HV857

HV857_13 SUTEX | Alldatasheet

Document overview

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Technical content

Features

► Patented audible noise reduction ► Patented lamp aging compensation ► 190 VPP output voltage for higher brightness ► Patented output timing for high efficiency ► Single cell lithium ion compatible ► 150nA shutdown current ► Wide input voltage range 1.8 to 5.0V ► Separately adjustable lamp and converter frequencies ► Output voltage regulation ► Split supply capability ► Available in 8-Lead MSOP and DFN packages

Applications

► LCD backlighting ► Mobile Cellular Phone ► PDAs ► Handheld wireless communication products ► Global Positioning Systems (GPS) General Description The Supertex HV857 is a high voltage driver designed for driving Electroluminescent (EL) lamps of up to 5.0 square inches. The input supply voltage range is from 1.8 to 5.0V. 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 ±95V. The chip can be enabled/disabled by connecting the resistor on RSW-Osc to VDD/GND. The HV857 has two internal oscillators, a switching MOSFET, and a high voltage EL lamp driver. The frequency for the switching 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 VDD pin. An external inductor is connected between the LX and VDD pins or V IN for split supply applications. A 0.003- 0.1µF capacitor is connected between CS and ground. The EL lamp is connected between VA and VB. 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 95V, the switching MOSFET is turned OFF to conserve power. The outputs VA and VB are configured as an H bridge and are switching in opposite states to achieve ±95V across the EL lamp. Typical Application Circuit Low Noise, High Voltage EL Lamp Driver IC EL Lamp + _ CS VIN LX CIN Enable Signal ON = VDD OFF = 0 D VDD CDD RSW REL VDD RSW-Osc REL-Osc GND VA VB CS LX HV857

Supertex inc. www.supertex.com Doc.# DSFP-HV857 A062013 HV857 Absolute Maximum Ratings Parameter Value Supply voltage, VDD -0.5V to 6.5V Operating temperature -40°C to +85°C Storage temperature -65°C to +150°C DFN-8 power dissipation 1.6W MSOP-8 power dissipation 300mW Output voltage, VCS -0.5 to +120V Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not im- plied. Continuous operation of the device at the absolute rating level may affect device reliability. All voltages are referenced to device ground. Pin Configuration 8-Lead MSOP (top view) Pads are at the bottom of the package. Exposed center pad is at ground potential. 8-Lead DFN (top view) VDD RSW-Osc REL-Osc GND VA VB CS LX VDD RSW-Osc REL-Osc GND VA VB CS LX Typical Thermal Resistance Package θja 8-Lead DFN 37OC/W 8-Lead MSOP 171OC/W Mounted on FR4 board, 25mm x 25mm x 1.57mm Sym Parameter Min Typ Max Units Conditions VDD Supply voltage 1.8 - 5.0 V --- fEL Operating drive frequency - - 1.0 kHz --- TA Operating temperature -40 - +85 OC --- Recommended Operating Conditions Sym Parameter Min Typ Max Units Conditions EN-L Logic input low voltage 0 - 0.2 V VDD = 1.8 to 5.0V EN-H Logic input high voltage VDD - 0.2 - VDD V VDD = 1.8 to 5.0V Enable/Disable Function Table Sym Parameter Min Typ Max Units Conditions RDS(ON) On-resistance of switching transistor - - 6.0 Ω I = 100mA VCS Max. output regulation voltage 85 95 105 V VDD=1.8 to 5.0V Product Marking H857 YWLL Y = Last Digit of Year Sealed W = Code for Week Sealed L = Lot Number = “Green” Packaging L = Lot Number YY = Year Sealed WW = Week Sealed = “Green” Packaging H857 LLLL YYWW Top Marking Bottom Marking 8-Lead DFN 8-Lead MSOP Package may or may not include the following marks: Si or Package may or may not include the following marks: Si or

Ordering Information

Part Number Package Packing HV857K7-G 8-Lead DFN 3000/Reel HV857MG-G 8-Lead MSOP 2500/Reel -G denotes a lead (Pb)-free / RoHS compliant package

