May 2000 TOKO, Inc.

Page 1

TK6592x

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

VCC

EL+

IND

GND

HV BOOST

CONTROL

BRIDGE

OSCILLATOR

EL-

VCC

IND

EL-

GND

EL+

BLOCK DIAGRAM

DESCRIPTION

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.

TK6592x

20P

ORDERING INFORMATION

TAPE/REEL CODE

TL: Tape Left

Lamp Frequency Code

TK6592 MTL

LAMP FREQUENCY CODE

TK65920

175 Hz

TK65921*

200 Hz

TK65922

225 Hz

TK65923*

250 Hz

TK65924

275 Hz

TK65925*

300 Hz

TK65926

325 Hz

TK65927*

350 Hz

TK65928

375 Hz

TK65929*

400 Hz

* Consult factory for availability
of other frequencies.

FEATURES

High Ratio of Brightness / Input Power

Constant Brightness Versus Input Supply Changes

Optimized for 9 nf to 27 nf Panel Capacitance

Panel Voltage Slew Rates Controlled for Life
Enhancement

Panel Peak to Peak Voltage Independent of Input
Voltage and Temperature

Panel Peak to Peak Frequency Independent of
Input Voltage and Temperature

Miniature Package (SOT23L-6)

Operates with Miniature Coil

Minimum External Components

Laser-Trimmed Fixed Frequency Operation

PWM Control Method

Adjustable Output Voltage

Lower Noise (Audio and EMI)

Split Power Supply Application

APPLICATIONS

Battery Powered Systems

Cellular Telephones

Pagers

LCD Modules

Wrist Watches

Consumer Electronics

MEDIUM EL LAMP DRIVER

Page 2

May 2000 TOKO, Inc.

TK6592x

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

Note 2: Converter supply current is dependent upon the DC resistance of inductor L

. 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.

TK6592x ELECTRICAL CHARACTERISTICS

= 3.6 V, T

= T

= 25

C, unless otherwise specified.

ABSOLUTE MAXIMUM RATINGS

Pin .................................................................... 6.5 V

All Pins Except V

and GND ............................... V

CLAMP

Power Dissipation (Note 1) ................................ 600 mW

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

Operating Temperature Range ................... -30 to +80

Junction Temperature ........................................... 150

SYMBOL

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNITS

Input Supply Range

2.7

3.6

Quiescent Current

Current into pin 6

200

µA

PEAK

Peak Current Threshold

LAMP

Lamp Frequency

See Table 1

BOOST

Boost Frequency

See Table 2

kHz

CLAMP

Boost Clamp Voltage

Force 100 µA into HV pin

105

120

(MAX)

Maximum Duty Cycle

OUT

Peak to Peak Lamp Voltage

(Note 3)

125

140

155

CONV

Converter Supply Current

(Notes 2, 3)

See Table 3

TEST CIRCUIT

CEL

12 nF

VCC

47 nF

EL +

GND

IND

EL -

VCC

680 µH

ICONV

Note: L

= Toko Low Profile D52FU Series: 875FU-681 M

= DIODES INC. DL4148

= AVX 12061C473KAT2A

May 2000 TOKO, Inc.

Page 3

TK6592x

TOKO PART NO.

MIN.

TYP.

MAX.

TK65920

157 Hz

175 Hz

193 Hz

TK65921

180 Hz

200 Hz

220 Hz

TK65922

202 Hz

225 Hz

248 Hz

TK65923

225 Hz

250 Hz

275 Hz

TK65924

247 Hz

275 Hz

303 Hz

TK65925

270 Hz

300 Hz

330 Hz

TK65926

292 Hz

325 Hz

358 Hz

TK65927

315 Hz

350 Hz

385 Hz

TK65928

337 Hz

375 Hz

413 Hz

TK65929

360 Hz

400 Hz

440 Hz

TK6592x ELECTRICAL CHARACTERISTICS

= 3.6 V, T

= T

= 25

C, unless otherwise specified.

TABLE 1: LAMP FREQUENCY

TOKO PART NO.

MIN.

TYP.

MAX.

