SUPERTEX HV8053

HV8051
HV8053
–
E
T
E
L
– OBSO
High-Voltage EL Lamp Driver
Ordering Information
Package Options
Device
Input Voltage
8-Lead SO
Die
HV8051
1.0V to 1.6V
HV8051LG
HV8051X
HV8053
2.4V to 3.5V
HV8053LG
HV8053X
General Description
Features
The Supertex HV8051 and HV8053 are high-voltage drivers
designed for driving EL lamps of typically 4nF and 12nF for a 1V
and 3V operation. The input supply voltage range is from 1.0V to
1.6V for HV8051 and 2.4V to 3.5V for HV8053. The device uses
a single inductor and a minimum number of passive components.
Typical output voltage that can be applied to the EL lamp is ±50V
for HV8051 and ±70V for HV8053.
Processed with HVCMOS® technology
1.0V to 3.5V operating supply voltage
DC to AC conversion
Adjustable output lamp frequency to control lamp color,
lamp life, and power consumption
Adjustable converter frequency to eliminate harmonics and
optimize power consumption
The HV8051/HV8053 has two internal oscillators, a switching
bipolar junction transistor (BJT), and a high-voltage EL lamp
driver. The frequency for the switching BJT is set by an external
resistor connected between the Rsw-osc pin and the supply pin
VDD. The EL lamp driver frequency is set by an external resistor
connected between REL-osc pin and the VDD pin. An external
inductor is connected between the Lx and VDD pins. A 0.1µF
capacitor is connected between Cs and GND pins. The EL lamp
is connected between VA and VB pins.
Applications
Pagers
Portable transceiver
The switching BJT charges the external inductor and discharges
it into the 0.1µF capacitor at Cs. The voltage at Cs will start to
increase. The outputs VA and VB are configured as an H bridge
and are switching in opposite states to achieve a peak-to-peak
voltage of two times the VCS voltage across the EL lamp.
Cellular phones
Remote control units
Calculators
Pin Configuration
ςΑ
Absolute Maximum Ratings*
Supply voltage, VDD
Operating temperature range
Storage temperature range
SO-8 power dissipation
15
-0.5V to +4.5V
-25°C to +85°C
-65°C to +150°C
400mW
Note:
*All voltages are referenced to GND.
VDD
1
8
REL-osc
RSW-osc
2
7
VA
Cs
3
6
VB
Lx
4
5
GND
top view
SO-8
15-9
HV8051/HV8053
Electrical Characteristics
DC Characteristics (Over recommended operating conditions unless otherwise specified, TA = 25°C)
Symbol
RDS(on)
IIN
VCS
Parameter
Min
Typ
On-resistance of switching transistor
Max
Units
15
Ω
mA
VDD supply current (including
inductor current)
HV8051
8.0
15
HV8053
40
65
Output voltage on VCS
HV8051
fEL
VA-B output drive frequency
HV8051
HV8053
fsw
D
Switching transistor frequency
I = 50mA
VDD = 1.0V to 1.6V. See Figure 1.
VDD = 2.4V to 3.5V. See Figure 2.
41
VDD = 1.0V to 1.3V. See Figure 1.
52
HV8053
Conditions
V
VDD = 1.3V to 1.6V. See Figure 1.
43
VDD = 2.4V to 3.0V. See Figure 2.
52
VDD = 3.0V to 3.5V. See Figure 2.
60
160
70
220
200
350
HV8051
50
HV8053
50
Switching transistor duty cycle
VDD = 1.0V. See Figure 1.
Hz
VDD = 1.6V. See Figure 1.
VDD = 2.4V to 3.5V. See Figure 2.
KHz
VDD = 1.0V to 1.6V. See Figure 1.
VDD = 2.4V to 3.5V. See Figure 2.
85
%
See Figures 1 and 2.
Recommended Operating Conditions
Symbol
VDD
CL
TA
Parameter
Supply voltage
Load capacitance*
Operating temperature
Min
Typ
Max
Units
Conditions
HV8051
1.0
1.6
V
@ VDD = 1.0V to 1.6V
HV8053
2.4
3.5
V
@ VDD = 2.4V to 3.5V.
HV8051
0
4.0
nF
@ VDD = 1.0V to 1.6V
HV8053
0
12
nF
@ VDD = 2.4V to 3.5V
-25
85
°C
*Larger panels can be driven with HV8051/HV8053. See application note AN-H33.
Block Diagram
–
E
T
E
L
– OBSO
VDD
Lx
Cs
Rsw-osc
Switch
Osc
Q
VA
GND
Q
Output
Osc
Q
VB
REL-osc
Q
15-10
HV8051/HV8053
Figure 1: VDD = 1.0V to 1.6V
4.5MΩ
1 VDD
REL-osc 8
5.1KΩ
560KΩ
1mH1
VDD
2 Rsw-osc
VA
7
3 Cs
VB
6
4 Lx
GND
5
3.2nF
0.1µF2
1N4148
0.1µF
100V
Equivalent load to a
1 square inch lamp
HV8051
Note:
1. Murata part # LQH4N102K04 (DC resistance < 25Ω)
2. Larger values may be required depending upon supply impedance.
For additional information, see application note AN-H33.