Supertex inc. www.supertex.com Doc.# DSFP-HV857 A062013 HV857 Block Diagram * The inductor used is a 220µH Murata inductor, max DC resistance of 8.4Ω, part # LQH32CN221K21. Figure 1: Typical Application/ Test Circuit Sym Parameter Min Typ Max Units Conditions VA – VB Peak to Peak output voltage 170 190 210 V VDD=1.8 to 5.0V IDDQ Quiescent VDD supply current - - 150 nA RSW-Osc = Low IDD Input current going into the VDD pin - - 150 µA VDD= 1.8 to 5.0V. See Figure 1 IIN Input current including inductor current - 20 25 mA See Figure 1* VCS Output voltage on VCS - 84 - V See Figure 1 fEL EL lamp frequency 205 240 275 Hz See Figure 1 fSW Switching transistor frequency - 80 - kHz See Figure 1 D Switching transistor duty cycle - 88 - % See Figure 1 C _ VREF Disable High Voltage Level Translator GND VDD Q Q Q VA CS LX VB Q RSW-Osc REL-Osc VSENSE EL Osc VDD Switch Osc 220µH* 3.3nF 100V 560kΩ 2.0MΩ BAS21 * Murata Inductor LQH32CN221K21 HV857 ON = V DD OFF = 0V Enable Signal V IN 4.7µF V DD 0.1µF 2.0kΩ Equivalent to 3.0in 2 lamp 10nF 1 VDD RSW-Osc REL-Osc GND VA VB CS LX HV857

Supertex inc. www.supertex.com Doc.# DSFP-HV857 A062013 HV857 Typical Performance Device Lamp Size VDD = VIN IIN VCS fEL Brightness HV857MG-G 3.0in2 3.3V 20.0mA 84V 240Hz 6.0ft-lm Typical Performance Curves for Figure 1 (EL Lamp = 3.0in2, VDD = 3.0V) IIN, VCS, Brightness vs Inductor Value 100 100 200 300 400 500 600 Inductor Value (µH) Brightness VCS IIN vs VIN VIN (V) V CS (V) lIN (mA) Brightness (ft-lm) lIN (mA) lIN (mA), VCS (V) Brightness (ft-Im) Brightness vs VIN VIN (V) IIN vs VCS 55 65 75 85 95 VCS (V) VCS vs VIN VIN (V) lIN

Supertex inc. www.supertex.com Doc.# DSFP-HV857 A062013 HV857 External Component Description External Component Description Diode Fast reverse recovery diode, BAS21 diode or equivalent. CS Capacitor 0.003µF to 0.1µF, 100V capacitor to GND is used to store the energy transferred from the inductor. REL Resistor 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 R EL 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 2MΩ resistor would provide lamp frequency of 205 to 275Hz. Decreasing the REL resistor by a factor of 2 will increase the lamp frequency by a factor of 2. fEL = (2MΩ)(240Hz) REL RSW Resistor 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, V CS, will also decrease. fSW = (560kΩ)(80Hz) RSW 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 C S. 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 switch- ing frequency of the inductor (controlled by R SW) should be increased to avoid saturation. A 220µH Murata (LQH32CN221) inductor with 8.4Ω series DC resistance is typically recommended. For inductors with the same inductance value, but with lower series DC resistance, lower R SW resistor 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, (V IN x I IN), will also increase. If the input power is greater than the power dissipation of the package, an external resistor in series with one side of the lamp is recom- mended to help reduce the package power dissipation.

