Datasheet TK83854MITL, TK83854MIMG, TK83854DITL, TK83854DIMG Datasheet (TOKO)

TK83854

HIGH POWER FACTOR PREREGULATOR

FEATURES

■ Control Boost PWM to 0.99 Power Factor

■ Limit Line Current Distortion to < 5%

■ Worldwide Operation without Switches

■ Feed-Forward Line Regulation

■ Low Noise Sensitivity

■ Pin Compatible with UC2854, and UC3854

(Licensed Source)

DESCRIPTION

The TK83854 family of integrated circuits provide active
power factor correction for power systems that otherwise
would draw non-sinusoidal current from sinusoidal power
lines. These parts implement all the control functions
necessary to build a power supply preregulator capable of
optimally using available power-line current while
minimizing line-current distortion. To do this, the TK83854
contains a voltage amplifier, a precision analog multiplier/
divider, a current amplifier, and a fixed-frequency PWM. In
addition, the TK83854 contains a power MOSFET gate
driver, 7.5 V reference, line anticipator, load-enable
comparator, low supply detector, and overcurrent
comparator.

The TK83854 family uses average current-mode control to
accomplish fixed-frequency current control with stability
and low distortion. Unlike peak current-mode control,
average current control accurately maintains sinusoidal
line current without slope compensation.

FEATURES (CONT.)

■ Low Start-Up Supply Current

■ Fixed-Frequency PWM Drive

■ Low-Offset Analog Multiplier/Divider

■ 1 Amp Totem-Pole Gate Driver

■ Precision Voltage Reference

circuitry that supplies power to this device, the TK83854
family features low start-up supply current.

These devices are available in 16-pin plastic dual in-line
(DIP) and 16-pin surface mount (SOP) packages.

TK83854

83854

SOP-16

83854

DIP-16

CA

I

SENSE

MULT

VA

GND

PKLMT

OUT

OUT

IAC

OUT

V

RMS

GTDRV
V

CC

C

T

SS
R

SET

V

SENSE

ENA
V

ref

The TK83854's high reference voltage and high oscillator
amplitude minimize noise sensitivity while fast PWM

BLOCK DIAGRAM

elements permit chopping frequencies above 200 kHz.

IC POWER

1

V

CC

GT

DRV

15 V

The TK83854 can be used in systems with line voltages
that vary from 75 to 275 V and with line frequencies across
the 50 Hz to 400 Hz range. To reduce the burden on the

ORDERING INFORMATION

TK83854

Package Code

PACKAGE CODE

D: DIP-16
M: SOP-16

TEMP. RANGE

I: -40 TO +85

C

(OPTIONAL)

Tape/Reel Code

Extended Temp. Range

TAPE/REEL CODE

TL: Tape Left
MG: Magazine

V

SENSE

V

ENA

RMS

IAC

SS

16/10 V

2.5/2.25 V

7.5 V

R
RSQ

V

7-5 V

REF
RUN

ref

GND

MULT

VA

V

CC

14 µA

OUT

AB

IM =

C

A

B

2

C

X

I

SENSECTRSET

PKLMTCA

OUT

OUT

RUN

OSC

January 1999 TOKO, Inc. Page 1

TK83854

ABSOLUTE MAXIMUM RATINGS

Supply Voltage ......................................................... 35 V

Power Dissipation TK83854D (Note 1) ..................... 1 W

Power Dissipation TK83854M (Note 2).............. 750 mW

GTDRV Current (Continuous) ................................. 0.5 A

GTDRV Current (50% Duty Cycle).......................... 1.5 A

Input Voltage (V

SENSE, VRMS

Input Voltage (ENA, I

) .................................... 11 V

, MULTOUT) .................. 11 V

SENSE

TK83854 ELECTRICAL CHARACTERISTICS

Test conditions: V
VI

SENSE

= 0 V, V

Temperature Range, unless otherwise specified.

LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU

CC

OUT(CA)

= 18 V, R

= 3.5 V, V

= 15 k to GND, CT = 1.5 nF, PKLMT = 1 V, ENA = 7.5 V, V

SET

OUT(VA)

= 5 V, V

= 7.5 V, No load on SS, CA

SENSE

Input Voltage (PKLMT)............................................... 5 V

Input Voltage (IAC, R

Storage Temperature Range ................... -55 to +150 °C

Operating Temperature Range ......................0 to +70 °C

Extended Temperature Range................... -40 to +85 °C

Junction Temperature .......................................... 150 °C

Lead Soldering Temperature (10 s) ..................... 235 °C

OUT

, PKLMT) ........................ 10 mA

SET

= 1.5 V, IAC = 100 µA,

OUT

RMS

, V

, GTDRV, TA = Operating

ref

, VA

I
I

V

V
I
I

V
I

A

∆V

I
I

)FFO(CC

)NO(CC

OLVU
OLVU

ANE

ANE

)SMR(V

V

)NO(

CC

V

)FFO(

CC

)TSYH(ANE

V

SMR

FFOtnerruCylppuSV0=ANE5.10.2Am

NOtnerruCylppuS 0161Am

dlohserhTno-nruT5.410.615.71V
dlohserhTffo-nruT90111V

gnisiR,dlohserhTelbanE04.255.207.2V

siseretsyHdlohserhTelbanE02.052.003.0V

tnerruCtupnIelbanEV0=ANE0.5-2.0-0.5Aµ

tnerruCtupnIV

V5=0.1-10.0-0.1Aµ

SMR

REIFILPMAEGATLOV

)AV(SO

)AV(B

)AV(LO

)AV(CS

SS

V

ESNES

)AV(TUO

tnerruCSSV5.2=SS02-41-6-Aµ

tnerruCsaiB005-52-005An

niaGpmAegatloV07001Bd

egatloVtesffOpmAegatloVAV

gniwStuptuOpmAegatloV 8.5ot5.0V

tnerruCtiucriCtrohSpmAegatloVAV

V0=8-8Vm

TUO

V0=03-21-5-Am

TUO

REIFILPMATNERRUC

V

)AC(SO

I

)AC(B

A

∆V

Note 1: Power dissipation is 1 W when mounted as recommended. Derate at 8 mW/°C for operation above 25°C.
Note 2: Power dissipation is 750 mW when mounted as recommended. Derate at 3.3 mW/°C for operation above 25°C.
Gen. Note: All voltages with respect to GND (Pin 1).
Gen. Note: All currents are positive into the specified terminal.

I

ESNES

)AC(LO

)AC(TUO

tnerruCsaiB005-021-005An

niaGpmAtnerruC08011Bd

egatloVtesffOpmAtnerruC4-4Vm

gniwStuptuOpmAtnerruC 61ot5.0V

Page 2 January 1999 TOKO, Inc.

TK83854 ELECTRICAL CHARACTERISTICS (CONT.)

Test conditions: V
VI

SENSE

= 0 V, V

Temperature Range, unless otherwise specified.

LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU

CC

OUT(CA)

= 18 V, R

= 3.5 V, V

REIFILPMATNERRUC

= 15 k to GND, CT = 1.5 nF, PKLMT = 1 V, ENA = 7.5 V, V

SET

OUT(VA)

