IMP522 POWER MANAGEMENT ADVANCE PRODUCT INFORMATION Dual EL Lamp Driver Key Features The IMP522 is a dual-output, high-voltage electroluminescent (EL) lamp driver. Either or both EL lamp driver outputs can be turned ON with the LMPSEL select pin. One EL lamp is connected between VA and VAB and the other is connected between VB and VAB. VAB is a common pin for both lamps. With an input supply voltage between 2.0V and 6.5V, the typical regulated lamp drive voltage is 220V peak-to-peak. ◆ Drive two EL lamps independently The device uses a single inductor and a minimum number of passive components: a storage capacitor, a fast recovery diode and two resistors to set the PWM and EL drive frequencies. These can be independently set to optimize brightness and minimize power consumption. RSW is connected between the RSW-OSC pin and the supply pin VDD to set the frequency for the internal 4.0Ω switching MOSFET. The switch duty cycle is 88%. The EL lamp driver frequency is set by REL connected between the REL-OSC pin and the VDD pin. ◆ Wide operating voltage range: 2V to 6.5V ◆ Digital LMPSEL pin — Activate either or both EL output drivers ◆ 220VP-P typical AC output voltage drives 30nF EL lamps ◆ Low current consumption: 2mA maximum ◆ Disable mode extends battery life — Disable current 2µA maximum ◆ Compact 10-pin MicroSO package ◆ High-voltage, low-cost CMOS process Designed to minimize battery current drain, the IMP522 draws 2mA maximum. A power-saving shutdown mode reduces current to 2µA maximum. Applications The IMP522 is available in a compact 10-pin MicroSO package and in die form. ◆ ◆ ◆ ◆ ◆ ◆ Block Diagram Cellular phones PDAs/Handheld computers Toys/Consumer electronics Safety Illumination LCD modules Remote controls LX (4) + Switch Oscillator Regulation Control VREF (1) VDD Three-Level Detector (9) LMPSEL Select A Lamp VA (8) Select B Lamp VAB (7) VDD (10) REL-OSC CS (3) – (2) RSW-OSC Dual Bridge Driver Lamp Drive Oscillator VB (5) (6) GND 522_01.eps © 2001 IMP, Inc. 408-432-9100/www.impweb.com 1 IMP522 Pin Configuration MicroSO VDD 1 RSW-OSC 2 CS 3 LX 4 VB 5 10 REL-OSC IMP522 9 LMPSEL 8 VA 7 VAB 6 GND 522_02.eps Ordering Information Part Number Input Voltage Temperature Range Pins-Package 2.0V to 6.5V – 40°C to +85°C 10-MicroSO IMP522EMB Add /T to ordering part number for Tape and Reel. Absolute Maximum Ratings VDD, RSW-OSC and REL-OSC . . . . . . . . . . . . . . . . . –0.5V to +7.0V CS, LX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5V to +120V Operating Temperature Range . . . . . . . . . . . . –40°C to +85°C Storage Temperature Range . . . . . . . . . . . . . . –65°C to +150°C Power Dissipation (MicroSO) . . . . . . . . . . . . . 500mW VA, VB, VAB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5V to VCS (pin 3) 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, VDD = 3.0V, RSW = 910kΩ, REL = 2.7MΩ, L = 220µH and TA = 25°C. Parameter ON-resistance of MOS Switch Output Voltage Regulation Output Voltage Peak-to-Peak (in regulation) Input Current at VDD Pin Powerdown Input Current Symbol RDS(ON) VCS VA-VAB, VB-VAB IDD IDDQ Input Crrent Plus Inductor Current IIN Output Drive Frequency Switching Frequency Switching Duty Cycle LMPSEL Low-Level Threshold LMPSEL High-Level Threshold LMPSEL Input Resistance LMPSEL Sink/Source Resistance LMPSEL Hysteresis fEL fSW DSW VIL VIH 2 RLMPSEL ILMPSEL Vhys Conditions Min I = 100mA VDD = 2.0 to 6.5V, T = –40°C to 85°C In Regulation LMPSEL = GND