TK65920

20.1 kHz

22.4 kHz

24.7 kHz

TK65921

23.0 kHz

25.6 kHz

28.2 kHz

TK65922

25.9 kHz

28.8 kHz

31.7 kHz

TK65923

28.8 kHz

32.0 kHz

35.2 kHz

TK65924

31.6 kHz

35.2 kHz

38.8 kHz

TK65925

34.5 kHz

38.4 kHz

42.3 kHz

TK65926

37.4 kHz

41.6 kHz

45.8 kHz

TK65927

40.3 kHz

44.8 kHz

49.3 kHz

TK65928

43.2 kHz

48.0 kHz

52.8 kHz

TK65929

46.1 kHz

51.2 kHz

56.3 kHz

TABLE 2: OSCILLATOR FREQUENCY

TOKO PART NO.

MIN.

TYP.

MAX.

TK65920

7.8 mA

15.6 mA

TK65921

9.0 mA

18.0 mA

TK65922

10.1 mA

20.2 mA

TK65923

11.2 mA

22.4 mA

TK65924

12.3 mA

24.6 mA

TK65925

13.4 mA

26.8 mA

TK65926

14.5 mA

29.0 mA

TK65927

15.6 mA

31.2 mA

TK65928

16.8 mA

33.6 mA

TK65929

17.9 mA

35.8 mA

TABLE 3: CONVERTER SUPPLY CURRENT

Page 4

May 2000 TOKO, Inc.

TK6592x

TYPICAL PERFORMANCE CHARACTERISTICS

USING TEST CIRCUIT

TK65929 Voltage Waveform Across 12 nF Lamp

TK65921 Voltage Waveform Across 12 nF Lamp

TK65921

PEAK TO PEAK LAMP VOLTAGE

vs. SUPPLY VOLTAGE

VCC (V)

2.5 3 3.5 4 4.5 5 5.5 6

OUT

(V)

120

130

140

150

160

L1 = 680 µH

L1 = 560 µH

TK65929

PEAK TO PEAK LAMP VOLTAGE

vs. SUPPLY VOLTAGE

VCC (V)

2.5 3 3.5 4 4.5 5 5.5 6

OUT

(V)

120

130

140

150

160

L1 = 680 µH

L1 = 560 µH

TK65921

LAMP FREQUENCY

vs. SUPPLY VOLTAGE

VCC (V)

2.5 3 3.5 4 4.5 5 5.5 6

LAMP

(Hz)

180

190

200

210

220

230

TK65929

LAMP FREQUENCY

vs. SUPPLY VOLTAGE

VCC (V)

2.5 3 3.5 4 4.5 5 5.5 6

LAMP

(Hz)

360

380

400

420

440

460

May 2000 TOKO, Inc.

Page 5

TK6592x

TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)

USING TEST CIRCUIT

TK65921

AVERAGE CONVERTER SUPPLY

CURRENT vs. SUPPLY VOLTAGE

VCC (V)

2.5 3 3.5 4 4.5 5 5.5 6

I CONV

TK65929

AVERAGE CONVERTER SUPPLY

CURRENT vs. SUPPLY VOLTAGE

VCC (V)

2.5 3 3.5 4 4.5 5 5.5 6

I CONV

TK65921

PEAK CURRENT THRESHOLD

vs. SUPPLY VOLTAGE

VCC (V)

2.5 3 3.5 4 4.5 5 5.5 6

I PEAK

TK65929

PEAK CURRENT THRESHOLD

vs. SUPPLY VOLTAGE

VCC (V)

2.5 3 3.5 4 4.5 5 5.5 6

I PEAK

TK65921

QUIESCENT CURRENT

vs. SUPPLY VOLTAGE

VCC (V)

2.5 3 3.5 4 4.5 5 5.5 6

I Q

(µ

100

150

200

TK65929

QUIESCENT CURRENT

vs. SUPPLY VOLTAGE

VCC (V)

2.5 3 3.5 4 4.5 5 5.5 6

I Q

(µ

100

150

200

Page 6

May 2000 TOKO, Inc.

TK6592x

TYPICAL PERFORMANCE CHARACTERISTICS (CONT.)

