TK75003
PWM CONTROLLER
FEATURES
s
Power Factor Correction/Line Harmonics
Reduction to Meet IEC1000-3-2 Requirements
s
Optimized for Off-Line Operation
s
Maximum Duty Ratio 88% (typ.)
s
Frequency Reduction for Improved Overcurrent
Protection
s
Low Standby Current for Current-Fed Start-Up
s
Current-Mode or Voltage-Mode Control
s
Internal User-Adjustable Slope Compensation
s
Functionally Integrated & Simplified 5-Pin Design
APPLICATIONS
s
Power Factor Correction Converters
s
Off-Line Power Supplies
s
Industrial Power Supplies
s
Telecom Power Supplies
s
Off-Line Battery Chargers
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.
TK75003
DRV
VCC
NC
NC
GND
3
7500
GND
CT
FB
Note: Pins 2 and 3 must be externally
connected for proper operation.
BLOCK DIAGRAM
VCC
ICT
CT
ICHG
205 µA
OSCILLATOR
IFR
146 µA
IDS
2 mA
fCLK
BANDGAP
REFERENCE
14.5 V
10.5 V
17.5 V
UVLO
ORDERING INFORMATION
Q
R
FREQUENCY
REDUCTION
LATCH
S
TK75003D
Tape/Reel Code
Temperature Code
SLOPE
COMPENSATION
PWM LATCH
S
Q
R
DRV
OVERCURRENT
DETECTOR
1.35 V
TEMP. CODE (OPTIONAL)
I: -40 to +85 C
TAPE/REEL CODE
MG: Magazine
FB
0.98 V
CURRENT
CONTROL
DETECTOR
GND
January 1999 TOKO, Inc.
Page 1
TK75003
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (Low Impedance Source) ................ 16 V
Supply Voltage (I
CC
< 30 mA) ...................... Self Limiting
Power Dissipation (Note 1) ................................ 825 mW
Output Energy (Capacitive Load) .............................. 5
µJ
C
T
and FB Pins ........................................................ 16 V
Junction Temperature ........................................... 150
°C
Storage Temperature Range ................... -55 to +150
°C
Operating Temperature Range ...................-20 to +80
°C
Extended Temperature Range ................... -40 to +85
°C
Lead Soldering Temperature (10 s) ...................... 235
°C
TK75003 ELECTRICAL CHARACTERISTICS
Test Conditions: V
CC
= 13 V, C
CC
= 4.7
µF,
C
T
= 800 pF, C
DRV
= 1000 pF, T
A
= T
j
= Full Operating Temperature Range.
Typical numbers apply at T
A
= 25
°C,
unless otherwise specified.
SYMBOL
I
CC(START)
I
CC(ON)
V
CC(ON)
V
CC(OFF)
V
HYST
V
CC(CLAMP)
PARAMETER
Start-up Supply Current
Operating Supply Current
UVLO Voltage ON
UVLO Voltage OFF
UVLO Hysteresis
Internal Clamp Voltage
TEST CONDITIONS
Current Source to V
CC
Pin
MIN
TYP
0.5
14.5
MAX
1.0
19.0
16.0
12.0
UNITS
mA
mA
V
V
V
V
CC
Sweeps Upward, (Note 3)
V
CC
Sweeps Downward
12.5
9.0
2.8
14.5
10.5
4.0
17.5
I
CC
= 25 mA, (Note 3)
16.0
19.0
V
OSCILLATOR SECTION (C
T
PIN)
f
DRV
V
CT(PK)
V
CT(VL)
I
CT(DIS)
C
T(MAX)
Frequency at DRV Pin
Peak Voltage
Valley Voltage
Discharge Current
Maximum Timing Capacitance
1.0
4.7
T
A
= T
j
= 25 ° C
T
A
= T
j
= Full Range (-20 to 80 ° C)
90
80
2.5
3.2
1.1
1.8
3.0
100
110
115
3.9
kHz
kHz
V
V
mA
nF
CURRENT DETECTOR, FEEDBACK AND FREQUENCY REDUCTION SECTIONS (FB PIN)
V
CCD
Current Control Detector
Reference Voltage
Overcurrent Detector
Reference Voltage
Propogation Delay to DRV Pin
Propogation Delay to DRV Pin
Slope Compensation Peak
Current
Slope Compensation Valley
Current
Slope Compensation Peak to
Valley
T
A
= T
j
= 25 ° C
T
A
= T
j
= Full Range (-20 to 80 ° C)
T
A
= T
j
= 25 ° C
T
A
= T
j
= Full Range (-20 to 80 ° C)
V
FB
Steps from 0 to 2 V
V
FB
Steps from 0 to 1.20 V, (Note 4)
V
CT
= V
CT(PK)
, T
A
= T
j
= 25 ° C, (Note 2)
V
CT
= V
CT(VL)
, T
A
= T
j
= 25 ° C, (Note 2)
V
CT
= V
CT(VL)
, T
A
= T
j
= 25 ° C, (Note 2)
-245
-65
-200
0.950
0.925
1.320
1.305
60
80
-200
-40
-160
1.350
0.980
1.010
1.035
1.380
1.395
130
180
-155
-15
-120
V
V
V
V
ns
ns
µA
µA
µA
V
OCD
t
FB,OC,PD
t
FB,CC,PD
i
SC(PK)
i
SC(VL)
i
SC(PK-VL)
Page 2
January 1999 TOKO, Inc.
