HV825 High Voltage EL Lamp Driver Ordering Information Package Options Device Input Voltage 8-Lead SO MSOP-8 Die HV825 1.0 to 1.6V HV825LG HV825MG* HV825X * Product supplied on 2500 piece carrier tape reels. Features General Description ❏ Processed with HVCMOS® technology The Supertex HV825 is a high voltage driver designed for driving EL lamps typically up to 6nF. The input supply voltage range is from 1.0V to 1.6V. The device uses a single inductor and a minimum number of passive components. Typical output voltage that can be applied to the EL lamp is ±56V. ❏ 1.0V to 1.6V operating supply voltage ❏ DC to AC conversion ❏ Output load of typically up to 6nF ❏ Adjustable output lamp frequency The HV825 can be enabled/disabled by connecting the RSW-osc resistor to VDD/ground. ❏ Adjustable converter frequency ❏ Enable function The HV825 has two internal oscillators, a switching bipolar junction transistor (BJT), and a high voltage EL lamp driver. The frequency for the switching BJT 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. A 0.01 to 0.1µF, 100V capacitor is connected between CS and ground. The EL lamp is connected between VA and VB. Applications ❏ Pagers ❏ Portable Transceiver ❏ Cellular phones ❏ Remote control units ❏ Calculators The switching BJT charges the external inductor and discharges it into the 0.01 to 0.1µF, 100V capacitor at CS. The voltage at CS will start to increase. The outputs VA and VB are configured as an H-bridge and are switching in opposite states to achieve a peak-to-peak voltage of two times the VCS voltage across the EL lamp. Absolute Maximum Ratings* Supply voltage, VDD Operating Temperature Range Storage Temperature Range -0.5V to +2.5V -25°C to +85°C Pin Configuration -65°C to +150°C MSOP-8 Power Dissipation 300mW SO-8 Power Dissipation 400mW Note: *All voltages are referenced to GND. For detailed circuit and application information, please refer to application notes AN-H33 and AN-H34. VDD 1 8 REL-osc RSW-osc 2 7 VA Cs 3 6 VB Lx 4 5 GND top view SO-8/MSOP-8 11/12/01 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 1 refer to the most current databook or to the Legal/Disclaimer page on the Supertex website. Supertex website: http://www.supertex.com. For complete liability information on all Supertex products, HV825 Electrical Characteristics DC Characteristics Symbol RDS(ON) IIN (Over recommended operating conditions unless otherwise specified, TA=25°C) Parameter Min Typ On-resistance of switching transistor VDD supply current (including inductor current) 30 Max Units Conditions 15 Ω 38 mA VDD=1.5V. See test circuit. 1.0 µA RSW-osc=GND I=50mA IDDQ Quiescent VDD supply current VCS Output voltage on VCS 52 56 62 V VDD=1.5V. See test circuit. VA-B Differential output voltage across lamp 104 112 124 V VDD=1.5V. See test circuit. fEL VA-B output drive frequency 400 Hz VDD=1.5V. See test circuit. fSW Switching transistor frequency 30 KHz VDD=1.5V. See test circuit. D Switching transistor duty cycle 88 % Recommended Operating Conditions Symbol Parameter VDD Supply voltage CL Load Capacitance TA Operating temperature Min Typ 1.0 0 Max Units 1.6 V 6.0 -25 Conditions nF +85 °C Max Units Enable/Disable Table Symbol Parameter Min Typ Conditions VIL Low level input voltage to RSW-osc resistor 0 0.2 V VDD=1.0V-1.6V. VIH High level input voltage to RSW-osc resistor VDD-0.5 VDD V VDD=1.0V-1.6V. 2 HV825 Block Diagram Lx VDD Cs RSW-osc Switch Osc Q VA GND Q Output Osc Q VB REL-osc Q Test Circuit Enable ON = VDD OFF = GND 1MΩ 1 VDD 2 RSW-osc 3 Cs VB 6 4 Lx GND 5 1MΩ 560µH* VIN= VDD = 1.0V to 1.6V 1N4148 REL-osc 8 VA 7 2.2K 4.7nF 0.1µF 0.1µF 100V CSW 1nF HV825MG or HV825LG *560µH Murata inductor (LQH4N561K04), max DC resistance of 14.5Ω. Typical Performance Lamp Size 1.5 in2 VDD IDD VCS fEL Brightness 1.5v 30mA 56v 450Hz 3.65ft-lm 3 Equivalent to a 1.5 square inch lamp. HV825 External Component Description External Component Selection Guide Line Diode Fast reverse recovery, 1N4148 or equivalent. CS Capacitor 0.01 to 0.1µF, 100V capacitor to GND is used to store the energy transferred from the inductor. REL-osc Resistor The lamp frequency is controlled via the REL-osc. The lamp frequency increases as the REL-osc decreases. As the lamp frequency increases, the amount of current drawn from the battery will increase and the output voltage VCS will decrease. This is because the lamp will draw more current from VCS when driven at higher frequencies. In general, as the lamp size increases, larger REL-osc is recommended to provide higher VCS. However, the color of the lamp is dependent upon its frequency and the shade of the color will change slightly with different frequencies. RSW-osc Resistor The switching frequency of the inductor is controlled via the RSW-osc. The switching frequency increases as the RSW-osc decreases. As the switching frequency increases, the amount of current drawn from the battery will decrease and the output voltage VCS will also decrease. LX Inductor The inductor LX is used to boost up the low input voltage. When the internal switch is on, the inductor is being charged. When the internal switch is off, the charge in the inductor will be transferred to the high voltage capacitor CS. The energy stored in the capacitor is connected to the internal H-bridge and therefore to the lamp. In general smaller value inductors, which can handle more current, are more suitable to drive larger size lamps. As the inductor value decreases, the switching frequency of the inductor (controlled by RSW-osc) should be increased to avoid saturation. The test circuit uses a Murata (LQH4N561) 560µH inductor. Using different inductor values or inductors from different manufacturers will affect the performance. As the inductor value decreases, smaller RSW-osc value shall be used. This will prevent inductor saturation. Inductor with the same inductance value (560µH) but lower series resistance will charge faster. The RSW-osc resistor value needs to be decreased to prevent inductor saturation and high current consumption. CSW Capacitor A 1nF capacitor is recommended from RSW-OSC to GND. This capacitor is used to shunt any switching noise that may couple into the RSW-OSC pin. 11/12/01 ©2001 Supertex Inc. All rights reserved. Unauthorized use or reproduction prohibited. 4 1235 Bordeaux Drive, Sunnyvale, CA 94089 TEL: (408) 744-0100 • FAX: (408) 222-4895 www.supertex.com