USING TEST CIRCUIT

TK65921

PEAK TO PEAK LAMP VOLTAGE

vs. TEMPERATURE

TEMPERATURE (

-50 -25 0 25 50 75 100 125

OUT

(V)

110

120

130

140

150

160

= 3.6 V

= 2.7 V

TK65929

PEAK TO PEAK VOLTAGE

vs. TEMPERATURE

TEMPERATURE (

-50 -25 0 25 50 75 100 125

OUT

(V)

110

120

130

140

150

160

VCC = 3.6 V

VCC = 2.7 V

TK65921

LAMP FREQUENCY

vs. TEMPERATURE

TEMPERATURE (

-50 -25 0 25 50 75 100 125

LAMP

)

170

180

190

200

210

220

TK65929

LAMP FREQUENCY

vs. TEMPERATURE

TEMPERATURE (

-50 -25 0 25 50 75 100 125

LAMP

)

340

360

380

400

420

440

TK65921

AVERAGE CONVERTER SUPPLY

CURRENT vs. TEMPERATURE

TEMPERATURE (

-50 -25 0 25 50 75 100 125

I CONV

(mA)

TK65929

AVERAGE CONVERTER SUPPLY

CURRENT vs. TEMPERATURE

TEMPERATURE (

-50 -25 0 25 50 75 100 125

I CONV

(mA)

May 2000 TOKO, Inc.

Page 9

TK6592x

clock is generated by dividing the high frequency clock by
128; this lower frequency clock corresponds to the drive
frequency of the EL Lamp. The laser-trimmed oscillators
are relatively insensitive to variations in temperature and
supply voltage. Therefore, they provide good control of the
lamp color emitted by the panel.

The circuit below illustrates a typical application where the
TK6592x is driving a 2-square-inch EL Lamp with a
capacitance of approximately 12 nF.

By keeping the ratio of the boost frequency and the H-
Bridge frequency constant, the peak-to-peak output voltage
from the TK6592x becomes primarily dependent upon the
capacitance of the EL Lamp, the peak current threshold of
the boost converter, and the value of the inductive element
used in the boost converter. For the TK6592x, the peak
current threshold is laser-trimmed to 52 mA. The capacitive
load of the EL Lamp is a function of panel size and is
typically fixed. Therefore, the high voltage output of the
boost converter can be set to a desired voltage by selecting
the appropriate value of the inductive element used in the
boost converter.

PEAK

= Boost Peak Current Threshold (52 mA)

= Capacitance of EL Lamp

L = Inductance Value

= (I

PEAK

/ 2) x (L /C

) x 128

THEORY OF OPERATION

An Electroluminescent (EL) Lamp is a strip of plastic,
coated with a phosphorous material that emits light when
a high voltage AC signal is applied to the terminals of the
device. EL panels have the ability to light the entire panel
uniformly. Because of this, they are gradually becoming
more popular and widespread than LEDs. The amount of
light emitted from an EL Lamp is typically proportional to
the magnitude of the voltage applied to the lamp.
Furthermore, the color of the light emitted by an EL Lamp
is somewhat dependent upon the frequency of the applied
drive signal. For most applications, a peak-to-peak voltage
of 100 to 170 V, with a drive frequency of 175 to 400 Hz,
provides optimal trade-off between lamp intensity and
power consumption.

The capacitance of the EL Panel is typically proportional to
the size of the lamp (a 1 square inch EL Panel typically
exhibits approximately 5 nF of capacitance load). The
TK6592x series of devices has been optimized to drive EL
panels, which are approximately 2-4 square inches in size.

The Boost section of the TK6592x consists of a controller
for stepping up a relatively low voltage (2.7 to 6 V) to a
much higher voltage (50 to 90 V) needed to drive the EL
Lamp. The boost section of the TK6592x uses a proprietary
architecture which provides a relatively constant output
power, independent of the input supply, without the need
for sensing the high voltage output of the boost converter.
By controlling the peak current through the switching
element of the boost converter, the boost section provides
a constant output power independent of the input supply.

