HV852
Initial Release
High Voltage, Low Noise,
Inductorless EL Lamp Driver
Features
►
No external components required when using an
external EL clock frequency
►
EL frequency can be set by an external resistor
►
Low Noise
►
DC to AC converter
►
Drives up to 5.3nF (approx. 1.5in
2
lamp) load
►
Output voltage regulation
►
Enable function
General Description
The Supertex HV852 is a high voltage, low noise, inductorless
EL (electroluminescent) lamp driver. It is designed to drive EL
lamps of up to 1.5in
2
, with capacitive values up to 5.3nF over
an input voltage range of 2.4V to 5.0V. The HV852 converts
a low voltage DC input to a high voltage AC output across an
EL lamp. It uses a charge pump scheme to boost the input
voltage eliminating the need for an external inductor, diode,
and high voltage capacitor commonly found in conventional
topologies.
The charge pump circuit discharges its energy into an EL lamp
through a high voltage H-bridge. Once the voltage reaches
its regulated limit, it is turned off to conserve power. The EL
lamp is then discharged to ground and the H-bridge changes
state to allow the charge pump to charge the EL lamp in the
opposite direction.
Applications
►
Cellular phone keypad
►
Watches
►
Small handheld wireless devices
►
MP3 Players
Typical Application Circuit
HV852
+
V
DD
-
C
DD
R
EL
V
DD
R
EL
EN
CLK
IN
V
A
V
B
GND
CLK
EN
EL
LAMP
V
DD
= ON
GND = OFF
EL Lamp frequency set by R
EL
1
HV852
Ordering Information
Package Options
DEVICE
MSOP-8
HV852
HV852MG-G
DFN-10
HV852K7-G
-G indicates package is RoHS compliant (‘Green’)
Absolute Maximum Ratings
Parameter
V
DD
, Supply Voltage
Operating Temperature
Storage Temperature
Power Dissipation MSOP-8
Power Dissipation DFN-10
Value
-0.5V to 6.5V
-25°C to +85°C
-65°C to +150°C
300mW
1.6W
Pin Configuration
V
DD
1
2
3
4
8
7
6
5
V
A
V
B
V
DD
1
2
3
4
5
10
9
8
7
6
V
A
V
B
GND
GND
C
LK
EN
R
EL
EN
CLK
IN
GND
C
LK
EN
R
EL
EN
CLK
IN
V
DD
Absolute Maximum Ratings are those values beyond which damage to the device may
occur. Functional operation under these conditions is not implied. Continuous operation
of the device at the absolute rating level may affect device reliability. All voltages are
referenced to device ground.
8-Lead MSOP (MG)
(top view)
10-Lead DFN (K7)
(top view)
Note:
Pads are at the bottom of the package.
Center heat slug is at ground potential.
Electrical Characteristics
(Over recommended operating conditions unless otherwise specified: T
A
= 25ºC, V
DD
= 3.5V)
Symbol
I
DDQ
V
A
or V
B
V
A
-V
B
I
DD
V
A
or V
B
V
A
-V
B
f
EL
t
rout
Parameter
Quiescent current
Peak output voltage
Peak to Peak output voltage
Operating current
Peak output voltage
Peak to Peak output voltage
EL lamp frequency
Output voltage rise time
Min
-
72
144
-
72
144
210
-
Typ
-
80
160
15.2
80
160
250
640
Max
200
88
176
30
88
176
300
-
Units
nA
V
Conditions
EN = 0V
No load
V
mA
V
V
Hz
µs
1.0in
2
lamp, 0V to 90% of final value
See Figure 1, V
DD
= 3.5V,
R
EL
= 1.5MΩ, Load = 3.3nF+1KΩ
Logic Inputs
V
IL
V
IH
I
IL
I
IH
EN
rise
EN
fall
C
in
Input logic low voltage
Input logic high voltage
Input logic low current
Input logic high current
Enable input rise time
(for delay turn off)
Enable input fall time
(for delay turn off)
Logic input capacitance
0
2.0
-
-
0.01
10µ
-
-
-
-
-
-
-
-
0.5
V
DD
1.0
1.0
10
5
10
V
V
µA
µA
ms
Using external R-C circuit, see Figure 2
s
pF
---
---
---
---
---
Recommended Operating Conditions
V
DD
f
EL
C
load
T
A
Input voltage
EL lamp frequency
EL lamp capacitance
Operating Temperature
2.4
50
0
-25
-
-
-
-
5.0
500
5.3
+85
V
Hz
nF
°C
---
---
---
---
2
HV852
Typical Output Waveform
Test Conditions:
HV852 driving a 1.0in
2
EL lamp
V
DD
= 3.6V and R
EL
= 1.5MΩ,
V
A
-V
B
waveform
Functional Block Diagram
V
DD
V
DD
EN
Capacitor
Charge
Pump Circuit
V
A
V
SENSE
Feedback
CLK
IN
CLK
EN
R
EL
V
DD
EL
Oscillator
High
Voltage
Level
Trans-
lators
V
B
MOSFET
Full Bridge
GND
Pin Description
Name
V
DD
R
EL
EN
CLK
IN
Description
Input supply voltage pin.
