1 pbl 380 85 july 1999 integrated circuit for transformerless driving of battery powered el (electroluminicent) lamps pbl 380 85 description. pbl 380 85 is a monolithic integrated circuit for supplyin g power to an el (electroluminicent) lamp. this is intended to replace the l cd background illumination system in battery powered handheld equipment with a low p ower el- lamp. especially suitable for mobile phones where current saving is highly im portant, as background illumination for both lcd and keyboard. output voltage max . 190v, min. 170v at max. 2ma constant current charge / discharge of the el- lamp. app lication dependent 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 under 170v by the duty cycle and the switching frequency of the control signal, over 170v 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 t he switcher control signal. the lamp control signal is divided by two by the circuit. the wa ve form of the output ac-signal is either triangular or trapezoid depending of the capacitan ce of the el-lamp, charge / discharge current and frequency of the lamp control signal.t he triangular or trapezoid wave form of the el-lamp driving voltage and the high switch ing frequency minimizes audible noise from the lamp and also reduces upcoming electr ical noise and harmonics. key features. ? minimum number of external components for function: 1 choke, 1 filter-capacitor and 1 resistor. ? easy adaption to various lamp specifications. ? easy dimming function by controlling the duty cycle. ? extensive current saving feature compared with leds. ? power down function <<1 m a. ? supply voltage down to 3v. ? comes in a 3x3 mm package ? lights up to 20nf lamp capacitance area depending on lamp parameter nf/cm 2 . 10 - pin plastic mini sop package functional diagram. pbl 380 85 2 51 0 9 8 6 3 4 1 el-lamp switcher control signal lamp control signal +supply pekka 1 1.1 1-98 pbl 380 85 t rue size pbl 380 85
2 pbl 380 85 at t amb = 25 c v+ = 2.75 v if no otherwise stated. for further conditions see figure. parameter condition symbol min. typ. max. unit battery voltage v bat 1.5 3.6 65* v v bat quiescent curren v+ off 0.1 m a logic supply voltage v+ 2.4 2.75 5.5 v v+ operating supply current sc + lc 50% 50% v+ quiescent supply current sc = 0 ; lc = 0 5 m a logic low level input voltage 0.3xv+ v logic high level input voltage 0.7xv+ v logic low level input current -100 100 m a dc/dc converter: booster output voltage, int.limited 90 v switch transistor sat. voltage 80ma inductor current 0.6 v switching frequency, set by the sc-signal frequency 50 khz h - bridge: output voltage el1 - el2 170 v pp output unbalance voltage el1 - el2 -5 +5 v output sink/source current range lower limit 0.1 ma output sink/source current range upper limit 1.5 ma output current x resistance product ( note1) i set * r set 9.5 10 10.5 v output drive frequency, set by the lc-signal frequency 250 hz note1: this product is the el1/el2 output current multiplied by the resistor value connected to i set . voltace at the i set pin is dependent of the v+ voltage asit is a quota of that voltage. * battery voltage max. 65v requires correctly chosen duty cycle and inductance. parameter symbol min. max. unit supply voltage, continuous v+ 0 90 v all inputs (zener protection) 6.5 v operating temperature range t amb -30 +85 c storage temperature range t stg -55 +150 c maximum ratings electrical characteristics
3 pbl 380 85 pin configuration. 10 pin plastic mini soic package pin descriptions: refer to pin configuration. so name function so name function 1 gnd ground connection 6 el2 el - lamp connection 2 sc switch control input 7 nc no connection 3i set control input for lamp driving capability 8 el1 el - lamp connection 4 lc lamp frequency control input 9 c boost capacitor connection 5v+ supply voltage 10 l inductor connection reference picture. some circuit curve forms . pbl 380 85 2 8 6 3 4 1 el-lamp pekka 2.12-98 v+ v bat 470 h 22nf series resistance (esr) < 1 4.7 nf 10 5 9 <5 sc lc el2 el1 ab c d a sc lc el1 el2 el1-el2 1 2 3 4 5 9 8 gnd sc i set lc v+ l c el1 nc el2 4 5 10 7 6
4 pbl 380 85 ordering information package temp. range part no. 10 pin plastic mini sop -30 to 85 c pbl 380 85/1msot tape and reel specifications subject to change without notice. 1522-pbl 380 85/1 uen rev.a ? ericsson components ab july 1999 information given in this data sheet is believed to be accurate and reliable. however no responsibility is assumed for the consequences of its use nor for any infringement of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of ericsson components ab. these products are sold only according to ericsson components ab's general conditions of sale, unless otherwise confirmed in writing. ericsson components ab s-164 81 kista-stockholm, sweden telephone: (08) 757 50 00 www.ericsson.se/microe f e d b a k h g c a 10 - pin mini sop dim. millimeters max. a b c d e f g h k 0.23 0.18 0.50 bsc 0.1 4.90 0.15 0.55 0.15 3.00 0.1 0.10 0.05 1.10 3.00 a +0.07 -0.08 tol. 3.0 3.0 0.05
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