The H-Bridge section of the TK6592x switches the high
voltage output of the boost converter to the two terminals
of the EL Lamp. By alternately switching the terminals of
the lamp between the high voltage supply and ground, the
peak-to-peak voltage developed across the lamp is
effectively twice the high voltage generated by boost
converter. Furthermore, the TK6592x limits the magnitude
of the drive currents through the H-Bridge switches in
order to minimize the edge rates developed across the EL
Lamp. This approach protects the EL Panel from large
current spikes and reduces the likelihood of high frequency
noise components being injected into neighboring circuitry.

The Oscillator section of the TK6592x generates a fixed
frequency clock source for the previously described Boost
and H-Bridge sections, without the need for external
components. The high frequency output of the oscillator is
used for driving the boost controller. A lower frequency

CEL

12 nF

VIN

47 nF

EL +

GND

IND

EL -

VCC

FIGURE 1: TYPICAL APPLICATION

Page 10

May 2000 TOKO, Inc.

TK6592x

With properly selected components, the TK6592x will
nominally support peak output voltages to 90 V
(180 V

PK-PK

). Should the EL Panel become disconnected

from the driver outputs, the removal of the load can cause
the output voltage to increase beyond 90 V. To protect
against this fault condition, a clamp circuit exists on the
high voltage output which nominally limits the output
voltage to a typical value of 105 V (210 V

PK-PK

THEORY OF OPERATION (CONT.)

DETAILS CONCERNING THE

H-BRIDGE SECTION OPERATION

In an effort to extend EL lamp life, reduce EMI emissions,
and reduce the power draw of the IC, current sources to
control the charging and discharging of the EL lamp panel
and special sequencing control of the H-bridge FETs were
added to the H-bridge of TK659xx.

Current sources were added between ground and the
sources of the low-side N-channel FETs (Figure 2).
Therefore, the current into and out of the EL panel is
controlled and limited.

The FETs are turned off and on in the sequence shown in
Figure 3. As is noted in Figure 3, there is a period of time
when both of lower N-channel FETs are turned on and both
of upper P-channel FETs are turned off. This provides a
period of time to discharge the EL panel capacitance
completely; before starting to recharge it again with current
from HV voltage rail. Therefore, this special sequencing
method prevents taking current off the HV voltage rail
during the discharge of EL panel capacitance and operates
more efficiently.

HVP

EL Panel

Current Source 1

Current Source 2

EL-

EL+

FIGURE 2: H-BRIDGE SCHEMATIC

VEL+

VEL =

VEL-

OFF

BOTH OFF

OFF

BOTH ON

Discharging

EL Panel

Capacitance

VEL+ VEL-

OFF

FIGURE 3: H-BRIDGE SEQUENCING WAVEFORMS

May 2000 TOKO, Inc.

Page 11

TK6592x

SUPPLY PIN (V

)

This pin is the positive input supply for the TK6592x. Good design practices dictate capacitive decoupling to the ground
pin.

GROUND PIN (GND)

The pin provides the ground connection for the IC.

IND PIN

This pin is periodically pulled to ground by a power transistor acting as an internal switch to the TK6592x. Externally, this
pin is typically connected to an inductor and a rectifying diode. By modulating the switching action of the internal switch,
the TK6592x can boost the relatively low voltage of the battery to the high voltage required to drive the EL Lamp.

HV PIN

This pin is connected to the filter capacitor and the cathode of the rectifying diode in order to generate a high voltage
supply. This high voltage supply is switched to the terminals of the EL Lamp through the H-Bridge.

PIN

This pin is connected to one side of the EL Panel.

PIN

This pin is connected to the other side of the EL Panel.

Note: Measuring the voltage across the EL lamp (EL

pin to EL

pin) should be done with balanced scope probes using

differential measurement techniques to obtain a true waveform of the voltage across the EL lamp.

PIN DESCRIPTIONS

Page 12

May 2000 TOKO, Inc.

TK6592x

DESIGN CONSIDERATIONS

INDUCTOR VALUE SELECTION

Designing an EL Driver utilizing the TK6592x is a very simple task. The primary component affecting the behavior of the
converter is the inductor. Essentially, the entire design task primarily consists of selecting the proper inductor value and
type given the operating conditions of the EL Panel (e.g., lamp capacitance, frequency, output voltage, supply range).
The following tables and charts are intended to simplify the selection of the inductor.