–
E
T
E
L
O
S
B
O
–
Figure 2: VDD = 2.4V to 3.5V
2MΩ
1 VDD
VDD
REL-osc 8
820KΩ
560µH1
5.1KΩ
2 Rsw-osc
VA
7
3 Cs
VB
6
4 Lx
GND
5
10nF
0.1µF2
47pF
100V
1N4148
0.1µF
100V
HV8053
1.0nF
Note:
1. Murata part # LQH4N561K04 (DC resistance < 14.5Ω)
2. Larger values may be required depending upon supply impedance.
For additional information, see application note AN-H33.
15-11
15
HV8051/HV8053
External Component Description
External Component
Selection Guide Line
Diode
Fast reverse recovery diode, 1N4148 or equivalent.
Cs Capacitor
0.01µF to 0.1µF, 100V capacitor to GND is used to store the energy transferred from the inductor.
REL-osc
The EL lamp frequency is controlled via an external REL resistor connected between REL-osc and VDD of the
device. The lamp frequency increases as REL decreases. As the EL lamp frequency increases, the amount
of current drawn from the battery will increase and the output voltage VCS will decrease. The color of the
EL lamp is dependent upon its frequency.
RSW-osc
The switching frequency of the converter is controlled via an external resistor, RSW between RSW-osc and
VDD of the device. The switching frequency increases as RSW decreases. With a given inductor, as the
switching frequency increases, the amount of current drawn from the battery will decrease and the output
voltage, VCS, will also decrease.
CSW Capacitor
A 1nF capacitor is typically recommended on RSW-osc to GND for HV8053. As the input voltage of the device
increases, a faster switching converter frequency is required to avoid saturating the inductor. With the
higher switching frequency, more noise will be introduced. This capacitor is used to shunt any switching
noise that may couple into the RSW-osc pin.
CLx Capacitor
In order to drive the HV8053 more efficiently when high brightness is required, a 47pF, 100V CLx capacitor
needs to be used at the Lx pin to GND. This capacitor reduces the total amount of current drawn by the
circuit by reducing the dv/dt voltage on the internal switch.
Lx Inductor
The inductor Lx is used to boost the low input voltage by inductive flyback. When the internal switch is on,
the inductor is being charged. When the internal switch is off, the charge stored in the inductor will be
transferred to the high voltage capacitor CS. The energy stored in the capacitor is then available to the
internal H-bridge and therefore to the EL lamp. In general, smaller value inductors, which can handle
more current, are more suitable to drive larger size lamps. As the inductor size decreases, the switching
frequency of the inductor (controlled by RSW) should be increased to avoid saturation.
560µH Murata inductors with 14.5Ω series DC resistance is typically recommended. For inductors with the
same inductance value but with lower series DC resistance, lower RSW value is needed to prevent high
current draw and inductor saturation.
Lamp Size
As the EL lamp size increases, more current will be drawn from the battery to maintain high voltage across
the EL lamp. The input power, (VIN x IIN), will also increase. If the input power is greater than the power
dissipation of the package (350mW), an external resistor in series with one side of the lamp is recommended to help reduce the package power dissipation.
–
E
T
E
L
O
Application Hints
S
B
O
–
should be bypassed with a capacitor located close to the lamp
driver. Values can range from 0.1µF to 1µF depending on supply
impedance. A supply bypass capacitor elsewhere in the host
circuit is sufficient if located close to the driver.
Start with a high conversion frequency to avoid inductor saturation. Adjust converter frequency (via RSW-osc) and inductor value
to obtain desired lamp drive voltage and supply current. Make
sure that inductor current does not approach saturation as
specified on the inductor data sheet. Higher VIN’s and smaller
inductors require a higher conversion frequency to avoid saturation.
For lower power consumption, set a low lamp drive frequency,
use a 1mH inductor, and adjust power conversion frequency for
minimum current draw.
For high brightness, set lamp drive frequency for desired hue,
use a 330µH inductor and adjust power conversion frequency
until desired brightness is obtained.
Adjust the lamp drive frequency via REL-osc to obtain desired
lamp brightness and hue.
For longer lamp life, use as low a lamp drive frequency as is
acceptable. Adjust converter frequency and inductor value to
obtain acceptable brightness.
If the desired VCS cannot be obtained, try decreasing lamp drive
frequency slightly.
If VCS is above 80 volts, insert a 2kΩ resistor in series with the
lamp.
For high lamp drive frequencies, employ a FET follower on the
output. See application note AN-H33.
Monitor overall power consumption. If above 350mW, insert a
resistor in series with the lamp to decrease device power
dissipation.
In keeping with good circuit design practice, the supply voltage
15-12