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IMP522
POWER MANAGEMENT ADVANCE PRODUCT INFORMATION Key Features
N Drive two EL lamps independently N Digital LMPSEL pin -- Activate either or both EL output drivers N 220VP-P typical AC output voltage drives 30nF EL lamps N Wide operating voltage range: 2V to 6.5V N Low current consumption: 2mA maximum N Disable mode extends battery life -- Disable current 2A maximum N Compact 10-pin MicroSO package N High-voltage, low-cost CMOS process
Dual EL Lamp Driver
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. 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 4.0 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. Designed to minimize battery current drain, the IMP522 draws 2mA maximum. A power-saving shutdown mode reduces current to 2A maximum. The IMP522 is available in a compact 10-pin MicroSO package and in die form.
Applications
N N N N N N Cellular phones PDAs/Handheld computers Toys/Consumer electronics Safety Illumination LCD modules Remote controls
LX (4)
Block Diagram
(2) RSW-OSC
VREF (1) VDD Three-Level Detector (9) LMPSEL
Select A Lamp Select B Lamp
VDD Lamp Drive Oscillator
(10) REL-OSC (6) GND
(c) 2001 IMP, Inc.
408-432-9100/www.impweb.com
-
VA (8) VAB (7) Dual Bridge Driver VB (5)
522_01.eps
Switch Oscillator
Regulation Control
+
CS (3)
1
IMP522
Pin Configuration
MicroSO
VDD RSW-OSC CS LX VB 1 2 3 4 5 IMP522 10 REL-OSC 9 8 7 6 LMPSEL VA VAB GND
522_02.eps
Ordering Information
Part Number
IMP522EMB
Input Voltage
2.0V to 6.5V
Temperature Range
- 40C to +85C
Pins-Package
10-MicroSO
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 . . . . . . . . . . . . -40C to +85C Storage Temperature Range . . . . . . . . . . . . . . -65C to +150C 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 = 910k, REL = 2.7M, L = 220H and TA = 25C.
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
Conditions
I = 100mA VDD = 2.0 to 6.5V, T = -40C to 85C In Regulation LMPSEL = GND VRSW-OSC < 100mA VDD = 2.0 to 6.5 T = -40C to 85C See Figure 1 LMPSEL = GND or VDD LMPSEL = floating See Figure 1 See Figure 1 See Figure 1
Min
Typ
4.0 110 220 650
Max
8.0 120
Units
V V A A
2
Input Crrent Plus Inductor Current
IIN
30 43 250 61 88 0.3 VDD 0.7 VDD 50 5 50
mA mA Hz kHz % V V k A mV
(c) 2001 IMP, Inc.
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 RLMPSEL ILMPSEL Vhys
Floating/Hign Impedance State
2
408-432-9100/www.impweb.com
IMP522
Pin Descriptions
Pin Number
1 2 3 4 5 6 7 8 9 10
Name
VDD RSW-OSC CS LX VB GND VAB VA LMPSEL REL-OSC
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. Ground. Common terminal for both EL lamps. Output for EL Lamp A. 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 OFF = 0V REL
1
RSW L
VDD
REL-OSC 10
2 RSW-OSC LMPSEL 3 CS
VA VAB GND
9 8 7 6 EL LAMP 10nF EL LAMP 10nF
+
VDD
- +
10F
FDLL400
4 LX
0.1F CS
5 VB
IMP522
L = 220H REL = 2.7M RSW = 910k
522_04.eps
Figure 1. Test Circuit
(c) 2001 IMP, Inc.
Electroluminescent Lamp Drivers
3
IMP522
Application Information
EL Lamp Drive
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.
EL Driver Output Overvoltage Regulator
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.
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 (<8) 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.
LMPSEL Signal
HIGH LOW Floating/ High Impedance
Lamp A Drive VA and V B A
OFF ON ON
Lamp B Drive VB and V B A
ON OFF ON
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
(c) 2001 IMP, Inc.
IMP522
Application Information
Power Sequencing
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. 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.
Power Saving Disable Mode
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. 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 910k, 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 2.7M, the frequency is 250Hz. For other resistor values, the frequency is inversely proportional to the resistor value: increasing the resistance will lower the frequency.
IN (Pulse)
ILX
VLX
Oscillator
522_03.eps
Nominal Resistor
REL = 2.7M RSW = 910k
Nominal Frequency
250Hz 61kHz
522_t03.eps
Figure 1. Driver Waveforms
EL Lamp Drive Inductor Switch (PWM)
(c) 2001 IMP, Inc.
Electroluminescent Lamp Drivers
5
IMP522
Package Dimensions
MicroSO (10-Pin)
a
Inches Min
A A1 A2 b C D e E E1 L a
Millimeters Max Min Max MicroSO (10-Pin)
E1 E
L D A2 A e
0.10mm 0.004in
----- 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
D
b
MicroSO (10-Pin).eps
A1
Thermal Resistance
JC JA 41C/W 113C/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: 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.
+ C
(c) 2001 IMP, Inc. Printed in USA Publication #: 2007 Revision: E Issue Date: 03/16/01 Type: Advance Info

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