ic-wk 2.4V CW LASER DIODE DRIVER

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Berenice Lawrence
6 years ago
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1 Rev A1, Page 1/12 FEATURES CW operation up to 0mA from 2.4..V supply voltage Rapid soft start after power-on Simple power adjustment via the external resistor Control loop accuracy better than 1% with changes in temperature, supply voltage and load current ntegrated reverse polarity protection for the ic and laser diode Strong suppression of transients with very small external capacitors ntegrated flyback path protects against transients Permanent shutdown with excessive temperature and overcurrent (i.e. if the laser diode is damaged or the feedback current path fails) Two feedback inputs permit all current LD types to be used (M/P/N configurations) Modulation via the feedback inputs is possible Wide monitor current range from 10µA to 2.mA Extended temperature range available as an option APPLCATONS Battery-powered LD modules LD Pointers PACKAGES (MSOP) SO BLOCK DAGRAM V C C...4nF TRANSENT PROTECTON MDK 4 MD LD - 1 D + VREF C 2 R NQ OVER CURRENT OVER TEMP. C... RM k 1 A 3 suitable laser diode configurations: N, P, M MD LD LD MD LD MD 2000

2 Rev A1, Page 2/12 DESCRPTON The device is a driver for laser diodes in continuous wave operation which requires only four external components. The broad power supply range of 2.4V to V and the integrated reverse battery protection allow for battery operation with a minimum of two cells. A reversed battery connection destroys neither the ic nor the laser diode. The ic includes integrated circuitry protecting against destruction by ESD, excessive temperature and overcurrent and a soft start which regulates the power and protects the laser diode when the power supply is switched on. The ic also filters the laser diode power supply for transients. The power supply is regulated and adapted for the laser diode used by an external resistor at. The monitor current acts as a reference and is regulated independent of the influence of temperature and supply voltage (range: 10µA to 2.mA). The capacitor at C determines the recovery time constants and start-up time. A second monitor input, pin MDK, allows the driver to be used for other types of laser diode configuration; alternatively, it can be used as an analog modulation input (DC to a few khz). n the event of failure, such as overcurrent in the laser path with a lack of feedback, for example, a quick power lockout is activated. The shutdown continues until power is reapplied, permitting a restart. The strain on power packs and batteries is relieved and the laser class is retained even in the event of a disturbance. PACKAGES SO, MSOP to EDEC Standard PN CONFGURATON SO (top view) PN FUNCTONS No. Name Function 1 Ground 2 C Capacitance for Power Control 3 A Reference Ground for C, RM 4 MDK Monitor nput 2 (MD Cathode, modulation) APC Setup, Monitor nput 1 (MD Anode) V Supply Voltage Laser Supply (LD Anode) Driver Output (LD Cathode) PN CONFGURATON MSOP (3mm)

3 Rev A1, Page 3/12 PACKAGE DMENSONS SOP (in mm) Min. Max. A B 1.2 BSC C D 0.3 REF E F..2 G H K 4 DEG L M 0 DEG DEG PACKAGE DMENSONS MSOP (in mm) Min. Max. A B 0. BSC C 0.33 D 0.2 E F 4..0 G H K 9 DEG 1 DEG L M 0 DEG DEG

4 Rev A1, Page 4/12 ABSOLUTE MAXMUM RATNGS Beyond these values damage may occur; device operation is not guaranteed. tem Symbol Parameter Conditions Fig. Unit Min. Max. G001 Voltage at - V G002 () Current in -0 0 ma G003 (C) Current in C ma G004 () Current in -0 0 ma G00 () Current in -0 0 ma G00 () Current in ma G00 (MDK) Current in MDK ma G00 (AGMD) Current in A ma E001 Vd() ESD Susceptibility at all pins ML-STD-3, Method 301, HBM 2 kv 100pF discharged through 1.kS TG1 Tj Operating unction Temperature C TG2 Tj Storage Temperature Range C THERMAL DATA Operating Conditions: = V tem Symbol Parameter Conditions Fig. Unit Min. Typ. Max. T1 Ta Operating Ambient Temperature Range (extended range on request) -2 C T2 Rthja Thermal Resistance Chip / Ambient SO package, soldered on PCB, no additional cooling areas 140 K/W All voltages are referenced to ground unless otherwise noted. All currents into the device pins are positive; all currents out of the device pins are negative.

