IMP525

IMP525 IMP | Alldatasheet

Document overview

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Technical content

SingSingle Cell Battle Cell Batterery Py Poowwerereded ElectrElectroluminescent Lamoluminescent Lampp DrDriviver/Iner/Invverertterer u Audio/TV remote control units u Pagers/Cellular phones u PDAs u Clocks and radios u Portable GPS receivers u LCD modules u Toys u Wide operating voltage range - from 0.9V to 2.5V u Simple design requires few passive components u 112V peak-to-peak typical AC output voltage u Adjustable output frequency controls lamp color and power consumption u Adjustable converter frequency minimizes circuit power consumption u Disable mode extends battery life u Disable current under 2mA u Compact MicroSO package option Key Features

Applications

525_01.eps VDD 1 LX C S VA VB R SW-OSC

2 Switch

Q Q Q VREF Lamp Drive Oscillator C GND 5 R EL-OSC Q The IMP525 is an Electroluminescent (EL) lamp driver designed for sys- tems that must operate below 1 volt. The input supply voltage range is 0.9V to 2.5V . Typical output lamp drive voltage is 112V . All four EL lamp- driving functions are on-chip. These are the switch-mode power supply, its high-frequency oscillator, the high-voltage H-bridge lamp driver and its low-frequency oscillator. EL lamps of up to 6nF capacitance can be dri- ven to high brightness. The circuit requires few external components; one inductor, one diode, one capacitor and two resistors. The resistors set the frequency for the two oscillators. A disable mode puts the chip into a low current-drain state. When dis- abled, quiescent current drops to 2mA maximum with a V DD of 1.5V . The chip can be disabled by connecting R SW, the oscillator frequency setting resistors, to ground. A disable pad, accessible only on the die, can also be used to disable the driver. An internal circuit shuts down the switching regulator when the lamp drive voltage exceeds 112V peak-to-peak. This conserves power and extends battery life. The IMP525 is available in MicroSO and SO-8 packages and in die form. POWER MANAGEMENT IMP , Inc. San Jose, CA 408-432-9100/www.impweb.com

Parameter Symbol Conditions Min Typ Max Units ON-resistance of MOS Switch R DS(ON) I = 50mA 15 W Operating Voltage 0.9 2.5 V Output Voltage at CS VCS VDD = 1.5V, See Figure 1, Table 1 52 58 65 V Output Voltage at CS VCS VDD = 0.9V, See Figure 1, Table 2 50 V Output Voltage Peak-to-Peak VA-VB VDD = 1.5V, See Figure 1 104 112 124 VP-P Quiescent VDD Supply Current, Disabled IQDIS Disable = HIGH 70 nA (Disable pin available on die only) Quiescent VDD Supply Current, Disabled IQDIS R SW -OSC = GND 1.0 2.0 mA VDD = 1.5V Input Current at VDD Pin IDD VDD = 0.9V to 1.5V 1.5 mA Input Current: IDD Plus Inductor Current IIN VDD = 1.5V 23 32 mA VA-B Output Drive Frequency fEL VDD = 1.5V, See Figure 1, Table 1 500 Hz Boost Converter Switching Frequency fSW VDD = 1.5V, See Figure 1, Table 1 26 kHz Switching Duty Cycle D SW VDD = 1.5V, See Figure 1 87.5 % Disable Input LOW Voltage VDISL GND 0.2 V (Disable pin available on die only) Disable Input HIGH Voltage VDISH VD D -0.5V VDD V (Disable pin available on die only)

Ordering Information

5 GND

8 R EL-OSC

525_02.eps IMP525 SO/Micr oSO Part Number Input Voltage Regulated Output Voltage Temperature Range Pins-Package IMP525EMA 0.9V to 2.5V YES –40°C to +85°C 8-MicroSO IMP525ESA 0.9V to 2.5V YES –40°C to +85°C 8-SO IMP525/D 0.9V to 2.5V YES 25°C Dice Absolute Maximum Ratings Supply Voltage, VDD, VRSW-OSC and VREL-OSC . . –0.5V to +3.5V Unless otherwise noted, VDD = 1.5V, RSW = 1MΩ , REL = 1.0MΩ , and TA = 25° C. 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