= 5 V, V

= 7.5 V, No load on SS, CA

SENSE

OUT

, VA

OUT

TK83854

= 1.5 V, IAC = 100 µA,

RMS

, V

, GTDRV, TA = Operating

ref

I

)AC(CS

V

)ESNESI(

I,egnaRtupnI

ESNES

TLUM,

WBGtcudorPWB-niaGpmAtnerruCT

tnerruCtiucriCtrohSpmAtnerruCAC

TUO

A

V0=03-21-5-Am

TUO

)3etoN(C°52=004008zHk

ECNEREFER

V

∆V

∆V

I

I

fer

V

)DAOL(fer

fer

V

)ENIL(fer

)CS(fer

fer

V

fer

egatloVecnerefeR

noitalugeRdaoLI<Am01-

noitalugeReniLV<V51

tnerruCtiucriCtrohSV

fer

I

fer

fer

T,Am0=

A

fer

CC

V0=05-82-21-Am

C°52=4.75.76.7V

.pmeTrevO,Am0=53.705.756.7V

Am0<51-551Vm

V53<01-201Vm

TIMILKAEP

V

)LP(SO

I

)LP(B

t

)LP(D

egatloVtesffOTMLKP 01-01Vm

tnerruCtupnITMLKPV1.0-=TMLKP002-001-Aµ

yaleD.porPVRDTGotTMLKP

Vm05-ot

Vm05morfgnillafTMLKP

REVIRDETAG

ot3.0-

5.2

V

571sn

V

)XAM(G

V

HG

V

)FFO(LG

egatloVtuptuOVRDTGmumixaMV<V81

HGIHegatloVtuptuOVRDTGV,ecruoSAm002

FFO,WOLegatloVtuptuOVRDTGV,kniSAm05

CC

CC

CC

daoLoN,V53<0.315.410.81V

V51=0.218.21V

V0=9.05.1V

kniSAm0020.12.2V

V

LG

I

)KP(G

t

t/

)G(R

)G(F

D

XAM

Note 3: Guaranteed by design; not 100% tested.
Gen Note: ENA input is internally clamped to approximately 14 V.

tnerruCVRDTGkaePdaoLFn010.1A

emiTllaF/esiRVRDTGdaoLFn153sn

,WOLegatloVtuptuOVRDTG

elcyCytuDmumixaMVRDTGAC

kniSAm011.04.0V

V7=59%

TUO

January 1999 TOKO, Inc. Page 3

TK83854

TK83854 ELECTRICAL CHARACTERISTICS (CONT.)

Test conditions: V
VI

SENSE

= 0 V, V

Temperature Range, unless otherwise specified.

LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU

REILPITLUM

I

)CAI(MO

CC

OUT(CA)

= 18 V, R

= 3.5 V, V

)DETIMIL

= 15 k to GND, CT = 1.5 nF, PKLMT = 1 V, ENA = 7.5 V, V

SET

OUT(VA)

= 5 V, V

tnerruCtuptuOreilpitluM

CAI(

= 7.5 V, No load on SS, CA

SENSE

R,Aµ001=CAI

TES

= 1.5 V, IAC = 100 µA,

OUT

, VA

OUT

RMS

, V

, GTDRV, TA = Operating

ref

k01=022-002-081-Aµ

tnerruCtuptuOreilpitluM

R(

oreZtnerruCtuptuOreilpitluMR,Aµ0=CAI

TES

TES

R,Aµ054=CAI

V

SMR

I

)CZ(MO

I

)TES(MO

)DETIMIL

V,Aµ05=CAI

V4=AV

V,Aµ001=CAI

V2=AV

I

MO

tnerruCtuptuOreilpitluM

V4=AV

V,Aµ002=CAI

V,Aµ003=CAI

V2=AV

V,Aµ001=CAI

V2=AV

k51=0.2-2.0-0.2Aµ

TES

SMR

SMR

SMR

SMR

SMR

,k51=

V6=AV,V1=

,V2=

,V2=

,V2=

,V1=

,V1=

082-552-022-Aµ

05-24-33-Aµ

83-72-21-Aµ

561-051-501-Aµ

052-522-051-Aµ

59-08-06-Aµ

KtnerruCniaGreilpitluM)4etoN(0.1-V

ROTALLICSO

f

CSO

V

PR

V

VR

Note 4: Multiplier gain constant (K) is defined by IOM = [K x I

C

T

C

T

ycneuqerFrotallicsO

edutilpmAkaeP-ot-kaePpmaR9.44.59.5V

egatloVyellaVpmaR8.01.13.1V

IAC

R

R

x (V

TES

TES

k51=645526zHk

k2.8=68201811zHk

OUT(VA)

- 1)] / V

RMS

2

.

