HV845 Initial Release Low Noise Dual EL Lamp Driver Features General Description Low audible noise Independent input control for lamp selection 180VPP 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 12-Lead QFN/MLP package ► ► ► ► ► ► ► ► ► ► ► The Supertex HV845 is a low noise, 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 minimum number of passive components to drive two EL lamps. The nominal regulated output voltage of ±90V 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 12 and 3) are at logic low. The HV845 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, which significantly 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 90V, the switching MOSFET is turned OFF to conserve power. Applications ► ► ► ► ► Dual display cellular phones Keypad and LCD backlighting Portable instrumentation Dual segment lamps Hand held wireless communication devices Typical Application Circuit 330µH + VIN LX CIN 4.7µF - D CS 3.3nF, 100V 3.3MΩ 1.0µF 5 1 + VDD - CDD 0.1µF 845kΩ 2 12 1.5V 0 1.5V 3 VDD 6 CS LX RSW-OSC EL1 COM1 C1 EL2 C2 GND COM2 4 0 HV845K7-G 1 10 EL Lamp 1 8 9 7 3.3MΩ 1.0µF EL Lamp 2 HV845 Pin Configuration Ordering Information Device C1 NC EL1 Package Options 12 11 10 QFN/MLP - 12 HV845 HV845K7-G VDD 1 RSW-OSC 2 -G indicates package is RoHS compliant (‘Green’) 9 EL2 8 COM1 C2 3 7 COM2 4 5 6 GND LX CS HV845K7-G Top View Absolute Maximum Ratings 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 QFN/MLP - 12 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 80 90 100 V VDD = 2.0V to 5.8V VDIFF Differential output peak to peak voltage (EL1 to COM1, EL2 to COM2) 160 180 200 V VDD = 2.0V to 5.8V IDDQ Quiescent VDD supply current - - 150 nA C1 = C2 = 0.1V - - 250 nA C1 = C2 = 0.3V IDD Input current into the VDD pin - - 250 μA VDD = 5.8V IIN Average input current including inductor current when driving both lamps - 20 30 mA VIN = 5.5V (See Figure 1) VCS Output voltage on VCS when driving both lamps - 87 - V VIN = 5.5V (See Figure 1) 2 HV845 Electrical Characteristics (cont.) Symbol Parameter Min Typ Max Units Differential output peak to peak voltage across each lamp (EL1 to COM1, EL2 to COM2) 160 180 200 V VIN = 5.5V (See Figure 1) 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 --- VDIF Conditions Functional Block Diagram LX CS VDD RSW-OSC EL1 Control logic and switch oscillator C1 C2 VCS + - C Disable VDD EL2 VSENSE Output Drivers VCS VREF COM1 Logic control and divide by 512 VCS COM2 GND Function Table Logic Inputs Outputs Device C1 C2 EL1 EL2 COM1 COM2 0 0 Hi Z Hi Z Hi Z Hi Z OFF 0 1 Hi Z ON Hi Z ON ON 1 0 ON Hi Z ON Hi Z ON 1 1 ON ON ON ON ON 3 HV845 Figure 1 - Test Circuit 330µH** 1N4148* + - CS 3.3nF, 100V LX CIN 4.7µF VIN 2.1in2 EL Lamp 1*** 5 1 + 845kΩ CDD 0.1µF VDD 2 12 3 VIH = ON 0 = OFF VDD 6 CS LX EL1 10 COM1 8 RSW-OSC C1 EL2 C2 GND COM2 620Ω 13nF 1.8in2 EL Lamp 2*** 9 7 620Ω 11nF 4 VIH = ON 0 = OFF HV845K7-G * 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 (V) VIN (V) IIN (mA) VCS (VPEAK) fEL (Hz) Lamp Brightness (cd/in2) EL1 EL2 7.96 13.89 - 6.91 - 12.89 Both EL1 and EL2 ON 13.93 13.02 11.24 EL1 ON 7.47 13.93 - - 13.22 EL1 ON EL2 ON EL2 ON 5.2V 3.0V 5.5V 6.42 88 195 Both EL1 and EL2 ON 13.42 13.30 12.05 EL1 ON 7.04 14.03 - 6.01 - 13.30 12.94 13.55 12.51 EL2 ON Both EL1 and EL2 ON 5.8V 4 HV845 Split Supply Configuration The HV845 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 HV845. 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 Battery Voltage = VIN LX CIN D CS EL Lamp 1 5 1 Regulated Voltage = VDD CDD RSW-OSC 2 12 VIH = ON 0 = OFF 3 VIH = ON 0 = OFF VDD 6 LX CS COM1 RSW-OSC EL2 C1 C2 EL1 GND COM2 4 10 8 9 EL Lamp 2 7 HV845K7-G Pin Configuration and Description Pin # Function 1 VDD Description Input voltage supply pin. 2 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. 3 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. 4 GND 5 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. 6 CS Connect a 100V capacitor between this pin and GND. This capacitor stores the energy transferred from the inductor. 7 COM2 Common lamp connection for EL2. 8 COM1 Common lamp connection for EL1. 9 EL2 10 EL1 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. 11 NC No connect. 12 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. Device ground. 5 HV845 12-Lead QFN/MLP (3x3) Package (K7) 3.00 ± 0.15 1.25 - 1.65 3.00 ± 0.15 1.25 - 1.65 Note 2 0.25 + 0.05 - 0.07 0.40 ± 0.10 Pin #1 Index 0.50 BSC Top View 0 - 14O 0.75 ± 0.05 0.20 Side View 0.0 - 0.05 Note: 1. All dimensions are in millimeters; all angles in degrees 2. Corner shape may differ from drawing (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.) Doc.# DSFP - HV845 062306 6