BA3899F

Standard ICs EL driver for portable sets BA3899F The BA3899F is an IC developed for EL drive applications. It uses a more compact interface than transformer systems, and is ideal for use in thin sets. •Applications notebooks and other portable devices Pagers, electronic •Features 1) Drive oscillation frequency can be set using external capacitance. 2) Equipped with standby control pin. •Absolute maximum ratings (Ta = 25°C) Parameter Power supply voltage Power dissipation Operating temperature Storage temperature Maximum applied voltage Symbol VCC Pd Topr Tstg VST Limits 8.0 450∗ – 10 ~ + 60 – 55 ~ + 125 8.0 Unit V mW °C °C V ∗ Reduced by 4.5mW for each increase in Ta of 1°C over 25°C. •Recommended operating conditions (Ta = 25°C) Parameter Power supply voltage Symbol VCC Min. 1.0 Typ. 5.0 Max. 7.0 Unit V •Block diagram SW1 8 SW2 7 VCC 6 STBY 5 STBY RSW2 OSC1 OSC2 1 GND 2 N.C. 3 C1 4 C2 1 Standard ICs BA3899F •Pin descriptions Pin No. 1 2 Pin name GND N.C. I/O I — Pin voltage — — VCC Internal equivalent circuit — — GND pin Function — 1k 3 C1 I/O — C1 OSC1 oscillator circuit; external capacitor pin GND VCC 200Ω 4 C2 I/O — C2 OSC2 oscillator circuit; external capacitor pin GND 1k STBY 50k Standby control pin (HIGH state: standby cancelled) When applying resistance, etc. to the STBY pin, be careful not to exceed the threshold values. 5 STBY I 0 200k GND 6 VCC I — — VCC input pin VCC 50k 7 SW2 O — SW2 switching output pin X1 X20 500Ω GND SW2 VCC 8 SW1 O — X1 X5 SW1 SW1 switching output pin GND 2 Standard ICs BA3899F CC •Electrical characteristics (unless otherwise noted, Ta = 25°C, V Parameter Supply current C1 pin oscillation frequency C2 pin oscillation frequency SW1 Source current Sink current Source current Pull-down resistance Symbol ICC fSW1 fSW2 ISW1SO ISW1SI ISW2SO RSW2 VSTON VSTOFF IQ (ST) Min. 3.0 75 17 100 – 40 3.2 400 1.0 — — Typ. 4.6 95 23 140 — 4.4 500 — — 0 = 5.0V, C1 = 0.033µF, C2 = 1500pF) Unit mA Hz kHz µA µA mA Ω V V µA Conditions When used as stand-alone unit — — VC1 = 1.0V, VC2 = 0.05V, VSW1 = 0V VC1 = 0.05V, VC2 = 0.05V, VSW1 = 1.0V VC1 = 0.05V, VC2 = 0.05V, VSW2 = 0V Vst = 0.35V, VSW2 = 0.3V — — — Max. 6.2 120 29 180 — 6.1 600 — 0.3 2.0 SW2 Standby pin control Operating voltage condition Non-operating Quiescent current in standby state •Measurement circuit fSW1 Counter VSW1 A fSW2 Counter VSW2 VCC A A VSTBY ISW1 ISW2 IQ 8 7 6 5 STBY RSW2 OSC1 OSC2 1 2 3 4 VC1 0.033µF ± 1% VC2 1500pF ± 1% Fig.1 3 Standard ICs BA3899F •Application example D1 ROHM: 1SS376 L1 1.5mH (TOKO: D73LC) Q2 Q1 SANYO: 2SC3645T ROHM: 2SC4061KP 8 + EL 16000pF R1 2k ∗ 2.2µF 100k VCC = 5V SW1 7 SW2 6 VCC 5 STBY STBY RSW2 RX 300k OSC1 OSC2 1 GND 2 N.C. 3 C1 4 C2 C1 8200pF ± 10% C2 1500pF ± 10% Fig. 2 ∗ Because of the characteristics of the EL element, continuous application of particularly high DC power supply voltage can shorten the lifetime of the element. To avoid this, we recommend inserting a switch in the power supply line. 4 Standard ICs D1 ROHM: 1SS376 L1 1mH (TOKO: 43FS) or (TDK: NL453232) Q2 Q1 SANYO: 2SC3143K5 ROHM: 2SC4061KP 8 SW1 7 SW2 6 VCC 5 STBY + BA3899F EL 5000pF R1 4.7k 2.2µF VCC = 1.5V VSTBY = 1.5V Hi: act STBY RSW2 OSC1 OSC2 1 GND 2 N.C. 3 C1 4 C2 C1 0.033µF ± 10% C2 1500pF ± 10% Fig. 3 5 Standard ICs notes •Operation output (1) EL