VRSW–OSC < 100mA VDD = 2.0 to 6.5 T = –40°C to 85°C See Figure 1 LMPSEL = GND or VDD LMPSEL = floating See Figure 1 See Figure 1 See Figure 1 Floating/Hign Impedance State 408-432-9100/www.impweb.com Typ Max Units 4.0 110 8.0 120 Ω V 2 V µA µA 220 650 30 mA 43 250 61 88 0.3 VDD 0.7 VDD 50 mA Hz kHz % V V kΩ µA mV ±5 50 © 2001 IMP, Inc. IMP522 Pin Descriptions Pin Number Name 1 VDD 2 3 RSW-OSC CS 4 LX Function Positive voltage supply. Inductor L may be connected here or to a separate unregulated supply. Switch-mode resistor pin. The external resistor RSW determines switching frequency. Boost converter storage capacitor. The voltage across the EL lamp is approximately equal to twice the voltage at CS. Connection to flyback inductor L. Output for EL Lamp B. 5 VB 6 GND 7 VAB Common terminal for both EL lamps. 8 VA Output for EL Lamp A. 9 LMPSEL 10 REL-OSC Ground. Digital three-state input pin. Select either lamp A or lamp B or both lamps. The EL lamp oscillator frequency setting pin. External resistor REL connected to VDD sets the EL Lamp drive frequency for both lamps. 522_t01.eps Application Information ON = VDD Enable/Disable Strobe REL OFF = 0V 1 REL-OSC 10 VDD RSW L + VDD 9 3 CS VA 8 4 LX VAB 7 5 VB GND 6 FDLL400 – + 10µF 2 RSW-OSC LMPSEL 0.1µF CS EL LAMP 10nF EL LAMP 10nF IMP522 L = 220µH REL = 2.7MΩ RSW = 910kΩ 522_04.eps Figure 1. Test Circuit © 2001 IMP, Inc. Electroluminescent Lamp Drivers 3 IMP522 Application Information EL Lamp Drive EL Driver Output Overvoltage Regulator The outputs VA – VAB and VB – VAB are configured as H-bridges, driven by the EL oscillator. Each output is switched between C S and ground on alternate phases, creating peak-to-peak signals across the EL lamps of twice the regulated voltage. The IMP522 maximum VCS output voltage is between 110V and 120V. The internal overvoltage regulator skips the inductor switching whenever the voltage on the C S pin exceeds the regulation threshold. The internal overvoltage detection trip point has a hysterisis of 1V and a range of 110V to 120V at room temperature. EL Lamp Selection: LMPSEL The digital input pin LMPSEL allows either or both EL lamps to be active. Lamp A is active when LMPSEL is LOW and lamp B is active when LMPSEL is HIGH. When LMPSEL is left floating or driven by a three-state driver in the high impedance state, both lamp driver outputs are active. LMPSEL Signal Lamp A Drive VA and VAB Lamp B Drive VB and VAB HIGH LOW Floating/ High Impedance OFF ON ON OFF ON ON PWM Circuit Switching The switching MOSFET is driven by the PWM signal (nominally 61kHz). During the first 88% of the period, the switch is ON, providing a low impedance path (<8Ω) from LX to ground. This causes the external inductor to charge. In the last 12% of the period, the MOSFET is turned OFF. This causes the voltage on the output of LX to rise up to a high value. At some point, this will forward-bias the external diode, thus pumping charge into the storage capacitor C S. The voltage on CS increases each cycle to between 110V and 120V. When the internal regulation trip-point is reached, the overvoltage regulator turns the MOSFET switch OFF to conserve power. 522_t02.eps The logic HIGH signal level is defined as greater than 0.7VDD and logic LOW is defined as less than 0.3VDD. A floating level is recognized with the signal level between 0.3VDD and 0.7VDD, or when the output impedance of the driving voltage signal source is infinite (driver in OFF state). Both drivers are OFF if the IMP522 is disabled. 