PBL38085 Datasheet, PDF (1/4 Pages) Ericsson – Integrated circuit for transformerless driving of battery powered EL (electroluminicent) lamps

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PBL 380 85
Integrated circuit for transformerless
driving of battery powered
EL (electroluminicent) lamps
Description.
Key features.
PBL 380 85 is a monolithic integrated circuit for supplying power to an EL • Minimum number of external
(electroluminicent) lamp. This is intended to replace the LCD background illumination
components for function: 1 choke, 1
system in battery powered handheld equipment with a low power EL- lamp. Especially
filter-capacitor and 1 resistor.
suitable for mobile phones where current saving is highly important, as background
illumination for both LCD and keyboard. Output voltage max. 190V, min. 170V at max. • Easy adaption to various lamp
2mA constant current charge / discharge of the EL- lamp. Application dependent
specifications.
parameters such as charge / discharge current are set by an external resistor. Two control
signals are needed one for the switcher and one for the lamp.The output voltage is set • Easy dimming function by
under 170V by the duty cycle and the switching frequency of the control signal, over 170V
controlling the duty cycle.
by an amplitude limiter that switches the switcher off. The switching frequency is app. 50
kHz. The light intensity is controlled by the dutycycle of the switcher control signal. The • Extensive current saving feature
lamp control signal is divided by two by the circuit. The wave form of the output AC-signal
compared with LEDs.
is either triangular or trapezoid depending of the capacitance of the EL-lamp, charge /
discharge current and frequency of the lamp control signal.The triangular or trapezoid • Power down function <<1µA.
wave form of the EL-lamp driving voltage and the high switching frequency minimizes
audible noise from the lamp and also reduces upcoming electrical noise and harmonics. • Supply voltage down to 3V.
• Comes in a 3x3 mm package
+supply
• Lights up to 20nF lamp capacitance
area depending on lamp
parameter nF/cm².
switcher control ²
signal
5
10
9
8
PBL 380 85
1
4
lamp control
signal
3
6
Pekka 11.11-98
EL-lamp
Functional diagram.
PBL ^{380 85}
PBL 380 ⁸⁵
True size
10 - pin plastic mini SOP package
1