drive As shown in Figure 4, the EL drive output consists of charging (rise in voltage caused by switching) and discharging waveforms. The switching frequency is determined by fSW2 and the charging and discharging timing by fSW1. BA3899F (4) Q1, Q2, and D1 The VO (Max.) shown in Figure 4 is applied to the output VO, so if using any transistor other than that recommended, caution is required concerning the pressure withstand value. Also, Q2 must have characteristics which allow it to keep pace with the switching speed of fSW2. tSW1 (fSW1) VO (Max.) t1 Charge t2 Discharge Fig.4 (2) Setting fSW1 The oscillation frequency is determined by charging and discharging of the external capacitance of the C1 pin. The value for C1 should be set based on the following equation. (5) RX (resistor for adjusting light volume) With a configuration like that shown in Figure 5, the volume of light can be adjusted. However, RX should be set so that IX satisfies the following condition. C1 = 1 VC1 × ( 1 + 1 ) I2 I1 1 = (3.14E – 6) × fSW1 × 1 fSW1 Ix ( = Vx – 0.2V ) < 40µA Rx (VCC = 5V) If IX > 40µA, LSI dispersion, temperature fluctuation, and other elements can cause oscillation of the C2 pin to stop. Be sure the above condition is satisfied. C2 4 Rx Vx Ix 1500pF The recommended setting range for fSW1 is 40Hz to 800Hz. However, the VO (Max.) shown in Figure 4 is determined by fSW1, so caution is required concerning the pressure withstand values of Q1, Q2, and D1. (3) fSW2 fSW2 is the switching pressure rise frequency, and is determined by the external capacitance of the C2 pin. This value (1500pF) is determined by the inductance value and the Q2 transistor capability. When changing this value, the drive capability of Q2 must be taken into consideration in order to avoid the possibility of malfunction. Fig.5 6 Standard ICs BA3899F •Electrical characteristic curves 10 QUIESCENT CURRENT: ICC (mA) 9 8 7 6 5 4 3 2 1 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 OSCILLATION FREQUENCY: fSW (Hz) C1 = 0.033µF C2 = 1500pF VST = 5V Rx = ∞ 75°C fSW1 75°C – 25°C 25°C C1 = 0.033µF C2 = 1500pF Rx = ∞ 10k 1k – 25°C 25°C fSW2 100 75°C – 25°C 25°C INPUT VOLTAGE: VCC (V) INPUT VOLTAGE: VCC (V) Fig. 6 Supply current (when used as stand-alone unit) vs. power supply voltage Fig. 7 Oscillation frequency of C1 and C2 pins vs. power supply voltage 250 SW1 SOURCE CURRENT: ISWISO (µA) SW1 SINK CURRENT: ISW1SI (%) 75°C 200 25°C – 25°C 100 3.0 VC1 = 0V VSW1 = 1.0V VST = 5V 2.0 150 75°C 25°C 1.0 – 25°C 10 0 0 1 2 3 4 5 6 7 8 9 10 INPUT VOLTAGE: VCC (V) 50 VC1 = 1.0V VSW1 = 0V 0 0 1 2 3 4 5 6 7 8 9 10 INPUT VOLTAGE: VCC (V) Fig. 8 SW1 sink current vs. power supply voltage Fig. 9 SW1 source current vs. power supply voltage SW2 PULL-DOWN RESISTANCE: RSW2 (Ω) 10 SW2 SOURCE CURRENT: ISW2SO (mA) 9 8 7 6 5 4 3 2 1 0 0 1 2 3 4 5 6 7 25°C 1000 900 800 700 600 500 400 300 200 100 0 VC1 = 1.0V VSW1 = 0V VST = 5V 75°C VCC = 5V VSW2 = 0.2V VST = 0V 75°C – 25°C 25°C – 25°C 8 9 10 0 1 2 3 4 5 6 7 8 9 10 INPUT VOLTAGE: VCC (V) INPUT VOLTAGE: VCC (V) Fig. 10 SW2 source current vs. power supply voltage Fig. 11 SW2 pull-down resistance vs. power supply voltage 7 Standard ICs BA3899F •External dimensions (Units: mm) 5.0 ± 0.2 8 6.2 ± 0.3 4.4 ± 0.2 5 1.5 ± 0.1 1 4 0.11 1.27 0.4 ± 0.1 0.3Min. 0.15 SOP8 8 0.15 ± 0.1