Supertex inc. HV860DB1 Low Noise, Dimmable EL Lamp Driver Demoboard General Description The Supertex HV860DB1 demoboard contains all necessary circuitry to demonstrate the features of the HV860 EL lamp driver. Simply connect it to a power supply and a lamp as shown in Figure1. For EL lamp dimming, either a potentiometer or an nchannel open drain PWM signal can be used, but not both. The potentiometer is used as a variable voltage divider to change the voltage at the VREG pin. The VREF is voltage divided to change the VREG voltage thereby changing the VCS voltage. The VCS voltage amplitude, and thereby the lamp brightness, increases when the potentiometer is rotated counter-clockwise, and the lamp brightness decreases when it is rotated clockwise. Specifications Parameter Value Input voltage: 2.4 to 4.5V 5.5V VIN inductor supply voltage: Typical supply current: 10mA Lamp size: 3.5in2 Lamp frequency: 200Hz Converter frequency: 150kHz Board Layout and Connection Diagram HV860DB1 EN VDD RSW REL PWM CDD VB RDIM CDIM RPWM Potentiometer VA CIN CS LX D VIN GND Actual Dimensions: 20mm x 25mm Connections: EN - (Enable Input) A CMOS logic input which enables/disables the lamp driver. A logic high (1.5V) enables the driver and a logic low (connect to GND) disables the driver. VDD - (IC Supply) Supplies the HV860 EL driver IC. The supplied demo board is optimized for 3.0V operation, with an operating range from 2.4V to 4.5V. It connects to the positive terminal of a power supply. PWM - (PWM Input) Supplies the PWM signal for dimming the EL lamp. The frequency of this signal can vary between 20kHz and 100kHz. For EL lamp dimming using the PWM input, either the potentiometer has to be removed or its value set to for maximum lamp brightness. The n-channel open drain PWM signal pulls the 10kΩ resistor to ground. When the duty cycle of this PWM signal is changed, the effective voltage on the VREG pin is changed. This changes the VCS voltage, and hence the lamp brightness. The higher the duty cycle, the higher the lamp brightness, and vice versa. VA and VB - (Lamp Connections) They connect to the EL lamp terminals. Polarity is irrelevant. VIN - (Inductor Supply) Supplies the high voltage power converter. The demo board is optimized for 5.5V operation. It connects to the positive terminal of a power supply. GND - (Circuit Ground) Connect to VDD and VIN negative terminals. Supply bypass capacitor for both VDD and VIN are provided on the demo board. External supply bypass capacitors are not required. Note: All of the above connections must be made before powering up the supply voltages. The VREG pin should not be touched after power-up. Doc.# DSDB-HV860DB1 A032813 Supertex inc. www.supertex.com HV860DB1 Figure 1: Circuit Schematic VIN + CIN 4.7μF - 2 1 2M Potentiometer 3.3MΩ 3 n-channel Open Drain PWM signal + VDD - 590kΩ CDD 0.1μF Cooper Inductor SD3114-221, 220μH 10kΩ 10 12 1 2.0MΩ 11 ON = 1.5V OFF = 0V 2 3 VREG VDD VREF HV860K7 5 LX CS BAS20HT1 7 3.3nF, 200V 1206 Package RSW-Osc REL-Osc VA EN VB GND 9 EL Lamp 8 4 Typical Performance The specific external components used in the circuit schematic are: LX = 220μH Cooper (SD3114-221), CS = 3.3nF 200V NPO and the 2MΩ potentiometer. Brightness Lamp Size (in2) VDD (V) VIN (V) IIN (mA) VCS (V) fEL (Hz) ft-lm cd/m2 3.5 3.0 5.2 9.0 110 190 6.20 21.21 3.5 3.0 5.5 8.4 110 190 6.22 21.27 3.5 3.0 5.8 7.9 110 190 6.24 21.33 Bill of Materials Component Description Package Manufacturer Part Number --- Cooper SD3114-221 LX 220μH inductor CS 3.3nF, 200V, NPO chip capacitor 1206 Tecate CMC-200/332JN1206T RSW 1%, 590kΩ chip resistor 0603 Any --- REL 1%, 2MΩ chip resistor 0603 Any --- RDIM 5%, 3.3MΩ chip resistor 0603 Any --- RPWM 1%, 10kΩ chip resistor 0603 Any --- CDIM Optional capacitor for dimming control --- --- --- CIN 4.7μF, 10V ceramic chip capacitor 0603 Any --- CDD 0.1μF, 16V ceramic chip capacitor 0603 Any --- SOD-323 Diodes Inc. BAS20HT1 --- Bourns Inc. 3352T-205 12-Lead QFN Supertex HV860K7 Diode 200V fast recovery diode POT 2MΩ Potentiometer U1 EL driver IC Note: The above circuit may be optimized further based on specification of the lamp used. 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-HV860DB1 A032813 100110 2 1235 Bordeaux Drive, Sunnyvale, CA 94089 Tel: 408-222-8888 www.supertex.com