Given the capacitance of the EL Lamp, and the peak output voltage requirements, the following table can be utilized to
select the value of the inductive component.

TABLE 4: PEAK OUTPUT VOLTAGE VS. INDUCTOR VALUE AND LAMP CAPACITANCE

As an example as to how the above table is to be used, assume that we have a 2-square-inch panel (12 nF capacitance)
and we would like the peak-to-peak voltage across the lamp to be 140 V. The peak voltage on either terminal would be
70 V (140 V / 2). Referring to the table above, we can see that using a 680

H coil the peak voltage developed across

a 12 nF Lamp would be approximately 70 V. In this particular example, the inductive component should have a value of
680

INDUCTOR TYPE SELECTION

After the value of the inductor has been selected, an appropriate coil type needs to be selected taking into account such
factors as DC resistance and current capability. The following charts can be utilized for selecting the proper family of Toko
Coils. Furthermore, the following charts will also indicate if the TK6592x is the appropriate driver given the frequency and
input supply requirements. If the TK6592x does not have sufficient drive capability given the input supply and frequency

INDUCTOR

VALUE

9.0 nF
LAMP

12.0 nF

LAMP

15.0 nF

LAMP

18.0 nF

LAMP

21.0 nF

LAMP

24.0 nF

LAMP

27.0 nF

LAMP

180 µH

42 V

36 V

32 V

29 V

27 V

25 V

24 V

220 µH

46 V

40 V

36 V

33 V

30 V

28 V

27 V

330 µH

56 V

49 V

44 V

40 V

37 V

34 V

33 V

390 µH

61 V

53 V

47 V

43 V

40 V

37 V

35 V

470 µH

67 V

58 V

52 V

48 V

44 V

41 V

39 V

560 µH

73 V

64 V

57 V

52 V

48 V

45 V

42 V

680 µH

81 V

70 V

63 V

57 V

53 V

50 V

47 V

820 µH

89 V

77 V

69 V

63 V

58 V

54 V

51 V

1000 µH

85 V

76 V

69 V

64 V

60 V

57 V

1200 µH

83 V

76 V

70 V

66 V

62 V

1500 µH

85 V

79 V

74 V

69 V

1800 µH

86 V

81 V

76 V

2200 µH

89 V

84 V

Note: The voltages indicated in the table above may not be achievable under certain circumstances (i.e., low battery or higher drive frequencies).

Refer to the charts on page 12 to determine which output voltage/coil combination can be supported by the EL driver.

Close to 100 V operation check capacitor C

voltage rating

May 2000 TOKO, Inc.

Page 13

TK6592x

requirements, the following charts will suggest the TK6593x family of EL Drivers which have higher drive capabilities.
To utilize the following charts in selecting an appropriate coil, perform the following steps:

1) From the following charts, select the chart that matches the part number of the Toko EL Driver that will be used in

the application. The part number of the Toko EL Driver will be dependant upon the desired frequency of the EL panel
(e.g., TK65921 = 200Hz).

2) Determine input supply voltage range (e.g., 4 to 6 V). The x-axis of the following charts represent the minimum

expected supply voltage. Below this minimum supply voltage the EL Driver output may begin to droop. On the
appropriate chart, draw a vertical line upward from the minimum supply voltage represented on the x-axis (e.g., 4V).

3) Draw a horizontal line passing through the chosen inductor value on the y-axis (e.g., 680

H).

4) The vertical and horizontal lines drawn in steps 2 and 3 respectively will intersect at a point. This point will lie in one

of four regions of the chart (e.g., D31FU). These four regions suggest which family of Toko Coils to use.

Of the three coil families suggested in these charts, the D31FU has the smallest physical size but also has higher DC
resistance. The D52FU series of coils has the largest physical size and the lowest DC resistance. The D52FU or the
D32FU can be used as a reasonable substitute for the D31FU. Similarly, the D52FU can be used as a replacement for
the D32FU. Substituting a coil with lower DC resistance will generally result in a system that will consume less power
supply current.

DESIGN CONSIDERATIONS (CONT.)

