IMP560 IMP560. EL Lamp p Driv

Transcription

1 POWER POWER MANAGEMENT MANAGEMENT Power Efficient E amp p Driv iver The is an Electroluminescent (E) lamp driver designed for systems with low E lamp drive voltage requirements. It is ideal for low ambient light applications or where small lamps are used. With just onehalf the inductor current of the IMP, the reduces system power consumption and extends battery life. Input supply voltage range is V to.5v and quiescent current is a low µa. Typical E lamp drive voltage is ±5V. All four E lamp-driving functions are on-chip. These are the switchmode power supply, its high-frequency oscillator, the high-voltage H-bridge lamp driver and its low-frequency oscillator. E lamps of up to nf capacitance can be driven to high brightness. The circuit requires few external components; a single inductor, a single diode, two capacitors and three resistors. Two of these resistors set the frequencies for two internal oscillators. An internal circuit shuts down the switching regulator when the lamp drive voltage exceeds V peak-to-peak. This conserves power and extends battery life. A disable mode puts the chip into a low current drain mode. With a.v supply, quiescent current drops to na maximum, 5nA typical. The chip is disabled by connecting the oscillator frequency setting resistor R SW to ground. The is available in MicroSO and SO- packages and in die or wafer form. Block Diagram V peak-to-peak typical AC output voltage ow input current (w/inductor current)...ma ow disabled input current...5na Wide operating voltage range - from V to.5v Simple design requires few passive components Adjustable output lamp frequency controls lamp color and power consumption Adjustable converter frequency for minimum power consumption IMP pin-compatible MicroSO package option Night lights Automotive displays Cellular phones Pagers Clocks and radios Portable GPS receivers CD module backlights Key Features Applications V DD X R SW-OSC Switch Oscillator GND 5 Regulation Control Q C V REF Q V A Bridge Output Driver and OSC Q R E-OSC Q 5_.eps Daily Silver IMP

2 Pin Configuration SO/MicroSO V DD R SW-OSC X R E-OSC V A 5 GND Pin Compatible With IMP 5_.eps Ordering Information Part Number Input Voltage Regulated Output Voltage Temperature Range Pins-Package EMA V to.5v YES C to 5 C -MicroSO ESA V to.5v YES C to 5 C -SO /D* V to.5v YES 5 C Dice /D** V to.5v YES 5 C Dice * Disable pad not active ** Disable pad active Absolute Maximum Ratings Supply Voltage, V DD, V RSW-OSC and V RE-OSC....5V to.v Output Voltage, V to V Operating Temperature Range C to 5 C Storage Temperature Range C to 5 C Power Dissipation (SO) mw Power Dissipation (MicroSO) mw Note: All voltages are referenced to GND. These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability. Electrical Characteristics Unless otherwise noted, V DD =.V, R SW = 5kΩ, R E = MΩ, and T A = 5 C. Parameter Symbol Conditions Min Typ Max Units ON-resistance of MOS Switch R DS(ON) I = ma.5 Ω Output Voltage Regulation V DD = to.5v V Output Voltage Peak-to-peak (in regulation) V A - V DD = to.5v V Quiescent V DD Supply Current, Disabled I DDIS V RSW-OSC < mv 5 na Input Current at V DD Pin I DD V DD =.V, See Figure µa Input Current at V DD Pin I DD V DD = 5.V, See Figure 5 5 µa Input Current: I DD Plus Inductor Current V DD =.V, See Figure ma V A-B Output Drive Frequency f E V DD =.V, See Figure Hz Switching Frequency f SW V DD =.V, See Figure 5 9 khz Switching Duty Cycle D SW V DD =.V, See Figure % Daily Silver IMP

3 Typical Characteristics, vs. V IN, vs. V IN = µh = µh (V), (ma) (V), (ma) 5_.eps 5_.eps, vs. V IN, vs. V IN = µh = 5µH (V), (ma) (V), (ma) 5_.eps 5_.eps, vs. V IN I DD vs. V DD = mh = 5µH (V), (ma) I DD (µa) 5 5_5.eps V DD (V) 5_.eps Daily Silver IMP Electroluminescent amp Driver

