HV832 HV832 Dual High Voltage, Low Noise EL Lamp Driver Features General Description ❏ 8-pin dual EL driver IC The Supertex HV832 is a high voltage driver designed for driving two EL lamps with a combined area of 3.5 square inches. The input supply voltage range is from 2.0V to 5.0V. The device is designed to reduce the amount of audible noise emitted by the lamp. 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 ±90V. ❏ Input control for lamp selection ❏ Split supply capability ❏ Patented output timing ❏ One minature inductor to power both lamps ❏ 150nA shutdown current The HV832 has an internal oscillator, a switching MOSFET, and two high voltage EL lamp drivers. The frequency for the switching MOSFET is set at 51KHz nominal. The EL lamp driver frequency is set by dividing the MOSFET switching frequency by 128. An external inductor is connected between the LX and VDD pins or VIN for split supply applications. A 0.001 to 0.01µF, 100V capacitor is connected between CS and Ground. The EL lamps are connected between EL1 to Com and EL2 to Com. ❏ Wide input voltage range (2.0V to 5.0V) ❏ Output voltage regulation ❏ No SCR output Applications ❏ Dual display cell phones An input control pin is available to select various modes of the device. Each logic pulse applied to the control pin will cause the device to change to the next mode. The sequence for the modes is: (1) EL1 on only, (2) EL2 on only, (3) both EL1 and EL2 on, and (4) device shuts down. During power up of the device, the mode will default to shut down. ❏ Keypad and LCD backlighting ❏ Dual segment lamps ❏ Handheld wireless communication devices 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 90V, the switching MOSFET is turned off to conserve power. The outputs EL1 to Com and EL2 to Com are configured as H bridges EL1/EL2 and Com are switching in opposite states to achieve 180V across the EL lamp. Typical Application VDD Logic Input Pulse EL Lamp 1 + VIN _ CIN 1 EL1 EL2 8 2 VDD Com 7 3 Control CS 6 4 GND LX 5 EL Lamp 2 HV832MG LX CS 12/13/01 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 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. HV832 Electrical Characteristics DC Characteristics (Over recommended operating conditions unless otherwise specified, TA = 25°C) Symbol Parameter Min Typ Max Units Conditions 7.0 Ω I = 100mA RDS(ON) On-resistance of switching transistor VCS Output regulation voltage 80 90 100 V VDD = 2.0V to 5.0V Vdiff differential output voltage across each lamp (EL1 to Com, EL2 to Com) 160 180 200 V VDD = 2.0V to 5.0V IDDQ Quiescent VDD supply current 150 nA IDD Input current into VDD pin 150 µA IIN Input current including inductor current 27 32 mA VCS Output voltage on VCS 38 43 68 78 87 62 70 78 V VDD = 2.0V to 5.0V VIN = 3.0V. Driving EL1 or EL2. See Figure 1. VIN = 3.0V. Driving both EL1 and EL2. See Figure 1. VIN = 3.0V. Driving EL1 or EL2. See Figure 1. VIN = 3.0V. Driving both EL1 and EL2, See Figure 1. fEL Vdiff output drive frequency 350 400 450 Hz VIN = 3.0V. See Figure 1. fSW Switching transistor frequency 44.8 51.2 57.6 KHz VIN = 3.0V. See Figure 1. fSW Drift Switching transistor frequency Drift +/- 5.0 KHz TA = -40°C to +85°C D Switching transistor duty cycle IIL Input logic low current going into the control pin. 0.6 IIH Input logic high current going into the control pin. 0.6 VIL Logic input low voltage 0 0.25 V VIH Logic input high voltage 1.75 VDD V 85 % See Figure 1. µA VDD = 