Page 4 January 1999 TOKO, Inc.

TK83854

PKLMT

NC

CA

OUT

10 k

MULT

IAC

OUT

NC

VA

OUT

V

RMS

10 k

10 k

TYPICAL PERFORMANCE CHARACTERISTICS

CURRENT AMPLIFIER GAIN AND

120
100

80
60
40

20

(dB)AND PHASE MARGIN ( )

OL(CA)

-20

A

PHASE vs. FREQUENCY

PHASE MARGIN

OPEN LOOP GAIN

0

0.1 1 10 100 1000 10000
FREQUENCY (kHz)

10 nF

10 nF

TEST CIRCUIT

GND

PKLMT

CA

OUT

I

100

10 k

10 k

120
100

80
60
40

20

(dB)AND PHASE MARGIN ( )

OL(VA)

-20

A

SENSE

MULT

IAC

VA

OUT

V

RMS

TA = TJ = 25 °C

VOLTAGE AMPLIFIER GAIN AND

PHASE vs. FREQUENCY

OPEN LOOP GAIN

0

0.1 1 10 100 1000 10000
FREQUENCY (kHz)

IM = (AB) / C

B

AC

PHASE MARGIN

7.5 V

GTDRV

R

V

SENSE

V

ENA

SET

V

0.1 nF

0.39 nF

CC

C

T

SS

ref

1.0 nF

100

0.01 nF

8.2 k
10 k
15 k

10 µF

1.0 nF

GATE DRIVE MAXIMUM DUTY

100

NC

V

CC

ENA

NC

0.1 µF

CYCLE vs. R

SET

95

90

85

80

DUTY CYCLE (%)

75

70

0 10 100

R

(kΩ)

SET

MULTIPLIER OUTPUT vs.

VOLTAGE ON MULTIPLIER

600

400

(µA)

200

MULTOUT

VA

= 5 V

OUT

V(rms) = 2 V

MULTOUT = 0 V

MULTOUT = 1 V

0

0 200 400 600 800

IAC (µA)

MULTOUT = 2 V

MULTOUT = 3 V

OSCILLATOR FREQUENCY

R

AND C

SET

1000

100

10

FREQUENCY (kHz)

1

10 nF

5 nF

1 10 100

R

(kΩ)

SET

VS.

T

100 pF

200 pF

500 pF

1 nF

2 nF

3 nF

GATE DRIVE RISE AND FALL TIMES

vs. LOAD CAPACITANCE

700

500

(ns)

F(G)

/ t

300

R(G)

t

FALL TIME

RISE TIME

100

0 .01 .02 .03 .04 .05

C

(µF)

LOAD

January 1999 TOKO, Inc. Page 5

TK83854

TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)

TA = TJ = 25 °C

MULTIPLIER OUTPUT vs. MULTIPLIER

INPUT (MULTOUT = 0 V)

300

V(rms) = 3 V

250

200

VA

OUT

= 5 V

150

VA

OUT

100

MULT OUT (µA)

50

VA

= 1.25 V

0

0 100 200 300 400 500

OUT

IAC (µA)

= 3 V

VA

OUT

= 2 V

MULTIPLIER OUTPUT vs. MULTIPLIER

INPUT (MULTOUT = 0 V)

160

V(rms) = 4 V

120

VA

= 5 V

OUT

VA

80

MULT OUT (µA)

VA

40

0

0 100 200 300 400 500

VA

IAC (µA)

OUT

OUT

VA

OUT

= 4 V

= 3 V

OUT

= 1.25 V

= 2 V

MULTIPLIER OUTPUT vs. MULTIPLIER

INPUT (MULTOUT = 0 V)

140

V(rms) = 5 V

100

VA

= 5 V

OUT

VA

OUT

60

MULT OUT (µA)

VA

= 1.25 V

20

OUT

0 100 200 300 400 500

IAC (µA)

= 3 V

Page 6 January 1999 TOKO, Inc.