4 Pin Descriptions Pin Number Name Function V DD Positive voltage supply for the. Inductor may be connected here or to a separate unregulated supply. R SW-OSwitch-mode resistor pin. Switching frequency is determined by an external resistor, R SW. Boost converter storage capacitor. The voltage across the E lamp is equal to twice the voltage at. X Connection to flyback inductance,. 5 GND Ground pin. E lamp drive. The lamp is connected in a high-voltage bridge circuit with providing the complementary connection to V A. The peak-to-peak AC voltage across the E lamp is thus two times. V A E lamp drive. (See above) R E-OSC The E lamp oscillator frequency setting pin. The oscillator frequency is controlled by external resistor R E. External Components External Component Description and Selection Guide Diode A fast reverse recovery diode, with BV >, such as a N. Capacitor This is the high voltage capacitor that stores the inductive energy transferred through the diode. A volt capacitor between nf and nf is recommended. Resistor R E The E lamp oscillator frequency setting resistor. This resistor, connected between the R E-OSC pin and ground, provides an oscillator frequency inversely proportional to R E ; as R E increases, the E lamp frequency decreases along with the current drawn by the lamp. amp color is also determined by this frequency. A MΩ resistor between the R E-OSC pin and the V DD supply results in a lamp frequency around 5Hz: a MΩ resistor will give Hz. Resistor R SW Switching Oscillator frequency setting resistor. The switching oscillator resistor is connected between the R SW-OSC pin and the V DD supply. The switching frequency is inversely proportional to the resistor value, dropping as the resistance increases. Inductor The inductor provides the voltage boost needed by means of inductive flyback. The internal MOSFET switch alternately opens and closes the ground connection for the inductor at the X pin. When this internal switch opens, the inductor potential will forward-bias the diode and the current will pass through the storage capacitor, charging it to a high voltage. Smaller inductors are preferred to prevent saturation. As the value of the inductor increases (and the series DC resistance of the inductor decreases), the switching frequency set by R SW should be increased to prevent saturation. In general, smaller value inductors that can handle more current are more desirable when larger area E lamps must be driven. High Voltages Present The generates high voltages and caution should be exercised. Daily Silver IMP

5 Application Information Test and Application Circuit,.V Figure shows the configured to drive a -square-inch E lamp, represented as a nf capacitor. ON = V DD OFF = V MΩ V IN =.V 5µH.µF N 5kΩ.µF V V DD R E-OSC R SW-OSC V A X GND 5 nf Equivalent to in lamp Note:. Murata part # QHN5K (DC resistance <.5 Ω). arger values may be required depending upon supply impedance. Figure..V Application 5_9.eps Test and Application Circuit, 5.V Figure shows a 5.V input application driving a -square-inch E lamp. ON = V DD OFF = V MΩ V IN = 5.V 5µH.µF N 5kΩ.µF V V DD R E-OSC R SW-OSC V A X GND 5 in lamp Note:. Murata part # QHN5K (DC resistance <.5 Ω). arger values may be required depending upon supply impedance. Figure. 5.V Application 5_.eps Daily Silver IMP Electroluminescent amp Driver 5

6 Enable/Disable Operation Figure shows the can be enabled via a logic gate that connects R SW to V DD, and disabled by connecting it to ground. R E may be connected either to V DD or to the gate. Enable/Disable Table R SW Connection V DD Ground State Enabled Disabled ON = V DD OFF = V CMOS Gate R E V DD R E-OSC V IN.µF 5V N R SW.µF V R SW-OSC V A X GND 5 E lamp Note:. Murata part # QHN5K (DC resistance <.5 Ω). arger values may be required depending upon supply impedance. 5_.eps Figure. Enable/Disable Operation Dual Supply Operation with.5attery The can also be operate from a single battery cell when a regulated voltage higher than V is also available. The dual supply configuration, shown in Figure, uses the regulated voltage to operate the while the energy for the highvoltage boost circuit comes from the battery. The current to run the internal logic is typically µa. The circuit of Figure can also be used with batteries that exceed.v as long as V DD does not exceed.5v. ON = V DD Regulated Voltage (V to.5v) OFF = V R E V DD R E-OSC Battery Voltage V IN.µF * N R SW.µF V R SW-OSC V A X GND 5 E lamp * arger values may be required depending upon supply impedance 5_.eps Figure. Dual Supply Operation with High Battery Voltages Daily Silver IMP

7 Package Dimensions N SO (-Pin) E H D A e B A MicroSO (-Pin) E E D A a C C SO (-Pin).eps Inches Min Max SO (-Pin)* Min Millimeters Max A A....5 B....5 C e.5. E H D.9.9. MicroSO (-Pin)** A.. A A b C D...9. e.5 BSC.5 BSC E.9 BSC.9 BSC E a * JEDEC Drawing MS-AA ** JEDEC Drawing MO-AA _t.at A e b A D.mm.in MicroSO (-Pin).eps Daily Silver IMP Electroluminescent amp Driver

8 Daily Silver IMP Microelectronics Co.,td keda Road, Hi-Tech Park, NingBo,Zhejiang, P.R.C. Post Code : 5 Tel:()-5-95 Fax:()-5-9 sales@ds-imp.com.cn Website: The IMP logo is a registered trademark of Daily Silver IMP. All other company and product names are trademarks of their respective owners. 5 Daily Silver IMP Revision : A Issue Date: //5 Type: Product