5 Rev A1, Page /12 ELECTRCAL CHARACTERSTCS Operating Conditions: = V, RM= 200S..0kS, Tj= C unless otherwise noted tem Symbol Parameter Conditions Tj Fig. Unit C Min. Typ. Max. Total Device 001 Permissible Supply Voltage 2.4. V 002 () Permissible Laser Drive Current power control range 0 ma 003 dc() Supply Current without load path closed control loop, (MDK)= 0, RM= 200S, ()= 0mA. ma 004 off() Supply Current on Reset 2.4 ma 00 r() Reverse Supply Current RM= 0kS - -3 ma 00 ton() Turn-on Delay : ÜV to 9% (); ()= 0mA, C= 4nF ()= 0mA, C= 0 10 µs µs E001 Vc()hi Clamp Voltage hi at,, MDK ()= 10mA, other pins open 9 V E002 Vc()hi Clamp Voltage hi at V()< +1V; ()= 10mA, other pins open 9 V E003 Vc()hi Clamp Voltage hi at ()= 10mA, other pins open V E004 Vc()hi Clamp Voltage hi at C ()= 10mA, other pins open V E00 Vc()lo Clamp Voltage lo at,, MDK,, C ()= -10mA, other pins open -9 V Reference and Monitor nputs, MDK, A 101 V() Reference Voltage at closed control loop, V() >Vs() mv 102 dv() Reference Voltage Temperature Drift at see 101; 120 µv/ C 103 err() nput Current in closed control loop, (MDK)= 0, ()= 20..0mA na 104 d() nput Current Temperature Drift in see 103; -2 2 na/ C 10 APCerr Control Error RM= 10kS, Tj= 0..0 C RM= 10kS, Tj= -2.. C % % 10 d(rm) Supply Voltage Suppression V(): 2.4VÜ.V, -1 1 % ()= 0mA 10 Rgnd() Resistor A- 3 S 301 Vf(MDK) Voltage at MDK Vf()= V() -V(MDK); (MDK)= 1µA..1mA 0. 2 V 302 CR() Current Ratio () / (MDK) (MDK)= 10µA..1mA TC() Current Ratio Temperature Coefficient () / (MDK) %/ C Laser Drive, 201 Vs() Saturation Voltage at ()= 40mA ()= 0mA mv mv 202 d(ld) Load Balancing Error (LD)= 20mA, (): 20mAÜ0mA -1 1 % 203 t() Overcurrent Threshold in ma 204 toff() Overcurrent Reset Delay lack of feedback: (RM)= 0 to ()= t(); ()= 20mA, C= 4nF ()= 20mA, C= ()= 0mA, C= 4nF ()= 0mA, C= µs µs µs µs

6 Rev A1, Page /12 ELECTRCAL CHARACTERSTCS Operating Conditions: = V, RM= 200S..0kS, Tj= C unless otherwise noted tem Symbol Parameter Conditions Tj Fig. Unit Laser Drive, (continued) C Min. Typ. Max. 20 Vf() Diode Forward Voltage - ()< 0mA 1.1 V 20 Rvcc() Transient Protection Resistor vs. 3 S Control Release Flip-Flop 401 en Set Threshold for Enable Flip-Flop 402 Toff Overtemperature Shutdown C V V V

7 Rev A1, Page /12 DESCRPTON OF FUNCTONS Turn-on behavior After switching on the supply voltage the output stage remains disabled until the internal enabling flip-flop is set by a sufficiently high voltage at. A quick soft start occurs during phase ; the control capacitor C is loaded at an accelerated rate until the output stage supplies current at. An open-circuit voltage at pin is used to verify the external resistance. Phase 2, the initialization process, begins when current starts to flow at. This phase ends when the laser reaches its threshold current and the monitor current produced raises the potential at resistor RM. The transition to CW operation (phase 3) is gradual and primarily influenced by the C and RM components. C is correctly dimensioned when the voltage overshoot at is at a minimum µA 0µA 0.V 2. 0mA 0mA -() V() V(C) V() () V() Phase Phase Phase 0s 10µs 20µs 30µs 40µs 0µs t Fig. 1: Turn-on behaviour Turn-off behavior functions without a fixed undervoltage lockout, thus the laser diode forward voltage is the prime factor determining the lowest possible supply voltage. f the voltage drops below this, the output stage is forcibly saturated and the laser current falls. n this instance simultaneously discharges control capacitor C so that no excessive laser diode currents occur when the supply voltage again rises. Disruptions in operation The power control is shut down with excessive driver temperature or when the laser current reaches the overcurrent shutdown threshold, for example when the feedback is interrupted. f the monitor diode or the preset resistor RM fail the device is shutdown in less than 0.2ms, provided that the supply voltage applied is high enough µA 0µA 0.V 2. 0mA V() V() -() V() V(C) Phase V Phase V () 0mA 100µs 10µs 200µs 20µs 300µs t Fig. 2: Turn-off behaviour

