HV845K7-G Supertex, HV845K7-G Datasheet
HV845K7-G
Manufacturer Part Number
HV845K7-G
Description
Display Drivers Low Noise Dual
Manufacturer
Supertex
Datasheet
1.HV845K7-G.pdf
(2 pages)
Specifications of HV845K7-G
Driver Type
EL Lamp Drivers
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
Package / Case
QFN-12
Minimum Operating Temperature
- 40 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Applications:
►
►
►
►
►
Dual display cellular phones
Keypad and LCD backlighting
Portable instrumentation
Dual segment lamps
Hand held wireless communi-
cation devices
Summary
12-Lead QFN/MLP
Product
Sheet
062606
(K7)
Product Overview:
The Supertex HV845 is a high voltage driver designed for driving two EL lamps with a combined
area of 3.5 square inches. The input supply voltage range is from 2.0 to 5.8V. The device is
designed to reduce the amount of audible noise emitted by the lamp. This device uses a single
inductor and minimum number of passive components to drive two EL lamps. The nominal
regulated output voltage of ±90V is applied to the EL lamps. The two EL lamps can be turned
ON and OFF by the two logic input control pins, C1 and C2. The device is disabled when both
C1 and C2 (pins 12 and 3) are at logic low.
The HV845 has an internal oscillator, a switching MOSFET, and two high voltage EL lamp
drivers. Each driver has its own half bridge common output COM1 and COM2, which significantly
minimizes the DC offset seen by the EL lamp. An external resistor connected between the RSW-
Osc pin and the voltage supply pin, VDD
lamp driver frequency is set by dividing the MOSFET switching frequency by 512. An external
inductor is connected between the LX and the VDD pins. Depending on the EL lamp size, a 1.0
to 10.0nF, 100V capacitor is connected between CS and GND. The switching MOSFET charges
the external inductor and discharges it into the capacitor at CS. The voltage at CS increases.
Once the voltage at CS reaches a nominal value of 90V, the switching MOSFET is turned OFF
to conserve power.
Features:
Audible noise reduction
Independent input control for lamp selection
180V
One miniature inductor to power both lamps
Low shutdown current
Wide input voltage range 2.0 to 5.8V
No SCR output
V
V
DD
IN
+
-
-
PP
+
regulated output voltage
1.5V
0
1.5V
0
Low Noise Dual EL Lamp Driver
C
0.1µF
C
4.7µF
DD
IN
Typical Application Circuit
330µH
LX
845k
,
sets the frequency for the switching MOSFET. The EL
12
1
2
3
VDD
RSW-Osc
C1
C2
Benefits:
Low audible noise levels
Conserves power, extends battery life
Uniform brightness over wide input voltage
range
Minimal external parts
Minimum battery usage while lamp is in standby
mode
Ease of design with commonly available supply
voltages in cellular phones
Eliminates high peak currents into the EL lamp,
avoids EMI concerns
5
LX
HV845
GND
4
Supertex inc.
CS
COM2
COM1
EL2
6
EL1
10
8
9
7
D
EL Lamp 1
EL Lamp 2
HV845
C
3.3nF,
100V
S
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HV845K7-G Summary of contents
Page 1
... Product Overview: The Supertex HV845 is a high voltage driver designed for driving two EL lamps with a combined area of 3.5 square inches. The input supply voltage range is from 2.0 to 5.8V. The device is designed to reduce the amount of audible noise emitted by the lamp. This device uses a single inductor and minimum number of passive components to drive two EL lamps. The nominal regulated output voltage of ± ...
Page 2
... Low Noise Dual EL Lamp Driver Ordering Information / Availability Part Number Package Option HV845K7-G 12-Lead QFN/MLP -G indicates the part is RoHS compliant (Green). Product Contact For any questions regarding the HV845, please contact your local area Supertex sales office, or contact the main office in the US at: ...