Document
Supertex inc.
HV850
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 5.0nF load (approx. 1.5in2 lamp) ►► Output voltage regulation ►► Enable function ►► EL Lamp dimming
Applications
►► Cell phone keypads and displays ►► Transceivers ►► MP3 players ►► Watches ►► Pagers ►► Measuring instruments/gauges
General Description
The Supertex HV850 is a high voltage electroluminescent (EL) Lamp Driver IC. It is designed to drive EL lamps of up to 1.5in2, with capacitive values up to 5.0nF. The HV850 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 external inductors, diodes, and high voltage capacitors, components 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.
The EL lamp frequency can be set either by an external resistor, REL, or by applying an external clock, where the clock frequency is divided by 128 to set the EL lamp frequency.
Typical Application Circuits (For VDD = 3.4V to 4.2V only)
VDD = ON GND = OFF
+ VDD
-
CDD
VDD GND
1 VDD
VA 8
HV850
2 REL
VB 7
3 EN
GND 6
4 CLKIN CLKEN 5 EL lamp frequency set by an external clock
EL Lamp VDD
+
VDD
CDD
-
VDD = ON GND = OFF
1 VDD
VA 8
REL HV850
2 REL
VB 7
3 EN
GND 6
4 CLKIN CLKEN 5
EL Lamp
EL lamp frequency set by REL
Supertex inc. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
HV850
Ordering Information
Package Options
Device
8-Lead MSOP 3.00x3.00mm body 1.10mm height (max)
0.65mm pitch
HV850
HV850MG-G
-G indicates package is RoHS compliant (‘Green’)
Pin Configuration
VDD 1 REL 2
EN 3 CLKIN 4
8 VA 7 VB 6 GND 5 CLKEN
8-Lead MSOP (MG)
(top view)
Absolute Maximum Ratings
Parameter
Value
VDD, supply voltage Operating temperature
-0.5V to 4.5V -25°C to +85°C
Storage temperature
-65°C to +150°C
Power dissipation
300mW
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Product Marking
Top Marking
H850 LLLL
L = Lot Number
YY = Year Sealed Bottom Marking WW = Week Sealed
YYWW
= “Green” Packaging
Package may or may not include the following marks: Si or
8-Lead MSOP (MG)
Recommended Operating Conditions
Sym Parameter
Min Typ Max Units Conditions
VDD fEL CLOAD TA
Input voltage EL lamp frequency EL lamp capacitance Operating temperature
3.0 - 4.2
V ---
50 - 500 Hz ---
0 - 5.0 nF ---
-25 - +85 OC ---
Electrical Characteristics (Unless otherwise specified VDD = 3.5V, TA = 25°C)
Sym Parameter
Min Typ Max Units Conditions
IDDQ Quiescent current
- - 150
VA or VB Peak output voltage
63 70 77
VA - VB Peak to peak output voltage 126 140 154
fEL EL lamp frequency
225 250 275
IDD Operating current
- - 16
VA or VB Peak output voltage
54 - 74
VA - VB Peak to peak output voltage 108 - 148
fEL EL lamp frequency
250 294 338
tROUT Output voltage rise time
1.5 -
-
nA EN = 0V
V No load.
V
Hz REL = 1.65MΩ or CLK = 32kHz
mA
V See Figure 1, VDD = 3.5V,
V
REL = 1.5MΩ, Load = 3.3nF + 1.0kΩ
Hz
ms fEL= 250Hz, 1in2 lamp, 10 to 90% of final value
Supertex inc. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com
2
HV850
Logic Inputs (Unless otherwise specified VDD = 3.5V, TA = 25°C)
Sym Parameter
Min Typ Max
VIL VIH IIL IIH
ENRISE
ENFALL
Input logic low voltage
Input logic high voltage
Input logic low current
Input logic high current Enable input rise time (for delay turn on) Enable input fall time (for delay turn off)
02.0 -
--0.01 -
10µ -
0.5 VDD 1.0 1.0
10
5.0
CIN Logic input capacitance
- - 10
Units V V µA µA
Conditions ---------
ms Using external R-C circuit, see Figure 2.
s
pF ---
Block Diagram
VDD EN
CLKIN CLKEN
REL
VDD
Capacitor Charge
Pump Circuit
VSENSE
Feedback
VDD
EL Oscillator
GND
High Voltage
Level Translators
VA VB
MOSFET Full Bridge
Figure 1: Typical Application Circuit (without Enable function)
+ VDD
1 VDD
VA 8
CDD
REL HV850
2 REL
VB 7
-
3 EN
GND 6
4 CLKIN CLKEN 5
EL Lamp
Load
REL
VDD
IDD Peak VA fEL
(MΩ) (V) (mA) (V) (Hz)
3.0 8.9 53
3.3nF + 1.0kΩ
1.5
3.5 10.2
61
294
Note: CDD = 2.2µF, 6.3V low ESR
4.0 10.4 66
Supertex inc. ● 1235 Bord.