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PDF HV816 Data sheet ( Hoja de datos )
| Número de pieza | HV816 | |
| Descripción | Dimmable EL Lamp Driver | |
| Fabricantes | Supertex | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de HV816 (archivo pdf) en la parte inferior de esta página. Total 6 Páginas | ||
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Supertex inc.
HV816
High Voltage, Dimmable
EL Lamp Driver
Features
►► 360VPP output voltage for high brightness
►► Large output load capability of up to 150nF
►► 2.7 to 5.5V operating supply voltage
►► Single lithium ion cell compatible
►► Adjustable output regulation for dimming
►► External switching MOSFET
►► Low audible noise
►► Output discharge slew rate control
►► 1.5V logic
►► Dedicated Enable pin
►► Two EL frequency controls
►► Independent lamp and converter frequency setting
►► Split supply capability
►► Available in 16-Lead 4x4 QFN package
Applications
►► Laptop keyboards
►► Netbook keyboards
►► Display signs
►► Portable instrumentation equipment
►► Electronic organizers
General Description
The Supertex HV816 is a high voltage Electroluminescent
(EL) lamp driver designed for driving a lamp capacitance of
up to 150nF, or an area of approximately 42 square inches.
It is comprised of a boost converter followed by an H-bridge.
The boost converter produces a regulated output voltage,
which is set at a nominal value of 180V using an internal refer-
ence voltage. The H-bridge is used to produce a differential
output drive and the EL lamp will therefore see ±180V (360V
peak-to-peak). The HV816 has two internal oscillators, one
for controlling the boost converter switching frequency and
the other for controlling the H-bridge switching frequency.
Having separate control of each switching frequency allows
flexibility in the circuit design.
The operating input supply voltage is 2.7 to 5.5V, but the En-
able (EN) and Select (SEL) interface to the device will accept
logic high levels down to 1.5V. The EN input is for turning the
device ON and OFF. The SEL input is for external logic control
of the H-bridge switching frequency, if required.
The HV816 boost converter stage uses a single inductor and
a minimum number of external components. The input voltage
to the inductor can be different from the input voltage to the
HV816 (split supply). The external inductor is connected either
between the LX and VDD pins or, for split supply applications,
between the LX pin and a higher voltage supply (shown as VIN
in the Block Diagram). An external MOSFET has to be driven
by the switch oscillator to generate a high voltage. The switch-
ing frequency for this MOSFET is set by an external resistor
connected between the RSW-Osc pin and the supply pin VDD.
During operation, the external switching MOSFET turns on and
allows energy to be stored in the inductor; this energy is trans-
ferred into the capacitor CS when the MOSFET turns off. The
voltage at the CS pin will increase with every switching cycle.
Once the voltage at the CS pin reaches the desired regulation
limit, nominally 180V, the external switching MOSFET is turned
OFF to conserve power.
The CS capacitor is connected between the CS pin and ground;
the CS pin is internally connected to the H-bridge. Energy from
the boost converter stage is stored in the capacitor before being
transferred to the EL lamp. Depending on the EL lamp sizes, a
1.0nF to 15nF capacitor should be used for CS.
The EL lamp switching frequency can be in the range of 100Hz
to 1.0kHz. This frequency can be set by either an external
logic signal at the SEL pin, with a frequency that is 4 times the
desired EL lamp switching frequency, or by an external resis-
tor connected between the REL-Osc and VDD pins. If external
frequency is input to the device at the SEL pin, the REL-Osc
pin should be connected to ground.
The HV816 has the provision to control the discharge rate of
the output to minimize audible noise emitted by the EL lamp,
which is connected between the VA and VB pins. An external
resistor from the RSLEW-OUT pin to ground controls the VA,
VB output discharge rate.
EL lamp dimming can be accomplished by changing the input
voltage to the VREG pin. The VREG pin allows an external
voltage source to control the VCS amplitude. The VCS voltage is
approximately 143 times the voltage at the VREG pin.
