TOKO TK75002DIMG Datasheet

TK75002

ERROR SIGNAL ISOLATOR

FEATURES

■ Eliminates Opto-coupler from Feedback Loop

■ Replaces TL431 and Eliminates Parasitic Zero

■ Pulse Transformer Driver

■ Same Transformer for Any Output Voltage

■ Peak Current Controlled

■ Automatic Volt-Second Balancing

■ Self-running Oscillator

■ Hi-performance Op-amp & Bandgap Reference

■ Functionally Integrated & Simplified 5-pin Design

DESCRIPTION

The TK75002 monitors the output voltage of a power
supply, generates an error signal, and transmits the error
signal across an isolation barrier using a small pulse
transformer. In conjunction with the pulse transformer, it
replaces the TL431/opto-coupler combination and
eliminates the undesirable zero created in the feedback
loop by that combination. The transformer is driven with
pulse amplitude modulation in a free-running oscillator
configuration. The period of oscillation is proportional to
the inductance of the pulse transformer. The magnitude of
the voltage pulse is internally limited so that the pulse
transformer design need not be changed for various output
voltages.

APPLICATIONS

■ Power Supplies with Primary-Side Controller

■ Low Isolation-Barrier Capacitance Equipment

■ Instrumentation

■ Industrial Process Control

■ Test Equipment

■ Data Acquisition

TK75002

75002

DRV

GND NC

NC

V

NC

COMPINV

CC

The TK75002 is available in an 8-pin DIP package.

BLOCK DIAGRAM

V

220 mV

CC

BUFFER

UVLO

GND

+

V

LS

-

ERROR AMPLIFIER

4 Ω

BANDGAP

REFERENCE

LEVEL SHIFTER

VLS = K(2.5 V - V

2.5 V

+

V

-

COMP

COMP

)

COMP

INV

1.35 V

ORDERING INFORMATION

TK75002D

EXTENDED TEMP. RANGE

I: -40 TO +85 C

Tape/Reel Code
Temperature Code

TAPE/REEL CODE

MG: Magazine

DRV

TRANSFORMER
RESET
DETECTOR

PAM LATCH

S

R

PEAK

CURRENT

DETECTOR

650 mV

Q

PAM SWITCH

January 1999 TOKO, Inc. Page 1

TK75002

ABSOLUTE MAXIMUM RATINGS

Supply Voltage ........................................................... 7 V

Power Dissipation (Note 1) ................................ 825 mW

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

Operating Temperature Range ...................-20 to +70 °C

TK75002 ELECTRICAL CHARACTERISTICS

Test conditions: V

LOBMYSRETEMARAPSNOITIDNOCTSETNIMPYTXAMSTINU

= 5 V, T

CC

= Full Operating Range. Typical numbers apply at TA = 25 °C, unless otherwise specified.

A

Extended Temperature Range (I) .............. -40 to +85 °C

Operating Voltage Range............................... 1.6 to 12 V

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

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

I

)FFO(CC

I

)NO(CC

V

CC

V

)NO(CC

V

)TSYH(CC

siseretsyHOLVUV

tnerruCylppuSybdnatSV

CC

tnerruCylppuSgnitarepOnepOniPVRD5.951Am

egnaRegatloVgnitarepO7.47V

dlohserhThgiHOLVUV

V5.3=0010060001Aµ

V=

PMOC

PMOC

)AE(fer

V=

)AE(fer

5.31.47.4V

51021003Vm

)SNIPPMOCDNAVNI(NOITCESREIFILPMARORRE

T

V

)AE(fer

A

LO

egatloV

niaGpooLnepO3556Bd

ecnerefeRlanretnItnelaviuqE

A

T

A

C°52=033.1053.1073.1V

egnaRlluF=13.193.1V

WBGtcudorPhtdiwdnaB-niaG 5.4zHM

RSSPoitaRnoitcejeRylppuSrewoP0507Bd
I
I
I

)KNIS(PMOC

)CRS(PMOC

VNI

tnerruCsaiBV

tnerruCkniSmumixaMV

tnerruCecruoSmumixaMV

PMOC

PMOC

V=

VNI

VottrohS=

CC

246 Am

ottrohS=DNG52-81-5-Am

PMOC

2-2.02Aµ

)NIPVRD(NOITCESROTALUDOMEDUTILPMAESLUP

I

)KP(VRD

t

D,FFO

V-

V

CC

V

V

HT,DRT

)NO(VRD

V-

)FFO(VRD

CC

edoiD

remrofsnarT

dlohserhT

niPVRDotnoitceteD

dlohserhTtnerruCevirDkaeP035557Am

kaePmorfyaleDffo-nruT

esluPssorcAegatloVkaeP

pmalCssorcAegatloVkaeP

I

I

rotceteDteseRremrofsnarT

Hµ5=L05571053sn

I=

VRD

VRD

V,

≥ V58.25.38.4V

)KP(VRD

CC

Am05=6.08.02.1V

092056059Vm

kegatSretfihSleveLfoniaG00.152.154.1V/V

Note 1: Power dissipation is 825 mW when mounted as recommended. Derate at 6.6 mW/°C for operation above 25 °C.

Page 2 January 1999 TOKO, Inc.

TYPICAL PERFORMANCE CHARACTERISTICS

GAIN (dB)

20

60

GAIN AND PHASE OF ERROR AMP

FREQUENCY (Hz)

0

10

2

103 104 105 106 10

7

40

-20

80

100

PHASE (°)

GAIN (dB)

180

150

120

90

60

30

0

PHASE ( )

TK75002

SUPPLY CURRENT vs.

SUPPLY VOLTAGE

12

10

STANDBY

8

(mA)

CC

I

6

4

0

3.8 4.0 4.1 4.2 5 7

PEAK DRIVE CURRENT THRESHOLD

80

70

(mA)

60

DRV(PK)

I

50

vs. TEMPERATURE

OVER SUPPLY RANGE

DEVICE ON

VCC (V)

INTERNAL REFERENCE VOLTAGE

vs. TEMPERATURE

1.40

1.38

1.36

(V)

ref

V

1.34

1.32

1.30

-40 0 40 80 120
TA (°C)

GAIN OF LEVEL SHIFTER (k) vs.

1.50

1.40

1.30

1.20

GAIN (V/V)

1.10

TEMPERATURE

5 V

PEAK VOLTAGE ACROSS

TRANSFORMER vs. TEMPERATURE

3.5

3.3

3.1

(V)

PK

V

2.9

2.7

2.5

-40 0 40 80 120
TA (°C)

40

-40 0 40 80 120

FREQUENCY vs. INDUCTOR

1.0

0.8

0.6

0.4

FREQUENCY (MHz)

0.2

0.0
0 10 20 30 40 50 60

INDUCTANCE (µH)

January 1999 TOKO, Inc. Page 3

TA (°C)

(V

CC

= 5 V)

(mA)
I

1.00

-40 0 40 80 120
TA (°C)

SUPPLY CURRENT vs. FREQUENCY

50

45

40

35

CC

30

25

20

0 0.2 0.4 0.6 0.8 1.0 1.2

(VCC = 5 V)

FREQUENCY (MHz)