Supertex inc. HV835 Initial Release Low Noise Dual EL Lamp Driver Features General Description ► ► ► ► ► ► ► ► ► ► ► The Supertex HV835 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 5.8V. The device is designed to reduce the amount of audible noise emitted by the lamp. This device uses a single inductor and a minimum number of passive components to drive two EL lamps. The nominal regulated output voltage of ±80V is applied to the EL lamps. The two EL lamps can be turned ON and OFF by the two logic input control pins, C1 and C2. The device is disabled when both C1 and C2 (pins 1 and 4) are at logic low. Low audible noise Independent input control for lamp selection 160VPP output voltage Split supply capability Patented output timing One miniature inductor to power both lamps Low shutdown current Wide input voltage range 2.0V to 5.8V Output voltage regulation No SCR output Available in MLP/DFN-10 package The HV835 has an internal oscillator, a switching MOSFET, and two high voltage EL lamp drivers. Each driver has its own half bridge common output (COM1 and COM2) connected to a single pin called COM which minimizes the DC offset seen by the EL lamp. An external resistor connected between the RSW-OSC pin and the voltage supply pin, VDD, sets the frequency for the switching MOSFET. The EL lamp driver frequency is set by dividing the MOSFET switching frequency by 512. An external inductor is connected between the LX and the VDD pins. Depending on the EL lamp size, a 1.0 to 10.0nF, 100V capacitor is connected between CS and Ground. The switching MOSFET charges the external inductor and discharges it into the capacitor at CS. The voltage at CS increases. Once the voltage at CS reaches a nominal value of 80V, the switching MOSFET is turned OFF to conserve power. Applications ► ► ► ► ► Dual display cellular phones Keypad and LCD backlighting Portable instrumentation Dual segment lamps Handheld wireless communication devices Typical Application Circuit 3.3MΩ 1.0µF EL Lamp 1 1.5V 1.5V 0 1 0 2 + VDD CDD 0.1µF 845kΩ 3 4 - 5 C1 EL1 VDD EL2 Com RSW-OSC C2 CS GND LX HV835K7-G + VIN CIN 4.7µF 10 3.3MΩ 1.0µF 9 EL Lamp 2 8 7 6 D LX 330µH CS 3.3nF, 100V - Supertex inc. · 1235 Bordeaux Drive, Sunnyvale, CA 94089 · Tel: (408) 222-8888 · FAX: (408) 222-4895 · www.supertex.com 1 HV835 Pin Configuration Ordering Information Device Pin 1 Package Options MLP/DFN-10 (K7) HV835 HV835K7-G -G indicates package is RoHS compliant (‘Green’) C1 EL1 VDD EL2 RSW-OSC COM C2 CS GND LX HV835K7-G Absolute Maximum Ratings Top View Parameter Note: Pads are on the bottom of the package. Back-side heat slug is at ground potential. Value Supply Voltage, VDD -0.5V to 7.5V Output Voltage, VCS -0.5V to 120V Operating Temperature Range -40°C to 85°C Package θja -65°C to 150°C MLP/DFN-10 60oC/W Storage temperature Thermal Resistance Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied. Continuous operation of the device at the absolute rating level may affect device reliability. All voltages are referenced to device ground. Note: Mounted on FR4 board, 25mm x 25mm x 1.57mm Recommended Operating Conditions Symbol VDD TA Parameter Min Typ Max Supply voltage 2.0 - 5.8 Operating temperature -40 - Units V o +85 C Conditions ----- Electrical Characteristics (Over recommended operating conditions unless otherwise specified: VIN = VDD = 3.3V, TA=25°C) Symbol RDS(ON) Parameter On-resistance of switching transistor Min Typ Max Units Conditions - - 10 Ω I = 100mA VDD Input voltage range 2.0 - 5.8 V --- VCS Output regulation voltage 72 80 88 V VDD = 2.0V to 5.8V VDIFF Differential output peak to peak voltage (EL1 to COM, EL2 to COM) 144 160 176 V VDD = 2.0V to 5.8V IDDQ Quiescent VDD supply current - - 150 nA C1 = C2 = 0.1V - - 250 nA C1 = C2 = 0.3V Input current into the VDD pin - - 200 μA VDD = 5.8V IIN Average input current including inductor current when driving both lamps - 16 25 mA VIN = 5.5V (See Figure 1) VCS Output voltage on VCS when driving both lamps - 80 - V VIN = 5.5V (See Figure 1) IDD 2 HV835 Electrical Characteristics (cont.) Symbol Parameter Min Typ Max Units - 160 - V VIN = 5.5V (See Figure 1) Differential output peak to peak voltage across each lamp (EL1 to COM, EL2 to COM) VDIF Conditions fEL VDIFF output drive frequency 170 200 230 Hz RSW = 845kΩ fSW Switching transistor frequency 87 102 118 kHz RSW = 845kΩ fSW temp Switching transistor frequency tempco - 15 - % TA = -40°C to +85°C D Switching transistor duty cycle - 85 - % TA = -40°C to +85°C IIL Input logic low current - - 1.0 μA VDD = 2.0V