An external resistor to V
DD
will set the EL lamp frequency. When using an external clock to set the EL lamp frequency, the
R
EL
pin should be connected to ground.
Enable input pin. Logic high will turn the device on. An external R-C circuit can be added for a delayed turn off.
Logic input pin. An external logic clock applied to this pad can be used to set the EL lamp frequency (see Figure 3). The
EL lamp frequency is the external clock frequency divided by 128. This is useful for applications requiring the EL lamp to
be synchronized to a system clock. Connect to ground when not in use.
Logic input pin. Logic high will cause the EL lamp frequency to be set by the CLK
IN
input. Logic low will cause the EL
lamp frequency to be set by the external R
EL
resistor.
IC ground pin.
EL lamp driver output pin. The EL lamp is connected across V
A
and V
B
terminals.
EL lamp driver output pin. The EL lamp is connected across V
A
and V
B
terminals.
CLK
EN
Gnd
V
B
V
A
3
HV852
Typical Performance
(The following was the observed performance when driving a 1.0in
2
green lamp)
Load
R
EL
V
DD
2.4V
3.0V
I
DD
17.56mA
17.53mA
17.44mA
17.65mA
18.35mA
V
A
-V
B
77V
79V
79V
79V
79V
f
EL
3.3nF+1KΩ
1.5MΩ
3.6V
4.2V
5.0V
245Hz
Figure 1: Typical Application
HV852
+
V
DD
-
C
DD
R
EL
V
DD
R
EL
EN
CLK
IN
V
A
V
B
GND
CLK
EN
EL
Lamp
V
DD
= ON
GND = OFF
Note: C
DD
= 2.2µF, 6.3V ceramic capacitor
Figure 2: Push Button Turn on with Delay Turn off
HV852
+
V
DD
Push Button
Turn On
C
DD
C
R
EL
V
DD
R
EL
EN
V
A
V
B
GND
CLK
EN
EL
Lamp
-
R
CLK
IN
RC time constant
will set Turn OFF
Delay time
Figure 3: Independent Programmable Output Frequency (f
EL
)
+
V
DD
-
V
DD
= ON
GND = OFF
V
DD
GND
f
CLK
Note: f
EL
= f
CLK
/128
C
DD
HV852
V
DD
R
EL
EN
CLK
IN
V
A
V
B
GND
CLK
EN
V
DD
EL
Lamp
EL Lamp frequency set exrernal clock
4
HV852
8-Lead SOIC Package (MG)
3.00 ± 0.20
4.90 ± 0.25
Note 2
3.00 ± 0.20
Top View
0.08 - 0.23
1.10 MAX
0.75 - 0.95
5° - 15°
(4 PLCS)
0° - 8°
0.15 MAX
0.65BSC
0.40 - 0.80
0.22 - 0.38
Side View
Notes:
1. All dimensions in millimeters; angles in degrees
2. Pin 1 identifier must be located within the indicated area
End View
5
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