PIN DESCRIPTION

TK83854

GROUND PIN (GND)

All voltages are measured with respect to GND. VCC and
V

should be bypassed directly to GND with a 0.1 µF or

ref

larger ceramic capacitor. The timing capacitor discharge
current also returns to this pin, so the lead from the
oscillator timing capacitor to GND should also be as short
and as direct as possible.

PEAK LIMIT (PKLMT)

The threshold for PKLMT is GND. Connect this input to the
negative voltage on the current sense resistor as shown in
Figure 1. Use a resistor to V

to offset the negative current

ref

sense signal up to GND.

CURRENT AMPLIFIER OUTPUT (CA

OUT

)

This is the output of a wide-bandwidth op-amp that senses
line current and commands the Pulse Width Modulator
(PWM) to force the correct current. This output can swing
close to GND, allowing the PWM to force zero duty cycle
when necessary. The current amplifier will remain active
even if the IC is disabled.

CURRENT SENSE MINUS (I

SENSE

)

This is the inverting input to the current amplifier. This input
and the non-inverting input MULT

remain functional

OUT

down to and below GND. Care should be taken to avoid
taking these inputs below –0.5 V, because they are
protected with diodes to GND.

MULTIPLIER OUTPUT AND CURRENT SENSE PLUS
(MULT

OUT

)

The output of the analog multiplier and the non-inverting
input of the current amplifier are connected together at
MULT
also apply to MULT
current, this is a high impedance input similar to I

. The cautions about taking I

OUT

. As the multiplier output is a

OUT

below –0.5 V

SENSE

SENSE

, so
the current amplifier can be configured as a differential
amplifier to reject GND noise. Figure 1 shows an example
of using the current amplifier differentially.

INPUT AC CURRENT (IAC)

be used for sensing instantaneous line voltage. The nominal
voltage on IAC is 6 V, so in addition to a resistor from IAC
to rectified line, connect a resistor from IAC to V
resistor to V

is one-fourth of the value of the resistor to

ref

. If the

ref

the rectifier, then the 6 V offset will be cancelled, and the
line current will have minimal crossover distortion.

VOLTAGE AMPLIFIER OUTPUT (VA

OUT

)

This is the output of the op-amp that regulates output
voltage. Like the current amplifier, the voltage amplifier will
also stay active even if the IC is disabled with either ENA
or VCC. This means that large feedback capacitors across
the amplifier will stay charged through momentary disable
cycles. Voltage amplifier output levels below ~1 V will
inhibit multiplier output.

RMS LINE VOLTAGE (V(rms))
The output of a boost PWM is proportional to the input

voltage, so when the line voltage into a low-bandwidth
boost PWM voltage regulator changes, the output will
change immediately and slowly recover to the regulated
level. For these devices, the V(rms) input compensates for
line voltage changes if it is connected to a voltage
proportional to the RMS input line voltage. For best control,
the V

VOLTAGE REFERENCE OUTPUT (V

V

ref

voltage should stay between 1.5 V and 3.5 V.

RMS

)

ref

is the output of an accurate 7.5 V voltage reference.
This output is capable of delivering 10 mA to peripheral
circuitry and is internally short circuit current limited. V

ref

is
disabled and will remain at 0 V when VCC is low or when
ENA is low. Bypass V

to GND with a 0.1 µF or larger

ref

ceramic capacitor for best stability.
ENABLE (ENA)
ENA is a logic input that will enable the PWM output,

voltage reference, and oscillator. ENA also will release the
soft start clamp, allowing SS to rise. When unused, connect
ENA to a +5 V supply or pull ENA high with a 22 k resistor.
The ENA pin is not intended to be used as a high-speed
shutdown to the GTDRV output.

This input to the analog multiplier is a current. The multiplier
is tailored for very low distortion from this current input (IAC
to MULT

), so this is the only multiplier input that should

OUT

January 1999 TOKO, Inc. Page 7

TK83854

PIN DESCRIPTION (CONT.)