TK65920, TK65921

INDUCTOR

VALUE

(
µ

1800

560

USE TK6593X

1200

820

390

D31FU

D32FU

D52FU

680

470

1000

1500

2200

MINIMUM SUPPLY (V)

3 4 5 6

180

TK65922, TK65923

INDUCTOR

VALUE

(
µ

1800

560

USE TK6593X

1200

820

390

D31FU

D32FU

D52FU

680

470

1000

1500

2200

MINIMUM SUPPLY (V)

3 4 5 6

180

TK65924, TK65925

INDUCTOR

VALUE

(
µ

H) 1800

560

USE TK6593X

1200

820

390

D31FU

D32FU

D52FU

680

470

1000

1500

2200

MINIMUM SUPPLY (V)

3 4 5 6

180

TK65926, TK65927

INDUCTOR

VALUE

(
µ

H) 1800

560

USE TK6593X

1200

820

390

D31FU

D32FU

D52FU

680

470

1000

1500

2200

MINIMUM SUPPLY (V)

3 4 5 6

180

TK65928, TK65929

INDUCTOR

VALUE

(
µ

H) 1800

560

USE TK6593X

1200

820

390

D31FU

D52FU

680

470

1000

1500

2200

D32FU

MINIMUM SUPPLY (V)

3 4 5 6

180

Page 14

May 2000 TOKO, Inc.

TK6592x

APPLICATION INFORMATION

SPLIT SUPPLY APPLICATION

The split power supply application of this EL driver IC is a circuit configuration (see Figure 4) in which the V

IC power

control

) is separated or split away from the main power input (V

power

) supplying current to the inductor.

CEL
5 nF

Vcontrol
from
2.7 to 6 V
max. 200 µA

22 nF

EL +

GND

IND

EL -

VCC

Vpower
from
0.9 to 20 V

FIGURE 4: SPLIT SUPPLY APPLICATION CIRCUIT

The voltage supplied to the V

pin of the IC (V

control

) needs to be maintained in the 2.7 V to 6.0 V range, but the current

draw on this power supply rail of the system would be very small (under 200

A). This V

control

can be used to turn on and

off the EL lamp driver, which permits the V

power

to be connected to the battery or other power source directly with the

least amount of resistance in the power path as possible.

Now with the V

power for the IC (V

control

) being supplied from a different source, the main power (V

power

) can be any

voltage between 0.9 V and 20 V. But it is critical to properly select the inductor such that the proper peak current
regulation is maintained over the input voltage operating range of the converter.

If the inductor value is too large the current will rise too slowly and not have time to reach its set peak current trip point
at low input voltages, but at high input voltage the current might rise too quickly and overshoot the set peak current trip
point.

The primary battery applications for this part are in a dual cell alkaline or dual cell Li-Ion system (such as a GPS or smart
cell phones). These systems are assumed to have a minimum useable input voltage of 1.8 V for the dual cell alkaline
system and 5.4 V for the dual cell Li-Ion system.

For low converter input voltages (1.8 V and 5.4 V minimum input voltages), Table 5 shows the recommended maximum
inductance value for a given device part number (therefore a given frequency of operation) and a minimum input voltage.
Each cell in the table gives three inductance values; each value (in

H) corresponds to each type of specialized Toko

EL driver inductors (D31FU, D32FU, and D52FU types of Toko inductors).

May 2000 TOKO, Inc.

Page 15

TK6592x

APPLICATION INFORMATION (CONT.)

PART NO.

f lamp
f converter

min.Vp L type

TK65920

175 Hz

22.4 kHz

TK65921
200 Hz
25.6 kHz

TK65922
225 Hz
28.8 kHz

TK65923
250 Hz
32.0 kHz

TK65924

275 Hz

35.2 kHz

TK65925
300 Hz
38.4 kHz

TK65926
325 Hz
41.6 kHz

TK65927
350 Hz
44.8 kHz

TK65928
375 Hz
48.0 kHz

TK65929
400 Hz
51.2 kHz

D31FU

1.8V D32FU

D52FU

390 µH
560 µH
680 µH

390 µH
470 µH
560 µH

390 µH
470 µH
470 µH

390 µH
390 µH
470 µH

330 µH
390 µH
470 µH

330 µH
390 µH
390 µH

330 µH
330 µH
390 µH

D31FU

5.4V D32FU

D52FU

1000 µH
1200 µH
2700 µH

1000 µH
1200 µH
2200 µH

1000 µH
1200 µH
1800 µH

1000 µH
1200 µH
1500 µH

1000 µH
1200 µH
1200 µH

After selecting the inductor type and value, Table 4 of the TK6592X data sheet can be used to determine the typical output
voltage for a given loading of EL lamp capacitance. If you wish to reduce this output voltage, just reduce the inductor's
inductance value.

