Supertex inc. HV857LDB1 Low Noise, High Voltage EL Lamp Driver IC Demoboard General Description The Supertex HV857LDB1 demoboard contains all necessary circuitry to demonstrate the features of the HV857L EL lamp driver. Simply connect it to a power supply and a lamp. For additional assistance in designing EL driver circuits, please refer to application notes AN-H33 (effect of external components on performance of Supertex EL drivers). Specifications Parameter Value Input voltage: 1.8 to 5.0V Typical supply current: 27mA Lamp size: 3.0in2 Lamp frequency: 204Hz Converter frequency: 70kHz Board Layout and Connection Diagram VDD CDD RSW HV857L REL EN VB VA CIN CS GND VIN LX D Actual Dimensions: 12mm x 12mm Connections: EN - Enable Input Enables/Disables the lamp driver. A logic high, (connect to VDD) enables the driver and a logic low, (connect to GND) disables the driver. This input can be connected to a mechanical switch or to a logic circuit output that has a source impedance of less than 20kΩ. VDD - IC Supply Supplies the HV857L EL driver IC. The supplied circuit is optimized for 3.0V operation. The operating range can be from 1.8 to 5.0V. Connect to the positive terminal of a power supply. VIN - Inductor Supply Supplies the high voltage power converter. Connect to the positive terminal of a power supply. GND - Circuit Ground Connect to VDD and VIN negative terminals. Supply bypass capacitors for both VDD and VIN are provided on the demo board. External supply bypass capacitors are not required. VA and VB - Lamp Connections Connect to an EL lamp. Polarity is irrelevant. Note: Make sure all the above connections are made before powering up the supply voltages. Doc.# DSDB-HV857LDB1 A032813 Supertex inc. www.supertex.com HV857LDB1 Circuit Schematic ON = VDD OFF = 0V Enable Signal 1 + RSW = 560kΩ VDD CDD 0.1µF - 3 REL = 2.0MΩ + 2 4 - VA RSW-Osc VB REL-Osc CS GND LX 8 EL Lamp 7 6 BAS21 5 CS 3.3nF 100V LX 220µH* HV857L CIN 4.7µF VIN VDD * Murata Inductor LQH32CN221K21 The above circuit may be optimized further based on specification of the lamp used. Typical Performance Lamp Size (in2) VDD = VIN IIN (V) (mA) 3.0 1.8 3.0 VCS Brightness fEL (V) (Hz) ft-lm cd/m2 27.06 70 202 2.49 8.51 2.0 26.95 73 202 3.04 10.40 3.0 3.0 27.01 90 204 5.49 18.78 3.0 4.0 21.94 96 204 5.97 20.42 3.0 5.0 17.55 98 204 6.24 21.33 Bill of Materials Component Description Package Manufacturer Part # LX 220µH Inductor - Murata LQH32CN221K21 CS 3.3nF, 100V, NPO chip capacitor 0805 Novacap 0805N332K101NT RSW 5%, 560kΩ resistor 0805 Any --- REL 5%, 2MΩ resistor 0805 Any --- CIN 4.7µF, 10V ceramic chip capacitor 0805 Any --- CDD 0.1µF, 16V ceramic chip capacitor 0603 Any --- Diode 250V fast recovery diode SOT-23 Diodes Inc BAS21 U1 EL driver IC MSOP-8 Supertex Inc HV857LMG-G Supertex inc. does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such applications unless it receives an adequate “product liability indemnification insurance agreement.” Supertex inc. does not assume responsibility for use of devices described, and limits its liability to the replacement of the devices determined defective due to workmanship. No responsibility is assumed for possible omissions and inaccuracies. Circuitry and specifications are subject to change without notice. For the latest product specifications refer to the Supertex inc. (website: http//www.supertex.com) Supertex inc. ©2013 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited. Doc.# DSDB-HV857LDB1 A032813 2 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: 408-222-8888 www.supertex.com