VOLTAGE AMPLIFIER INVERTING OUTPUT (V

SENSE

This is normally connected to a feedback network and to
the boost converter output through a divider network.

OSCILLATOR CHARGING CURRENT AND MULTIPLIER
LIMIT SET (R

A resistor from R

SET

)

to ground will program oscillator

SET

charging current and maximum multiplier output. Multiplier
output current will not exceed 3.75 V divided by the resistor
from R

to ground.

SET

SOFT-START (SS)
SS will remain at GND as long as the IC is disabled or V

CC

is too low. SS will pull up to over 8 V by an internal 14 µA
current source when both VCC becomes valid and the IC is
enabled. SS will act as the reference input to the voltage
amplifier if SS is below V

. With a large capacitor from SS

ref

to GND, the reference to the voltage regulating amplifier
will rise slowly, and increase the PWM duty cycle slowly.
In the event of a disable command or a supply dropout, SS
will quickly discharge to ground and disable the PWM.

)

interaction between the gate impedance and the GTDRV
output driver that might cause the GTDRV output to
overshoot excessively. Some overshoot of the GTDRV
output is always expected when driving a capacitive load.

OSCILLATOR TIMING CAPACITOR (CT )

A capacitor from CT to GND will set the PWM oscillator
frequency according to this relationship:

f

= 1.25 / (R

OSC

SET

x CT)

POSITIVE SUPPLY VOLTAGE (VCC)

Connect VCC to a stable source of at least 20 mA above 17
V for normal operation. Also bypass VCC directly to GND to
absorb supply current spikes required to charge external
MOSFET gate capacitances. To prevent inadequate
GTDRV signals, these devices will be inhibited unless V

CC

exceeds the upper undervoltage lockout threshold and
remains above the lower threshold.

GATE DRIVER (GTDRV)
The output of the PWM is a totem pole MOSFET gate

driver on GTDRV. This output is internally clamped to
15 V so the IC can be operated with VCC as high as 35 V.
Use a series gate resistor of at least 5 ohms to prevent

Page 8 January 1999 TOKO, Inc.

APPLICATION INFORMATION

TK83854

A 250 W PREREGULATOR

Figure 1 shows a typical application of the TK83854 as a
preregulator with high power factor and efficiency. The
assembly consists of two distinct parts, the control circuit
centering on the TK83854 and the power section.

The power section is a "boost" converter, with the inductor
operating in the continuous mode. In this mode, the duty
cycle is dependent on the ratio between input and output
voltages. Also, the input current has low switching frequency
ripple, which means that the line noise is low. Furthermore,
the output voltage must be higher than the peak value of
the highest expected AC line voltage, and all components
must be rated accordingly.

In the control section, the TK83854 provides PWM pulses
to the power MOSFET gate (GTDRV, Pin 16). The duty
cycle of this output is simultaneously controlled by four
separate inputs to the chip:

INPUT PIN # FUNCTION

V

11 Output DC Voltage

SENSE

IAC 6 Line Voltage Waveform
I
V

/MULT

SENSE

8 RMS Line Voltage

RMS

4/5 Line Current

OUT

Additional controls of an auxiliary nature are provided.
They are intended to protect the switching power MOSFET
from certain transient conditions, as follows:

INPUT PIN # FUNCTION

ENA 10 Start-up Delay

SS 13 Soft Start

PKLMT 2 Maximum Current Limit

Soft-Start (SS)

The voltage at Pin 13 (SS) can reduce the reference
voltage used by the error amplifier to regulate the output
DC voltage. With Pin 13 open, the reference voltage is
typically 7.5 V. An internal current source delivers
approximately 14 µA from Pin 13. Thus, a capacitor
connected between that pin and GND will charge linearly
from zero to 7.5 V in 0.54 x C seconds, with C expressed
in microfarads.

