current rating of 9.0 A.

—Urcuit conversion efficiency ~PA) was calculated without the power IOSSof the RFI filter.

,. ... .,.,.-

MC34262 ●MC33262 ,’ ,’.-: MOTOROU

,, 13’,

,,:. ;,..,-..

Figure 25. Error Amp Compensation

II—

—

ErrorAmp I

lo@ + I ‘2

+‘L

_— II

~~ ET

v—— ___!–; J

—

Figure 26. Current Waveform Spike Suppression .~.t:+,,

.,,.

Figure 2z<&tive Current Waveform

,y$~ke Suppression

,,:.

-I

—

*I l-’ /!

‘Sense

Comparator Comparator

Anegative turn-oft spike can be observed on the trailing edge of the

current waveform. Thie epike is due to the parasitic inductance of resistor

R7, and if it is excessive, it can cause circuit instabihfy. The addition of

Shott~ diode D1 can effectively clamp the negative spike. The addition of

the external RC filter shown in Hgure 26 may provide sufficient spike

attenuation.

—

MOTOROU

14 MC34262 ●MC33262

—

figure 28. Printed tircuit Board and ComDonent Lavout

(Circuits of Pigures 15 and 16) -

.,..,,., -.....:.-

.$?,..

!(BottomMew) I

NOTE Use 2oz. copper laminate for optimum circuit performance.

MC34262 ●MC33262 MOTOROU

DSUFFIX

PLASTIC PACKAGE

CASE 751-03

m(SO-8)

,---

-B- Pj+l 0.25 (0.OIO)@ IB@]

@h7PL

NOTES

1. DIMENSIONS“K ANO “W ARE OATUMS ANO

TIS ADATUM SURFACE.

2. DIMENSIONING AND TOLERANCING PER ANSI

V14.5M, 1982.

3. CONTROLUNG DIM MILUMETER,

4. DIMENSION “~ ~0 “W DO NOT INCLUDE

MOLD PROTRUSION.

5. MAXIMUM MOLO PROTRUSION 0.15 [0.008)

PER SIDE.

~p I!.:‘2. DIMENSION LTO CENTER OF LEADS WHEN

.,.( ‘:\:*t#t:.?-

.$+\FORMED PARALLEL

~:*?,\.:*,,~:~>Q\, 3. PACXAGE CONTOUR OPTIONAL (ROUND OR

*\;:<,,SQUARE CORNERS),

SIONS A AND B ARE OATUMS.

=l~,,lk!~ 6.,” ~~, =0”.,C,NG PER ANS,

4. DIMENf

,+;$ 5. DIMENS,u,w,,,u m,,” ,vw-,,,

V14.5M,19B2.

MILUMETERS INCHES

DIM MIN MAX MIN MAX

A9.40 10,1s 0.370 0.400

BS.lo 8,60 0.240 0.2S0

c3.94 4.45 0,155 0.175

D0.38 0.51 0.015 0.020

F1.02 1,52 0,040 0.060

G2.54 Ssc 0.100 Ssc

H0.76 1.27 0,0S0 0.050

J0.20 0,30 0.008 0,012

K2.92 3,42 0.115 0,135

L7.62 BSC 0.300 Ssc

M– 10” –10”

N0.51 0.78 0,020 0,030

~’:?...,:+~.

!.>’-’

'otoro'areseweS%%ttomakechan?eswithoutfutihernO~cetOanYprOduCtsherein. MOtOrOlamakesnOwarranV, representationorg.aranteeregardng

the sultablll~ d~~~ucts for any particular purpose, nor does Motorola assume any liability arising out of the apphcation or use of any product or circuit,

and specifi@ d?~aims any and all liability, including without hmitation consequential or incidental damages. ‘Typicav parameters can and do vary indifferent

aPPlicati$~.Al!:$ Perating Parameters, includin9 ‘TYPicals” must be validated for each customer application by customer’s technical experts. Motorola does

not c- -Wcense under its patent rights nor the tights of othere. Motorola products are not designed, intended, or authorized for use as components in

syst%-ded for surgical implant into the body, or other apphcafions intended to support or sustain life, or for any other application in which the failure of

t~~<~,wla product could create asituation where personal injuryordeathmay occur. Should Buyer purchase or use Motorola products for any such

‘*tied ‘r unauthorized aPPflca~on, Buyer shall indemniW and hold Motorola and its oficera, employees, subsi~aries, affiliates, and distributors harmless

a9*st all claims, costs, damages, and exPenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death

associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part.

Motorola and @are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/Affirmative Action Employer,

—

Literature Distribution Centers:

USA: Motorola Uterature Distribution; P.O.Box20912; Phoenix, Arizona 85036.

EUROPE: Motorola Ltd.; European Literature Centre; 88 Tannere Drive, Blakelands, Milton Keynes, MK145BP,England.

JAPAN:Nippon Motorola Ltd.; 4-32-1, Nishi-Gotanda, Shinagawa-ku, To&o 141, Japan. —

ASIA PACIFIC:Motorola Semiconductors H,K. Ltd.; Silicon Harbour Center, No. 2Dai King Street, Tai Po Industrial Estate,

Tai Po, N.T.,Hong Kong. —

‘, o

-MMO-ROLA

MC3426tiD

oIPHX3S341+ PRINTED IN USA 3/93 IMPERIAL LITHO 90345 10,000 LIN/lNT YCAAAA llllllllllllllllllllllllllllllllllllllllllllllllllllll