4 408-432-9100/www.impweb.com © 2001 IMP, Inc. IMP522 Application Information Power Sequencing Power Saving Disable Mode To power up the chip, the RSW-OSC pin is connected to VDD through the external RSW resistor. The voltage on the pin will charge up to VDD/2. An internal threshold detector circuit monitors the pin voltage and when it exceeds the threshold range (0.2V to 0.9V) it powers up the oscillator and internal bias modules. This starts a delay counter which is one half of the EL oscillator period, after which power to the high voltage internal modules is applied. The IMP522 is then operating fully. The IMP522 can be powered up and down with RSW-OSC. In normal operation, this resistor on the RSW-OSC pin is connected to VDD or another voltage source. To power down (disable) the IMP522, RSW is connected to ground. To power down the chip, RSW is driven to ground via a switch or logic gate. When the voltage on the driver side of the resistor falls below VDD/2, there will be no input bias current into the RSW-OSC pin. This immediately powers down the internal high-voltage circuits, which effectively shuts the lamp off. At this point the oscillator and bias modules still draw quiescent current, but oscillations have ceased. As the RSW-OSC pin voltage falls below 0.1, the oscillator and bias modules are also fully powered down. IN (Pulse) When disabled, the IMP522 quiescent current drops to typically 20nA. In die form, an extra pin ENABLE is available (contact factory). Connecting this pad to VDD disables the chip. The ENABLE signal can be driven by a microcontroller. Oscillator Frequency Adjustment The EL lamp drive and PWM boost converter oscillation frequencies can be programmed independently. The RSW resistor, connected between the RSW-OSC pin and VDD, determines the Inductor Switching (or PWM-) frequency. For the recommended nominal resistor value of 910kΩ, the frequency is 61kHz. For other resistor values, the frequency is inversely proportional to the resistor value. Increasing the resistance will lower the frequency. The REL resistor, connected between the REL-OSC pin and VDD, determines the EL lamp drive frequency. For the recommended nominal resistor value of 2.7MΩ, the frequency is 250Hz. For other resistor values, the frequency is inversely proportional to the resistor value: increasing the resistance will lower the frequency. ILX VLX Oscillator Nominal Resistor Nominal Frequency EL Lamp Drive Inductor Switch (PWM) REL = 2.7MΩ RSW = 910kΩ 250Hz 61kHz 522_03.eps Figure 1. Driver Waveforms 522_t03.eps © 2001 IMP, Inc. Electroluminescent Lamp Drivers 5 IMP522 Package Dimensions Inches MicroSO (10-Pin) Min a Millimeters Max Min Max MicroSO (10-Pin) + E1 E L D ––––– 0.0433 0.0020 0.0059 0.0307 0.0370 0.0059 0.0098 0.0051 0.0091 0.1142 0.1220 0.0197 BSC 0.1990 0.1871 0.1142 0.1220 0.0157 0.0276 0° 6° –––– 1.10 0.050 0.15 0.78 0.94 0.15 0.25 0.13 0.23 2.90 3.10 0.50 BSC 5.05 5.05 2.90 3.10 0.40 0.70 0° 6° 522_t04.at3 C A2 A A1 A2 b C D e E E1 L a D A e b 0.10mm 0.004in MicroSO (10-Pin).eps A1 Thermal Resistance θJC θJA 41°C/W 113°C/W 522_t05.at3 IMP, Inc. Corporate Headquarters 2830 N. First Street San Jose, CA 95134-2071 Tel: 408-432-9100 Fax: 408-434-0335 e-mail: [email protected] 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. © 2001 IMP, Inc. Printed in USA Publication #: 2007 Revision: E Issue Date: 03/16/01 Type: Advance Info