HV830 High Voltage EL Lamp Driver Ordering Information Package Options Device Input Voltage 8-Lead SO Die HV830 2.0V to 9.5V HV830LG HV830X Features General Description ❏ Processed with HVCMOS® technology ❏ 2.0V to 9.5V operating supply voltage ❏ DC to AC conversion ❏ 200V peak-to-peak typical output voltage ❏ Large output load capability – typically 50nF ❏ Permits the use of high-resistance elastomeric lamp connectors ❏ Adjustable output lamp frequency to control lamp color, lamp life, and power consumption ❏ Adjustable converter frequency to eliminate harmonics and optimize power consumption ❏ Enable/disable function ❏ Low current draw under no load condition ❏ Very low standby current – 30nA typical The Supertex HV830 is a high-voltage driver designed for driving EL lamps of up to 50nF. EL lamps greater than 50nF can be driven for applications not requiring high brightness. The input supply voltage range is from 2.0V to 9.5V. 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 ±100V. The chip can be enabled by connecting the resistors on RSW-osc and REL-osc to VDD and disabled when connected to GND. The HV830 has two internal oscillators, a switching MOSFET, and a high-voltage EL lamp driver. The frequency for the switching converter 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. A 0.01µF to 0.1µF capacitor is connected between CS and GND. The EL lamp is connected between VA and VB. The switching MOSFET charges the external inductor and discharges it into the Cs capacitor. The voltage at Cs will start to increase. Once the voltage at Cs reaches a nominal value of 100V, the switching MOSFET is turned OFF to conserve power. The outputs VA and VB are configured as an H-bridge and are switched in opposite states to achieve 200V peak-to-peak across the EL lamp. Applications ❏ Handheld personal computers ❏ Electronic personal organizers ❏ GPS units ❏ Pagers Pin Configuration ❏ Cellular phones ❏ Portable instrumentation Absolute Maximum Ratings* Supply Voltage, VDD -0.5V to +10V VDD 1 8 REL-osc Output Voltage, VCs -0.5V to +120V RSW-osc 2 7 VA Operating Temperature Range -25°C to +85°C Cs 3 6 VB -65°C to +150°C Lx 4 5 GND Storage Temperature Range Power Dissipation Note: *All voltages are referenced to GND. 400mW SO-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, HV830 Electrical Characteristics DC Characteristics (VDD = 3.0V, RSW = 1MΩ, REL = 3.3MΩ, TA = 25°C unless otherwise specified) Symbol Parameter Min Typ Max Units Conditions 6 Ω I = 100mA 100 110 V VDD = 2.0V to 9.5V 200 220 V VDD = 2.0V to 9.5V nA RSW-osc = Low 150 µA VDD = 3.0V. See Figure 1. 40 mA VDD = 3.0V. See Figure 1. V VDD = 3.0V. See Figure 1. 280 Hz VDD = 3.0V. See Figure 1. 75 KHz VDD = 3.0V. See Figure 1. RDS(on) On-resistance of switching transistor 2 VCS Output voltage VCS Regulation 90 VA - VB Output peak to peak voltage 180 IDDQ Quiescent VDD supply current, disabled 30 IDD Input current going into the VDD pin 100 IIN Input current including inductor current 35 VCS Output voltage on VCS 95 fEL VA-B output drive frequency 220 250 fSW Switching transistor frequency 55 65 D Switching transistor duty cycle 88 % Recommended Operating Conditions Symbol Parameter VDD Supply voltage fEL VA-B Output drive frequency TA Operating temperature Min 2.0 Enable/Disable Table -25 Typ Max Units 9.5 V 1.5 KHz +85 °C Conditions (See Figure 2) RSW resistor HV830 VDD Enable 0V Disable Block Diagram Lx VDD Cs RSW-osc Enable* Switch Osc Q VA GND Disable + C _ Q Vref Output Osc Q VB REL-osc Q * Alternate Enable is available in die form only. 2 HV830 Figure 1: Test Circuit, VIN = 3.0V ON = VDD OFF = 0V 5.1MΩ 1 VDD REL-osc 8 2 RSW-osc VA 7 3 Cs VB 6 4 Lx GND 5 1MΩ 220µH1 VDD = VIN = 3.0V BAS21LT1 0.1µF2 0.01µF 200V 10 square inch lamp. HV830 1nF Notes: 1. Murata part # LQH4N221K04 (DC resistance < 5.4Ω) 2. Larger values may be required depending upon supply impedance. For additional information, see Application Notes AN-H33 and AN-H34. Enable/Disable Configuration The HV830 can be easily enabled and disabled via a logic control signal on the RSW and REL resistors as shown in Figure 2 below. The control signal