TK75003D TOKO, Inc, TK75003D Datasheet

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TK75003D

Manufacturer Part Number
TK75003D
Description
PWM CONTROLLER
Manufacturer
TOKO, Inc
Datasheet
FEATURES
Power Factor Correction/Line Harmonics
Reduction to Meet IEC1000-3-2 Requirements
Optimized for Off-Line Operation
Maximum Duty Ratio 88% (typ.)
Frequency Reduction for Improved Overcurrent
Protection
Low Standby Current for Current-Fed Start-Up
Current-Mode or Voltage-Mode Control
Internal User-Adjustable Slope Compensation
Functionally Integrated & Simplified 5-Pin Design
DESCRIPTION
The TK75003 is a simple primary side controller optimized
for off-line switching power supplies including power factor
correctors. It is suitable for both voltage-mode and current-
mode control and has advanced features not available in
controllers with a
higher pin count. The key to full
functionality in a 5-pin design is that the current signal and
the error signal are added together and fed into the
feedback pin. A sawtooth current flowing out of the feedback
pin provides a slope compensation ramp (in current-mode
applications) or a PWM ramp (in voltage-mode
applications), in proportion to the resistance terminating
that pin. If the sum of the current sense signal, error signal
and ramp signal exceeds the Overcurrent Detector
threshold indicating that the Current Control Detector has
lost control of the switch current, the charging current of
the timing capacitor will be reduced to about 25% for the
remainder of the clock period. The reduced charging
current causes no more than a one-third reduction in
switching frequency, effectively preventing short-circuit
current runaway.
ORDERING INFORMATION
TK75003D
TEMP. CODE (OPTIONAL)
I: -40 to +85 C
January 1999 TOKO, Inc.
APPLICATIONS
Power Factor Correction Converters
Off-Line Power Supplies
Industrial Power Supplies
Telecom Power Supplies
Off-Line Battery Chargers
I CT
C T
146 µA
Tape/Reel Code
Temperature Code
TAPE/REEL CODE
FB
MG: Magazine
TK75003
PWM CONTROLLER
TK75003
DRV
GND
GND
C T
Note: Pins 2 and 3 must be externally
connected for proper operation.
BLOCK DIAGRAM
BANDGAP
REFERENCE
I CHG
205 µA
10.5 V
OSCILLATOR
f CLK
I DS
I FR
2 mA
R
FREQUENCY
Q
REDUCTION
LATCH
S
PWM LATCH
SLOPE
COMPENSATION
S
Q
OVERCURRENT
R
DETECTOR
1.35 V
CURRENT
CONTROL
DETECTOR
0.98 V
GND
V CC
NC
NC
FB
V CC
UVLO
14.5 V
17.5 V
DRV
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TK75003D Summary of contents

Page 1

... The reduced charging current causes no more than a one-third reduction in switching frequency, effectively preventing short-circuit current runaway. ORDERING INFORMATION TK75003D TEMP. CODE (OPTIONAL) I: -40 to +85 C January 1999 TOKO, Inc. APPLICATIONS Power Factor Correction Converters ...

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... ° January 1999 TOKO, Inc ...

Page 3

... Note 1: Power dissipation is 825 mW when mounted. Derate at 6.6 mW/ C for operation above 25 C. Note 2: For temperature dependence refer to "Slope Compensation Peak Current vs. Temperature" graph. Note 3: The UVLO "on" voltage is guaranteed always to be below the internal clamp voltage. Note 4: Guaranteed by design; not 100% tested. January 1999 TOKO, Inc 800 pF 1000 pF, T ...

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... C DRV = DRV = 500 DRV = 120 0 400 800 FREQUENCY (kHz 4.7 µF 1 µF VS. CURRENT CONTROL REFERENCE TEMPERATURE VS. 1.00 0.98 0.96 0.94 0.92 0.90 10000 -40 0 TEMPERATURE ( C) FREQUENCY REDUCTION RATIO VS. TEMPERATURE -40 0 1200 1600 TEMPERATURE ( C) January 1999 TOKO, Inc 120 VS 120 ...

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... TYPICAL PERFORMANCE CHARACTERISTICS (CONT.) SLOPE COMPENSATION RAMP GND 600 800 pF 450 300 150 TIME (µs) January 1999 TOKO, Inc. i SC(PK) i SC(PK - VL) i SC(VL) 20 TK75003 Page 5 ...

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... The Undervoltage Lockout (UVLO) feature with hysteresis minimizes the start-up current which allows a low-power boot-strap technique to be used for the housekeeping power. The duty ratio of the TK75003 is limited to approximately 88% by the time required to discharge the timing ramp. January 1999 TOKO, Inc. ...

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... January 1999 TOKO, Inc. PIN DESCRIPTIONS current with a peak value of about 200 A. The error signal is needed for stabilizing the output voltage or current. The ...

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... T)] + [(V AUX 1 D3 AUX 1 can be calculated as follows OUT OVERSHOOT is the additional voltage appearing OVERSHOOT can be calculated as follows OUT D2 January 1999 TOKO, Inc. is the AUX . The T)]) 2 D3 AUX ...

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... R yields: AUX R = 20.6 AUX Rounding the result to the nearest 5% standard value gives AUX January 1999 TOKO, Inc. DESIGN CONSIDERATIONS (CONT.) can be calculated as OVERSHOOT and T is the 2 FIGURE 1: TK75003 IN A FLYBACK POWER SUPPLY or the voltage V AUX AUX (a) SCHEMATIC ...

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... AUX + DRV PWM RAMP FB GND TL431 (a) CYCLE-BY-CYCLE CURRENT LIMIT (b) VOLTAGE AT FEEDBACK PIN keeps the timing pin at ground potential 1 is turned off. The off-time 1 January 1999 TOKO, Inc 0.98 V FEEDBACK VOLTAGE 0 (b) 1 ...

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... V FEEDBACK VOLTAGE LEVEL FB FIGURE 6: TIMING PIN AND FEEDBACK PIN VOLTAGES WITH CONSTANT OFF-TIME CURRENT- MODE CONTROL January 1999 TOKO, Inc. TK75003 IN NON-ISOLATED APPLICATIONS Although the IC was intended for off-line power-supply applications with the voltage-error amplifier at the isolated + V OUT output easy and economical to use the device in non- isolated applications, too ...

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... I(MIN)(PK EFF = 107 OUT (at peak of minimum line voltage 1.95 A L1(PK) I I(MIN)(PK) (Note 1 4.312 kohms 7 MAX CCD SC(PK) January 1999 TOKO, Inc 100 kHz 0.88 MAX I = 200 A SC(PK 0.98 V CCD = 120 0.684 : 0.33 A ...

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... 250 V 10 600 V, 1 85-265 VAC 0.1 µF FIGURE 9: BOOST POWER FACTOR CORRECTOR APPLICATION CIRCUIT January 1999 TOKO, Inc. (Note 2 0.201 ohms L1(PK 2 220 ...

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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 ...

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