2.0V to 5.0V. See Figure 1. * The inductor used is a 330uH Murata inductor, max DC resistance of 10 Ohms, part # LQH32CN331. Recommended Operating Conditions Symbol Parameter Min Typ Max Units VDD Supply voltage 2.0 5.0 V TA Operating temperature -40 85 °C Ordering Information Absolute Maximum Ratings* Supply voltage, VDD Output voltage, VC S Operating Temperature Range Conditions Package Options -0.5V to 7.5V -0.5V to +120V Device MSOP-8 Die HV832 HV832MG* HV832X -40°C to +85°C * Product supplied on 2500 piece carrier tape reels. Storage Temperature Range 8 Pin MSOP Power Dissipation -65°C to +150°C 300mW * All voltages are referenced to ground. 2 HV832 Function Table Control Pin EL1 EL2 Com IC Power up HI Z HI Z HI Z OFF 1st pulse L to H ON HI Z ON ON 2nd pulse L to H HI Z ON ON ON 3rd pulse L to H ON ON ON ON 4th pulse L to H HI Z HI Z HI Z OFF Pin Configuration EL1 1 8 EL2 VDD 2 7 Com Control 3 6 VCS GND 4 5 LX top view MSOP-8 3 HV832 Functional Block Diagram LX VDD CS Control Control Logic & Switch Osc GND Disable EL1 Vsen + C _ Vref EL Osc = Switch Osc ÷ 128 High Voltage Level Translator EL2 Com Figure 1: Typical Application Circuit/Test Circuit VDD = VIN VDD Logic Input Pulse EL Lamp 1=1.5in2 1 EL1 EL2 8 2 VDD Com 7 CS 6 LX 5 3 Control VIN 4 + _ GND HV832MG 4.7µF EL Lamp 2=1.5in2 IN914* LX 330µH 3.3nF 100V LX = 330µH Murata (LQH32CN331) * any (equivalent or better) >90V, fast reverse recovery diode Device HV832MG Lamp EL1 or EL2 ON Both EL1 and EL2 ON VDD 3.0V IDD VCS 27mA 78V 38mA 70V 4 fEL 400Hz Brightness 7.5ft-lm 6.2ft-lm HV832 Typical Performance Curves for Figure 1 with one output ON (EL Lamp=1.5in2, VDD=3.0V) Vcs vs Vin 100 Iin vs Vin 30 28 80 lin (mA) 70 26 24 22 60 20 50 1.5 2 2.5 3 3.5 4 4.5 5 1.5 5.5 2.5 3.5 5.5 Vin (V) Vin (V) Brightness vs Vin Iin vs Vcs 10 30 9 28 lin (mA) 8 7 6 26 24 22 5 4 20 1.5 2.5 3.5 4.5 5.5 60 65 70 75 Vin (V) 80 85 90 Vcs (V) IIN, VCS, Brightness vs. Inductor Value Iin, Vcs, Brightness vs. Inductor Value 90 10 80 Vcs 70 Iin(mA), Vcs(V) IIN (mA), VCS (V) Brightness (ft-lm) 4.5 9 60 8 50 Brightness 40 7 30 20 6 Iin 10 0 5 200 300 400 Inductor Value (µH) 5 500 600 Brightness (ft-lm) VCS (V) 90 95 HV832 External Component Description External Component Selection Guide Line Diode Fast reverse recovery diode, IN914 or equivalent. Cs Capacitor 0.003µF to 0.1µF, 100V capacitor to GND is used to store the energy transferred from the inductor. 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. 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 (300mW), an external resistor in series with one side of the lamp is recommended to help reduce the package power dissipation. Split Supply Configuration The HV832 can also be used for handheld devices operating from a battery where a regulated voltage is available. This is shown in Figure 2. The regulated voltage can be used to run the internal logic of the HV832. The amount of current necessary to run the internal logic is 150µA Max at a VDD of 3.0V. Therefore, the regulated voltage could easily provide the current without being loaded down. Figure 2: Split Supply Regulated Voltage=VDD Logic Input Pulse + Battery Voltage=VIN _ EL Lamp 1 1 EL1 EL2 8 2 VDD Com 7 3 Control CS 6 4 GND LX 5 EL Lamp 2 HV832MG CIN LX CS 12/13/01rev.8 ©2001 Supertex Inc. All rights reserved. Unauthorized use or reproduction prohibited. 6 1235 Bordeaux Drive, Sunnyvale, CA 94089 TEL: (408) 744-0100 • FAX: (408) 222-4895 www.supertex.com