TK75002DIMG TOKO [TOKO, Inc], TK75002DIMG Datasheet

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TK75002DIMG

Manufacturer Part Number
TK75002DIMG
Description
ERROR SIGNAL ISOLATOR
Manufacturer
TOKO [TOKO, Inc]
Datasheet
EXTENDED TEMP. RANGE
I: -40 TO +85 C
FEATURES
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.
The TK75002 is available in an 8-pin DIP package.
January 1999 TOKO, Inc.
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
TK75002D
ORDERING INFORMATION
Temperature Code
Tape/Reel Code
TAPE/REEL CODE
MG: Magazine
APPLICATIONS
DRV
Power Supplies with Primary-Side Controller
Low Isolation-Barrier Capacitance Equipment
Instrumentation
Industrial Process Control
Test Equipment
Data Acquisition
TRANSFORMER
RESET
DETECTOR
DETECTOR
CURRENT
PEAK
PAM LATCH
S
R
650 mV
ERROR SIGNAL ISOLATOR
Q
BLOCK DIAGRAM
PAM SWITCH
220 mV
TK75002
BUFFER
V CC
DRV
GND
UVLO
GND
INV
NC
4
V LS
ERROR AMPLIFIER
+
-
V LS = K(2.5 V - V COMP )
+
-
LEVEL SHIFTER
REFERENCE
TK75002
BANDGAP
2.5 V
V COMP
1.35 V
Page 1
V CC
NC
NC
COMP
COMP
INV

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TK75002DIMG Summary of contents

Page 1

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 ...

Page 2

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 ...

Page 3

TYPICAL PERFORMANCE CHARACTERISTICS SUPPLY CURRENT vs. SUPPLY VOLTAGE 12 10 STANDBY 8 6 DEVICE 3.8 4.0 4.1 4 (V) PEAK DRIVE CURRENT THRESHOLD vs. TEMPERATURE 80 70 OVER SUPPLY RANGE -40 ...

Page 4

TK75002 The TK75002 can be used in conjunction with either an opto-coupler or a pulse transformer to isolate an error signal developed by its internal op-amp. The op-amp can be externally compensated and features a precision reference voltage at the ...

Page 5

V PIN CC This pin is connected to the supply voltage. The operation of the IC is enabled when the supply voltage exceeds 4.1 V, which is the upper threshold of the undervoltage lockout circuit. The operation is disabled when ...

Page 6

TK75002 THE PARASITIC ZERO AND HOW IT IS ELIMINATED IN THE TK75002 In a feedback-regulated isolated power supply, isolation is usually provided by an opto-coupler whose photodiode section is connected between the output of the power supply and the output ...

Page 7

APPLICATION INFORMATION (CONT 2 COMP - FIGURE 4: ELIMINATING THE Feed-forward OF THE SUPPLY VOLTAGE IN THE TK75002 ISOLATION WITH PULSE TRANSFORMER Figure 5 shows an application where the error signal is ...

Page 8

TK75002 APPLICATION INFORMATION (CONT.) TEST CIRCUIT EXAMPLE This simple circuit shown in Figure 7 is designed to allow the user to probe and observe the characteristic performance and behavior of either a TK75001 or a TK75003 operating with a TK75002. ...

Page 9

APPLICATION INFORMATION (CONT.) V CC1 V CC2 DRV GND NC TK75002 INV 33 k GND2 January 1999 TOKO, Inc 0.1 µF NC COMP 3 3.9 k FIGURE 7: TEST CIRCUIT ...

Page 10

TK75002 DIP 9.5 e 2.54 0.46 Dimensions are shown in millimeters Tolerance: x.x = 0.2 mm (unless otherwise specified) TOKO AMERICA REGIONAL OFFICES Midwest Regional Office Western Regional Office Toko America, Inc. Toko America, Inc. 1250 ...

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