|
Details, datasheet, quote on part number:HV857MG
| |
Datasheet text preview:
HV857
HV857
Demo Kit Available
High Voltage EL Lamp Driver for Low Noise Applications
General Description
The Supertex HV857 is a high voltage driver designed for driving Electroluminescent (EL) lamps of up to 5 square inches. The input supply voltage range is from 1.8V to 5.0V. The device uses a single inductor and a minimum number of passive components. The nominal regulated output voltage that is applied to the EL lamp is ±95V. The chip can be enabled/disabled by connecting the resistor on Rsw-osc to VDD/ground. The HV857 has two internal oscillators, a switching MOSFET, and a high voltage EL lamp driver. The frequency for the switching MOSFET is set by an external resistor connected between the Rsw-osc pin and the supply pin VDD. The EL lamp driver frequency is set by an external resistor connected between REL-osc pin and the VDD pin. An external inductor is connected between the LX and VDD pins or VIN for split supply applications. A 0.003-0.1µF capacitor is connected between Cs and ground. The EL lamp is connected between VA and VB. The switching MOSFET charges the external inductor and discharges it into the capacitor at Cs. The voltage at Cs will start to increase. Once the voltage at Cs reaches a nominal value of 95V, the switching MOSFET is turned OFF to conserve power. The outputs VA and VB are configured as an H bridge and are switching in opposite states to achieve ±95V across the EL lamp.
Features
Patent pending audible noise reduction Patent pending lamp aging compensation 190VPP output voltage for higher brightness Patented output timing for high efficiency Single cell lithium ion compatible 150nA shutdown current Wide input voltage range 1.8V to 5.0V Separately adjustable lamp and converter frequencies Output voltage regulation Split supply capability
Applications
LCD backlighting Mobile cellular phones PDAs Handheld wireless communication products Global Positioning Systems (GPS)
Typical Application
ON=VDD OFF=0 Regulated Voltage=VDD Enable Signal
1 VDD 2 RSW-osc
VA VB
8
EL Lamp
7
VDD=VIN
+ _
CIN
3 REL-osc 4 Gnd
CS 6 LX 5 LX CS
HV857MG
07/24/03
Supertex Inc. does not recommend the use of its products in life support applications and will not knowingly sell its products for use in such applications unless it receives an adequate "products liability indemnification insurance agreement." Supertex does not assume responsibility for use of devices described and limits its liability to the replacement of devices determined to be defective due to workmanship. No responsibility is assumed for possible omissions or inaccuracies. Circuitry and specifications are subject to change without notice. For the latest product specifications, refer to the Supertex website: http://www.supertex.com. For complete liability information on all Supertex products, refer to the most current databook or to the Legal/Disclaimer page on the Supertex website.
1
HV857
Electrical Characteristics
DC Characteristics (Over recommended operating conditions unless otherwise specified, TA=25°C)
Symbol RDS(on) VCs VA VB IDDQ IDD IIN VCs fEL fSW D Parameter On-resistance of switching transistor Max. output regulation voltage Peak to Peak output voltage Quiescent VDD supply current Input current going into the VDD pin Input current including inductor current Output voltage on VCs EL lamp frequency Switching transistor frequency Switching transistor duty cycle 205 20 84 240 80 88 275 85 170 95 190 Min Typ Max 6.0 105 210 150 150 25 Units V V nA µA mA V Hz KHz % I=100mA VDD=1.8V to 5.0V VDD=1.8V to 5.0V RSW-OSC=Low VDD=1.8V to 5.0V. See Figure 1. See Figure 1.* See Figure 1. See Figure 1. See Figure 1. See Figure 1. Conditions
* The inductor used is a 220µH Murata inductor, max DC resistance of 8.4, part # LQH32CN221K21.
Recommended Operating Conditions
Symbol VDD fEL TA Supply voltage Output drive frequency Operating temperature -40 Parameter Min 1.8 Typ Max 5.0 1 85 Units V KHz °C Conditions
Enable/Disable Function Table
Symbol EN-L EN-H Parameter Logic input low voltage Logic input high voltage Min 0 VDD-0.2 Typ Max 0.2 VDD Units V V Conditions VDD=1.8V to 5.0V VDD=1.8V to 5.0V
Absolute Maximum Ratings*
Supply Voltage, VDD Operating Temperature Range Storage Temperature Range MSOP-8 Power Dissipation Output voltage, VCS -0.5V to +6.5V -40° to +85°C -65°C to +150°C 300mW -0.5 to +120V
Pin Configuration
V DD RSW REL Gnd
1 2
8 7
VA VB CS LX
Note: *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.
MSOP-8
3 4
Top View
6 5
Ordering Information
Package Options Device HV857 MSOP-8 HV857MG* Die HV857X
* Product supplied on 2500 piece carrier tape reels.
2
HV857
Block Diagram
LX VD D CS RS W Switch Osc
Q
GND Disable
+ C _
Vsen Vref High Voltage Level Translators
Q
VA
VDD
Q
Rel
EL Osc
Q
VB
Figure 1: Typical Application/Test Circuit
ON=VDD OFF=0 VDD Enable Signal VIN=VDD 2.0K Equivalent to 3.0in2 lamp
1 VDD 2 RSW-osc
VA VB
8
10nF
7
+
VIN
_
1.0µF
2.0M
3 REL-osc 4 Gnd
CS 6 LX 5 SB01-15
HV857MG
220µH 3.3nF 100V
LX=220µH Murata (LQH32CN221K21) SB01-15=150V Sanyo Diode
Typical Performance
Device HV857MG Lamp Size 3.0 in2 VIN 3.3V IIN 20mA VCS 84V f EL 240Hz Brightness 6.0ft-lm
3
|
|
