The TK6592x Electroluminescent (EL) Lamp Driver has
been optimized for battery controlled systems where power
consumption and size are primary concerns. The miniature
device size (SOT23L-6), together with the miniature Toko
EL coils (D32FU, D31FU, D52FU), further helps system
designers reduce the space required to drive the small EL
panels.
The proprietary architecture (detailed in the Theory of
Operation section) of the TK6592x provides a constant
output power to the lamp, independent of variations in the
battery voltage. This architecture allows the output voltage
to remain relatively constant as battery voltages decay,
without the need for directly sensing the high voltage
output of the EL driver.
* Consult factory for availability
of other frequencies.
TAPE/REEL CODE
TL: Tape Left
APPLICATIONS
■ Battery Powered Systems
■ Cellular Telephones
■ Pagers
■ LCD Modules
■ Wrist Watches
■ Consumer Electronics
The oscillator circuits for the boost converter and lamp
driver are both internally generated in the TK6592x, without
the need for external components. The clock frequency of
the boost converter is laser-trimmed to ensure good initial
accuracy that is relatively insensitive to variations in
temperature and supply voltage. The clock frequency of
the lamp driver tracks the frequency of the boost converter
by a constant scaling factor.
Furthermore, the drive architecture of the TK6592x has
been designed to limit peak drive current delivered to the
lamp. This approach limits the slew rate of the voltage
across the lamp and has the potential to improve lamp life
and decrease RF interference.
The TK6592x is available in a miniature, 6-pin
SOT23L-6 surface mount package
TK6592x
+
EL
HV
-
EL
BLOCK DIAGRAM
V
CC
HV BOOST
CONTROL
OSCILLATOR
H
BRIDGE
V
CC
GND
IND
IND
GND
HV
EL
EL
+
-
May 2000 TOKO, Inc.Page 1
TK6592x
ABSOLUTE MAXIMUM RATINGS
VCC Pin.................................................................... 6.5 V
All Pins Except V
and GND ...............................V
CC
CLAMP
Power Dissipation (Note 1) ................................ 600 mW
TK6592x ELECTRICAL CHARACTERISTICS
VCC = 3.6 V, TA = Tj = 25 °C, unless otherwise specified.
SYMBOLPARAMETERTEST CONDITIONSMINTYPMAXUNITS
Storage Temperature Range ................... -55 to +150 °C
Operating Temperature Range ...................-30 to +80 °C
Junction Temperature ........................................... 150 °C
V
CC
I
Q
I
PEAK
F
LAMP
F
BOOST
V
CLAMP
D
(MAX)
V
OUT
I
CONV
Note 1: Power dissipation is 600 mW when mounted as recommended (200 mW In Free Air). Derate at 4.8 mW/°C for operation above 25 °C.
Note 2: Converter supply current is dependent upon the DC resistance of inductor L1. Lower DC resistances will result in lower supply currents.
Note 3: When using test circuit below.
Gen. Note: Refer to “INDUCTOR VALUE SELECTION” and “INDUCTOR TYPE SELECTION” of Design Considerations Section for choosing
inductor.
Input Supply Range2.73.66V
Quiescent CurrentCurrent into pin 6200µA
Peak Current Threshold445260mA
Lamp FrequencySee Table 1Hz
Boost FrequencySee Table 2kHz
Boost Clamp VoltageForce 100 µA into HV pin90105120V
Maximum Duty Cycle889296%
Peak to Peak Lamp Voltage(Note 3)125140155V
Converter Supply Current(Notes 2, 3)See Table 3mA
TEST CIRCUIT
I
L
1
680 µH
CONV
V
CC
C
EL
12 nF
+
EL
HVGND
-
EL
D
C
47 nF
1
1
V
CC
IND
Note: L1 = Toko Low Profile D52FU Series: 875FU-681 M
D1 = DIODES INC. DL4148
C1 = AVX 12061C473KAT2A
Page 2May 2000 TOKO, Inc.
TK6592x ELECTRICAL CHARACTERISTICS
VIN = 3.6 V, TA = Tj = 25 °C, unless otherwise specified.