Supertex inc. www.supertex.com Doc.# DSFP-HV857 A062013 HV857 Minimization of EL Lamp Audible Noise The EL lamp, when lit, emits an audible noise. This is due to EL lamp construction and it creates a major problem for applications where the EL lamp can be close to the ear such as cellular phones. The noisiest waveform is a square wave and the quietest waveform has been assumed to be a sine wave. After extensive research, Supertex has developed a wave- form that is quieter than a sine wave. The waveform takes the shape of approximately 2RC time constants for rising and 2RC time constants for falling, where C is the capaci - tance of the EL lamp, and R is the external resistor, R SER, connected in series with the EL lamp. This waveform has been proven to generate less noise than a sine wave. The audible noise from the EL lamp can be set at a desired level based on the series resistor value used with the lamp. It is important to note that use of this resistor will reduce the voltage across the lamp. Reduction of voltage across the lamp will also have another effect on the over all per- formance of the Supertex EL drivers, age compensation (patented). This addresses a very important issue, EL lamp life that most mobile phone manufacturers are concerned about. Effect of Series Resistor on EL Lamp Audible Noise and Brightness As EL lamp ages, its brightness is reduced and its capaci - tance is diminished. By using the RC model to reduce the audible noise emitted by the EL lamp, the voltage across the lamp will increase as its capacitance diminishes. Hence the increase in voltage will compensate for the reduction of the brightness. As a result, it will extend the EL lamp’s half-life (half the original brightness). Increasing the value of the series resistor with the lamp will reduce the EL lamp audible noise as well as its brightness. This is due to the fact that the output voltage across the lamp will be reduced and the output waveform will have rounder edges.

Supertex inc. www.supertex.com Doc.# DSFP-HV857 A062013 HV857 8-Lead DFN Package Outline (K7) 3.00x3.00mm body, 0.80mm height (max), 0.65mm pitch Symbol A A1 A3 b D D2 E E2 e L L1 θ Dimension (mm) MIN 0.70 0.00 0.20 REF 0.65 BSC 0.30 0.00* 0O JEDEC Registration MO-229, Variation WEEC-2, Issue C, Aug. 2003. * This dimension is not specified in the JEDEC drawing. Drawings not to scale. Supertex Doc. #: DSPD-8DFNK73X3P065, Version C081109. Seating Plane θ Top View Bottom View A D E L V iew B Note 1 (Index Area D/2 x E/2) Note 3 Note 2 Note 1 (Index Area D/2 x E/2) 8 8 eb Side View View B Notes: 1. A Pin 1 identifier must be located in the index area indicated. The Pin 1 identifier can be: a molded mark/identifier; an embedded metal marker; or a printed indicator. 2. Depending on the method of manufacturing, a maximum of 0.15mm pullback (L1) may be present. 3. The inner tip of the lead may be either rounded or square.

Supertex inc. does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such appl ications unless it receives an adequate “product liability indemnification insurance agreement.” Supertex inc. does not assume responsibility for use of devices described, and limits its liabilit y to the replacement of the devices determined defective due to workmanship. No responsibility is assumed for possible omissions and inaccuracies. Circuitry and specifications are subject to change without notice. For the latest product specifications refer to the Supertex inc. (website: http//www.supertex.com) ©2013 Supertex inc. All rights reserved. Unauthorized use or reproduction is prohibited. Supertex inc.

1235 Bordeaux Drive, Sunnyvale, CA 94089

Tel: 408-222-8888 www.supertex.com HV857 (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-HV857 A062013 8-Lead MSOP Package Outline (MG) 3.00x3.00mm body, 1.10mm height (max), 0.65mm pitch View B View A-A Seating Plane Gauge Plane L View B EE1 D e b A A2 Seating Plane A A Top View Side View Note 1 (Index Area D/2 x E1/2) Symbol A A1 A2 b D E E1 e L L1 L2 θ θ1 Dimension (mm) 0.65 BSC 0.40 0.95 REF 0.25 BSC 0O 5O JEDEC Registration MO-187, Variation AA, Issue E, Dec. 2004. * This dimension is not specified in the JEDEC drawing. Drawings are not to scale. Supertex Doc. #: DSPD-8MSOPMG, Version H041309. Note: 1. A Pin 1 identifier must be located in the index area indicated. The Pin 1 identifier can be: a molded mark/identifier; an embedded metal marker; or a printed indicator.