1. CALICE ANL, MAR18, 2008 Ivo Polak, IPASCR, Prague1 A fast LED driver prototype for HCAL calibration CALICE meeting at ANL, USA

2. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague2 Proposal for calibration system Fast LED driver is a key part of calibration system A tunable calibration light in the range 0 to 100MIP Simplification of the optical system: one LED -> one side emitting fibre, one row of scintillator tiles See Jara’s talk Comments on optical system II

3. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague3 LED driver strategy not only for SiPM calibration At AHCAL prototype (uses SiPM), we used CMB, calibration system with UV-LED 400nm driven by very fast rectangular pulses (1ns rise/fall time). Steep Rectangular waveform satisfied the needs to vary pulse-width, BUT creates lots of harmonics  electromagnetic crosstalk! We have found fixed pulse-width to about 6ns, we can go to use narrow band ->smooth waveform ≈ less RF interference = Quasi Resonant LED driver (single pulse)

4. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague4 Quasi-Resonant LED driver LC circuit, heavily dumped 2CH board primary tested With printed Cu inductor 2ns pulse-width Prototyping Used my lovely single side copper foil PCB We need more work on components optimization to recent LED Simulation pulse-width 5ns with 33nH inductance

5. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague5 2CH QRLED board Consists of: Double sided PCB 2 QRLED driver 2PIN photodiode preamp Rate generator 1Hz to 10kHz Voltage regulators Amplitude control V-calib and T-calib interface

6. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague6 2CH QRLED board There is a detail of two QRLED driver Printed inductors with taps, left is connected by tin joint Two trimmers equalize delays between CH A and B

7. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague7 Principal schema of QRLed driver A A

8. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague8 PIN PD response to UVLED LED current 1V => 1A PIN

9. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague9 PIN PD response to UVLED LED current 1V => 1A PIN

10. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague10 PIN PD response to UVLED LED current 1V => 1A PIN

11. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague11

12. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague12 Further increase of the LED amplitude We see a change of the shape PIN 1mV/div LED current 1V => 1A

13. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague13 Further increase of the LED amplitude We see a change of the shape LED current 1V => 1A PIN 2mV/div

14. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague14 Maximum amplitude of the LED We see a change of the shape LED current 1V => 1A PIN 2mV/div

15. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague15 In wider time scale, increase of the amplitude PIN 2mV/div

16. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague16 In wider time scale PIN

17. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague17 In wider time scale PIN

18. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague18 Highest amplitude -> funny distortion PIN LED current 1V => 1A At this amplitude LED is shining visible

19. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague19 A response to Slower PMT LED is over full power PMT LED voltage at cathode sync

20. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague20 PIN crosstalk test PIN Reference amplitude LED current 1V => 1A

21. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague21 Optically shielded, same LED amplitude Electrical crosstalk to PIN NO crosstalk

22. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague22 Different LEDs More different LEDs will be tested “PPT UVLEDs” 400nm are very fast! One blue pioneer has been tested Each type of the LED needs a bit of matching of 2 components at QRled driver

23. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague23 Another Blue LED, too slow! 2ns -> 10ns PIN LED current 1V => 1A

24. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague24 Another Blue LED, too slow! 2ns -> 20ns Electrical optical LED current 1V => 1A PIN

25. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague25 Conclusion QR LED driver is very promising technique to reduce Electro-Magnetic-Interferences 2 PCBs of the two-channel QR LED driver are ready to further test March – linearity test April – more assembled PCBs to test May – designing of multichannel system with light transfer in side-emitting fibers, first approach to mechanical integration to a new detector design

26. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague26 Backup slides

27. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague27 QR LED driver Simulation oscilloscope

28. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague28 Simulation at 1.5V amplitude XSC1 : Upper trace - sync pulse Lower trace – voltage at LED hot end XSC2: Lower trace LED current

29. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague29 Simulation at 3V XSC1 : Upper trace - sync pulse Lower trace – voltage at LED hot end XSC2: Lower trace LED current

30. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague30 Tests shows more power on LED We see response of PIN photodiode at oscilloscope Amplitude up to 2mVpeak @ 50 Ω

31. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague31 Prototype of QR LED driver

32. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague32 Response to low amplitude at prototype LED current (cyan) (voltage @ 10Ohm) PIN response (yellow) LED anode (violet)

33. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague33 Response to middle amplitude at prototype Pulse width ~ 6ns

34. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague34 Response to high amplitude at prototype 200mA current at LED Pulse width ~ 6ns

35. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague35 Response to high amplitude at prototype The Light from LED was optically blocked to PIN.

36. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague36 LED Current View of the LED pulse for a small amplitude (0.6 A) Measured with 1GHz voltage differential probe and 1GHz scope TDS4104 at 1Ω smd resistor 4ns/div 0.5A/div

37. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague37 LED current View of the LED pulse for a middle amplitude (1.0 A) Measured with 1GHz voltage differential probe and 1GHz scope TDS4104 at 1Ω smd resistor 4ns/div 0.5A/div

38. CALICE ANL, MAR18, 2008 Ivo Polak, IoP Prague38 LED current View of the LED current pulse for the highest amplitude (2.3 A) Measured with 1GHz voltage differential probe and 1GHz scope TDS4104 at 1Ω smd resistor 4ns/div 0.5A/div