TK65920-7.8 mA15.6 mA
TK65921-9.0 mA18.0 mA
TK65922-10.1 mA20.2 mA
TK65923-11.2 mA22.4 mA
TK65924-12.3 mA24.6 mA
TK65925-13.4 mA26.8 mA
TK65926-14.5 mA29.0 mA
TK65927-15.6 mA31.2 mA
TK65928-16.8 mA33.6 mA
TK65929-17.9 mA35.8 mA
May 2000 TOKO, Inc.Page 3
TK6592x
V
(V)
V
(V)
6
TYPICAL PERFORMANCE CHARACTERISTICS
USING TEST CIRCUIT
TK65929 Voltage Waveform Across 12 nF LampTK65921 Voltage Waveform Across 12 nF Lamp
PEAK TO PEAK LAMP VOLTAGE
160
150
140
OUT
130
120
2.5 3 3.5 4 4.5 5 5.5 6
230
220
210
(Hz)
TK65921
vs. SUPPLY VOLTAGE
L1 = 680 µH
L1 = 560 µH
VCC (V)
TK65921
LAMP FREQUENCY
vs. SUPPLY VOLTAGE
PEAK TO PEAK LAMP VOLTAGE
160
150
140
OUT
130
120
2.5 3 3.5 4 4.5 5 5.5 6
460
440
420
(Hz)
TK65929
vs. SUPPLY VOLTAGE
L1 = 680 µH
L1 = 560 µH
VCC (V)
TK65929
LAMP FREQUENCY
vs. SUPPLY VOLTAGE
200
LAMP
F
190
180
2.5 3 3.5 4 4.5 5 5.5
VCC (V)
400
LAMP
F
380
360
2.5 3 3.5 4 4.5 5 5.5 6
VCC (V)
Page 4May 2000 TOKO, Inc.
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
6
USING TEST CIRCUIT
TK6592x
AVERAGE CONVERTER SUPPLY
CURRENT vs. SUPPLY VOLTAGE
18
16
14
12
(mA)
10
8
CONV
I
6
4
2
0
2.5 3 3.5 4 4.5 5 5.5
PEAK CURRENT THRESHOLD
60
55
50
(mA)
45
PEAK
I
40
TK65921
VCC (V)
TK65921
vs. SUPPLY VOLTAGE
AVERAGE CONVERTER SUPPLY
CURRENT vs. SUPPLY VOLTAGE
26
24
22
20
(mA)
18
16
CONV
I
14
12
10
8
2.5 3 3.5 4 4.5 5 5.5 6
PEAK CURRENT THRESHOLD
60
55
50
(mA)
45
PEAK
I
40
TK65929
VCC (V)
TK65929
vs. SUPPLY VOLTAGE
35
30
2.5 3 3.5 4 4.5 5 5.5 6
VCC (V)
TK65921
QUIESCENT CURRENT
vs. SUPPLY VOLTAGE
2.5 3 3.5 4 4.5 5 5.5 6
VCC (V)
(µA)
I
200
150
100
Q
50
0
35
30
2.5 3 3.5 4 4.5 5 5.5 6
VCC (V)
TK65929
QUIESCENT CURRENT
vs. SUPPLY VOLTAGE
0
2.5 3 3.5 4 4.5 5 5.5 6
VCC (V)
(µA)
I
200
150
100
Q
50
May 2000 TOKO, Inc.Page 5
TK6592x
V
(V)
V
(V)
F
(H
)
F
(H
)
5
(°C)
TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)
USING TEST CIRCUIT
PEAK TO PEAK LAMP VOLTAGE
160
150
140
OUT
130
120
110
-50 -25 0 25 50 75 100 125
220
210
z
200
TK65921
vs. TEMPERATURE
VCC = 3.6 V
VCC = 2.7 V
TEMPERATURE (°C)
TK65921
LAMP FREQUENCY
vs. TEMPERATURE
PEAK TO PEAK VOLTAGE
160
150
140
OUT
130
120
110
-50 -25 0 25 50 75 100 125
440
420
z
400
TK65929
vs. TEMPERATURE
VCC = 3.6 V
VCC = 2.7 V
TEMPERATURE (°C)
TK65929
LAMP FREQUENCY
vs. TEMPERATURE
LAMP
190
180
170
-50 -25 0 25 50 75 100 125
TEMPERATURE (°C)
AVERAGE CONVERTER SUPPLY
CURRENT vs. TEMPERATURE
14
12
10
(mA)
CONV
8
I
6
4
-50 -25 0 25 50 75 100 12
TK65921
TEMPERATURE (°C)
LAMP
380
360
340
-50 -25 0 25 50 75 100 125
TEMPERATURE (°C)
AVERAGE CONVERTER SUPPLY
CURRENT vs. TEMPERATURE
22
20
18
(mA)
CONV
16
I
14
12
-50 -25 0 25 50 75 100 125
TK65929
TEMPERATURE
Page 6May 2000 TOKO, Inc.
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