to 5.8V IIH Input logic low current - - 1.0 μA VDD = 2.0V to 5.8V VIL Logic input low voltage 0 - 0.3 V --- VIH Logic input high voltage 1.5 - VDD V --- Functional Block Diagram LX CS VDD RSW-OSC EL1 Control logic and switch oscillator C1 C2 VCS + - C Disable EL2 VSENSE Output Drivers VREF VDD VCS COM1 Logic control and divide by 512 COM VCS COM2 GND Function Table Logic Inputs Outputs Device C1 C2 EL1 EL2 COM 0 0 Hi Z Hi Z Hi Z OFF 0 1 Hi Z ON ON ON 1 0 ON Hi Z ON ON 1 1 ON ON ON ON 3 HV835 Figure 1 - Test Circuit VIH = ON 0 = OFF 2.1in2 EL Lamp 1*** VIH = ON 0 = OFF 1.8in2 EL Lamp 2*** 1 2 + CDD 0.1µF 845kΩ VDD 3 4 - 5 C1 EL1 EL2 VDD Com RSW-OSC C2 CS GND LX 10 620Ω 620Ω VIN 11nF 8 7 1N4148* 6 HV835K7-G + 13nF 9 LX 330µH** CIN 4.7µF CS 3.3nF, 100V * or any (equivalent or better) > 90V, fast recovery diode ** Cooper LPO6610-334MLB *** The bigger sized lamp should be tied to EL1 and the smaller sized lamp to EL2 (pins 10 and 9 respectively) Typical Performance Lamp VDD VIN IIN VCS fEL Lamp Brightness EL1 EL2 6.15mA 13.26 cd/m2 --- 5.08mA --- 13.12 cd/m2 Both EL1 and EL2 ON 9.10mA 12.72 cd/m2 12.23 cd/m2 EL1 ON 5.7mA 13.34 cd/m2 --- --- 13.24 cd/m2 EL1 ON EL2 ON EL2 ON 5.2V 3.0V 5.5V 4.76mA 80Vpeak 200Hz Both EL1 and EL2 ON 8.52mA 12.84 cd/m2 12.43 cd/m2 EL1 ON 5.45mA 13.42 cd/m2 --- 4.41mA --- 13.30 cd/m2 7.94mA 13.00 cd/m2 12.55 cd/m2 EL2 ON Both EL1 and EL2 ON 5.8V 4 HV835 Split Supply Configuration The HV835 can be used in applications operating from a battery where a regulated voltage is available. This is shown in Figure 2. The regulated voltage can be used to drive the internal logic of HV835. The amount of current used to drive the internal logic is less than 200µA. Therefore, the regulated voltage could easily provide the current without being loaded down. Figure 2 - Split Supply Configuration VEN = ON 0 = OFF VEN = ON 0 = OFF EL Lamp 1 1 2 Regulated Voltage = VDD RSW-OSC CDD 3 4 5 Battery Voltage = VIN C1 EL1 VDD EL2 RSW-OSC Com C2 CS GND LX 10 9 EL Lamp 2 8 7 D 6 HV835K7-G LX CS CIN Pin Configuration and Description Pin # Function Description 1 C1 Enable input signal for EL Lamp 1. Logic high will turn ON the EL lamp 1 and logic low will turn it OFF. Refer to the function table. 2 VDD Input voltage supply pin. 3 RSW-OSC External resistor connection to set both the switching MOSFET frequency and EL Lamp frequency. The external resistor should be connected between VDD and this pin. The EL lamp frequency is the switching frequency divided by 512. The switching frequency is inversely proportional to the resistor value. A 845kΩ resistor will provide a nominal switching frequency of 102kHz and an EL lamp frequency of 200Hz. To change the frequency to fEL1, the value of the resistor RSW-OSC1 can be determined as RSW-OSC1 = (845 x 200) / fEL1 kΩ. 4 C2 Enable input signal for EL Lamp 2. Logic high will turn ON the EL lamp 2 and logic low will turn it OFF. Refer to the function table. 5 GND 6 LX Drain of internal switching MOSFET. Connection for an external inductor. When the switching MOSFET is turned ON, the inductor is being charged. When the MOSFET is turned OFF, the energy stored in the inductor is transferred to the high voltage capacitor connected at the CS pin. 7 CS Connect a 100V capacitor between this pin and GND. This capacitor stores the energy transferred from the inductor. 8 COM 9 EL2 10 EL1 Device ground. Common lamp connection for both EL1 and EL2. Connect one end of both the lamps to this pin. EL lamp 2 connection. For optimum performance, the smaller of the two lamps should be connected to this pin. EL lamp 1 connection. For optimum performance, the larger of the two lamps should be connected to this pin. 5 HV835 10-Lead DFN/MLP (3x3) Package (K7) 3.00 2.20 All dimensions are in millimeters 1.60 3.00 0.30 +0.15 -0.10 0.50 Pin #1 Index 0.25 Top View +0.05 -0.07 0.20 0.7 - 0.8 0.0 - 0.05 Side View (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to http://www.supertex.com/packaging.html.) 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 "product liability indemnification insurance agreement". Supertex 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 or inaccuracies. Circuitry and specifications are subject to change without notice. For the latest product specifications, refer to the Supertex website: http//www.supertex.com. ©2006 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited. Supertex inc. 1235 Bordeaux Drive, Sunnyvale, CA 94089 TEL: (408) 222-8888 / FAX: (408) 222-4895 Doc.# DSFP - HV835 NR051806 www.supertex.com 6