HV823LG Supertex, HV823LG Datasheet - Page 7

• Manufacturer Part Number: HV823LG
• Description: Display Drivers EL LAMP DRIVER
• Manufacturer: Supertex

Specifications of HV823LG

• Driver Type: EL Lamp Drivers
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOIC-8 Narrow
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

External Component Description
External Component
Diode
CS Capacitor
REL-Osc
RSW-Osc
CSW Capacitor
LX Inductor
Lamp
Supertex inc.
Selection Guide Line
Fast reverse recovery diode, 1N4148 or equivalent.
0.01µF to 0.1µF, 100V capacitor to GND is used to store the energy transferred from the induc-
tor.
The EL lamp frequency is controlled via an external R
and VDD pins of the device. The lamp frequency increases as R
frequency increases, the amount of current drawn from the battery will increase and the output
voltage V
A 2.0MΩ resistor would provide lamp frequency of 330 to 450Hz. Decreasing the R
tor of 2 will increase the lamp frequency by a factor of 2.
The switching frequency of the converter is controlled via an external resistor, R
RSW-Osc and VDD pins of the device. The switching frequency increases as R
With a given inductor, as the switching frequency increases, the amount of current drawn from
the battery will decrease and the output voltage, V
A 1.0nF capacitor is recommended on RSW-Osc to GND when a 0.01μF C
This capacitor is used to shunt any switching noise that may couple into the RSW-OSC pin.
The C
noise. A C
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 C
tor is connected 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 value decreases, the switching frequency of the inductor (controlled by R
increased to avoid saturation.
560µH Murata inductors with 14.5Ω series DC resistance is typically recommended. For induc-
tors with the same inductance value but with lower series DC resistance, lower R
needed to prevent high current draw and inductor saturation.
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, (V
greater than the power dissipation of the package (400mW), an external resistor in series with
one side of the lamp is recommended to help reduce the package power dissipation.
SW
capacitor may also be needed when driving large EL lamp due to increase in switching
●
CS
SW
1235 Bordeaux Drive, Sunnyvale, CA 94089
will decrease. The color of the EL lamp is dependent upon its frequency.
larger than 1.0nF is not recommended.
7
●
IN
Tel: [phone]
CS
x I
, will also decrease.
IN
), will also increase. If the input power is
EL
resistor connected between REL-Osc
S
. The energy stored in the capaci-
EL
●
decreases. As the EL lamp
www.supertex.com
S
capacitor is used.
SW
SW
EL-Osc
SW
between the
) should be
decreases.
SW
HV823
by a fac-
value is