can be from a microprocessor. RSW and REL are typically very high values. Therefore, only 10’s of microam- peres will be drawn from the logic signal when it is at a logic high (enable) state. When the microprocessor signal is high the device is enabled and when the signal is low, it is disabled. Figure 2: Enable/Disable Configuration Remote Enable ON =VDD OFF = 0V REL 1 VDD REL-osc 8 2 RSW-osc VA 7 3 Cs VB 6 4 Lx GND 5 RSW Lx + VIN = VDD - EL Lamp BAS21LT1 4.7µF 15V HV830LG CS 200V 1nF Split Supply Configuration Using a Single Cell (1.5V) Battery Split Supply Configuration for Battery Voltages of Higher than 9.5V The HV830 can also be used for handheld devices operating from a single cell 1.5V battery where a regulated voltage is available. This is shown in Figure 3. The regulated voltage can be used to run the internal logic of the HV830. The amount of current necessary to run the internal logic is typically 100µA at a VDD of 3.0V. Therefore, the regulated voltage could easily provide the current without being loaded down. The HV830 used in this configuration can also be enabled/disabled via logic control signal on the RSW and REL resistors as shown in Figure 2. Figure 3 can also be used with high battery voltages such as 12V as long as the input voltage, VDD, to the HV830 device is within its specifications of 2.0V to 9.5V. 3 HV830 External Component Description External Component Selection Guide Line Diode Fast reverse recovery diode, BAS21LT1 or equivalent. Cs Capacitor 0.01µF to 0.1µF, 200V capacitor to GND is used to store the energy transferred from the inductor. REL-osc The EL lamp frequency is controlled via an external REL resistor connected between REL-osc and VDD of the device. The lamp frequency increases as REL decreases. As the EL lamp frequency increases, the amount of current drawn from the battery will increase and the output voltage VCS will decrease. The color of the EL lamp is dependent upon its frequency. A 3.3MΩ resistor would provide lamp frequency of 220 to 280Hz. Decreasing the REL-osc by a factor of 2 will increase the lamp frequency by a factor of 2. RSW-osc The switching frequency of the converter is controlled via an external resistor, RSW between RSW-osc and VDD of the device. The switching frequency increases as RSW decreases. With a given inductor, as the switching frequency increases, the amount of current drawn from the battery will decrease and the output voltage, VCS, will also decrease. CSW Capacitor A 1nF capacitor is recommended on RSW-osc to GND when a 0.01µF CS capacitor is used. This capacitor is used to shunt any switching noise that may couple into the RSW-osc pin. The CSW capacitor may also be needed when driving large EL lamp due to an increase in switching noise. Lx Inductor The inductor Lx is used to boost the low input voltage by inductive flyback. When the internal switch is on, the inductor is being charged. When the internal switch is off, the charge stored 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 EL 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) should be increased to avoid saturation. 220µH Murata inductors with 5.4Ω series DC resistance is typically recommended. For inductors with the same inductance value but with lower series DC resistance, lower RSW value is needed to prevent high current draw and inductor saturation. Lamp As the EL lamp size increases, more current will be drawn from the battery to maintain high voltage across the EL lamp. The input power, (VIN x IIN), will also increase. If the input power is greater than the power dissipation of the package (400mW), an external resistor in series with one side of the lamp is recommended to help reduce the package power dissipation. Figure 3: Split Supply Configuration Remote Enable ON = VDD OFF = 0V REL VDD = Regulated Voltage 1 VDD REL-osc 8 2 RSW-osc VA 7 3 Cs VB 6 4 Lx GND 5 RSW Lx + VIN = Battery Voltage EL Lamp BAS21LT1 – 0.1µF* CS 200V HV830LG 1nF *Larger values may be required depending upon supply impedance. For additional information, see Application Notes AN-H33 and AN-H34. 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