8 Rev A1, Page /12 APPLCATONS NFORMATON +VB +VB Fig. 3: circuit for N-type laser diodes (cathode MD to anode LD) Fig. 4: circuit for P-type laser diodes (anode MD to cathode LD) +VB Fig. : circuit for M-type laser diodes (common cathode for LD and MD) Fig. : using the second monitor input as a switching input (N-type lasers) +VB 1 2 C 3 A 4 MDK Fig. : using the second monitor input for modulation (N-type lasers) Fig. : using both monitor inputs to amplify the current (N-type lasers)

9 Rev A1, Page 9/12 +V 1 +VB 1 LED C A MDK C A MDK 100µF 1 ZD1 1.V C R Q1 BD... C 2 C Fig. 10: circuitry for higher laser diode currents (0mA..4A) using an external power transistor 3 A +VB 4 MDK R2 R C LED1 Fig. 9: safety circuit with a second monitoring the optical output power 3 A 100µF 4 MDK Q1 Fig. 11: circuitry for higher laser diode currents (0mA..4A) using an external power MOSFET Dimensions for external components Component Range Comments.. filter capacitor for the laser diode supply (0)..100µF optional, may be omitted if offers sufficient filtering 22nF..220nF ca. selection depends on laser diode operated example: () / (MD)= 3mA / 0.2mA 1nF..10nF optional, additional ESD protection capacitor 200S..0kS ca. 2kS selection depends on laser diode operated example: = V() / (MD)= / 0.2mA = 2kS

10 Rev A1, Page 10/12 DEMO BOARD comes with two Demo Boards (.2mm x 20mm) for test purposes. The following figures show the circuitry and the top and bottom of the test boards (layout are on a scale of 4:1). +V -V n/a C 2 C n/a LA 3 A PD 4 MDK 4.k P1 10k Fig. 12: schematic diagram of demo board WK1D for P-/M-type laser diodes Fig. 13: demo board WK1D (top side) Fig. 14: demo board WK1D (bottom side)

11 Rev A1, Page 11/12 +V -V n/a LK 2 C n/a C 3 A PD 4 MDK 4.k P1 10k Fig. 1: schematic diagram of demo board WK2D for N-type laser diodes Fig. 1: demo board WK2D (top side) Fig. 1: demo board WK2D (bottom side)

12 Rev A1, Page 12/12 ORDERNG NFORMATON Type Package Order designation WK demo board for P-/M-type lasers WK demo board for N-type lasers SO MSOP SO MSOP WK1D DEMO WK2D DEMO For information about prices, terms of delivery, other packaging options etc., please contact: ic-haus GmbH Tel Am Kuemmerling 1 Fax D-294 Bodenheim GERMANY This specification is for a newly developed product. ic-haus therefore reserves the right to modify data without further notice. Please contact us to ascertain the current data. The data specified is intended solely for the purpose of product description and is not to be deemed guaranteed in a legal sense. Any claims for damage against us - regardless of the legal basis - are excluded unless we are guilty of premeditation or gross negligence. We do not assume any guarantee that the specified circuits or procedures are free of copyrights of third parties. Copying - even as an excerpt - is only permitted with the approval of the publisher and precise reference to source.

ic-wkn 15V CW LASER DIODE DRIVER

ic-wkn 15V CW LASER DIODE DRIVER Rev A1, Page 1/7 FEATURES Ë CW operation up to 300 ma from 2.4..15 V supply voltage Ë Rapid soft start after power-on typical within 70 Ë Optimised for N-type laser diodes Ë Simple power adjustment via