TABLE 5: DUAL CELL ALKALINE AND DUAL CELL LI-ION INDUCTANCE SELECTION TABLE

NOISE CONSIDERATIONS

There are two specific noise types relevant to the user when it comes to choosing EL Drivers: the Audio Noise and the
Electromagnetic Interference (EMI) Noise.

The EMI Noise would most likely come from the boost converter/coil section. The Toko EL Driver has specifically been
designed to address this issue.

The device runs at a fixed frequency and the frequency is controlled tightly in order to avoid interference.

Furthermore, the panel frequency is forced to be a 128 submultiple of the boost frequency avoiding any type of beating
frequencies.

By choosing shielded coils, the EMI noise problem can further be reduced.

The Audio Noise can come from several components which make up the system.

The coil, if operated in the audio range would be a source of noise. The Toko EL Driver was carefully designed to give
the user the choice of 10 frequencies such that the coil frequency will always be above audio range. Since the device
operates at a fixed frequency in discontinuous conduction mode, there are no possible submultiples which would cause
audible noise.

The filter capacitor can be a source of audio noise. Furthermore, depending on how this cap is mounted, the mounting
can act as an amplifier (as a speaker box). Certain ceramic caps driven from a high voltage source as in the EL Driver
case, demonstrate a PIEZOELECTRIC effect which is distinguishable in the Audio Range.

Other types of caps, such as film type do not denote an audio noise.

The panel itself, being operated well into the Audio Range (175 Hz to 400 Hz) and of a capacitive nature driven from high
voltage may also display Audible Noise. Mounting of this panel can enhance or diminish this natural effect of the panel.

Page 20

May 2000 TOKO, Inc.

TK6592x

Marking Information

Marking

TK65920

TK65921

TK65922

TK65923

TK65924

TK65925

TK65926

TK65927

TK65928

TK65929

0.95

0.32

0.1

+0.15
- 0.05

3.5

1.2

0.15

0.3

3.3

2.2

0.4

0.95

3.0

0.6

1.0

Recommended Mount Pad

0 - 0.1

15 max

1.4 max

Marking

+0.3
- 0.1

+ 0.3

(3.4)

+0.15

- 0.05

Dimensions are shown in millimeters
Tolerance: x.x =

0.2 mm (unless otherwise specified)

0.1

+0.15
- 0.05

0.4

5 PL

SOT23L-6

PACKAGE OUTLINE

Printed in the USA

TOKO AMERICA REGIONAL OFFICES

Toko America, Inc. Headquarters
1250 Feehanville Drive, Mount Prospect, Illinois 60056
Tel: (847) 297-0070 Fax: (847) 699-7864

IC-xxx-TK6592x

0798O0.0K

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. No license is granted by implication or otherwise under any patent or patent rights of TOKO, Inc.

Western Regional Office
Toko America, Inc.
2480 North First Street , Suite 260
San Jose, CA 95131
Tel: (408) 432-8281
Fax: (408) 943-9790

Midwest Regional Office
Toko America, Inc.
1250 Feehanville Drive
Mount Prospect, IL 60056
Tel: (847) 297-0070
Fax: (847) 699-7864

Eastern Regional Office
Toko America, Inc.
107 Mill Plain Road
Danbury, CT 06811
Tel: (203) 748-6871
Fax: (203) 797-1223

Semiconductor Technical Support
Toko Design Center
4755 Forge Road
Colorado Springs, CO 80907
Tel: (719) 528-2200
Fax: (719) 528-2375

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: TK65924M

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: TK65924M