Peak Current Limit (PKLMT)

Use Pin 2 to establish the highest value of current to be
controlled by the power MOSFET. With the resistor divider
values shown in Figure 1, the 0.0 V threshold at Pin 2 is
reached when the voltage drop across the 0.25 Ω current
sense resistor is 7.5 V x 1.6 k / 10 k = 1.2 V, corresponding
to 4.8 A. A bypass capacitor from Pin 2 to ground is
recommended to filter out very high frequency noise.

CONTROL INPUTS

Output DC Voltage Sense (V

The threshold voltage for the V

)

SENSE

input is 7.5 V and the

SENSE

input bias current is typically -10 nA. The values shown in
Figure 1 are for an output voltage of 400 VDC. In this
circuit, the voltage amplifier operates with a constant low
frequency gain for minimum output excursions. The

0.047 µF feedback capacitor places a 15 Hz pole in the
voltage loop that prevents 120 Hz ripple from propagating
to the output current.

Line Waveform (IAC)

PROTECTION INPUTS

Enable (ENA)

The ENA input must reach 2.5 V before the V

ref

and
GTDRV outputs are enabled. This provides a means to
shut down the gate in case of trouble, or to add a time delay
at power up. A hysteresis gap of 200 mV is provided at this
terminal to prevent erratic operation. Undervoltage
protection is provided directly at Pin 15, where the on/off
thresholds are 16 V and 10 V, respectively.

In order to force the line current waveshape to follow the
line voltage, a sample of the power line voltage waveform
is introduced at Pin 6. This signal is multiplied by the output
of the voltage amplifier in the internal multiplier to generate
a reference signal for the current control loop.

This input is not a voltage, but a current (hence IAC). It is
set up by the 220 k and 910 k resistive divider (see Figure

1). The voltage at pin 6 is internally held at 6 V, and the two
resistors are chosen so that the current flowing into pin 6
varies from zero (at each zero crossing) to about 400 µA
at the peak of the waveshape. The following formulas were

January 1999 TOKO, Inc. Page 9

TK83854

APPLICATION INFORMATION (CONT.)

used to calculate these resistors:
R

IAC

= V

PK(MAX)

/ 400 E - 6
= (260 VAC x 2 ) / 400 µA
= 910 k
R

REF

= R

/ 4 = 220 k

IAC

where VPK is the peak line voltage.

Line Current (I

/MULTOUT )

SENSE

The voltage drop across the 0.25 Ω current-sense resistor
is applied to Pins 4 and 5 as shown. The current-sense
amplifier also operates with high low-frequency gain, but
unlike the voltage amplifier, it is set up to give the current­control loop a very wide bandwidth. This enables the line
current to follow the line voltage as closely as possible. In
the present example, this amplifier has a zero at about
500 Hz, and a gain of about 18 dB thereafter.

RMS Line Voltage (V

RMS

)

An important feature of the TK83854 preregulator is that it
can operate with a three-to-one range of input line voltages,
covering everything from low line in Japan (85 VAC) to
high line in Europe (255 VAC). This is done using line feed­forward, which keeps the input power constant with varying
input voltage (assuming constant load power). To do this,
the multiplier divides the line current by the square of the
rms value of the line voltage. The voltage applied to Pin 8,
proportional to the average of the rectified line voltage (and
proportional to the RMS value), is squared in the TK83854,
and then used as a divisor by the multiplier block. The
multiplier output, at Pin 5, is a current that increases with
the current at Pin 6 and the voltage at Pin 7, and decreases
with the square of the voltage at pin 8.

With R

SET

= 15 k:

I

OM(MAX)

= -3.75 V / 15 k = -250 µA

It is also important to note that the multiplier output current
will never exceed twice IAC.

With the 3.9 k resistor from MULT

to the 0.25 Ω current

OUT

sense resistor, the maximum current in the current sense
resistor will be:

I

RCS(MAX)

Having selected R
resistor from MULT

= (-I

OM(MAX)

SET

x 3.9 k) / 0.25 Ω = -3.9 A

, the current sense resistor, and the

to the current sense resistor,

OUT

calculate CT for the desired PWM oscillator frequency from
the equation:

CT = 1.25 / (f

OSC

x R

SET

)

PWM Frequency

The PWM oscillator frequency in Figure 1 is 100 kHz. This
value is determined by CT at Pin 14 and R
R

should be chosen first because it affects the maximum

SET

at Pin 12.

