HV8051 HV8053 – E T E L – OBSO High-Voltage EL Lamp Driver Ordering Information Package Options Device Input Voltage 8-Lead SO Die HV8051 1.0V to 1.6V HV8051LG HV8051X HV8053 2.4V to 3.5V HV8053LG HV8053X General Description Features The Supertex HV8051 and HV8053 are high-voltage drivers designed for driving EL lamps of typically 4nF and 12nF for a 1V and 3V operation. The input supply voltage range is from 1.0V to 1.6V for HV8051 and 2.4V to 3.5V for HV8053. 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 ±50V for HV8051 and ±70V for HV8053. Processed with HVCMOS® technology 1.0V to 3.5V operating supply voltage DC to AC conversion Adjustable output lamp frequency to control lamp color, lamp life, and power consumption Adjustable converter frequency to eliminate harmonics and optimize power consumption The HV8051/HV8053 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 0.1µF capacitor is connected between Cs and GND pins. The EL lamp is connected between VA and VB pins. Applications Pagers Portable transceiver The switching BJT charges the external inductor and discharges it into the 0.1µF 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. Cellular phones Remote control units Calculators Pin Configuration ςΑ Absolute Maximum Ratings* Supply voltage, VDD Operating temperature range Storage temperature range SO-8 power dissipation 15 -0.5V to +4.5V -25°C to +85°C -65°C to +150°C 400mW Note: *All voltages are referenced to GND. VDD 1 8 REL-osc RSW-osc 2 7 VA Cs 3 6 VB Lx 4 5 GND top view SO-8 15-9 HV8051/HV8053 Electrical Characteristics DC Characteristics (Over recommended operating conditions unless otherwise specified, TA = 25°C) Symbol RDS(on) IIN VCS Parameter Min Typ On-resistance of switching transistor Max Units 15 Ω mA VDD supply current (including inductor current) HV8051 8.0 15 HV8053 40 65 Output voltage on VCS HV8051 fEL VA-B output drive frequency HV8051 HV8053 fsw D Switching transistor frequency I = 50mA VDD = 1.0V to 1.6V. See Figure 1. VDD = 2.4V to 3.5V. See Figure 2. 41 VDD = 1.0V to 1.3V. See Figure 1. 52 HV8053 Conditions V VDD = 1.3V to 1.6V. See Figure 1. 43 VDD = 2.4V to 3.0V. See Figure 2. 52 VDD = 3.0V to 3.5V. See Figure 2. 60 160 70 220 200 350 HV8051 50 HV8053 50 Switching transistor duty cycle VDD = 1.0V. See Figure 1. Hz VDD = 1.6V. See Figure 1. VDD = 2.4V to 3.5V. See Figure 2. KHz VDD = 1.0V to 1.6V. See Figure 1. VDD = 2.4V to 3.5V. See Figure 2. 85 % See Figures 1 and 2. Recommended Operating Conditions Symbol VDD CL TA Parameter Supply voltage Load capacitance* Operating temperature Min Typ Max Units Conditions HV8051 1.0 1.6 V @ VDD = 1.0V to 1.6V HV8053 2.4 3.5 V @ VDD = 2.4V to 3.5V. HV8051 0 4.0 nF @ VDD = 1.0V to 1.6V HV8053 0 12 nF @ VDD = 2.4V to 3.5V -25 85 °C *Larger panels can be driven with HV8051/HV8053. See application note AN-H33. Block Diagram – E T E L – OBSO VDD Lx Cs Rsw-osc Switch Osc Q VA GND Q Output Osc Q VB REL-osc Q 15-10 HV8051/HV8053 Figure 1: VDD = 1.0V to 1.6V 4.5MΩ 1 VDD REL-osc 8 5.1KΩ 560KΩ 1mH1 VDD 2 Rsw-osc VA 7 3 Cs VB 6 4 Lx GND 5 3.2nF 0.1µF2 1N4148 0.1µF 100V Equivalent load to a 1 square inch lamp HV8051 Note: 1. Murata part # LQH4N102K04 (DC resistance < 25Ω) 2. Larger values may be required depending upon supply impedance. For additional information, see application note AN-H33. – E T E L O S B O – Figure 2: VDD = 2.4V to 3.5V 2MΩ 1 VDD VDD REL-osc 8 820KΩ 560µH1 5.1KΩ 2 Rsw-osc VA 7 3 Cs VB 6 4 Lx GND 5 10nF 0.1µF2 47pF 100V 1N4148 0.1µF 100V HV8053 1.0nF Note: 1. Murata part # LQH4N561K04 (DC resistance < 14.5Ω) 2. Larger values may be required depending upon supply impedance. For additional information, see application note AN-H33. 15-11 15 HV8051/HV8053 External Component Description External Component Selection Guide Line Diode Fast reverse recovery diode, 1N4148 or equivalent. Cs Capacitor 0.01µF to 0.1µF, 100V 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. 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 typically recommended on RSW-osc to GND for HV8053. As the input voltage of the device increases, a faster switching converter frequency is required to avoid saturating the inductor. With the higher switching frequency, more noise will be introduced. This capacitor is used to shunt any switching noise that may couple into the RSW-osc pin. CLx Capacitor In order to drive the HV8053 more efficiently when high brightness is required, a 47pF, 100V CLx capacitor needs to be used at the Lx pin to GND. This capacitor reduces the total amount of current drawn by the circuit by reducing the dv/dt voltage on the internal switch. 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 then available 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 size decreases, the switching frequency of the inductor (controlled by RSW) should be increased to avoid saturation. 560µH Murata inductors with 14.5Ω 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 Size 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 (350mW), an external resistor in series with one side of the lamp is recommended to help reduce the package power dissipation. – E T E L O Application Hints S B O – should be bypassed with a capacitor located close to the lamp driver. Values can range from 0.1µF to 1µF depending on supply impedance. A supply bypass capacitor elsewhere in the host circuit is sufficient if located close to the driver. Start with a high conversion frequency to avoid inductor saturation. Adjust converter frequency (via RSW-osc) and inductor value to obtain desired lamp drive voltage and supply current. Make sure that inductor current does not approach saturation as specified on the inductor data sheet. Higher VIN’s and smaller inductors require a higher conversion frequency to avoid saturation. For lower power consumption, set a low lamp drive frequency, use a 1mH inductor, and adjust power conversion frequency for minimum current draw. For high brightness, set lamp drive frequency for desired hue, use a 330µH inductor and adjust power conversion frequency until desired brightness is obtained. Adjust the lamp drive frequency via REL-osc to obtain desired lamp brightness and hue. For longer lamp life, use as low a lamp drive frequency as is acceptable. Adjust converter frequency and inductor value to obtain acceptable brightness. If the desired VCS cannot be obtained, try decreasing lamp drive frequency slightly. If VCS is above 80 volts, insert a 2kΩ resistor in series with the lamp. For high lamp drive frequencies, employ a FET follower on the output. See application note AN-H33. Monitor overall power consumption. If above 350mW, insert a resistor in series with the lamp to decrease device power dissipation. In keeping with good circuit design practice, the supply voltage 15-12