TK75003
TK75003 ELECTRICAL CHARACTERISTICS (CONT.)
Test Conditions: V
CC
= 13 V, C
CC
= 4.7
µF,
C
T
= 800 pF, C
DRV
= 1000 pF, T
A
= T
j
= Full Operating Temperature Range.
Typical numbers apply at T
A
= 25
°C,
unless otherwise specified.
SYMBOL
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
FREQUENCY REDUCER (OVERCURRENT PROTECTION TIMING)
f
DRV(FR)
/ f
DRV
Frequency Reduction
Ratio
V
FB
= 1.2 V, 1.6 V
20
30
40
%
OUTPUT SECTION (DRV PIN)
D
DRV(MAX)
t
DRV(RISE)
t
DRV(FALL)
V
DRV(HIGH)
Maximim Duty Ratio
Rise Time
Fall Time
Output Voltage HIGH
1000 pF load, V
CC
= 15 V
1000 pF load, V
CC
= 15 V
I
DRV
= -40 mA
I
DRV
= -100 mA
I
DRV
= 40 mA
V
DRV(LOW)
Output Voltage LOW
I
DRV
= 100 mA
I
DRV
= 5 mA, V
CC
= 9 V
Note 1:
Note 2:
Note 3:
Note 4:
Power dissipation is 825 mW when mounted. Derate at 6.6 mW/°C for operation above 25
°C.
For temperature dependence refer to "Slope Compensation Peak Current vs. Temperature" graph.
The UVLO "on" voltage is guaranteed always to be below the internal clamp voltage.
Guaranteed by design; not 100% tested.
85
88
25
25
91
75
75
%
ns
ns
V
V
10.1
10.0
11.0
10.8
0.1
0.2
1.0
0.25
0.50
1.50
V
V
V
January 1999 TOKO, Inc.
Page 3
TK75003
TEST CIRCUIT
DRV
VCC
GND
OSCILLOSCOPE
GND
NC
1 µF
NC
CCC
4.7 µF
1000 pF
CT
FB
OSCILLOSCOPE
CT
800 pF
20 k
TYPICAL PERFORMANCE CHARACTERISTICS
SUPPLY CURRENT
VS.
SUPPLY VOLTAGE
106
20
16
ICC (mA)
FREQUENCY AT DRV PIN
VS.
TIMING CAPACITANCE
TA = -40
°C
1.00
0.98
CURRENT CONTROL REFERENCE
VS.
TEMPERATURE
DEVICE ON
FREQUENCY (Hz)
12
0.6
STANDBY
0.4
0.0
TA = 85
°C
104
VCCD (V)
1000
10000
105
0.96
0.94
0.92
0
4
8
12
16
18
103
10
100
0.90
-40
0
40
80
120
VCC (V)
SLOPE COMPENSATION PEAK
CURRENT
VS.
TEMPERATURE
60
-100
50
iSC(PK) (µA)
CT (pF)
TEMPERATURE (°C)
INPUT CURRENT
VS.
FREQUENCY AT DRV
50
FREQUENCY REDUCTION RATIO
VS.
TEMPERATURE
FREQ. REDUCTION RATIO (%)
ICC (mA)
-140
48
40
30
20
CDRV = 0 nF
10
CDRV = 1 nF
CDRV = 500 pF
-180
46
-220
-260
44
0
400
800
1200
1600
FREQUENCY (kHz)
-40
0
40
80
120
-40
0
40
80
120
TEMPERATURE (°C)
TEMPERATURE (°C)
Page 4
January 1999 TOKO, Inc.
TK75003
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
SLOPE COMPENSATION RAMP
RFB = 3 K to GND
CT = 800 pF
iSC(PK)
600
450
VFB (mV)
iSC(PK - VL)
300
150
0
0
5
10
TIME (µs)
15
20
iSC(VL)
January 1999 TOKO, Inc.
Page 5
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