SET

value of IOM according to the equation:

I

OM(MAX)

= -3.75 V / R

SET

This effectively sets a maximum PWM-controlled current.

Page 10 January 1999 TOKO, Inc.

TH1

KC015L

R

25

910 K

F

1

6 A

C

1

0.47 µF

Q

3

ZVN4206A

R

9

91 K

C

12

0.1 µF

R

24 K

R

910 K

R

220 K

R

20 K

8

28

10

21

1KBU8J

R

470 K

1N4148

1N4746A
R

20

3 K

C

7

0.47 µF

TK83854

APPLICATION INFORMATION (CONT.)

D

9

IC POWER

1

R

511 K

R
10 K

15 V

17

V

OUT

385 VDC

18

R

16

20

V

CC

D

4

1N5821

GT

DRV

BR

~

+

D

R

27

8.2 M

V

SENSE

V

0.01 µF

11

ENA

IAC

RMS

C

MUR110

C

14

0.1 µF
C

17

0.1 µF
D

MUR110

V

CC

SS

10

0.47 µF

~

-

R

23

D

D

22

30 K

TIP50GE

Q

2

5

3

R

13

75 K

R

12

27 K

+

C

C

9

16

220 µF

1 µF

12

C

16 V

2.5 V

7.5 V

1N5406

L

5

14 µA

1

1 mH

D

13

R

7

240 K

C6 0.047 µF

VA

2

X

1N4148

OUT

MULT

IM =

A

B

C

R

3.9 K

AB

C

I

2

D

7

1N5817

OUT

LIMIT

0.25

C

13

68 pF

D

10

I

SENSE

C

C

1000 pF

R

1

C

15

1N4737

T

11

680 pF

R

24 K

6

RUN

1.6 K

OSC

R

3.9 K

R

PKLMT

D

MUR860

Q

1

IRF840

3

4

C3 270 pF

D8 1N5817

R

R
RSQ

R

SET

R

14

15 k

2

+

C

2

330 µF

C4 1 µF

10 K

29

V

ref

7-5 V

REF

RUN

GND

FIGURE 1: 250 W PREREGULATOR

January 1999 TOKO, Inc. Page 11

TK83854

PACKAGE OUTLINE

SOP-16

DIP-16

Lot Number

16 9

7.5

81

10.3

2.3

+0.15

-0.05

0.4

16

1 8

Çl

0.12

Dimensions are shown in millimeters
Tolerance: x.x = ± 0.2 mm (unless otherwise specified)

e

1.27

0.1

0 ~ 0.3

2.8 max

9

Marking

6.35

0.76

1.7

e

1.27

Recommended Mount Pad

0.7

+

0.3

10.3

Country of Origin

0 ~ 10

Marking Information

9.53

1

e

+0.15

-0.05

0.25

Marking
TK83854 83854

19.05

0.3
+

3.3

4.2

0.3
+

3.2

e

2.54

Dimensions are shown in millimeters
Tolerance: x.x = ± 0.2 mm (unless otherwise specified)

0.5 min

0.5

M0.25

+0.15

e

-0.05

0.25

0 ~15

1

7.62

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Tel: [phone]
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Visit our Internet site at http://www.tokoam.com

The information furnished by TOKO, Inc. is believed to be accurate and reliable. However, TOKO reserves the right to make changes or improvements in the design, specification or manufacture of its
products without further notice. TOKO does not assume any liability arising from the application or use of any product or circuit described herein, nor for any infringements of patents or other rights of
third parties which may result from the use of its products. No license is granted by implication or otherwise under any patent or patent rights of TOKO, Inc.

Page 12 January 1999 TOKO, Inc.

All Rights Reserved

IC-167-TK83854

0798O0.0K

Printed in the USA© 1999 Toko, Inc.