1DDD356AA-K01 データシートの表示（PDF） - Unspecified

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1DDD356AA-K01

Electroluminescent Lamp Driver IC

Unspecified 

Block Diagram of the Driver Circuitry

E

1.0 µF

V+

L+

CLF1

CLF2

Low

Frequency

Oscillator

High

Frequency

Oscillator

VOUT

EL Lamp

L-

GND

Theory of Operation

Electroluminescent (EL) lamps are essentially capacitors with one transparent electrode and a special phosphor material

in the dielectric. When a strong AC voltage is applied across the EL lamp electrodes, the phosphor glows. The

required AC voltage is typically not present in most systems and must be generated from a low voltage DC source.

Thus, Durel developed its patented Three-Port (3P) switch-mode inverter circuit to convert the available DC supply

to an optimal drive signal for high brightness and low-noise EL lamp applications. The Durel 3P topology offers the

simplicity of a single DC input, single AC output, and a shared common ground that provides an integrated EMI

shielding.

The D356A drives the EL lamp by repeatedly pumping charge through an external inductor with current from a DC

source and discharging into the capacitance of the EL lamp load. With each high frequency (HF) cycle the voltage on

the lamp is increased. At a period specified by the lamp frequency (LF) oscillator, the voltage on the lamp is discharged

to ground and the polarity of the inductive charging is reversed. By this means, an alternating positive and negative

voltage is developed at the single output lead of the device to one of the electrodes of the EL lamp. The other lamp

electrode is commonly connected to a ground plane, which can then be considered as electrical shielding for any

underlying circuitry on the application.

The EL driving system is divided into several parts: on-chip logic and control, on-chip high voltage output circuitry,

discharge logic circuitry, and off-chip components. The on-chip logic controls the output frequency (LF), as well as the

inductor switching frequency (HF), and HF and LF duty cycles. These signals are combined and buffered to regulate

the high voltage output circuitry. The output circuitry handles the power through the inductor and delivers the high

voltage to the lamp. The selection of off-chip components provides a degree of flexibility to accommodate various lamp

sizes, system voltages, and brightness levels. Since a key objective for EL driver systems is to save space and cost,

required off-chip components were kept to a minimum.

Durel provides a D356A Designer’s Kit, which includes a printed circuit evaluation board intended to aid you in

developing an EL lamp driver configuration using the D356A that meets your requirements. A section on designing

with the D356A is included in this datasheet to serve as a guide to help you select the appropriate external components

to complete your D356A EL driver system.

Typical D356A configurations for driving EL lamps in various applications are shown on the following page. The

expected system outputs, such as lamp luminance, lamp output frequency and voltage and average supply current

draw, for the various sample configurations are also shown with each respective figure.

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