Frequency (Hz) R EL (MΩ ) EL Lamp Drive Frequency 525_08.eps VDD = 1.5V TA = 25°C 400 800 1200 1600 2000 2400 Frequency (kHz) R SW (MΩ ) 525_10.eps 100 125 150 Boost Converter Switching Frequency VDD = 1.5V TA = 25°C Period (ms) R EL (MΩ ) 525_07.eps EL Lamp Drive Period VDD = 1.5V TA = 25°C Period (ms) R SW (MΩ ) 525_09.eps 100 Boost Converter Switching Period VDD = 1.5V TA = 25°C

1 VDD Positive voltage supply for the IMP525. Inductor Lmay be connected here or to a separate supply. 2 R SW -OSC Switch-mode resistor pin. Switching frequency is determined by external resistor RSW , connected between pin 2 and VDD . 3 C S Boost converter storage capacitor. The voltage across the ELlamp is equal to twice the voltage at CS. 4 LX Connection to flyback inductance, L. 5 GND Ground pin. 6 VB EL lamp drive. The lamp is connected to a high-voltage bridge circuit with VB providing the complementary connection to VA. 7 VA EL lamp drive. (See above) 8 R EL-OSC The EL lamp oscillator frequency-setting pin. The frequency is controlled by resistor REL, connected from pin 8 to VDD . Disable Pad DIS Available only in die form. Setting DIS HIGH disables the chip. External Component Description and Selection Guide Diode A fast reverse recovery diode, with BV > 100, such as a 1N4148. Capacitor CS The high voltage capacitor that stores the inductive energy transferred through the catch diode. A 100 volt capacitor between 10nF and 100nF is recommended. Resistor R EL The EL lamp oscillator frequency-setting resistor. REL is connected between pin 8 and VDD , providing a frequency inversely proportional to REL; as REL increases, the ELlamp frequency decreases along with the current drawn by the lamp. Lamp color is also determined by this frequency. A 1M Ω resistor between the R EL-OSC pin and the VDD supply results in a lamp frequency around 500Hz. Resistor RSW Switching Oscillator frequency-setting resistor. RSW is connected between the RSW -OSC pin and the VDD supply. The switching frequency is inversely proportionalto the resistor value, dropping as the resistance increases. Capacitor CSW This is an optional noise-suppression capacitor connected from ground to the RSW -OSC pin. A 100pF capacitor is recommended. Inductor L 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 LX pin. When the switch opens, the inductor potential will forward-bias the diode and the current will pass through to the storage capacitor CS, charging it to a high voltage. As the value of the inductor is increased, the switching frequency set by RSW should also be increased to prevent saturation. In general, smaller value inductors that can handle more current are more desirable when larger-area ELlamps must be driven. A small electrolytic capacitor (10mF, 16V), normally present across the inductor supply V IN, will likely eliminate the need for CSW . External Components

L 0°– 8° C HE N e D B A1 A SO (8-Pin).eps Inches Millimeters Min Max Min Max MicroSO (8-Pin) A1 0.0020 0.0059 0.050 0.15 A2 0.0295 0.0374 0.75 0.95 b 0.0098 0.0157 0.25 0.40 C 0.0051 0.0091 0.13 0.23 D 0.1142 0.1220 2.90 3.10 e 0.0256 BSC 0.65 BSC E 0.193 BSC 4.90 BSC E1 0.1142 0.1220 2.90 3.10 L 0.0157 0.0276 0.40 0.70 a 0° 6° 0° 6° SO (8-Pin) A 0.053 0.069 1.35 1.75 A1 0.004 0.010 0.10 0.25 B 0.013 0.020 0.33 0.51 C 0.007 0.010 0.19 0.25 e 0.050 1.27 E 0.150 0.157 3.80 4.00 H 0.228 0.244 5.80 6.20 L 0.016 0.050 0.40 1.27 D 0.189 0.197 4.80 5.00 SO (8-Pin) Package DimensionsMicroSO (8-Pin) e b D E1 E a L C D 0.10mm 0.004in A MicroSO (8-Pin).eps

IMP, Inc. Corporate Headquarters 2830 N. First Street San Jose, CA 95134-2071 Tel: 408-432-9100 Tel: 800-438-3722 Fax: 408-434-0335 Fax-on-Demand: 1-800-249-1614 (USA) Fax-on-Demand: 1-303-575-6156 (International) e-mail: info@impinc.com http://www.impweb.com The IMP logo is a registered trademark of IMP, Inc. All other company and product names are trademarks of their respective owners. © 1998 IMP, Inc. Printed in USA Part No.: IMP525 Preliminary Document Number: IMP525-8-9/98 IMP525IMP525