iC-WJB 2.7 V LASER DIODE DRIVER Rev E1, Page 1/12 FEATURES APPLICATIONS ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ Battery supplied LD modules ♦ LD Pointers Simple APC adjustment via an external resistor Continuous (CW) or pulsed operation of up to 300 kHz Laser diode current of up to 100 mA Adjustable watchdog for input signals Soft power-on and thermal protection Driver shutdown in case of overtemperature and undervoltage Operation at 2.
iC-WJB 2.7 V LASER DIODE DRIVER Rev E1, Page 2/12 DESCRIPTION The iC-WJB device is a driver IC for laser diodes in continuous or pulsed operation of up to 300 kHz. The wide power supply range of 2.7 to 6 V and the integrated reverse battery protection allows for batteryoperation with two to four AA/AAA cells. The laser diode is activated via switching input IN.
iC-WJB 2.7 V LASER DIODE DRIVER Rev E1, Page 3/12 ABSOLUTE MAXIMUM RATINGS Beyond these values damage may occur; device operation is not guaranteed. Item No. Symbol Parameter Conditions Unit Min. Max. -0.3 6.
iC-WJB 2.7 V LASER DIODE DRIVER Rev E1, Page 4/12 ELECTRICAL CHARACTERISTICS Operating Conditions: VCC = 2.7...6 V, RSET = 2.7...27 kΩ, I(AMD) = 0.15...1.5 mA, Tj = -25...125 °C, unless otherwise noted. Item No. Symbol Parameter Conditions Unit Min. Typ. Max.
iC-WJB 2.7 V LASER DIODE DRIVER Rev E1, Page 5/12 ELECTRICAL CHARACTERISTICS Operating Conditions: VCC = 2.7...6 V, RSET = 2.7...27 kΩ, I(AMD) = 0.15...1.5 mA, Tj = -25...125 °C, unless otherwise noted. Item No. Parameter Conditions Unit Min. 405 Vs(CI)wd Saturation Voltage at CI with IN = lo I(CI) = 300 µA, t(IN = lo) > tp (*) 406 407 Isc(CWD) Pull-Up Current at CWD V(CWD) = 0, IN = lo tpmin Min.
iC-WJB 2.7 V LASER DIODE DRIVER Rev E1, Page 6/12 APPLICATIONS INFORMATION Laser Power Adjustment The iC-WJB device can be adapted to CW laser diodes of up to 40 mW. When the supply voltage is higher than approx. 4.5 V, LD models in common cathode configuration can be used. The pin ISET is used for the adjustment to the sensitivity of the monitor diode and to set the desired optical laser power. The setpoint for the averaging control of the monitor diode current is pre-set at this pin.
iC-WJB 2.7 V LASER DIODE DRIVER Rev E1, Page 7/12 RSET = CR1 ∗ V (ISET ) 3 ∗ 1.22 V = = 24.4 k Ω Iav (AMD) 0.15 mA with the Electrical Characteristics No. 301 for V(ISET) and No. 108 for current ratio CR1. Averaging control (APC) The control of the average optical laser power requires a capacitor at pin CI. This capacitor is used for averaging and must be adjusted to the selected pulse repetition frequency and the charging current preset with RSET. The ratios are linear in both cases, i.e.
iC-WJB 2.7 V LASER DIODE DRIVER Rev E1, Page 8/12 laser pulses indicate that the undervoltage detector is active. 2.55 V V(CI) Figure 8 shows the signals during normal operation, without the watchdog being activated. The potential at CWD rises during pulse pauses but does not reach the watchdog activation threshold. 2.45 V V(IN) 5.0 V I(KLD) 0V 5V V(CWD) 0A Time Figure 6: Turn-on behaviour, detailed view f(IN) = 100 kHz (1:1), CI = 470 nF, RSET = 10 kΩ 0V 3V V(CI) 2V I(AMD) 300 uA 5.
iC-WJB 2.7 V LASER DIODE DRIVER Rev E1, Page 9/12 Furthermore, the introduction of the watchdog permits long pulse pauses and activation of the laser diode with pulse packets. 2.7..6V D1 ZD6V8 R2 2Ω S1 C1 47uF VCC 1 GND KLD 8 0..2Ω AMD 2 CI 100nF RSET 15kΩ R1 7 CWD KLD C3 4.
iC-WJB 2.7 V LASER DIODE DRIVER Rev E1, Page 10/12 2.7..6V C1 47uF 1 GND KLD 8 CI 22nF R3 27kΩ LD MD 7 CWD WDOG 3 RSET 27kΩ 4 VMOD 0..1.3V C3 2nF 0..2Ω AMD 2 R1 IN CI 6 REF ISET VCC 5 C2 100nF iC−WJB Figure 11: Analogue modulation during CW operation Analogue modulation during CW operation The modulation cut-off frequency is determined by the capacitor CI as well as by the operating point set with the resistor RSET.
iC-WJB 2.7 V LASER DIODE DRIVER Rev E1, Page 11/12 ALD J1 VCC LD C3 2nF C1 47uF MONITOR IN LASER IC1 GND 1 GND KLD 8 R1 2Ω KLD AMD 2 AMD 7 CWD WDOG 3 IMOD RMOD 15kΩ I 6 II REF 4 CWD ....... AGND IN CI CI 470nF RSET 15kΩ ISET VCC 5 iC−WJ/WJZ/WJB C2 100nF Figure 12: Schematic diagram of the Demo Board Figure 13: Demo Board (components side) This specification is for a newly developed product.
iC-WJB 2.7 V LASER DIODE DRIVER Rev E1, Page 12/12 ORDERING INFORMATION Type Package Order Designation iC-WJB SO8 MSOP8 iC-WJB SO8 iC-WJB MSOP8 iC-WJB EVAL WJ1D WJB Evaluation Board For technical support, information about prices and terms of delivery please contact: iC-Haus GmbH Am Kuemmerling 18 D-55294 Bodenheim GERMANY Tel.: +49 (61 35) 92 92-0 Fax: +49 (61 35) 92 92-192 Web: http://www.ichaus.com E-Mail: sales@ichaus.com Appointed local distributors: http://www.ichaus.de/support_distributors.