Supertex inc. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
1 page  
HV816
Pin Configuration and External Component Description
Pin #
Pin Name Description
External resistor, RSW, from the RSW-Osc to VDD pins sets the switch converter frequency. The switch
converter frequency is inversely proportional to the external RSW resistor value. Reducing the resistor
1
RSW-Osc
value by a factor of two will result in increasing the switch converter frequency by two. A CSW capacitor
is recommended from RSW-Osc to the VDD pin to shunt any switching noise that may couple into the
RSW-Osc pin. A CSW capacitor with a value of 100nF is typically recommended.
External resistor, REL, from the REL-Osc to VDD pins sets the EL frequency. The EL frequency is
inversely proportional to the external REL resistor value. Reducing the resistor value by a factor of two
2
REL-Osc
will result in increasing the EL frequency by two. The SEL pin should be connected to ground if the
REL resistor is used to set the EL frequency. A CFEL capacitor is recommended from the REL-Osc to
VDD pins to shunt any switching noise that may couple into the REL-Osc pin. A CFEL capacitor with a
value of 100nF is typically recommended.
External logic signal input to set the EL frequency. The REL-Osc pin should be connected to ground
3 SEL to use this pin. The output EL frequency is ¼ of the frequency input at this pin. This pin if not used,
should be connected to ground. Input logic high is 1.5V to VDD. Input logic low is 0 to 0.2V.
Input voltage to set VCS regulation voltage. This pin allows an external voltage source to control the
4
VREG
VCS amplitude. The VCS voltage = (143 ± 5%) x VREG. An external resistor, RREG, connected between
the VREG and VOUT pins controls the VCS charging rate. The charging rate is inversely proportional
to the RREG resistor value.
5
VOUT
Switched internal reference voltage.
6
VDD
Device low voltage input supply pin.
7
GND
Device ground.
An external resistor, RSLEW, from this pin to ground controls the slew rate of VA and VB output dis-
charge. The output discharge slew rate is inversely proportional to the RSLEW resistor value. The VA,
8 RSLEW-OUT VB output discharge time is given by the equation
tVA-fall
or
tVB-fall
=
(RSLEW x CEL)
43.73
sec
9
EN
Enable logic pin to turn the device ON/OFF. Input logic high is 1.5V to VDD. Input logic low is 0 to
0.2V.
10 VA
Lamp connections. The polarity is irrelevant. The EL load capacitance is up to 150nF.
11 VB
12
CS
High voltage regulated output. Connection for an external high voltage capacitor to ground. A 0.001µF
to 0.015µF 200V capacitor can be used to store the energy transferred from the inductor.
13
HVGND
High Voltage Ground. Connect it to device ground
14
VDRIVE
Drive voltage for the Gate voltage and also internal regulated voltage for the output drivers. An exter-
nal capacitor (CG) is required at this pin to ground.
Gate control pin for the switching MOSFET. Connection for an external MOSFET. The external
MOSFET is used to boost the low input voltage by inductive flyback. When the MOSFET is ON, the
inductor is being charged. When the MOSFET is OFF, the charge stored in the inductor will be trans-
ferred to the high voltage capacitor CS. The energy stored in the capacitor is transferred to the internal
15
GATE
H-bridge, and therefore to the EL lamp. In general, low RON MOSFET’s, which can handle more cur-
rent, are more suitable to drive larger size lamps. Also, a small value inductor should be used. But
as the RON value and the inductor value decrease, the switching frequency of the inductor (controlled
by RSW) should be increased to avoid inductor saturation. The inductor input voltage (VIN) is recom-
mended to be minimum 4.5V to get the 180V output regulation voltage with 150nF EL load.
16
LX
Drain of the internal N-channel MOSFET. The internal MOSFET is used to generate the GATE pin
voltage at startup.
Supertex inc. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
5
5 Page | ||
| Páginas | Total 6 Páginas | |
| PDF Descargar | [ Datasheet HV816.PDF ] | |
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